GERMANATV-DVWK RULES AND STANDARDS

STANDARDATV-DVWK-A 134E

Planning and Constructionof Wastewater Pumping Stations

June 2000

STANDARDATV-DVWK-A 134E

Planning and Constructionof Wastewater Pumping Stations

June 2000

Publisher/Marketing:Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e. V.German Association for Water, Wastewater and WasteTheodor-Heuss-Allee 17 • 53773 Hennef • GermanyTel.: +49 2242 872-333 • Fax: +49 2242 872-100E-Mail: kundenzentrum@dwa.de • Internet: www.dwa.de

GERMANATV-DVWK RULES AND STANDARDS

ATV-DVWK-A 134E

June 2000 2

The German Association for Water, Wastewater and Waste, DWA (former ATV-DVWK), is the spokesman in Germany for all universal questions on water and is involved intensely with the development of reliable and sustainable water management. As politically and economically independent organisation it operates specifically in the areas of water management, wastewater, waste and soil protection.

In Europe the DWA is the association in this field with the greatest number of members and, due to its spe-cialist competence it holds a special position with regard to standardisation, professional training and infor-mation of the public. The ca. 14,000 members represent the experts and executive personnel from munici-palities, universities, engineer offices, authorities and businesses.

The emphasis of its activities is on the elaboration and updating of a common set of technical rules and standards and with collaboration with the creation of technical standard specifications at the national and in-ternational levels. To this belong not only the technical-scientific subjects but also economical and legal demands of environmental protection and protection of bodies of waters.

Imprint

Publisher and marketing: DWA German Association for Water, Wastewater and Waste Theodor-Heuss-Allee 17 D-53773 Hennef, Germany Tel.: Fax: E-Mail: Internet:

+49 2242 872-333 +49 2242 872-100 kundenzentrum@dwa.de www.dwa.de

Translation: Richard Brown, Wachtberg Printing (English Version): DWA ISBN-13: 978-3-937758-45-9 The translation was sponsored by the German Federal Environmental Foundation (DBU) Printed on 100 % Recycling paper.

© DWA Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e.V., Hennef 2007 (German Association for Water, Wastewater and Waste)

All rights, in particular those of translation into other languages, are reserved. No part of this Standard may be reproduced in any form - by photocopy, microfilm or any other process - or transferred into a language usable in machines, in particular data processing ma-chines, without the written approval of the publisher.

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Foreword Standard Specification EN 752-6 “Drainage systems outside buildings”, Part 6 “Pumping stations”, elabo-rated by its Technical Committee TC 165 “Wastewater Engineering”, has been issued by the European Committee for Standardisation (CEN). It was to be adopted into the German Standards as DIN EN 752-6. Supplementary to this the earlier Standard ATV-A 134 “Planning and Construction of Wastewater Pumping Stations with Small Inflows” has been revised and expanded by ATV Specialist Committee 1.3 “Wastewater pumping stations”, so that it can be applied, like the standard specification, for small and large wastewater pumping stations including their pressure mains.

Standard ATV-DVWK-A 134E supplements Standard Specification EN 752-6 and provides advanced information and proposals as to how, taking account of economic aspects, pumping stations can be planned and built. EN 1671 is to be applied for pumping stations with pressure drainage.

It deals exclusively with the employment of rotodynamic pumps for the conveyance of wastewater, for which they are mainly employed. This does not, however, exclude other delivery plant (see “Kommunale Abwasserpumpwerke” [Municipal wastewater pumping stations], Vulkan-Verlag,). Statements made here also apply equally for such pumping stations so far as they do not demand other technical solutions. It would be beyond the framework of the Standard to go into these in detail.

Conveyor spirals with their completely different delivery principle and thus also other structural concept are also dispensed with, although it is just these which are relatively frequently employed to raise wastewater before the wastewater treatment plant.

The special requirements affecting these are laid down in Standard Specification DIN 1184 Part 4 “Pumping stations; Archimedean screw pumps; directives for planning”. Taking into account the wastewater-specific requirements (e.g. explosion protection) indicated in this Standard, these apply equally for wastewater pumping stations.

Facilities in the field of wastewater as a rule are used for a long time. They must, in addition, have a high availability for the protection of surface waters against pollution and for the securing of local hygiene. Great significance is given to ideas on quality. Cost reductions are possible. They may, however, not be at the expense of the environment.

With a comparison both investment costs as well as operating costs are always to be considered with the annual costs arising from both components.

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Authors This Standard has been elaborated by the ATV-DVWK Specialist Committee ES-3 “Wastewater Pumping Stations” within the ATV-DVWK Main Committee ES “Drainage Systems”.

ATV-DVWK Specialist Committee ES-3 has the following members:

EVERS, Peter Dr.-Ing., Essen HAENDEL Heinz Dipl.-Ing., München († 1997) HANITSCH, Peter H. Dipl.-Ing., Frankfurt am Main (Vice Chairman) KOCH, Günther Dipl.-Ing., Stuttgart NAUPOLD, Lutz Dipl.-Ing., Bremen TOCHTERMANN, Wolfgang Dipl.-Ing., Berlin (Chairman) TORNOW, Manfred Dipl.-Ing., Berlin ZANDER, Bernd Dipl.-Ing., Braunschweig In addition the following have collaborated: MAHRET, Hansjoachim Dipl.-Ing., Berlin WARNOW, Dietrich Dipl.-Ing., Berlin

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Contents

Foreword .................................................................................................................................................. 3

Authors ................................................................................................................................................... 4

List of pictures ......................................................................................................................................... 7

User Notes................................................................................................................................................ 8

1 Area of Application .................................................................................................................. 8

2 Planning and Dimensioning.................................................................................................... 8 2.1 Type of Structure and Structural Dimensions of the Pumping Station ...................................... 9 2.2 Wastewater Inflow...................................................................................................................... 10 2.3 Ordinates and Pumping Heads.................................................................................................. 11 2.4 Pumping Task ............................................................................................................................ 11 2.5 Expansion Possibilities............................................................................................................... 11 2.6 Minimum Completely Free Passage .......................................................................................... 11 2.7 Flow Rate and Inside Diameter of the Pressure Main ............................................................... 12 2.8 Number of Cycles of the Pumping Plant and Dimensioning of the Inlet Chamber .................... 12 2.9 Digestion of the Wastewater ...................................................................................................... 12

3 Structural Engineering ............................................................................................................ 13 3.1 Methods of Laying Foundations................................................................................................. 13 3.2 Verification of Stability................................................................................................................ 13 3.3 Building Protective Measures .................................................................................................... 14 3.4 Design of the Structure .............................................................................................................. 14 3.4.1 Inlet Chamber............................................................................................................................. 14 3.4.2 Machinery Room........................................................................................................................ 14 3.4.3 Superstructure, Entrances ......................................................................................................... 14 3.4.4 Stairs, Ladders, Step Irons, Platforms ....................................................................................... 14 3.4.5 Heating/Heat Removal ............................................................................................................... 15 3.4.6 Windows, Doors ......................................................................................................................... 15 3.4.7 Earthing...................................................................................................................................... 15 3.4.8 Lightning Protection ................................................................................................................... 15 3.4.9 External Design and Outside Facilities ...................................................................................... 15 3.4.10 Connection of Pipelines, Protective Pipes and Similar to the Building ...................................... 15

4 Mechanical Engineering .......................................................................................................... 16 4.1 Rotodynamic Pumps.................................................................................................................. 16 4.1.1 Design of the Pumps.................................................................................................................. 16 4.1.2 Impeller Shapes and Completely Free Passage ....................................................................... 16 4.1.3 Notes on Design......................................................................................................................... 18 4.1.4 Type of Mounting ....................................................................................................................... 18 4.1.4.1 Horizontally Mounted Pumps (Dry-well Installation) .................................................................. 19 4.1.4.2 Vertically Mounted Pumps (Dry-well Installation) ...................................................................... 19 4.1.4.3 Submerged Pumps (Wet-well Installation)................................................................................. 19 4.2 Pump Drives............................................................................................................................... 20 4.2.1 Electric Motors ........................................................................................................................... 20 4.2.2 Combustion Engines .................................................................................................................. 20 4.3 Pipelines in the Pumping Station ............................................................................................... 22

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4.4 Gate Valves............................................................................................................................... 22 4.4.1 Gate Valves with Elastomer Coated Obturators ....................................................................... 23 4.4.2 Parallel Slide Gate Valves......................................................................................................... 24 4.4.3 Tapered Gate valves ................................................................................................................. 24 4.5 Non-return Valves ..................................................................................................................... 24 4.6 Pump Air Bleeding..................................................................................................................... 24 4.7 Admission Gate Valves ............................................................................................................. 25 4.8 Water Supply Facilities.............................................................................................................. 26 4.9 Washdown Facilities.................................................................................................................. 26 4.10 Machinery Room Drainage........................................................................................................ 26 4.11 Ventilation Facilities for Machinery Rooms ............................................................................... 26 4.12 Ventilation Facilities for Inlet Chambers.................................................................................... 27 4.13 Lifting Gear................................................................................................................................ 27

5 Electrical Engineering............................................................................................................. 28 5.1 External and Structural Prerequisites........................................................................................ 28 5.2 Energy Supply ........................................................................................................................... 28 5.2.1 Energy Supply with a Voltage up to 1000 V (Low Voltage) ...................................................... 28 5.2.2 Energy Supply with a Voltage over 1000 V (Medium High Voltage)......................................... 29 5.2.3 Measurement of Consumption .................................................................................................. 30 5.3 Switchboard Plant, Actuators and Appliances .......................................................................... 30 5.3.1 Main Drives................................................................................................................................ 30 5.3.2 Ancillary Drives.......................................................................................................................... 31 5.3.3 Ancillary Facilities...................................................................................................................... 31 5.3.4 Operating and Measuring System............................................................................................. 31 5.4 Emergency Power Supply ......................................................................................................... 31 5.5 Types of Protection and Regulations ........................................................................................ 32 5.5.1 Explosion Protection.................................................................................................................. 32 5.5.2 Protection against Accidental Contact ...................................................................................... 32

6 Measurement Engineering ..................................................................................................... 33 6.1 Level Measuring Systems ......................................................................................................... 33 6.2 Delivery Pressure Measuring Systems ..................................................................................... 33 6.3 Flow Measuring Systems .......................................................................................................... 33 6.4 Transmission of Measured Values............................................................................................ 33

7 Wastewater Pressure Pipelines ............................................................................................. 34 7.1 Pressure Pipelines .................................................................................................................... 34 7.2 Pipeline Routes ......................................................................................................................... 34 7.3 Dimensioning............................................................................................................................. 34 7.4 Stresses..................................................................................................................................... 35 7.5 Pipe Materials............................................................................................................................ 35 7.6 Corrosion and Corrosion Protection.......................................................................................... 36

8 Commissioning ....................................................................................................................... 36 8.1 Pumping Station ........................................................................................................................ 36 8.2 Pressure Main ........................................................................................................................... 37

9 Information on Standard Specifications, Directives, Standards, Advisory Leaflets (Selection) ................................................................................................................................ 37

9.1 General Terms and Conditions for Engineering Services, (VOB)............................................. 37 9.2 Standard Specifications............................................................................................................. 38

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9.2.1 Building Standards ..................................................................................................................... 38 9.2.2 Pipes and Fittings....................................................................................................................... 38 9.2.3 Mechanical Engineering............................................................................................................. 39 9.2.4 Measurement Technology.......................................................................................................... 39 9.2.5 Electrical Engineering ................................................................................................................ 40

9.3 Directives, Standards and Advisory Leaflets........................................................................ 41 9.3.1 of the ATV .................................................................................................................................. 41 9.3.2 of the DVGW .............................................................................................................................. 41 9.3.3 of the VDI ................................................................................................................................... 41 9.3.4 of the VDMA [German Association of Mechanical Engineering Establishments] ...................... 42

10 Annexes .................................................................................................................................... 42 Annex 1: Example of a pumping station with rotodynamic pumps in horizontal, dry-well installation ...... 43 Annex 2: Basic circuit diagram.................................................................................................................. 47

List of pictures Fig. 1: Examples for types of pumping station construction with pumps in dry-well installation ........... 9 Fig. 2: Examples of types of pumping station construction with pumps in wet-well installation................... 10 Fig. 3: Examples of inflow hydrographs with dry weather, mainly residential area ................................ 10 Fig. 4: Examples of inflow hydrographs with dry weather, strong industrial influence ........................... 10 Fig. 5: Pumping diagram rotodynamic pump .............................................................................................. 16 Fig. 6: Single port non-clog impeller ............................................................................................................ 17 Fig. 7: Multi-port non-clog impeller............................................................................................................... 17 Fig. 8: Spiral non-clog impeller ..................................................................................................................... 17 Fig. 9: Non-chokable impeller ....................................................................................................................... 17 Fig. 10: Cross-section of a horizontally mounted rotodynamic pump ........................................................ 18 Fig. 11: Dry-well and horizontally mounted rotodynamic pump with fitted motor...................................... 19 Fig. 12: Dry-well and vertically installed rotodynamic pump........................................................................ 19 Fig. 13: Section of a wet-well and vertically installed submerged motor pump......................................... 21 Fig. 14: Integration of the pump pressure main ............................................................................................ 22 Fig. 15: Tapered gate valves with respectively internal ad external spindle threads................................ 23 Fig. 16: Gate valves with elastomer coated obturators................................................................................ 24 Fig. 17: Parallel slide gate valve..................................................................................................................... 24 Fig. 18: Check valve ......................................................................................................................................... 25 Fig. 19: Basic forms for ready-built stations..................................................................................................... 29

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User Notes This Standard is the result of honorary, technical-scientific/economic collaboration which has been achieved in accordance with the principles applicable therefore (statutes, rules of procedure of the ATV-DVWK and the Standard ATV-DVWK-A 400). For this, according to precedents, there exists an actual presumption that it is textually and technically correct and also generally recognised.

The application of this Standard is open to everyone. However, an obligation for application can arise from legal or administrative regulations, a contract or other legal reason.

This Standard is an important, however, not the sole source of information for correct solutions. With its application no one avoids responsibility for his own action or for the correct application in specific cases; this applies in particular for the correct handling of the margins described in the Standard.

1 Area of Application The pumping station, with the discharge of waste-water, has its particular significance in that, through the avoidance of too deep a position, it can improve the economic efficiency of a drain-age system. It is extensively independent of to-pographical conditions and makes it possible to feed effluents into receiving waters and sewers even at high levels. Furthermore, using pumping stations, wastewater can be conveyed for widely spread catchment areas to treatment facilities sited at suitable locations.

Wastewater pumps, which are mainly installed in the tank facilities (see ATV-A 166 [Not available in English]), are also frequently employed for the surface feeding and, in particular, for the empty-ing of stormwater tanks. The Standard applies analogously for these, however the technical re-quirements are to be matched to the tank-specific requirements (e. g. impeller shape, completely free passage, no continuous operation).

Pumping stations are also suitable for control of flow in larger networks.

It is emphasised, that this Standard is not to be employed where special drainage methods are used. These cases are dealt with in Standard ATV-A 116E.

2 Planning and Dimensioning

The pumping station has to be so dimen-sioned that, with the taking into account of sufficient reserves the same disposal security as with discharge under gravity is achieved.

The basic requirements to be placed on a wastewater pump are an automatic, fault-free operation with which the unhygienic and haz-ardous maintenance tasks remain limited to a minimum.

The initial considerations to be made for planning and dimensioning, the relevant factors for the se-lection of terrain or location as well as the deci-sive criteria for the dimensioning and equipping of the pumping station are presented in detail in EN 752. The following notes serve as supplement.

The layouts of the routes for the supply and disposal pipelines and the method of their laying are to be agreed with the authorities representing public interests. Rights of way for pedestrians, vehicles and pipelines are, if necessary, to be agreed.

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2.1 Type of Structure and Structural Dimensions of the Pumping Station

The type of structure and the structural dimen-sions are determined by the pumping tasks (see Section 2.4), the type of pump installation (wet- or dry-well) and corresponding with the equipping through the associated scope of ancillary facilities (transformer room, switchboard plant, tank farm), other ancillary facilities (fixed crane, heating and ventilation plants, standby plant) as well as, if re-quired, further necessary ancillary rooms (stores, workshops) and social rooms. The arrangement of the pumps in dry-well installation (vertical or horizontal) has effects on the dimensions of the building.

As a rule, wastewater pumping stations are equipped with rotodynamic pumps. They are not self-priming and therefore should be in-stalled sufficiently low so that the water flows in under gravity in order to avoid being sub-ject to abnormal occurrences. Fundamentally at least two pumps should be installed.

Before the decision as to whether the pumps should be installed with wet- or dry-wells, the planner should clarify with later operation the dif-ferences in construction, equipping and, in par-ticular, operation of the pumping station.

With wet-well installation safety against flooding and lower investment costs are up against in-creased unhygienic and in part hazardous mainte-nance work with greater expense with personnel.

In addition, the decision has to be made whether the pumping station should be provided with a superstructure (see Section 3.4.3).

In flood areas the superstructure must be so designed that, with flooding, an endangering of the pumping station is excluded.

For smaller pumping stations there are also pre-fabricated stations as a complete design. They must meet the requirements placed here.

Examples for the different types of construction are presented in Figs. 1 and 2 and in Appendix 1.

Before the decision is made on a solution, in addition to the technical, environmentally relevant, operational, personnel, social, ener-getic and other criteria, the financial and eco-nomic effects of the possible variants must also be taken into consideration. In addition to investment costs it is essential that the op-erating and capital costs are included in the consideration of economic efficiency.

Fig. 1: Examples for types of pumping station construction with pumps in dry-well installation

Inlet chamber ventilation via roof Inlet chamber open at top or covered, depending on local situation

Inlet chamber open at top or covered, depending on local situation

Access to inlet chamber

Sanitary room

Ventilator room

Switchboard plant

Inlet chamber

Assembly opening

Machinery room

2 centrifugal pumps

2 centrifugalpumps

2 centrifugalpumps

Inlet chamber

Inlet chamber Machinery

room Machinery room

Assembly opening Assembly opening

Sanitary room

Switchboard plant

Switchboard plant

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Inlet chamber ventilation via roof Inlet chamber open at top or covered, depending on local situation

Inlet chamber open at top or covered, depending on local situation

Switchboard plant Switchboard plant Switchboard plant Sanitary room Sanitary room

Fittings shaft Fittings shaft Fittings shaft

Assembly opening

Assembly opening

Suspension Inlet chamber

2 submersible motor-driven pumps

2 submersiblemotor-driven pumps

2 submersiblemotor-driven pumps

Suspension Inlet chamber

Suspension Inlet chamber

Fig. 2: Examples of types of pumping station construction with pumps in wet-well installation

2.2 Wastewater Inflow

The daily inflow of wastewater has to be as-certained for the determination of the size of the pumping station. It is influenced by:

• the type of drainage method (combined or separate),

• size and structure of the catchment area,

• number of inhabitants,

• number and type of connected industrial and commercial concerns.

The inflow is presented in a hydrograph, which reflects the inflow of wastewater in the course of a day (see Figs. 3 and 4).

There can be considerable differences both in the characteristics and in the daily quantities between working and non-working days. With rainfall one has to reckon with an increased yield of wastewa-ter (see ATV-A 118E).

The hydrograph is the basis for the arrangement of the delivery plant (determination of the operat-ing points, selection of the type of pumps, deci-sion on the employment of drives with one, sev-eral or variable rotational speeds).

Fig. 3: Examples of inflow hydrographs with dry weather, mainly residen-tial area

%Q

t h

Daily mean

Imhoff curve Workday Saturday Sunday

0 2 4 6 8 10 12 14 16 18 20 22 24

180

160

140

120

100

80

60

40

20

Fig. 4: Examples of inflow hydrographs

with dry weather, strong industrial influence

% Q

t h

Daily mean

Imhoff curve Workday Saturday Sunday

0 2 4 6 8 10 12 14 16 18 20 22 24

180

160

140

120

100

80

60

40

20

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2.3 Ordinates and Pumping Heads

The ordinate of the invert of the inflow sewer, the switch-on and switch-off ordinate of the pumps, the outlet ordinate of the pumping destination and the gradient of the terrain between pumping sta-tion and the pumping destination are of consider-able significance in order to be able to dimension a pumping station.

The pumping head, in addition to the pure static heights, also includes the friction losses which are determined depending on the speed of the medium being pumped as well as the inside di-ameter and length of the pressure main. In addi-tion, with the delivery by several pumping stations into a common pressure main, depending on the current operation of the individual stations differ-ent pumping heads arise which influence the ar-rangement of the pumps (see Section 4.1.1).

2.4 Pumping Task

As pumping task can be, for example, the func-tion as pump-over station (delivery of the waste-water into another catchment area), connecting pump station (delivery into a pressure main net-work together with other pumping stations), pumping station ahead of a wastewater treatment plant, emptying of stormwater tanks etc.

The effects of the delivery flows on the down-stream drainage system (gravity or pressure main system) with possible further connected systems and the wastewater treatment systems, are to be taken into account with the employment of waste-water pumping stations. Here, not only hydraulic aspects such as, for example, discharge capacity (overloading due to unfavourable layout of the pipeline, height and/or dimension) play a role but also the actual status of the drains concerned, i.e. renovations are possibly to be undertaken.

2.5 Expansion Possibilities

With planning it is to be considered whether, in the course of time, the required delivery flow has to be increased. If this is the case, then the pos-sibility of a later expansion must be taken into ac-count. It can, for example, be sufficient, taking in-to account the motor output, later to increase the revolutions of the rotodynamic pump which is driven via belt drives or to enlarge the impeller of

the rotodynamic pump; under certain circum-stances, however, room for a larger or additional machine must also be planned within the struc-ture. Equally the laying of an additional pipeline can also be necessary (see also Section 7.3).

2.6 Minimum Completely Free Passage

Experience has shown that, with sewer networks, a formation of textile balls cannot be excluded. Nevertheless, one can dispense with screens in so far as suitable types of pump and sufficient free cross-section are selected in the complete delivery facility.

In order to guarantee a secure delivery a com-pletely free passage of 100 mm both for the de-livery installation as well as for fittings and the pressure main are recommended. The use of specially developed, blockage-free impellers with a free cross-section of less than 100 mm (see Section 4) and appropriate selection of the pipe-line diameter is to be examined.

The pumps of smaller wastewater pumping sta-tions therefore are not only to be dimensioned according to inflows but insensitivity to blockage and minimum speed are also relevant parame-ters. This can, in relation to the wastewater in-flow, lead to over-dimensioning of the pumps.

An inside diameter of 80 mm for the pressure main should not be undercut.

Smaller completely free passages combined with shredders and appropriate pipeline diameters should only be used in special cases, for example for the disposal of waste from individual real es-tate, when the connection to a central plant is sought for water management, technical or eco-nomic reasons (see ATV-A 116E, ATV-A 200 [Not available in English]). Shredded materials can lead to increased deposits in sewers and pressure mains. Various problems can also occur in the wastewater treatment plant with increased produc-tion of shredded material. The employment of shredders should therefore be clarified, already with the planning, with the operator and, if neces-sary, with the approval authorities.

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2.7 Flow Rate and Inside Diameter of the Pressure Main

The following aspects are to be taken into ac-count with the determination of the flow rate in the main:

The lower limit of the flow rate should lie between 0.5 m/s with larger and 1.0 m/s with smaller total delivery times of the connected pumping stations. Depending on the composition of the wastewater higher flow rates must be selected with longer downtimes.

A too low a flow rate leads to deposits and thus to reductions of the cross-section so that the danger of blockage increases.

The highest speed of the delivery flow is depend-ent on the nominal width. For a pipeline length of up to ca. 500 m the following speeds should not be undercut:

Inside diameter in mm 80 100 150 200

Speed in m/s 2.0 2.0 2.2 2.4

Delivery in l/s 10 16 40 75

Flow rates greater than 2.5 m/s should be avoided.

With pipelines of more than 500 m length appro-priately lower speeds are to be preferred to avoid unacceptable pressure surges, for example with pump failure. Investigation of pressure surge should be undertaken.

The optimum nominal width is to be determined through an efficiency calculation and this com-pared with the above guidance values.

With the determination of the diameter of the pres-sure main attention is to be paid that the inside dia-meter of a pipe can deviate considerably from the nominal width depending on the material.

2.8 Number of Cycles of the Pump-ing Plant and Dimensioning of the Inlet Chamber

The available volume of the inlet chamber for the employment of rotodynamic pumps with fixed revolutions results as follows between switch-on and switch-off levels:

ZQ

V pm0.9=

V = volume in m3 Qpm = mean pump delivery flow in l/s Z = number of cycles per hour

A number of cycles of 15 per hour should not be exceeded.

The number of cycles is dependent on the stabil-ity of the mechanical and electrical plant compo-nents, in particular the electric motors (see Sec-tion 5.3).

2.9 Digestion of the Wastewater

With comparatively small daily delivery quantities and long pressure mains the retention time of the wastewater in the pressure main is very large and therefore the danger of digestion of the wastewa-ter is present. There is strong odour development and the aggressiveness of the wastewater in-creases. The possible biogenic hydrogen sul-phide corrosion has to be taken into account with the selection of pipe material.

Detailed information for countermeasures is given in Advisory Leaflet ATV-M 168 [Not available in English].

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3 Structural Engineering

Pumping stations, elevators and pumping points are structures which consist of an underground part and, as far as possible, an over ground part. Prefabricated shafts are also used for the construction of smaller wastewater pumping stations. The type of subsoil and the groundwater condi-tions are decisive contributory factors for deter-mining the type of construction work.

3.1 Methods of Laying Foundations

Before start of construction, investigations of the subsoil and existing underground build-ings are to be carried out. Firmly planned construction projects of other parties in the vicinity must also be taken into consideration.

As essential assessment criteria the following are to be determined:

• type of soil (cohesive, non-cohesive, non-plastic and similar in accordance with DIN 18196 and DIN 18300),

• soil structure (inclusions of all types),

• bearing capacity,

• settlement behaviour,

• groundwater (rush, variations in level, utilisa-tion or non-utilisation),

• surrounding buildings,

• load carrying traffic areas,

• aggressiveness of soil and groundwater,

• contaminated sites.

According to the thus determined conditions vari-ous methods for the construction of the under-ground part are possible:

• sloped excavation,

• revetted excavation (e. g. Berlin lining),

• excavation with pile sheeting,

• well-foundation (caisson),

• compressed air foundation work.

3.2 Verification of Stability

Stability is to be verified for

• the excavation and

• the structure itself.

With this it can be necessary to carry out verifica-tion for the construction state (e.g. safety against buoyancy) and for the finished state separately.

The concrete must be impermeable to water in accordance with DIN 1045 and show high resistance against chemical attack through the employment of cements with high resis-tance to sulphate in accordance with DIN 1164, Part 1. Assumptions about loads are to be made in accordance with DIN 1055. To limit the width of cracks and for improved crack distri-bution a method of conservation of crack limita-tion is to be planned. The concrete covering in the underground part should be at least 4 cm.

For safety against buoyancy, calculations must be carried out with the factor μ = 1.1, whereby the highest possible level of the groundwater or the high water level is to be taken into account. Here the soil friction or the weight of the demountable assemblies my not be taken into account. Verification of water pressure is to be carried out for both internal and external water pressure.

The highest possible water level in the inlet chamber must be assumed to be the upper surface of the ground.

As one has to reckon with wastewater with aggressive substances the values in DIN 4030 are to be observed for the evaluation of the level of attack.

As a rule the upper limiting values are to be taken into account in order to make allowance for a possible unfavourable change of the composition of the wastewater (for some considerable time one has ascertained damage to existing buildings which can be traced back to a change in compo-sition of the wastewater). Therefore, in accor-dance with the provisions of DIN 1045 on con-crete covers, the water-cement ratio, concrete texture and similar are to be taken into account.

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3.3 Building Protective Measures

The best protective effect is achieved through the quality of the material itself. With very aggressive water or soil characteristics or the danger of bio-genic hydrogen sulphide corrosion additional pro-tective measures in the form of coats of paint, coatings or sheathing can be necessary.

3.4 Design of the Structure (For this see Annex 1)

Fundamentally attention is to be paid to suffi-cient entrances secure against flooding and free space around the operational installa-tions which have to be served, maintained and/or repaired.

3.4.1 Inlet Chamber

Inlets in the inlet chamber are to be so designed that the following are avoided:

• entry of air into the pumps,

• stripping of gases,

• accumulations of solids on installations and

• unfavourable streaming of the pumps.

The inlet chamber is to be so designed that no dead space results and depositing is avoided (slope ≥ 60°). With the employment of concrete this is to be compacted carefully and covered with a compound screed using cement with a high resistance to sulphide and is to be smoothed. In special cases an additional acid re-sistant coating or a ceramic sheeting can be sen-sible. Enclosed inlet chambers must be equipped with an effective ventilation (see Section 4.12). With regard to inlet chamber space see Section 2.8.

3.4.2 Machinery Room

The dimensions of the room result from the dimensions of the machines, the free space around the machines and the space requirement for stairs. For the pumps, assembly holes are to be arranged in the roof above them. The floor is to be made as far as possible anti-skid. A pump well (see Section 4.10) for draining the pump room is to be planned. See Section 4.11 with regard to ventilation.

3.4.3 Superstructure, Entrances

The superstructure with entrances must be secure against flooding. It enables the accom-modation of:

• electrical plant,

• standby equipment,

• stationary ventilation plant,

• spare parts,

• non-stationary operational equipment,

• social facilities

and guarantees at all times a weather-independent and secure access to the pumps and inlet chamber.

Requirement for space for the energy supply plant (see Section 5.2) is to be taken into ac-count.

The inlet chamber and the associated ventila-tor room must be accessible from outside and their doors must be capable of being opened outwards only. Access from the pump room is not permitted.

Only the switch room and the toilets are to be ac-cessible via the pump room. A crane rail or shackle, dimensioned for the largest assembly part, is to be provided in the ceiling. With larger pumping stations a crane system can also be necessary (see Section 4.13).

All rooms are to be so equipped that they require little maintenance and servicing.

3.4.4 Stairs, Ladders, Step Irons, Platforms

Pump rooms which are not at ground level should be provided with stairs. Steep and spiral stair-ways should be avoided, i.e. they are an alterna-tive only with tight space conditions.

The stairs are to be designed according to the re-commendations of the agency responsible for ac-cident insurance. Climbing ladders and climbing irons are to be installed in exceptional cases only. Above 5 m total length they are basically to be provided with a system to prevent falling. Above

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the entrance points with ladders are to be pro-vided with insertible or extendable stay bars of at least 1 m in length or handholds.

Vertical ladders in the inlet chamber should not be permanently mounted below the water level, but should be foldable or removable. They may not be made of aluminium. In the place of a back protection, vertical ladders are to be equipped with a protective rail or other safety device. With particularly deep inlet chambers it is recom-mended that an intermediate platform be in-stalled. As for handrails, corrosion resistant steel Material No. 1.4571 is equally suitable.

3.4.5 Heating/Heat Removal

All rooms are to be maintained frost-free. The heat emitted by the electrical plant and equip-ment is to be included with the calculation of the heat requirement. In special cases a heat re-moval can be necessary (see also Section 5.3.1).

3.4.6 Windows, Doors

Windows and doors are to be designed as far as possible secure against break-in and damage. Windows can be dispensed with if sufficient aera-tion and ventilation as well as lighting of the rooms can be provided alternatively.

3.4.7 Earthing

The earthing device is to be so dimensioned that, in the case of a fault, the currents to earth do not exceed the earth potential of 50 V with alternating current and 120 V with direct current. In order to achieve the necessary re-sistance, foundation earth connectors are to be laid in buildings and, if required, addition-ally lattice networks are to be laid in open ground. VDE [Association of German Electri-cal Engineers] regulations are to be observed (see Section 5.5).

3.4.8 Lightning Protection

For the protection of people and plant pump-ing station buildings must be provided with a lightning protection system. Here, in accor-dance with the ABB [German Committee for

Lightning Conductor Construction], the metallic construction components of roofs and facades can be included in the lightning protection system both for collector devices and for conducting, if these are reliably connected to this. The conduc-tors of the lightning protection system are to be connected with the earthing system via “spacers” (see Section 5.5).

For further prevention of damage through the ef-fects of a lightning strike the lightning protection system should be installed in accordance with the Standard Specification DIN IEC 61024-1-2, VDE 0185 Part 102 (see Annex 2).

3.4.9 External Design and Outside Facilities

The route to the pumping station is to be matched suitably in width and surfacing to the local re-quirements.

The superstructure is to be matched in size and form and in the materials employed, for example for the outer façade, with the surroundings. Planted strips several metres wide have proved their use-fulness as visual and emission protection (see An-nex 1). With a view to later maintenance of the out-side facilities, attention is to be paid in the planning that these cause the lowest possible expense.

With sensitive locations it is recommended that architects and landscape gardeners are already involved with the planning.

3.4.10 Connection of Pipelines, Protective Pipes and Similar to the Building

Every rigid pipeline laid underground, which is fixed between two points with different subsidence characteristics must be con-nected flexibly. This applies, for example, for in-flow sewers which run from the inlet structure to the pumping station.

Pipe fairleads through walls and roofs are to be suitably sealed.

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4 Mechanical Engineering

4.1 Rotodynamic Pumps

4.1.1 Design of the Pumps

Section 2 “Planning and Dimensioning” is rele-vant for the design of the pumps. The delivery head is made up of:

• the difference in height (Hgeo) between the highest point in the pressure side of the sys-tem and the water level in the inlet chamber,

• the admission pressure (Hadm), e. g. through conveyance in an already otherwise streamed pressure pipeline, and

• the pressure loss (Hloss) in the pipes and fit-tings.

Due to changes in level in the outlet and in the inlet chamber as well as a varying admission pressure there results a range of the pipeline characteristic curves in accordance with Fig. 5.

The operating range of the pump lies between the intersection point of the throttle curve with the highest and lowest pipe characteristic curve. In the case of a compound or parallel operation, at-tention is to be paid for an as steep as possible throttle curve with the selection of the pump.

Fig. 5: Pumping diagram rotodynamic pump

The matching of a changed inflow can be under-taken through the modification of the revolutions and, in addition, through change of the impeller diameter.

With all pumps the cavitation behaviour should be examined in order to avoid cavitation, noises, er-ratic running and material wear.

A measure for the cavitation behaviour is the NPSH value (net positive suction head), i.e. the net energy head (= absolute energy head less the vaporisation pressure head) in the entry cross-section of the pump impeller. The NPSH value of the plant (NPSHP) is compared with the NPSH value of the pump (NPSHR). In every case the drop must be NPSHP > NPSHR.

The NPSHR value must be given by the pump manufacturer. The ratio

1.3 NPSHRNPSHP ≥

should be sought for security against cavitation with water pumps.

Further details can be taken from DIN 24260, Part 1 “Rotodynamic pumps and rotodynamic pump systems” [Not available in English].

4.1.2 Impeller Shapes and Completely Free Passage

For the conveyance of untreated wastewater with coarse and fibrous constituents specially shaped impellers are employed (see Figs. 6 to 9) which, to a great extent, prevent blockages and the for-mation of clogs.

The non-clog impeller is employed as single and multi-port non-clog impeller.

The single port non-clog impeller (see Fig. 6) has the following characteristics:

• constant completely free passage from the en-trance to the intake to the exit to the pressure pipe corresponding to the completely free pas-sage of the impeller,

• efficiency as a rule less than with multi-port non-clog impellers,

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• hydraulic out-of-balance, which can only be extensively compensated, and this at great expense, related to a defined operation point. A rate of rotation above 1450 min-1 should be avoided, with large impellers a rate of rotation of 1000 min-1 should not be exceeded.

Fig. 6: Single port non-clog impeller The multi-port non-clog impeller (see Fig. 7) is, as a rule, a two or three port non-clog impeller. In comparison with the single port non-clog impeller it is characterised by the following features:

• greater delivery heads are achieved.

• a static and dynamic balancing is relatively simple to carry out. Higher rates of rotation, and due to this, greater delivery heads are also possible.

• variable speed operation is without problem.

• noise- and vibration-free running is easier to achieve.

Fig. 7: Multi-port non-clog impeller

It is, however, more susceptible to blockage than the single port non-clog impeller as, with the same delivery flow, the completely free passage of the impeller channels are smaller.

The spiral non-clog impeller (see Fig. 8) is a semi-axial single-vane impeller with helicoidal or screw formed inlet component. It runs very quietly and therefore is employed with rotational speeds of 3000 min-1.

Fig. 8: Spiral non-clog impeller The non-chokable impeller (see Fig. 9) effects the transport medium indirectly only. With the con-veyance of wastewater it can be employed with rotational speeds up to 3000 min-1. The characteristic curve is usually flatter and the efficiency lower than with the other impellers.

Fig. 9: Non-chokable impeller All given impeller shapes are, in principle, suit-able for employment in screenless pumping sta-tions, under the assumption that the requirements of Section 2.6 are met. They are employed nor-mally up to the following pressure values in the point of operation:

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• single-port non-clog impeller up to 4 bar,

• spiral non-clog impeller up to 6 bar,

• multi-port non-clog impeller up to 10 bar,

• non-chokable impeller up to 10 bar.

The rate of flow in the impeller channels should, as far as possible, not undercut 2 m/s as other-wise the danger of pump blockage is very great.

4.1.3 Notes on Design

With a dry-well wastewater pump (see Fig. 10) sufficiently large cleaning ports are provided on the intake and outlet to the pressure pipe so that blockages can be removed from inside the pumps manually. With smaller pumps the size of the cleaning ports should approach the nominal width of the pumps. With larger pumps they should be 180 to 200 mm.

Longer downtimes and possibilities of repair are achieved through an exchangeable obturator in the area of the suction mouth of the pump casing and a locking ring on the reverse side of the impeller. In principle, with large pumps, they should be provided. With these an exchangeable obturator is recommended also on the pressure side, i.e. on the bearing side of the pump casing.

Attention is to be paid that every impeller is pro-vided with vanes on the back or pressure side of the impeller disk.

The sealing of the pump in the area of the shaft can be achieved using gland or axial face seals. If a gland seal is used then attention is to be paid that the shaft protective covering is highly wear resistant and packings are easy to exchange without greater dismantling.

Assessment criteria with the employment of axial face seals, also with pumps with submersible mo-tor, are a short separation between impeller and first bearing and the employment of specially formed axial face seals which, in particular, do not allow wastewater to penetrate to the contact pressure rings of the seals (danger of contamina-tion). A transmitter which signals a possible entry of water into the sealing oil which lubricates and cools the axial face seal as well as preventing immediate entry of water into the machinery room, should be installed.

4.1.4 Type of Mounting

With the installation of the pumps a differentiation must be made between horizontal and vertical pumps. Submersible motor-driven pumps can also be employed in dry-well installation and thus, with suitable arrangement of the electrical con-nections, ensure the pumping of wastewater even with flooding of the pump room. With its employ-ment in dry-well installation the question of hea-tremoval from the motor is to be clarified with the pump manufacturer.

Fig. 10: Cross-section of a horizontally mounted rotodynamic pump

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4.1.4.1 Horizontally Mounted Pumps (Dry-well Installation)

In the horizontal layout (see Fig. 11) there is the space saving design of the pump with saddle mounted motorist which, moreover, offers even more advantages.

In this way, with the drive of the pump via v-belts, an easy matching to a possibly changed inflow is possible by changing the transmission ratio; moni-toring and certain repairs on the pump are signifi-cantly more simple.

The pump should have a base frame. The bracket for the mounting of the electric motor is to secured with bolts so that it is removable.

Fig. 11: Dry-well and horizontally mounted rotodynamic pump with fitted motor

To tension the v-belts the motor must be mounted so that it is adjustable. Through the compact con-struction the unit is substantial insensitive to vibra-tion. The installation of a pump with motor in modu-lar construction is also possible.

4.1.4.2 Vertically Mounted Pumps (Dry-well Installation)

The vertical type of installation (see Fig. 12) offers a greater security against flooding through the high mounting of the electrical motor.

The connection between pump and motor is always to be elastic for the acceptance of ad-justment tolerances and for the damping of vi-bration and impact.

4.1.4.3 Submerged Pumps (Wet-well Installation)

If a submersible motor-driven pump in wet-well in-stallation (see Fig. 13) is employed, then attention is to be given to certain peculiarities. Inlet cham-bers are explosion endangered zones. In accor-dance with the regulations of the [German] Asso-ciation for Social Insurance against Occupational Accidents (VBG) pump casings and components, in contact with water, made from aluminium alloys in explosion endangered plant components of wastewater treatment plants of Zones 0 and 1 are not permitted. Fundamentally the motor must be protected against explosion in accordance with VDE 0170/0171, and that is, as a rule, in E Ex dll BT3. cleaning ports on the casing are ruled out. Every wet-well installed pump should be capable of being installed and removed without emptying the inlet chamber and without tightening or loosen-ing of bolts on their pressure joints. The mounting parts required for this are subjected to corrosive at-tack to a particularly high degree. They should be made from stainless steel Material No. 1.4571; this also applies to nuts, bolts and washers.

Fig. 12: Dry-well and vertically installed

rotodynamic pump

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4.2 Pump Drives

Electric motors are almost exclusively employed for driving the pumps. However, for reasons of disposal security, an uncertain energy supply or to cover peaks it can be necessary to employ another type of drive, for example, combustion engines.

4.2.1 Electric Motors

For rotodynamic pumps the electric motors should be designed (see Section 5.3.1) for the limiting power requirement of the specified operating range. The same applies for the coupling between pump and motor. Where an increasing wastewater production is to be expected it is, however, sensi-ble possibly to design the motor and the coupling more robustly, in any case, however, the associ-ated electrical parts of the plant, in accordance with the expansion capacity of the pump.

The following reserve capacities should be pro-vided as a minimum with regard to a sufficient en-gine power to avoid blocking of the impeller:

With pressure mains with elevator effect and such which, with every start-up, have to be completely or in part primed, the increased necessary power requirement for this is additionally to be taken into account.

It is to be examined whether special measures are necessary for the protection of the pressure mains against possible pressure surges (see Section 2.7) or in order to avoid inadmissibly high currents at make of the pump motors.

To these belongs the so-called smooth starter for cage rotor motors. It prevents undesired load peaks for pumps and motors.

It should be equipped with the reverse function, i.e. a smooth coast down.If, in addition to a smooth start and coast down, the revolutions are also vari-

able then the employment of a static frequency converter is recommend. Using this, submersible motors and explosion protected motors can be op-erated with variable revolutions. The possible change of revolutions is to be clarified with the pump manufacturer. Here the flow rate in the im-peller channels is to be noted (see Section 4.1.2).

With the employment of a static frequency con-verter, due to the increased heat loss, the motor should have a reserve capacity of 10 to 15 %. With low revolutions an external ventilation of the motor can be necessary. In order to protect it from inad-missible heating the windings should be monitored using thermofeelers, i.e. so-called positors.

4.2.2 Combustion Engines

As a rule, diesel motors with a nominal speed of 1500 min-1 are employed as combustion engines. Their speed is adjustable but, for economic run-ning the adjustable speed range used should not go below 75 % of the nominal speed, this means that, under certain circumstances, a mechanical in-termediate gear becomes necessary.

For low capacities motor and gearbox often form one unit which is connected with the pump by means of an elastic coupling.

With diesel engines of higher performance, gear-box and pump are to be connected using an elastic coupling. The connection between diesel engine and gearbox should be via a universal joint shaft. It can counterbalance axle variations which, after longer periods of time, cannot be excluded with re-spectively separate foundations.

A reverse rotation of the diesel engine is to be prevented under all circumstances!

Mainly water-cooled diesel engines with internal and external cooling water circuits are employed. Oil coolers for gearboxes of higher performance are to be included in the cooling system.

Power requirement of the pump in kW

Reserve capacity of the driving motor

up to 7.5 ca. 50%

7.5 – 20 ca. 25%

20 -50 ca. 15%

over 50 ca. 10%

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Watertight cable lead

Axial face seals

Fig. 13: Section of a wet-well and vertically installed submerged motor pump To remove the radiated heat of the diesel engines and to introduce sufficient combustion air the rooms in which they are installed are to be pro-vided with air inlet and outlet openings for outside air. With diesel engines of higher performance and/or smaller rooms inlet and outlet air blowers can additionally be necessary.

Precautionary measures for winter operation are to be taken

Diesel plants create high noise levels; this means that structural measures are to be taken in the interest of the operating staff and the environment. The approval authorities will, under certain circumstances, issue requirements. The scope of the measures to be taken depends on the position of the installation room and the usage identification of the area in the land devel-opment plan in which the pumping station lies The measures to be taken include:

• structure-borne damping machine mountings,

• structure-borne and airborne noise damping designs in the exhaust discharge system,

• airborne noise inhibiting structures in the inlet and outlet air lines,

• airborne noise damping outfitting of walls, ceil-ings and doors.

The exhaust lines are to be insulated using an appropriate material which guarantees a surface temperature of the finished insulation of ≤ 70 °C.

It is to be clarified with the approval authorities which limiting values of atmospheric pollution in the diesel exhaust gas must be met. It is possible that soot filters or catalytic exhaust gas cleaners could be required.

The diesel engine plant must satisfy the pro-visions of the valid ordinances of the [Ger-man] Technical Instructions Air (TA Luft) and Noise (TA Lärm) of the Federal German Im-mission Protection Law.

Fuel storage is also to be planned for energy sup-ply of the diesel motor. It should consist of storage tanks and a service tank. The service tank should be arranged at a sufficient height so that the fuel flows to the diesel engine.

For a secure operation of diesel engine plants a certain number of operational monitoring mes-sages are unavoidable. To these belong:

• fuel tank overfilled,

• lack of fuel,

• cooling water temperature too high,

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• lack of cooling water,

• lubricating oil pressure too low or lack of lubri-cating oil (emergency shutdown!).

4.3 Pipelines in the Pumping Station

For the proper operation of dry-well installed pumps the suction (inlet) pipeline must al-ways be laid inclined upwards to the pump. The nominal width of the suction pipeline should be at least the diameter of the intake mouth of the pump and be not less than 100 mm. A check valve and, following this, a gate valve are to be provided, looking in the direction of flow, on the pressure side of the pump.

Similarly, with a dry-well installed pump, a gate valve should always be inserted in the suction line. Only in this way is it ensured that, with the removal of a blockage or repair of a pump or of a check valve, that pumping operation does not have to be interrupted.

The integration of the pump pressure mains must always be horizontally into the main pipeline (see Fig. 14), as otherwise the vertical pipeline becomes clogged.

Fig. 14: Integration of the pump

pressure main A pressure pipe emergency connection should be provided for a transportable pump for the case of pump room flooding or of total pump failure. The emergency connection should be provided flood-ing- and frost-free in at least DN 100 and as

short, vertically upwards, easily accessible con-nection piece with gate valve and blind flange.

Using steel as the pipe material for pressure mains within the pumping station, for reasons of corrosion, this should be thick-walled. Then an in-ternal wall corrosion protection can be dispensed with. With wet-well installation of pumps and where later renovations are possible under diffi-cult conditions only, the employment of Material No. 1.4571 is recommended.

Pipeline fixtures should be arranged with short separation and be made particularly stable. With longer pipelines they should be displaceable axi-ally (heat expansion). The pipelines must, in addi-tion, always be so anchored that they transfer no forces to the pump.

For perfect assembly, i.e. for stress-free connec-tion, for the balancing of length tolerances and to avoid damage to seals, depending on the re-quirements, loose or fixed detachable fittings or compensators should be incorporated in the pipe-lines. Detachable fittings can, however, also be avoided through suitable arrangement of the pipeline, so that pipe elbows with flanges can take over their task.

All painting is to be carried out with the observa-tion of Advisory Leaflet ATV-M 263 (Not available in English).

Larger wall fairleads are, if absolute sealing is re-quired (e.g. against groundwater), to be carried out as wall flanged pipes with one or more wall flanges. In principle these are to be built-in from the start as, with later installation sealing problems can occur.

4.4 Gate Valves

With gate valves it is differentiated between mod-els with internal and external spindle threads (see Fig. 15).

Preferred is the model with external spindle threads as, through removal of the spindle nut and the spindle thread from the area of the wastewater, heavy wear is avoided and the spin-dle is easy to grease. Nevertheless the greater installation height is to be noted. Ductile cast iron (DCI) is to be preferred to grey cast iron (GCI) as casing material due to the essentially greater se-curity against fracture.

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Attention is to be paid, with gate valves with me-chanical drive, that the maximum possible actuat-ing power cannot damage the gate valve.

To avoid corrosion on components of the gate valve the following materials are recommended for use in wastewater:

Spindle: Stainless steel Mat. No. 1.4571

Spindle nut: Zinc-free cast bronze

Mat. No. 2.1060

Seating ring: Zinc-free cast bronze

Mat. No. 2.1060

Due to their design tapered and parallel slide gate valves are especially suited for a controlled closure and opening (see EN 752-6, Section 9.3)

Clack valves are not suited for wastewater as tex-tiles can wrap around spindle and swing valve and can prevent the closure procedure.

4.4.1 Gate Valves with Elastomer

Coated Obturators

These gate valves have a straight valve opening without valve pocket and an elastic seal (see Fig. 16).

They are particularly suitable as gate valve eve-rywhere where they are almost exclusively open.

Deposits which have settled and hardened in the valve pocket with tapered gate valves (applies only with horizontal mounting) are thus avoided. Gate valves with elastomer coated obturators, however, are not suitable as throttles.

The dimensions of the gate valve with elastomer coated obturator, depending on the nominal pres-sure, correspond with the tapered gate valves. Materials for spindle and spindle nut here also should be the above given.

Fig. 15: Tapered gate valves with respectively internal ad external spindle threads

Internal spindle threads External spindle threads

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Fig. 16: Gate valves with elastomer coated obturators

4.4.2 Parallel Slide Gate Valves

Parallel slide gate valves (see Fig. 17) are char-acterised by the following advantages:

• very short construction length,

• all installation positions are permitted,

• easy adjustment of the parallel slide seal,

• spindle and spindle nut are located outside the wastewater stream even with non-rising spindles,

• the parallel slide gate valve can also be supplied as throttle valve,

• cutting effect with solid matter in the wastewater,

• cost efficient.

4.4.3 Tapered Gate valves

The tapered gate valve (see Fig. 15) is very robust and has proved itself in rough wastewater opera-tion. The exception here is, however, the gate valve with two-part (elastic) wedge with which the slider can become clogged with textiles.

Gate valves are standardised up to DN 600 in DIN 3352, Parts 1 – 8.

Fig. 17: Parallel slide gate valve

4.5 Non-return Valves

The non-return valve, when fully opened, may not hinder the passage of solid matter. For this the check valve with a casing made of grey cast iron or ductile cast iron is particularly suitable (see Fig. 18). The later is to be preferred. It should be fitted with lever and weight. With this it offers the possibility of assessing the output of the pump. With small nominal widths (< 150 mm) with low static head of water a backwashing can also be introduced by raising the flap by means of the lever. Where a check valve fails due to too small a degree of opening as a result of small flow rates, a ball check valve should be employed.

4.6 Pump Air Bleeding

Through conveyance of the rotodynamic pump up to the inlet side breakdown of the pumping flow or through leaking glands a dry-well installed roto-

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dynamic pump empties itself into the inlet cham-ber after shutting down. Should the return valve be located immediately or just slightly above the pump pressure connection piece the pump cas-ing remains filled with air.

As rotodynamic pumps in such a state cannot nor-mally pump they must be bled of air beforehand. For this the bleed line with horizontally mounted pumps must run from the highest point of the pump casing or, with vertically mounted pumps, as short as possible in front of the return valve.

The bleed line should end in the inlet chamber. With this it is to be led so high in the pump room that even with maximum water level in the inlet chamber a perfect bleeding of the air is possible (see Annex 1).

To avoid pumping into the bypass through the bleed line and its blocking, that will cer-tainly occur within the shortest time, the line within the machinery room must have a shut-off device, which automatically closes with the start-up of the pump and, with the shut-down of the pump, opens with a time delay (time until the impeller of the pump has stopped turning). Solenoid or pinch valves are suitable as shut-off devices.

Where a return valve is located so high that the air from the pump can be forced into the pressure main through the rising water level no bleed line is necessary. With wet-well installed submersible motor-driven pumps this is often the case.

4.7 Admission Gate Valves

For the following reasons it is necessary to sepa-rate the inlet chamber of a pumping station from the inflow:

• for cleaning tasks in the inlet chamber or for the removal of bulky items and solid matter from the inlet chamber,

• for visual checks in the inlet chamber as well as examination of the level switch and other measuring equipment in the inlet chamber as well as measuring runs for the determination of the pump conveyance flow,

• to dry out the inlet chamber for necessary maintenance tasks.

Therefore, from the very beginning, an admis-sion gate valve should be planned with the construction of a wastewater pumping sta-tion. With a small wastewater pumping station manual operation as far as possible using an above ground column should be sufficient. With a larger works the gate valve should have an elec-tric actuator, explosion protected in the Class E Ex dII BT3. The most suitable gate valve is one without casing with external threaded spindle, which can be installed in a sewer manhole. Due to watertightness it is to be so installed in the manhole shaft that the slider plate is pressed against the frame by the water, i.e. from the in-flow side.

Threaded spindle, rods as well as all bolts and all anchor bolts, should be manufactured from Mate-

Fig. 18: Check valve

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rial No. 1.4571 or equivalent. The seals and guides should be made from a zinc-free bronze, for example Material No. Nr. 2.1060.

4.8 Water Supply Facilities

In accordance with VBG 54 [Regulations of the Trade Association] (UVV 25) [Accident Prevention Ordinance] washing facilities with running water must be available in pumping stations. Further details are to be found in the Implementation Instructions to the VBG 54 (ZH 1/177). In addition, water for cleaning purposes in the machinery room and inlet chamber is, in par-ticular required (see also Section 4.9).

With the installation of water supply facilities potable and non-potable water connections must be differentiated.

If a potable water connection is intended then, in addition to the respective regulations of the Federal German States and water supply con-cerns, DIN 1988 as well as the DVGW [German Technical and Scientific Association for Gas and Water] Standard W 345 must also be ob-served.

4.9 Washdown Facilities

A supply of water should be provided in order to be able to clean the pump room of a pumping station with dry-well installed pumps.

To clean the inlet chamber an output of from 4 to 6 m3/h is required. A fire hydrant is ideal as water source to which a DN 25 hose with D-spout in accordance with DIN 14365 can be connected.

Due to the danger of corrosion the washdown pipeline in the inlet chamber should be made from PE Hard plastic in accordance with DIN 19533 or stainless steel Material No. 1.4571, PN 10.

Attachment of the pipeline should take place also using plastic, or better, stainless steel (Material No. 1.4571 or equivalent) clips. The bolts/screws used for this must also be made implicitly from stainless steel of the same quality.

The washdown pipeline in the inlet chamber may be connected with a potable water pipe-

line in accordance with DIN 1988, Part 4, only indirectly via a water tank and a downstream booster system. Only a pipe disconnector ap-proved by the DVGW which automatically and visibly establishes a 20 mm long break in the pipe as soon as the water pressure falls below a cer-tain safety value may also be employed in short-term operation. DIN 1988, Part 5, gives further in-formation.

With several plants of the same type a transport-able washdown facility, if required equipped with water tank, can also be employed.

4.10 Machinery Room Drainage

For the discharge of leaking water and/or washdown water and for the draining of pumps a pump well is to be provided at the deepest point of the machinery room and a light sub-mersible motor-driven pump with the greatest pos-sible free impeller passage and automatic level switch is to be so connected to a fixed pipe that, with blockage, it can be removed easily and cleaned at any time by hand. The pipeline must be so laid that a siphoning over to the machin-ery room is prevented, i.e. as a rule using a gooseneck via the highest possible ordinate of the backwater of the wastewater inflow.

The drainage pump should have a return valve immediately behind the pressure hose. The in-stallation of a gate valve in the fixed pipeline is useful.

The size of the pump well depends on the pump selected. It should not undercut the dimensions 500 x 500 mm and a depth of 300 mm.

4.11 Ventilation Facilities for Machinery Rooms

In accordance with VBG 54 (UVV 25) rooms of wastewater treatment systems as well as stormwater tanks and pump pits (inlet cham-bers) must be equipped with an effective ven-tilation. Details on the type of ventilation are to be found in the Implementation Instruction of the VBG 54.

With an above-ground structure usually the win-dows and, additionally, shaft ventilation suffices for small machinery rooms. All air inlet and outlet

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openings to the outside are to be provided with protective screens for birds and weather, whereby the protective screen for weather must be seated outside of the protective screen for birds. Further information is contained in VDI [As-sociation of German Engineers] Standard 3803.

If a machinery room lies well below ground level then a five times the hourly forced air exchange should be sought. This is most usefully achieved using an exhaust fan and appropriate air resupply openings.

4.12 Ventilation Facilities for Inlet Chambers

Enclosed rooms of wastewater discharge facilities and pump wells (inlet chambers) must be equipped in accordance with VBG 54 with effective ventilation (see Section 4.11).

For the inlet chamber of small wastewater pump-ing stations a stationary or transportable me-chanical aerator is, as a rule, sufficient. The dis-placed air must be able to flow via a sufficiently dimensioned free cross-section. With larger pumping stations both a mechanical aerator as well as an air extractor should be installed.

Fundamentally with ventilation plants attention is to be paid that no short circuits form between in-flow and outflow air areas.

Both the external inflow as well as the outflow openings are to be so arranged that the neighbourhood is neither hazarded nor in-convenienced by exiting gases. With pumping stations with superstructure they should be as high as possible, whereby the outlet of the outgo-ing air channel should be located above the ridge of the roof (as far as available), that is outside a possible lee of the wind.

For practical purposes the ventilators should be permanently installed in separate above-ground rooms. These rooms are, as is also the inlet chamber, to be considered as explosion endan-gered and therefore must receive a natural di-agonal ventilation.

All horizontal air channels are to be laid with a slight gradient so that any condensed water that forms can run off to the ventilator or inlet cham-ber respectively. Every ventilator itself is to be

provided with an outlet pipe at the lowest point of its casing, which exits into the ventilation channel to the inlet chamber. Thus it is avoided that water which, under certain circumstances, can even freeze, can collect in the ventilator and lead to its destruction.

All channel sections and naturally also the connection to the ventilator must be joined, sealed, with each other. Firms involved in as-sembly are to be informed urgently on this point.

Air distribution must be so designed that the air can exit both ca. 1 m above the floor of the empty inlet chamber and also above the maximum water level of the inlet chamber.

Ventilators and air channels are to be manufac-tured from corrosion resistant material.

4.13 Lifting Gear

Crane systems are required for the installation and removal of machinery. With smaller pumping stations without superstructure it is to be exam-ined whether mobile lifting gear can be employed, otherwise a slewing pillar crane should be pro-vided. In smaller pumping stations with super-structure the lifting device can be designed as single-beam crane trolley with suspended pulley block. With this, the crane girder is to be so di-rected that the heaviest plant component can be placed directly on to the assembly point. With lar-ger pumping stations a double-beam travelling crane with crane trolley should be installed in the machinery room. With this a picking up and set-ting down of a load is possible in the complete area of the room. While longitudinal and trans-verse movement is entirely possible by hand an electrical drive for lifting is a particular advantage when pumps are installed very deep. To be noted is, that for crane systems > 1 t which are permanently installed, a crane mainte-nance platform, which can be installed trans-portable or fixed, is essential for mainte-nance, repair and the legally prescribed tests.

The height and weight of the machine parts including securing and overall height of the lifting gear, the crane trolley and the crane carrier are to be checked for the dimensioning of the crane system and clear height of the superstructure. Here thought is to be given to possible expansion of the machine plant.

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Statics must take into account all working and constant loads.

Before first commissioning, following building modifications and with lifting gear for loads greater than 1 t, the complete crane system must be tested once a year by a specialist.

5 Electrical Engineering (for this see also Annex 2)

5.1 External and Structural Prerequisites

Electro-technical installations, in particular switchboard plant, must be housed dry, free of dust and pollutants.

If electro-technical devices are installed as switch boxes in the open, attention must be additionally paid to their maintenance-friendly accessibility as well as to protection against damage through road traffic or vandalism. Switchboard plant and transformers may not be installed in areas en-dangered by flooding.

Rooms with electro-technical installations are to be aerated and ventilated as well as heated so that their function remains assured.

Electro-technical plant may be accessible for a very limited circle of trained or specially instructed technical personnel only. The electrical opera-tional rooms and also the switching plant, so far as it is not installed in electrical opera-tional rooms, must be kept under lock and key.

All doors to electrical operational rooms must be equipped with a panic lock (escape lock), which can be opened from inside, even when locked, without aids.

Information for the design and dimensioning of electrical operational rooms can be found in the VDE Regulations.

Allowance should be made for the protection of structures from oil, acids, overpressure as well as for fire protection.

Floor coverings must be insulated and secure against electrical breakdown for the corre-sponding operational voltages. The coverings may not lead to a build-up of static electricity.

5.2 Energy Supply

The energy supply as a rule is from the low volt-age network (400/230 V, 50 Hz) of the responsi-ble ESC (= energy supply company). It can, how-ever, be also required from the medium high voltage network 20, 10 or 6 kV, in exceptional cases 30 kV and more. If a particularly high op-erational or supply security respectively is neces-sary, one should provide two independent feed-ers, laid on two separate cable routes and secured against simultaneous connection (con-siderable additional costs!).

For the securing of the electrical energy supply of a wastewater pumping station the connected load must be determined and contact made with the responsible ESC as early as possible.

The clarification of the supply conditions must take place with the responsible ESC immediately after establishment of the essen-tial consumers, that is at a very stage, as they have a considerable influence on the room pro-gramme, the costs and the design of the pumping station.

Every ESC has available application forms for the establishment of the connected load, in which the required data such as the number and capacity of the individual consumers is entered.

5.2.1 Energy Supply with a Voltage up to 1000 V (Low Voltage)

Depending on local conditions there is a maxi-mum possible connected load (standard value ca. 10 to 50 kVA) for the low voltage supply (LV sup-ply) which depends on the respective ESC. Al-ready for cost reasons an attempt should be made, as far as possible, to manage with a LV supply (in general 400/230 V AC), without limiting oneself operationally.

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5.2.2 Energy Supply with a Voltage over 1000 V (Medium High Voltage)

If the supply conditions do not allow a low voltage supply a medium high voltage supply is neces-sary. Medium high voltage switchboard plants are, in any case, to be installed in locked operat-ing rooms. For medium high voltage systems one or more transformers are required. Ready-made assembled small switchboard plants (compact plants) are available for smaller transformer ca-pacities (see Fig. 19).

The switchboard plants for voltage levels above 1000 V should, for the protection of personnel, be employed only as plants secured against acciden-tal arcing in accordance with Pehla Directive No. 2, Criterion 1 to 6, with firmly installed switchgear or on a rail mounted platform (retractable).

In order that the switchgear still remains operable even with failure of the mains and the appropriate information is retained, it is recommended that both the drive of the switchgear and the control and reporting systems are designed independent of the mains supply (battery).

Fig. 19: Basic forms for ready-built stations

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5.2.3 Measurement of Consumption

As a rule this is provided and installed by the ESC. The build-up of the metering facility de-pends on the voltage levels used and thus has an influence on the room programme. It is to be clarified with the ESC where the electricity con-sumption meter is to be installed.

5.3 Switchboard Plant, Actuators and Appliances

Low voltage switchboard plants are normally pro-duced in the shape of standardised sheet steel cabinet systems which are secure against acciden-tal arcing to increase the protection of personnel.

As a rule a modular method, otherwise an inser-tion method, is employed for the power items.

To control and monitor the machines motor con-trol cards (electronic) can be used for the realisa-tion of the basic circuitry and basic locking mechanism.

Higher voltage switches are realised through the employment of stored-programmable control sys-tems (SPS).

Unavoidable blind current components should be compensated using fixed or regulatable blind cur-rent compensation. For later expansion a space and capacity reserve of from 15 – 20 % should be planned.

All switching plant is to be installed safe from flooding.

5.3.1 Main Drives

As far as possible, three phase squirrel-cage mo-tors with small current at make should be pro-vided as drive motors for the wastewater pumps (see Section 4.2.1).

Winding sensing devices can be planned to pro-tect the motor against overload. For drives with operationally conditioned long down-times, and with high air humidity, a down-time heater can be practical.

The IP 54 system of protection is to be preferred.

Every drive has a control selection switch with the positions MANUAL – OFF – AUTOMATIC.

The switching ON and OFF of the pumps is de-pendent on water level, in special cases the de-livery flow can be over or underlaid. Operating conditions must be recognisable on the electrical control panel. Pump exchange switch, current meter and operating hours counter should be in-tegrated. In addition each drive has one (or more) EMERGENCY OFF switches in situ, which en-gage directly in the control system.

Faults always lead to the immediate shutdown of the plant. With this the control system, goes into locked status, an automatic restart following a fault may not occur.

Modification of the number of pump revolutions is possible through pole changing motors (2 or 3 rpm) or using frequency converter drives (infi-nitely variable, simultaneous starter in the lower rpm range).

Frequency converter drives create heat and noise which possibly has respectively to be dissipated or restrained. In addition, converters create harmonic waves in the power supply. The power supply reactions of these harmonic waves must be compensated.

Attention is to be paid that the adjustment of the rpm modifies all characteristic curves of the pumps.

There are the following possibilities for the auto-matic operation of the pumps:

• Pumping control Conveyance of the pump is monitored.

• Protection against dry running It is prevented that the pump lowers the water level in the inlet chamber below a permitted level and thus runs dry.

• Simultaneous start Simultaneous start of large consumers is pre-vented to avoid expensive peak loads.

• Reserve pump with malfunction With malfunction of the service pump the re-serve pump takes over operation automati-cally.

• Conveyed quantity- or pressure control

• Parallel operation of several pumps

• Reclosure preventing device The immediate reclosure following switching

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off for operational reasons is prevented de-pending on time in order to avoid the inadmis-sible heating of electrical components and/or heavy start.

• Monitoring of oil and cooling water

• Alternating closure With every new closure impulse another drive is switched on in preselected sequence.

5.3.2 Ancillary Drives

Ancillary drives are, inter alia:

• Actuators for fittings,

• Inlet chamber ventilators, if required pump room ventilators,

• Drainage pumps for pump rooms,

• Booster pumps for wash down facilities,

• Grease or oil pumps for bearing lubrication,

• Lifting gear,

• Compressors.

5.3.3 Ancillary Facilities

These cover:

• Electrical heating for frost protection,

• Lighting plant, additional emergency lighting,

• Battery systems,

• Plug connections for three phase 400 V to 63 A, 230 V/16 A AC and extra-low voltage 25 V/10 A,

• Water heaters for sanitary objects,

• Connections for measuring technology, fused outlets 230 V,

• Reserve outlets; for each voltage level 1 to 3 reserve outlets.

5.3.4 Operating and Measuring System

Recording of operating and fault messages:

Operating messages should be displayed indi-vidually optically, fault messages shown indi-vidually optically and collectively acoustically. The fault messages can, if required, be combined to-gether as a group fault message.

A test key for all illuminated displays is recom-mended.

The remote transmission of operating and fault messages as well as status signals can, for ex-ample take place via a cable or leased lines.

Remote transmission is, however, only sensible if there are possibilities of acceptance or of calling up this information in rotation as well as for its operational processing.

A telephone connection is necessary, alterna-tively paging or service radio. In any case per-sonnel working in the pumping station must be available or must be capable of making contact with the control centre.

5.4 Emergency Power Supply

Depending on the security of the energy supply, possibilities of retaining the wastewater in cases of failure and the operational significance of the pumping station in the drainage system, a mobile or a stationary, automated emergency power equipment is required.

• Mobile plant This requires a signal of the fault at the central point, a possibility that the plant can be trans-ported in and connected to the switchboard plant rapidly and without complications, whereby, at the same time, the separation from the power supply and locking must take place.

• Automatic plant Automatic emergency power supply systems switch in immediately following voltage break-down and, with a time delay, switch off follow-ing reestablishment of the power supply. For rotational maintenance their must be a possibility of running the emergency power

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bility of running the emergency power system under load over several hours.

• Special cases The energy supply of the complete works or parts of this can take place with the aid of a stationary, automatic generator (see Section 4.2.2).

5.5 Types of Protection and Regulations

All equipment and installations must corre-spond with the relevant VDE and VBG regula-tions as well as the technical connection con-ditions (TAB) of the responsible ESC.

An earthing of the complete plant, incl. the conductive plant components which do not belong to the operating power circuit, in ac-cordance with the VDE is to be carried out with the aid of the foundation earth planned by the customer and, if required, additional earthing (see Section 3.4.7).

Equipotential bonding between all conductive components must be carried out whereby protection against lightning strike is included in the bonding.

Lightning protection in accordance with ABB is required for superstructures (see Section 3.4.8).

5.5.1 Explosion Protection

With the pumping station, as a rule, the inlet chamber, inlet shaft and, possibly, the ventilator room are explosion endangered areas.

The operating equipment therein must be so installed and the plant so mounted and oper-ated that no explosion can be caused.

Zones 0, 1 and 2 are differentiated according to the timely and local probability of the presence of dangerous atmospheres capable of explosion.

Valid as “explosion endangered rooms” are all rooms or areas in which, according to local or operational conditions, atmospheres capable of explosion can collect. In the area of the pumping station they are, in general, to be assigned to Zone 1, so that the Explosive Ordinance is to be applied.

5.5.2 Protection against Accidental Contact

In order to protect personnel working in a pump-ing station from the results of an electrical acci-dent such as

• three-phase power accident,

• arcing accident or

• three-phase power accident with an intrinsi-cally non-hazardous current,

the following protection against accidental contact is necessary:

• protection with direct contact,

• protection against direct contact,

• partial protection against accidental contact,

• protection with indirect contact.

Protective measures with indirect contact are fundamentally required with all electrical plant or equipment (see Section 3.4.7).

Protective measures without earth conductor:

• double insulation,

• protective low voltage,

• fuse.

Protective measures with earth conductor:

• protective earth,

• earthing,

• earthed conductor system,

• fault-voltage [German = FU] protective circuit,

• residual current [German = FI] operated device.

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6 Measurement Engineering

The external prerequisites are practically identical with those of electrical engineering. The transmit-ters must, however, as a rule be install in situ. Therefore, with these devices there is the in-volvement of large expense for protection against moisture, cold, dust, corrosion through pollutants, mechanical damage as well as possibly for ex-plosion protection.

With the employment of electronic components conditions are to be created which allow the elec-trical equipping of various type and design to ex-ist alongside each other.

6.1 Level Measuring Systems

Level measuring systems are required for the de-termination of the respective water level on the inlet side and, in special cases, also on the outlet side and for the automatic control of the pumping plant.

The following measuring methods are employed:

• electrical pressure sensor,

• depth sounder.

6.2 Delivery Pressure Measuring Systems

Delivery pressure measuring systems are re-quired for the determination of the pressure head at the pump and the pressure in the pressure pipeline.

Electric pressure sensors, which are flanged di-rectly to the pressure pipeline, are suitable for suc-tion and pressure measurement. A further possi-bility lies in the employment of spring-tube manometers in overpressure secure design in accordance with DIN 16005 with a damping de-vice and reinforced dial train as well as pure wa-ter seal.

6.3 Flow Measuring Systems

Permanently installed flow measuring systems are to be employed when a continuous measur-

ing of the delivery flow is necessary for an accu-rate determination of the delivery efficiency of the pumping station. The manufacturer-specific in-stallation conditions (e.g. calming stretches) are to be observed.

Magnetic-inductive flow measurement (MID) The measuring method functions without contact, therefore is reliable and easily maintained. The measuring system in addition is the only one ca-pable of calibration.

Ultrasonic flow measurement Flow measurements with the aid of the Doppler effect are available. These systems are, however, significantly less accurate than the MID and not capable of calibration.

Flow monitoring In the area of wastewater flow monitoring is pos-sible using the signals of the MID or from the po-sition of the flap of the non-return valve.

6.4 Transmission of Measured Values

The electrical transmission of the measured val-ues takes place via electronic measuring trans-ducers which convert the measured value into a proportionally formed direct current of 0...20 mA or 4...20 mA and/or of 0...10 V.

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7 Wastewater Pressure Pipelines

7.1 Pressure Pipelines

Pressure pipelines serve for the transport of the wastewater from the pumping station to the des-tination. Pump and pressure pipeline are to be dealt with as hydraulic unit. The relationship is given, on one hand, by the pump characteristic curve (throttle curve) and the pipeline characteris-tic curve on the other (see Section 4.1.1).

The pressure pipeline must be able to accept the internal and external pressure on the sys-tem continuously and without damage. To this belong the pressure transient processes (e.g. water hammer), if no other safety measures are taken.

7.2 Pipeline Routes

Basically the pressure pipeline should represent the shortest possible connection between the pumping station and the discharge point.

The pipeline should as far as possible be laid straight constant with the run of the vertical posi-tion in order to keep the hydraulic losses low through small changes of direction. If the ground permits the pipeline should be designed with a steady incline in order to transport the air also conveyed to the end of the pipeline.

Digested matter in the wastewater can lead to the formation of H2S and thus to an endangering of the pipe inner walls. In particular the employment of cement-bonded materials (concrete pipes, ce-ment-fibre and cement-mortar lining) is problem-atic here (see Advisory Leaflet ATV-M 168).

Pipelines must be laid at depths safe from frost or be appropriately protected. The re-quired crown covering in Germany lies between 0.8 m and 1.5 m.

For static reasons (see ATV-A 127E) a greater minimum covering can be necessary in view of extreme traffic loading. Further security measures in the form of protective pipes or concrete cladding can be considered for use.

At significant high points pressure mains must equipped with venting and ventilation fittings.

Venting is necessary in order that the pipeline can be completely emptied and a return flow due to siphoning effect is prevented. Ventilation is re-quired for the controlled filling of the pipeline. With filled pipelines it is necessary to be able to remove entrained air or the gas cushions result-ing from the formation of gas. Gas cushions can lead to higher energy losses as a result of a nar-rowing of the flow cross-section.

If, in the case of repair with pumps at standstill, the pipeline does not empty itself due to geodetic gradient, emptying pipelines with connection to the wastewater and combined wastewater sewer system or for suction vehicles are to be planned for suitable low points.

Monitoring ports, for example for pipe inspection using cameras, venting and ventilation as well as emptying fittings, are, from a practical point, to be accommodated in shafts which should be equipped with a pump well at the bottom.

7.3 Dimensioning

The required pipe diameter is determined based on the delivery flow determined through the hy-draulic calculation (see Sections 2.6 and 2.7).

The pressure rating of the pipeline to be used is determined according to the static and dynamic effective internal pressure. Both the nominal width (DN) of the pipes and the pressure rating (PN) must correspond with DIN 2401 and DIN 2402 respectively.

The minimum and maximum speeds of the deliv-ery flow are to be observed. Furthermore the statements in Section 2.7 apply.

As the delivery flow conditioned by the wastewa-ter yield is subjected to considerable variations it can be practical, if required, to lay instead of one pressure pipeline a second (or more), which can, at the same time, serve as reserve pipeline. The pipe material is determined through the hydraulic, mechanical and chemical stresses which can have an effect both internal and external.

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Pipe wall thickness is dependent on the required pressure rating, the external loads and the type of material.

The hydrostatic pressure is determined from the geodetic height difference. The dynamic loading results from the pressure loss and the unsteady pressure changes (pressure surges) combined through the individual pipe losses.

The overall dynamic pressure loss is made up from the pressure loss through pipe friction and the individual losses due to mountings, fittings such as, for example, elbows cross-section cham-bers and branches as well as through losses at inlets and outlets. For details see The ATV Hand-book „Bau und Betrieb der Kanalisation“ [“Con-struction and operation of sewer systems]”.

7.4 Stresses

Pressure mains are subject to different stresses. They are caused by:

• transport and storage,

• installation,

• external forces,

• internal forces,

• temperature,

• abrasion,

• corrosion.

With the stresses through transport and storage, installation as well as through external forces a wastewater pressure main does not differ from drinking water pipelines. Important information can be found in EN 1610, DIN 4124 and DIN 19630.

With the internal forces attention is drawn particu-larly to stresses due to pressure surges. Pressure surges result following unsteady flow processes with the switching on and off of pumps, changes to the pump rpm or adjustment of gate valves and failure of pump drives. Physical bases and calcu-lation procedures for pressure surges are con-tained in DVGW Advisory Leaflet W 303.

With wastewater pressure mains the pressure (water hammer) problem is reinforced in that the

wastewater can form gases which combine in the high points into gas cushions. Pressure surges which occur in the presence of gas cushions are not predictable. Therefore the high points of wastewater pressure mains are to be inspected by rotation, even during operation, and if neces-sary vented.

With the exception of external temperature stresses against which a pipeline is to be pro-tected through minimum cover and/or insulation, with varying or even continuous high tempera-tures of the pumped medium, an additional stress of the pipeline can occur. The pipe material here is to be selected with particular care.

Abrasion occurs with pressure mains if increased mineral substances occur in the wastewater. Ef-fects are to be expected particularly in the area of changes of direction and throttle points. It can be necessary to counter these through increasing wall thickness, for example through the selection of a higher nominal pressure rating, in the critical area.

7.5 Pipe Materials

The medium to be transported in wastewater pressure mains, as opposed to drinking water, cannot be described precisely. Wastewater can contain many putrefactive substances so that fresh and older wastewater in their behaviour with regard to some materials is different. Therefore, the selection of material is to be made taking into account local conditions. If required, appropriate pre-treatment and pipe protective measures are to be planned.

As materials there are available:

• metallic materials,

• cement bonded materials,

• ceramic materials and

• plastic.

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7.6 Corrosion and Corrosion Protection

Significant wastewater-specific attacks with wastewater pressure mains are, above all to be expected on the inner wall. With this the composi-tion of the wastewater and its time-dependent possible change are of significance as well as the possible aggressiveness with partial (with gas formation in the crown areas) or complete filling of the pipeline.

Here it should be noted that wastewater pressure mains made from certain materials also have components such as fittings, seals and mount-ings made from other materials.

Pipe materials susceptible to corrosion must be protected through internal and external in-sulation. Thus steel pipes receive externally a polyethylene jacket or coating with polyurethane tar and, internally, an epoxy-resin or cement mor-tar lining. With pressure pipes made from ductile cast irons external spray galvanisation, bitumen paint or epoxy-resin coating and internally ce-ment mortar lining are used. Reinforced concrete and fibre-cement pipes in many cases receive an additional coating on a bitumen basis or of epoxy-resin (see DIN 4030), for example with the dan-ger of sulphide formation in the wastewater and with high sulphate content.

8 Commissioning The documentation of all plant components must be available for commissioning (see ATV-A 148E).

8.1 Pumping Station

Acceptance with functional testing and trial runs of the individual component parts must precede commissioning of the pumping sta-tion. Those responsible for planning and con-struction work, from the undertaking and, for rea-sons of warranty, also representatives of the manufacturer and/or supply companies are to take part in this.

Before commissioning the electrical plant all short circuit and overcurrent protective sys-tems are to be checked for correct setting and are to be secure. All switching and control procedures are to be carried out first without loading (cold testing). Only then can the facility be released for operation.

In general the pumps have been subjected to a test bench trial at the manufacturer’s works. This factory acceptance serves for the examination of whether the guaranteed delivery data are achieved. In contrast to that the test run in the pumping station is to provide information on its mechanical and hydraulic behaviour, freedom from vibration, heating of bearings and correct functioning of ancillary facilities (lubrication, cool-ing, ventilation, possibly regulation/control, dis-plays) under the local installed conditions.

In detail the following are recommended as con-trols:

• tension-free assembly,

• adjustment of end bearings and torque,

• direction of pump rotation,

• pump sequential switching,

• setting of rpm,

• venting of the pump casing,

• sealing,

• noises,

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• vibrations,

• temperatures,

• pressure surges,

• non-return valve clapper knock,

• measurement and control technology,

• remote monitoring and control,

• emergency energy supply.

The pumps should be tested under full load for at least two hours. If there is not enough water available for a test run it has proved advanta-geous if the existing water can be pumped via a diversion in a circle.

For the commissioning and later operation it is necessary that the operating personnel re-ceive precise knowledge of the plant engi-neering already with assembly and that they have already received instruction.

The pumping station can be taken into operation after the functional testing.

With this the requirements of the pressure main commissioning are to be observed.

In the run-in phase (ca. 4 weeks) it is recom-mended that the complete operating cycle has in-creased monitoring as, from experience, an in-creased number of faults occur on the plant components during this period.

8.2 Pressure Main

An internal pressure test in accordance with DIN 4279 is to be undertaken before commis-sioning. For commissioning the ventilation fit-tings to be operated manually are to be opened and controlled during the filling procedure.

With the connection of the pressure main to the existing network with different pressure poten-tials, it should be noted that pressure surges re-sult through too rapid opening or closing of the gate valves, which can lead to damage to the pressure main. Once a flow is no longer detect-able the gate valve can be opened very slowly. Closure is carried out analogously.

Immediately after commissioning of a new pres-sure main the first pressure pipe characteristic curve should be adopted. It serves for the estab-lishment of a practical and economic dimension-ing and for the evaluation of the delivery pumps in this pressure main.

9 Information on Standard Specifica-tions, Directives, Standards, Advisory Leaflets (Selection)

The documents listed below have been men-tioned in this Standard and must be taken into account in the respectively valid version inter alia with the design and construction of a wastewater pumping station. [Translators note: Where there is a known official translation the title is given in English only. Otherwise a courtesy translation is given in square brackets after the German title.]

9.1 General Terms and Conditions for Engineering Services, (VOB)

Part C, General Technical Regulations for Engineering Services:

DIN 18017 Part 1

Lüftung von Bädern und Spül-aborten ohne Außenfenster durch Schächte und Kanäle, ohne Mo-torkraft; Einzelschachtanlagen [Ventilation of baths and flush toi-lets without outer windows through shafts and channels, without motor drive, single shaft facilities]

DIN 18300 Erdarbeiten [Earthworks] DIN 18303 Verbauarbeiten [Timbering to

trenchwork] DIN 18304 Rammarbeiten [Pile driving] DIN 18305 Wasserhaltungsarbeiten

[Predraining works] DIN 18306 Entwässerungskanalarbeiten

[Sewage channel works] DIN 18331 Beton und Stahlbetonarbeiten

[Concrete and reinforced concrete works]

DIN 18335 Stahlbauarbeiten [Steel construction works]

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DIN 18336 Abdichtung gegen drückendes Wasser [Sealing against water under pressure]

DIN 18363 Anstricharbeiten [Painting works] DIN 18364 Korrosionsschutzarbeiten an Stahl-

und Aluminiumbauten [Works for protection of steel and aluminium structures]

DIN 18379 Lüftungstechnische Anlagen [Ventilation systems]

DIN 18381 Gas-, Wasser- und Abwasserinstal-lationsarbeiten innerhalb von Ge-bäuden [Gas, water and wastewater installation works inside of buildings]

DIN 18382 Elektrische Kabel- und Leitungsar-beiten in Gebäuden [Electrical cable and line works inside buil-dings]

9.2 Standard Specifications

DIN 4045 Wastewater engineering - Vocabu-lary

EN 752 Parts 1-7

Drain and sewer system outside buildings

EN 1671 Pressure sewerage systems out-side buildings

9.2.1 Building Standards

DIN 1045 Structural use of concrete; design and construction

DIN 1055 Parts 1- 6

Drain and sewer systems outside buildings

DIN 1084 Parts 1-3

Control (Quality control) of con-crete structures and reinforced concrete structures

DIN 1164 Parts 1,2,8,

Portland-, Eisenportland-, Hoch-ofen- und Trasszement; Begriffe, Bestandteile, Anforderungen, Liefer-ung [Portland, iron Portland, blast furnace slag and trass cement; Terms, requirements, delivery]

DIN 1986 Drainage systems on private ground

DIN 1988 Drinking water supply systems DIN 2000 Zentrale Trinkwasserversorgung;

Leitsätze für Anforderungen an Trinkwasser, Planung, Bau und Betrieb der Anlagen [Central drink-ing water supply; Guidelines regarding requirements for drinking water, planning, construction and operation of plants]

DIN 2001 Private and individual drinking water supply; governing principles

DIN 4030 Assessment of water, soil and gases for their aggressiveness to concrete

DIN 4124 Excavations and trenches – slopes, breadths of working spaces, plank-ing and strutting

DIN 18196 Earthworks – Soil classification for civil engineering purposes

9.2.2 Pipes and Fittings

DIN 1333 Zahlenangaben [Presentation of Numerical data]

DIN 2440 Steel tubes; medium-weight suitable for screwing

DIN 2448 Seamless steel pipes and tubes DIN 2458 Welded steel tubes DIN 2605 Parts 1-2

Steel butt-welding pipe fittings

DIN 2614 Cement mortar linings for cast iron pipes, steel pipes and fittings

DIN 3352 Parts 1-8

Gate Valves [available in English Parts 1-4 only]

DIN 4032 Concrete pipes and fittings DIN 4035 Stahlbetonrohre und zugehörige

Formstücke aus Stahlbeton [Reinforced concrete pipes and associated fittings made from reinforced concrete]

DIN 4279 Parts 1-10

Testing of pressure pipelines for water by internal pressure [Parts 1,7,8 not available in English]

DIN 8061 Unplasticized polyvinyl chloride pipes (PVC-U) – General quality requirements and testing

DIN 8062 Unplasticized polyvinyl chloride pipes (PVC-U, PVC-HI); dimen-sions

DIN 8063 Parts 1-12

Pipe joint assemblies and fittings for unplasticized polyvinyl chlo-ride (U-PVC) pressure pipelines

DIN 8074 Polyethylene (PE) pipes – Dimensions

DIN 8075 Polyethylene (PE) pipes – Dimensions – General quality requirements, testing

DIN 8077 Polypropylene (PP) pipes – Dimensions

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DIN 8078 Polypropylene (PP) pipes – Ge-neral requirements and testing

DIN 14 365 Parts 1-2

Multi-purpose branch pipes for nominal pressure 16; dimen-sions materials, construction, marking

DIN 19532 Rohrleitungen aus weichmacher-freiem Polyvinylchlorid (PVC hart, PVC-U) für die Trinkwasserver-sorgung [Pipelines made from unplasticized polyvinyl chloride [PVC-H, PVC-U for drinking wa-ter supply]

DIN 19533 Pipelines of high density PE and low density PE for drinking water supply; pipes, pipe connections and fittings for pipelines

DIN 19534 Rohre und Formstücke aus weichmacherfreiem Polyvinyl-chlorid (PVC-U) mit Steckmuffe, für Abwasserkanäle und –leitungen [Pipelines and fittings made from unplasticized polyvi-nyl chloride (PVC-U) with sleeves, for drains and sewers]

DIN 19537 High density polyethylene (HDPE) pipes and fittings for drains and sewers; technical delivery con-ditions

DIN 19630 Richtlinien für den Bau von Rohrleitungen [Directives for the construction of pipelines]

DIN 19800 Part 1

Asbestos-cement pipes and fittings for pressure pipelines; pipes, dimensions

DIN 19850 Parts 1-2

Fibre-cement pipes and fittings for drains and sewers; Part 1: dimensions of pipes, branches and bends; Part 2: Dimensions of joint assemblies

DIN 30675 Parts 1-2

External corrosion protection of buried pipes; corrosion protec-tion systems for steel and ductile iron pipes

EN 295 Vitrified clay pipes and fittings and pipe joints for drains and sewers

EN 545 Ductile iron pipes, fittings, accessories and their joints for water pipelines – Requirements and test methods

EN 639 Common requirements for con-crete pres-sure pipes including joints and fittings

EN 640 Common reinforced concrete pressure pipes and distributed reinforcement concrete pressure pipes (non-cylinder type), includ-ing joints and fittings

EN 642 Prestressed concrete pressure pipes, cylinder and non-cylinder, including joints, fittings and spe-cific requirement for prestressing steel for pipes

EN 764 Pressure equipment; Terminol-ogy and symbols – Pressure, temperature and volume

EN 1032 Testing of mobile machinery in order to determine the whole body vibration emission value - General

EN 1299 Mechanical vibration and shock – Vibration isolation of machines – Information for the application of source isolation

EN 1610 Construction and testing of drains and sewers

9.2.3 Mechanical Engineering

DIN 1184 Part 4

Pumping stations; archimedean screw pumps; directives for plan-ning

DIN 1944 Acceptance tests on rotodynamic pumps (VDI rules for rotodynamic pumps)

DIN 24260 Part 1

Kreiselpumpen und Kreiselpum-penanlagen; Begriffe, Formelzei-chen, Einheiten [Rotodynamic pumps and rotodynamic pump sys-tems; Terms, symbols, units]

DIN 24293 Kreiselpumpen – Technische Un-terlagen – Begriffe, Lieferumfang, Ausführung [Rotodynamic pumps – Technical documents – Terms, delievery range, layout]

DIN 45635 Part 1

Measurement of noise emitted by machinery

9.2.4 Measurement Technology

DIN 1319 Fundamentals of metrology DIN 16005 Überdruckmessgeräte mit elasti-

schem Messglied für die allg. An-wendung [Overpressure meas-urement equipment with elastic measuring unit for general appli-cations]

EN 837-1 Pressure gauges - Part 1: Bourdon tube pressure gauges - dimensions, metrology, requirements and testing

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EN 837-3 Pressure gauges – Part 3: Dia-phragm and capsule pressure gauges; dimensions, metrology, requirements and testing

VDE 0410 VDE-Bestimmung für elektrische Messgeräte; Sicherheitsbestim-mung für anzeigende und schrei-bende Messgeräte und Zubehör [VDE regulations for electrical me-tering equipment; safety regulations for indicating and recording measuring equipment and acces-sories]

9.2.5 Electrical Engineering

VDE 0100 Bestimmungen für das Errichten von Starkstromanlagen mit Nenn-spannungen bis 1000 V [Regula-tions for the erection of power in-stallations with rated voltages up to 1000 V

VDE 0105 Betrieb von Starkstromanlagen [Operation of power installations]

as well as i.a.: EN 50110 Part 1

Operation of power installations

VDE 0160 Ausrüstung von Starkstromanla-gen mit elektronischen Betriebs-mitteln [Electronic equipment for use in power installations]

as well as i.a.: EN 61800 Part 3

Adjustable speed electrical power drive systems

VDE 0165 Errichten elektrischer Anlagen in explosionsgefährdeten Bereichen [Installation of electrical plant in explosion-endangered areas]

as well as i.a.: EN 60079 Part 10

Elektrische Betriebsmittel für gas-explosionsgefährdete Bereiche [Electrical apparatus for explosive gas atmospheres]

VDE 0170/0171

Elektrische Betriebsmittel für explosionsgefährdete Bereiche [Electrical apparatus for potential-ly explosive atmospheres]

As well as i.a.: DIN EN 50014

Elektrische Betriebsmittel für exp-losionsgefährdete Bereiche; All-gemeine Bestimmungen [Electrical appraratus for explosive gas at-mospheres; General conditions]

DIN EN 50015 Elektrische Betriebsmittel für ex-plosionsgefährdete Bereiche; Öl-kapselung [Electrical apparatus for potentially explosive atmospheres; Oilimmersion]

DIN EN 50016 Elektrische Betriebsmittel für exp-losionsgefährdete Bereiche; Über-druckkapselung [apparaturs for explosive gas atmospheres; Pres-surized enclosures]

DIN EN 50017 Elektrische Betriebsmittel für exp-losionsgefährdete Bereiche; Sand-kapselung [Electrical apparatus for potentially explosive atmospheres]

DIN EN 50018 Elektrische Betriebsmittel für explosionsgefährdete Bereiche; Druckfeste Kapselung [Electrical apparatus for explosive gas at-mospheres; Flameproof enclosures]

DIN EN 50019 Elektrische Betriebsmittel für explosionsgefährdete Bereiche; erhöhte Sicherheit [Electrical appa-ratus for explosive gas atmosphereareas; Increased safety]

DIN EN 50020 Elektrische Betriebsmittel für explosionsgefährdete Bereiche; Eigensicherheit [Electrical appara-tus for potentially explosive at-mospheres; Intriusic safety]

DIN EN 50021 Elektrische Betriebsmittel für ex-plosionsgefährdete Bereiche; Betriebsmittel der Zündschutzart [Electrical apparatures for explosi-ve gas atmosphere; Apparatus with “e”-type protection]

DIN EN 50039 Elektrische Betriebsmittel für explosionsgefährdete Bereiche; Eigensichere elektrische Systeme [Electrical apparatus for explosive gas atmosphere; Intrinsically safe systems]

DIN IEC 61024-1-2; VDE 0185 Part 102

Blitzschutz baulicher Anlagen [Protection against lightning of structural works]

VDE 0266 Halogenfreie Kabel mit ver-bessertem Verhalten im Brandfall [Halogen-free cables with im-proved characteristics in the case of fire]

VDE 0660 Niederspannungs-Schaltgeräte [Low voltage switch gear]

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as well as i.a.: EN 60439 Parts 1-5

Low voltage switchgear and con-trol gear - combinations

EN 60947 Parts 1-7

Low voltage switchgear and con-trol gear

VDE 0670 Wechselstromschaltgeräte für Spannungen über 1 kV [AC equip-ment for voltages above 1 kV]

VDE 0800 Fernmeldetechnik [Telecommuni-cations engineering]

9.3 Directives, Standards and Advisory Leaflets

9.3.1 of the ATV ATV-A 105E Selection of the Drainage System ATV-A 110E Hydraulic Dimensioning and Per-

formance Verification of Sewers and Drains

ATV-A 116E Special Sewer Systems - Vacuum Drainage Service – Pressure Drainage Service

ATV-A 118E Hydraulic Dimensioning and Verifi-cation of Drainage Systems

ATV-A 127E Static Calculation of Drains and Sewers

ATV-A 128E Standards for the Dimensioning and Design of Stormwater Struc-tures in Combined Sewers

ATV-A 142E Sewers and Drains in Water Catchment Areas

ATV-A 148E Service and Operating Instructions for Personnel of Wastewater Pump-ing Stations, Wastewater Pressure Pipelines and Stormwater Tanks

ATV-A 166 Bauwerke der zentralen Regenwas-serbehandlung und -rückhaltung - Konstruktive Gestaltung und Aus-rüstung [Structures for Centralised Treatment, Retention, Design and Equipping of Stormwater Facilities]

ATV-A 200E Principles for the Disposal of Wastewater in Rurally Structured Areas

ATV-A 241 Bauwerke der Kanalisation [Structures in Sewer Systems]

ATV-M 168E Corrosion of Wastewater Systems – Wastewater Discharge –

ATV-M 176 Hinweise und Beispiele zur konstruk-tiven Gestaltung und Ausrüstung von Bauwerke der zentralen Regenwas-serbehandlung und –rückhaltung - [Notes and Examples for the Design and Equipping of Structures for Centralised Wastewater Treatment and Retention]

ATV-M 263E Recommendations for Corrosion Protection of Steel Components in Wastewater Treatment Plants Us-ing Coating and Cladding

9.3.2 of the DVGW

DVGW W 302 Hydraulische Berechnung von Rohrleitungen und Rohrnetzen [Hydraulic calculation of pipelines and pipe networks]

DVGW W 303 Dynamische Druckänderungen in Wasserversorgungsanlagen [Dy-namic pressure changes in water supply facilities]

DVGW W 342 Werkseitig hergestellte Zement-mörtelauskleidungen für Guss- und Stahlrohre [Factory produced ce-ment mortar cladding for cast and steel pipes]

DVGW W 345 Schutz des Trinkwassers in Was-serrohrnetzen vor Verunreinigung [Protection of drinking water from pollution]

9.3.3 of the VDI

VDI 2058 Beurteilung von Arbeitslärm in der Nachbarschaft [Assessment of work noise in the neighbourhood]

VDI 3743 Bl. 1 Sheet 1]

Emissionskennwerte technischer Schallquellen – Pumpen – Kreisel-pumpen [Characteristic values of emissions from technical noise sources – pumps - rotodynamic pumps]

VDI 3803 Raumlufttechnische Anlagen Bau-liche und technische Anforde-rungen [Ventilation and air condi-tioning facilities; structural and technical requirements]

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9.3.4 of the VDMA [German Associa-tion of Mechanical Engineering Establishments]

VDMA 24 261 Part 1

Pumpen – Benennung nach Wir-kungsweise und konstruktiven Merkmalen – Kreiselpumpen [Pumps – designation according to functional and design characteris-tics – rotodynamic pumps]

VDMA 24 297 Kreiselpumpen, Technische Anfor-derungen, Richtlinien [Rotodyna-mic pumps, Technical require-ments, directives]

10 Annexes

Annex 1: Example of a pumping station with rotodynamic pumps in horizontal, dry-well installation

Annex 2: Basic circuit diagram

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assembly opening for emergencyconnection inlet air machinery room

Control box

Annex 1 (Fig. 2) Example of a pumping station with rotodynamic pumps in horizontal dry-well installation

Fig. 1 Fig. 3 Fig. 5 Fig.2 Fig. 4 Fig. 6

Plan I – I Superstructure

Control box

20 20 1.90 3.20

5.70 20

20

1.50

20

1.

30

20

1.70

20

DN 300

Entrance Inlet chamber

Inlet air Inlet chamber

Building wastewater drain DN 100

Pressure main DN 125

WC

Railing removable

Exhaust air machinery room

Equipment andventilator

room

Exhaust air inlet chamber

Machinery room drainage

Booster system with water reservoir i.a.w. DN 1986 for washdown facility inlet chamber

C

B

A A

C

B

Inflow sewer

Annex 1 (Fig. 1) Example of a pumping station with rotodynamic pumps in horizontal dry-well installation

Section A – A

Fig. 1 Fig. 3 Fig. 5 Fig. 2 Fig. 4 Fig. 6

Alternative detail See also alternative detail

Lose detachable fitting(s) (=> building settlement

Suction line DN 100 with cutoff sit

Inlet sewer DN 300

Inlet gate valve

IIBIE

Steel pipe DN 300 with sleeve and wall flange

Suction line DN 100 Wall flange

Lose flange with welding neck Gate valve Detachable fitting

Flange adapter with cleaning port

DN 100

IIBIE

Booster system

Carrier for crane trolley

Aeration and ventilation of the ventilator room via door grill

Exhasut air Inlet chamber

IIBIE

10

60

5.61

2.

50

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Annex 1 (Fig. 3) Example of a pumping station with rotodynamic pumps in horizontal dry-well installation

Fig. 1 Fig. 3 Fig. 5 Fig. 2 Fig. 4 Fig. 6

Section B – B

Machinery room

Inlet air Non-insulated roof

Exhaust air inlet chamber

Facade including thermal insulation according to local conditions

Sealing down to 1 m belowsurface of ground Machinery drainage to inlet shaft

Pump ventilation pipeline

Shut-off device

Hose connection Hose pipe Cellar drainage pump

Pipe – wall fairlead

Pressure main DN 125

Gate valve for ground installation with surface box

Emergency connection

Ventilator

Door

IIBIE IIBIE

DN

50

DN

50

R ½

”

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Annex 1 (Fig. 4) Example of a pumping station with rotodynamic pumps in horizontal dry-well installation

Fig. 1 Fig. 3 Fig. 5Fig. 2 Fig. 4 Fig. 6

40

DN 300

A

Plan II – II Underground part

A

B

B

C

C

40

4.50 5. 30

908010Inlet sewer

Inlet chamber

Pump sump Machinery room drainage

Machinery room

Pressure main DN 125 Inlet air machinery room

404040 3.00 1.50

5.70

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Annex 1 (Fig. 5)

Example of a pumping station with rotodynamic pumps in horizontal dry-well installation

Section C – C

Exhaust air inlet chamber

Exhaust air

Inlet air

WC

Inlet air inlet chamber Ventilator with explosion-protect ed motor

Pump ventilation pipelineDN 50

Suction line DN 100

IIBIE

IIBIE

Fig. 1 Fig. 3 Fig. 5 Fig. 2 Fig. 4 Fig. 6

Annex 1 (Fig. 5) Example of a pumping station with rotodynamic pumps in horizontal dry-well installation

General Plan

Fig. 1 Fig. 3 Fig. 5 Fig. 2 Fig. 4 Fig. 6

Drinking water pipeline Electricity cable

Communications cable Inlet sh aft

Enclosure

Pumping station

DN 125

DN 300

DN

125

Pr

essu

re m

ain

Inle

t sew

er D

N 3

00

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Energy supply from ESC Change over Mains Standby

Compen- sation

SPS/ MSK

Main drive

Ancillary drives

24V-

SPS/MSK

StarterCB

KWh

or

KWh

Pow

er s

uppl

y 1

If re

quire

d P

ower

su p

ply

2

Con

sum

ptio

n m

easu

rem

ent

(5.2

.3)

From

sta

ndby

pla

nt

Pla

nt c

ontro

l

Biln

d cu

rrent

co

mpe

nsat

ion

Mai

n dr

ive

Air

com

pres

sor

Shu

t-off

devi

se

Aer

atio

n In

let c

ham

ber

Aer

atio

n M

achi

ner y

room

s. Section 5.2.1 5.2.2 5.2.3

Remarke Agree with ESC and observe their connection conditions

5.4 5.3 5.3.1 5.3.2 Dependent on engine outputwhich run-up is to be chosento be decussed with the EDC

Ancillary plant

Basic circuit diagram

Cel

lar d

rain

ings

Boos

ter

proc

ess

wat

er

Gre

ese

or

oil p

ump

Lifti

ng

devi

ce

Hea

ting

Ligh

ting

230

V ...

.

Low

vol

tage

so

cket

s

DC

so

cket

s

War

m w

ater

he

atin

g

Mea

sure

men

t and

co

ntro

l fac

ilitie

s

Batte

ry

Con

trol

Emer

genc

y lif

ting

SPS

Sign

al s

yste

m,

Rem

ote

dat

trans

emis

sion

Res

erve

out

lets

400

V

Res

erve

out

lets

230

V

Annex 2 (Fig. 2) Basic circuit diagram

Annex 2 (Fig. 1) Basic circuit diagram