refurbishing wastewater treatment plant for rs hq - … wastewater treatment plant for rs hq cur...

REF. NO.: #RS

A4

010

NOME FILE: HB-KBL-1780-035-010-GEN-REP-A4-General_Report-R02

serial 2016/1HQ27020

CUR 1780

PHASE NAME Drawn

Checked

Approved

L. MONTESI

F. FREDDI

L. FAINELLI

STAMPS

REV. NO. REV. DESCRIPTION DATE

35% DESIGN

SECTION OF REFERENCE

CATEGORY

REP

GEN

DOC TITLE

General Report SIZE CLASSIFICATION

OFFICIAL USE ONLY

00 First Issue 04 / 10 / 2016

CUR 1780 - REFURBISHING WASTEWATER TREATMENT PLANT FOR RS HQ RS HQ, KABUL, AFGHANISTAN

01 Design review 10 / 11 / 2016

02 Design review 18 / 11 / 2016

03 Design review 25 / 11 / 2016

HB-KBL-1780-CUR 1780 – REFURBISHING WASTEWATER TREATMENT PLANT FOR RS HQ CUR 1780 serial 2016/1HQ27020

OFFICIAL USE ONLY HB-KBL-1780-035-010-GEN-REP-A4-General_Report-R03

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PAGE INTENTIONALLY LEFT BLANK

DISTRUCTION NOTE:

All documents and drawings contained in this design are intended for official use only. Destroy documents

and drawings by any method that will prevent Disclosure of Contents or reconstruction of the Document to

not authorized persons.



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REFURBISHING WASTEWATER TREATMENT PLANT

RS HQ, KABUL, AFGHANISTAN

GENERAL REPORT

INDEX

1. EXECUTIVE SUMMARY ........................................................................................................................... 5

2. BACKGROUND ........................................................................................................................................ 6

3. PROJECT SCOPE .................................................................................................................................... 6

4. STATUS OF OPERATION OF THE INFRASTRUCTURE ....................................................................... 7

4.1. Current situation ...................................................................................................................................... 7

4.1.1. Pre-treatment system ...................................................................................................................... 7

4.1.2. Biological system ............................................................................................................................ 7

4.2. Site Visit .................................................................................................................................................... 7

4.3. Analysis and considerations on WWTP ................................................................................................ 8

5. Requirements and specific environmental conditions ........................................................................ 8

6. Waste water treatment plant proposed solution ................................................................................ 10

6.1. Pre-treatment plant proposed solution ............................................................................................... 10

6.1.1. Sewage incoming and lifting sections (Tank#1)......................................................................... 11

6.1.2. Fine screening section .................................................................................................................. 11

6.1.3. Grit, degreasing and oil separation section ................................................................................ 12

6.1.4. Accumulation, homogenizing and feeding section.................................................................... 13

6.2. Calibration of the current biological system ...................................................................................... 13

6.3. Up-grade of the existing biological system (to 3.000 pe) .................................................................. 14

6.4. Maintenance of the current disinfection system ................................................................................ 15

6.5. Up-grade of the sludge treatment system ........................................................................................... 15

7. CONSTRUCTION DETAILS ................................................................................................................... 18

7.1. Area -preliminary operations ................................................................................................................ 18

7.2. WWTP discharge ................................................................................................................................... 18

7.3. Water line treatment .............................................................................................................................. 18

7.3.1. Pre-treatment section .................................................................................................................... 18

7.3.2. Biological reactor system ............................................................................................................. 19

7.3.3. Disinfection system ....................................................................................................................... 19

8. ELECTRICAL PROVISIONS................................................................................................................... 21

8.1.1. Pre-treatment system .................................................................................................................... 21



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8.1.2. WWTP upgrade .............................................................................................................................. 21

9. CIVIL WORKS ......................................................................................................................................... 21

9.1.1. Pre-treatment system .................................................................................................................... 21

9.1.2. WWTP upgrade .............................................................................................................................. 21

10. TIME SCHEDULE ................................................................................................................................... 23

ANNEX 1 - Operation & Maintenance, Monitoring Sheet



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1. EXECUTIVE SUMMARY

NSPA has been tasked for the refurbishing of the Wastewater Treatment Plant (WWTP) at RS HQ, Kabul,

Afghanistan. NSPA has then commissioned IRD Engineering to provide a 35% design solution to serve as

basis for a design & build contract.

The 35% Design has identified in more detail all the technical solutions on the following systems:

- interventions on the existing pre-treatment system;

- interventions on the existing biological system;

- realization of a new third line similar to the existing ones;

- implementation of the new sludge line.

Technical solutions have been developed in compliance with the applicable standards and regulations in

force, based on an accurate technical assessment also including related costs and timelines.

The design solution is further explained in the following paragraphs. The timing estimated for the

implementation of the works is about 7 months.

NOTE: DESIGN REVISION DATED NOVEMBER 18TH

, 2016 Upon request of NSPA notified on 16/11/2016, the U.V. system previously proposed at the end of the

treatment has been deleted, based on the assumption stated by the end user that current chlorination

system works properly. However, in order to ensure that the effluent discharged into the Kabul river is

compliant with international standards (free chlorines content <1 mg/L) and local laws, a free chlorine

analyzer measurement system shall be installed, which analyzes the samples taken in the final sampling

manhole.



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2. BACKGROUND

The existing WWTP was last upgraded starting in 2009 and completed in 2012. The upgrade was to service

a camp population of 2000. Currently, camp population is reported to be approximately 2500 people living

and working there. Due to the increased population, the existing WWTP is currently not yet able to treat the

sewage coming from network and the prediction of a further personnel growth (3,000) makes the WWTP

upgrade necessary and urgent.

This causes an environmental issue. Without properly sized bio-reactors and filter components, the RS HQ

WWTP is operating at minimal environmental efficiency. The limited solid waste removal (25-30%) directly

affects the quality of the effluent discharge into the Kabul River and the ability to abide to WWTP effluent

permits. Additionally, the existing limited size of the overflow tank exposes HQ RS to substantial HAZMAT

accidents, environmental discharges and related clean-up costs. If, for any reason, sewage trucks cannot

access Camp RS, will result in human waste contamination outside of the WWTP, sewage back-ups in

accommodation buildings and non-compliance discharges into Kabul River.

Currently the plant is designed to support 2,000 personnel; this limit has already been exceeded. Such limit

has already been exceeded being camp population at present 2,500 circa not including transients, and the

number is expected to reach 3,000 in the next future. The WWTP must be sized to accommodate the

expected increase over time and the final target is to design an upgrade of the facility up to 3,000 PE.

Furthermore, the current system equipment designed to reduce the volume of sludge was never installed

during the last upgrade. This leads to an increased amount of sludge water to be disposed of and fills up the

overflow tank quickly. For this three times a day it is necessary to bring in sewage tanker trucks to remove

sewage in order to prevent backup and overflow of raw sewage into Camp RS. Any interruption to this

sewage truck service could lead to an environmental and health situation endangering RS personnel and

jeopardizing the mission as a large part of the camp would become uninhabitable and unable to support

operations.

Finally the current system is reliant on sewage/tanker trucks to haul raw sewage away from the camp, which

creates a critical Force Protection vulnerability. If these trucks are not able to access, the base there will be a

sewage overflow.

3. PROJECT SCOPE

The following general requirements are a summary of the SoW.

The SOW calls for a feasibility study of the existing WWTP System and a proposal on how to upgrade it to

meet required standards. There should be at least two optional proposed concept solutions in the feasibility

study.

The WWTP shall meet European standards and be calculated in order to serve as a peak a camp population

of 3000 people. This shall enable the new WWTP to both meet any future increase of population and to

create a buffer against unexpected problems in the sewage treatment system as well as to allow for

maintenance during operations.

The following specific requirements are considered as guidelines of the design:

- the current WWTP must remain functional as possible (based on the chosen technical solution)

throughout up-grade construction;

- the chosen technical solution must have an efficient and safe operation, easy O&M phases, fast

realization.

The current WWTP was designed in 2008 for civil inflow, but due to the specific context it treats municipal,

industrial and hospital waste waters. This inflow mix has been used as input for the design.



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4. STATUS OF OPERATION OF THE INFRASTRUCTURE

4.1. Current situation

4.1.1. Pre-treatment system

The flow phases of raw sewage pre-treatment system are described as follows:

- Raw sewage, from Tank#1, is lifted at average flow rate and conveyed to the mechanical fine screen (2

parallel lines);

- The waste water passes by gravity through the Oil and Grit removal system;

- Effluent discharges by gravity from Oil and Grit removal system to Tank #2.

Next to the Oil and Grit removal system there is a Grit Classifier equipment.

4.1.2. Biological system

Current biological system is composed by two similar lines of modules for EFLOSAF technology.

EFLOSAF is a biological treatment process based on submerged aerated biofilter (a type of attached growth

biological oxidation process). The active biological process is performed using an extremely efficient

Submerged Aerated Filter.

The flow of raw sewage to the treated final effluent is composed as follows:

- Raw sewage, from Tank#2, is lifted at average flow rate and delivered to the bio-zone (aerated bio-filter),

through autoscreen located on top of biozone module (2 parallel lines);

- Biologically treated liquor discharges from the bio-zone;

- Biologically treated liquor passes by gravity through the Final Settlement Tank;

- Effluent discharges from settlement tank to a chlorination;

- Final effluent is filtered via pressure sand filters prior to discharge or reuse.

The accumulated sludge (settled) & grease stored in the sludge holding tank is dewatered in order for

volume reduction. A complete system contains:

- Sludge transfer pump;

- Flocculation;

- Reactor tank with mixer;

- Polymer dosing set;

- Sludge dewatering unit (screw type);

- Interconnects pipes, valves, instruments and control panel.

The dewatering system function manually based on the accumulation rate of sludge and the stored quantity.

4.2. Site Visit

The site survey has been performed by the technical expert team on July 2016. All inspections required for

assessment have been carried out on electrical and electromechanical equipment, piping and each element

related to the above mentioned systems. As consequence of the survey other design and monitoring

documents have been shared.

The inspections on site included the following main items:

- system element/equipment inspection aimed to detect the status of operation and maintenance of the

elements including their state of conservation;

- gathering of data sheets and technical specifications related to each system, element and/or equipment,

including operational test document and any other certification of compliance;

- gathering of instructions, requirements and recommendations coming from end users;

- more details about information gathered during site survey are shown on drawings from #100 to #110.



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4.3. Analysis and considerations on WWTP

As reported in the documents of project and described in drawing #110, the critical issues of the existing

WWTP system are:

- The pre-treatment system doesn’t work. It does not adequately filter out fine tissue papers/solids and it

found further downstream in the treatment process;

- Biological system should be removing more of the polluting than at present. This leads to an increase in

sludge production, higher BOD and COD. Current discharge from Camp RS does not meet standards

set by GIRoA (Afghan law). Should be to European standards. Without properly sized bio-reactors and

filter components, the RS HQ WWTP is operating at minimal environmental efficiency. The limited solid

waste removal (25-30%) directly affects the quality of the effluent discharge into the Kabul River and the

ability to abide to WWTP effluent permits;

- In the current system is difficult for the operators to determine the exact amounts of helping chemicals;

- Current system equipment designed to reduce the volume of sludge never installed during the last

upgrade. This leads to an increased amount of sludge water to be disposed of and fills up the overflow

tank quickly. For this three (3) times a day it is necessary to bring in sewage tanker trucks to remove




operations;

- Current system is reliant on sewage/tanker trucks to haul raw sewage away from the camp, which

creates a critical Force Protection vulnerability. If these trucks are not able to access, the base there will

be a sewage overflow.

5. Requirements and specific environmental conditions

The design data are summarized in the following tables. These values are standard (from literature) for the

inlet raw waste water, because the specific laboratory tests are not available.

Type of sewer -- Sewer

Inflow rate % 100

Personnel PE 3.000

Organic load per PE gCODPE-1d

-1 120

Organic load per PE cBOD5PE-1d

-1 60

Suspended solid load gSSPE-1d

-1 90

Nitrogenous load gTNPE-1d

-1 12

Due to the impossibility to detect the distribution of daily flow, maximum flow rates (sewer), minimum flow

and design flow, they are determined on the basis of empirical coefficients to be applied to the average flow

rate, valid for urban areas with a size similar to 3000 population equivalents:

Average flow (Q24) PEwater supplied

Maximum flow Q243.0

Minimum flow Q240.2

The hydraulic and pollutant load is summarized in the following table. Due to the impossibility to detect the

exactly production of waste water for PE, these data are obtained considering the actual population of the



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HQ (2.500) and the contemporary daily flow data obtained from the inspections on the site and from the

official documents of projects (460 mc/d average to daily discharge), and the result is 0.184 m3d

-1 for PE.

Since the average flow used to design of the current 2.000 PE WWTP was 450 mc/d (in the amount of 0.225

m3d

-1 for PE), we choose this last value as conservativeness factor.

Supplied water per PE

(from estimate)

m3d

-1 0.184

Supplied water per PE

(from design of existing WWTP)

m3d

-1 0.225

Hydraulic flow m3d

-1 675,00

Average flow m3h

-1 28,13

Maximum sewerage flow m3h

-1 84,39

Minimum sewerage flow m3h

-1 5,63

Design flow m3h

-1 28,13

COD kgd-1

360

BOD5 kgd-1

180

SST kgd-1

270

Nitrogen kgd-1

36

COD mgdm-3

533

BOD5 mgdm-3

267

SST mgdm-3

400

Nitrogen mgdm-3

53

Concerning the effluent quality we refer to the European Council Directive 1991/271/CE:

Parameter Units Maximum Value Reduction (%)

Suspended solid mgl-1

35 90

COD mgl-1

125 75

BOD5 (without nitrif.) mgl-1

25 80

From the documents we can deduce that the effluent quality expect is:

Parameter Units Maximum Value

Suspended solid mgl-1

25

BOD5 mgl-1

20

pH - 6-9

Residual free chlorine mgl-1

1

Fecal coliforms MPN/100 ml < 400

The capacity of the plant (3,000 PE) does not require the fulfillment of the emission limits for nitrogen and

phosphorus if discharged into sensitive areas (threshold required when temperatures are above 12°C).

The current WWTP must remain functional as possible (based on the chosen technical solution) throughout

up-grade construction;



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6. Waste water treatment plant proposed solution

As reported in the documents of project, as described in drawing #110, the issues of the existing WWTP

system are:

- The pre-treatment system doesn’t work. It does not adequately filter out fine tissue papers/solids and it

found further downstream in the treatment process;

- Biological system should be removing more of the polluting than at present. This leads to an increase in

sludge production, higher BOD and COD. Current discharge from Camp RS does not meet standards

set by GIRoA (Afghan law). Should be to European standards. Without properly sized bio-reactors and

filter components, the RS HQ WWTP is operating at minimal environmental efficiency. The limited solid

waste removal (25-30%) directly affects the quality of the effluent discharge into the Kabul River and the

ability to abide to WWTP effluent permits;

- In the current system is difficult for the operators to determine the exact amounts of helping chemicals;

- Current system equipment designed to reduce the volume of sludge never installed during the last

upgrade. This leads to an increased amount of sludge water to be disposed of and fills up the overflow

tank quickly. For this three (3) times a day it is necessary to bring in sewage tanker trucks to remove




operations;

- Current system is reliant on sewage/tanker trucks to haul raw sewage away from the camp, which

creates a critical Force Protection vulnerability. If these trucks are not able to access, the base there will

be a sewage overflow.

For this reason the up-grade of the current WWTP should be consist of four steps:

- Reactivate the pre-treatment system, with maintenance work and implementation of the new

equipments;

- Calibrate the current biological system, with maintenance work and service;

- Up-grade of the biological system with the third line modules implementation (to 3.000 PE);

- Up-grade of the sludge treatment system, with new high performing equipment.

An appropriate indicator will be installed in the sampling manhole for the control of free residual chlorine in

the effluent, before it will be discharged into the Kabul river.

6.1. Pre-treatment plant proposed solution

From the analysis of the current situation, by project documents and inspection reports, we can detail some

issues for the pre-treatment system:

- Lack of functionality (frequent failures) of pumping station of the pre-treatment system;

- Mechanical fine screen undersized;

- Difficult cleaning and maintenance of the manual fine screen (possible section by-pass);

- Screening campactor not installed;

- Wrong hydraulic connection from Tank #1 to the grit classifier;

- Lack of cleaning in the buried tanks and septic conditions on the held sludge.

The solution, that we will propose to recover pre-treatment system efficiency, consists of these actions:

- Installation of a new pumping system (anti-clogging pump);

- Installation of a roto-screen on the current screening system (3 mm span);



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- Installation of a screening compactor system (to reduce the volume of separated waste and unpleasant

smells);

- Correction of the grit separator hydraulic connections;

- Buried tanks cleaning and installation of a mixing system and an air supply system, to prevent

sedimentation and septic conditions.

6.1.1. Sewage incoming and lifting sections (Tank#1)

This section already exists and provides similar function to the current plant.

The electro-mechanical part of the incoming section needs to be upgraded with new kind of pumps (anti-

clogging pump).

Flygt N-Impeller - adaptive

The up-grade is carried on by 2 submersible pumps, anti-clogging type (with adaptive impeller), out of which

one operating and the other one in stand-by or to be used in emergencies (for excess inflow). Each pump

will have a capacity of about 35 m3h

-1.

The pumps will be installed with a coupling joint (which makes easier the extraction of the pumps for

maintenance). The pipes of each pump will be equipped with one way valve, suitable for sewage.

6.1.2. Fine screening section

The waste waters are conveyed from the first tank (Tank#1) to a new section of fine screening (Rotoscreen)

to remove a part of suspended solids based on the grid size. A fine grid 3 mm is recommended because the

primary sedimentation is not provided. Normally more than 30% removal of suspended solids is thus

achieved.

The Rotoscreen will be installed higher than the following section in order to allow the discharge by gravity.

The Rotoscreen will be also installed with an automatic by-pass system.



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Rotoscreen

The current system will be used as screening back-up, in case of failure or emergency on the rotoscreen

system.

Finally, the separated waste from Rotoscreen will be adduct to the compactor system (on the ground level),

that provides to reduce the waste volume and helping to prevent unpleasant smells.

6.1.3. Grit, degreasing and oil separation section

The waste waters are then passed by gravity to the existing degreasing and oil-separation aerated section.

Grit and oil removal system

The size is:

Gross length m 9.35

Width m 3.50

Depth (H) m 3.20

This section is very important in order to cope with problems occurring at production points (kitchens and

dining facilities) with oil and grease; normally they should be equipped with a grease trap, and other

production points (washing areas, filling points, workshops, etc.) where hydrocarbons should be properly

separated.



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The Grit classifier equipment hydraulic connections will be verified, and eventually corrected. For this

equipment will be also implemented an extraordinary maintenance work.

6.1.4. Accumulation, homogenizing and feeding section

After the “Grit, degreasing and oil separation” section, the waste water is then passed by gravity to the

existing Tank#2. In this tank, there is the pumping station that feeds the water to the existing biological

system (EFLOSAF Line 1 and Line 2).

The first step is cleaning the Tank#2, to remove the settled (and probably septic) sludge.

After this we propose to transform the Tank#2 to an accumulation/homogenization section (with the existing

pumping station also).

This new section can:

- homogenize the concentration of the polluting (COD, BOD, SST, etc..);

- equalize the biological system influent flow;

- mitigate the effect of eventually biocide substance and of any toxic or inhibitory substances.

It helps the efficiency of the entire WWTP.

An extraordinary maintenance work will be also implemented for the existing pumps.

The size of this underground tank (Tank#2) is not known; so we can suppose that this section can sufficient

equipped with one of Jet Aeretor, like this:

Jet Aerator

In the next design step, after acquisition of the underground tank design, it could be confirmed or specified

exactly the equipment that we need.

6.2. Calibration of the current biological system

Current biological system is composed by two similar lines of modules for EFLOSAF technology.

EFLOSAF is a biological treatment process based on submerged aerated biofilter (a type of attached growth

biological oxidation process). The active biological process is performed using an extremely efficient

Submerged Aerated Filter.



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The flow of raw sewage to the treated final effluent is composed as follows:

- Raw sewage, from Tank#2, is lifted at average flow rate and delivered to the bio-zone (aerated bio-filter),

through autoscreen located on top of biozone module;

- Biologically treated liquor discharges from the bio-zone;

- Biologically treated liquor passes by gravity through the Final Settlement Tank;

- Effluent discharges from settlement tank to a chlorination;

- Final effluent is filtered via pressure sand filters prior to discharge or reuse.

The accumulated sludge (settled) & grease stored in the sludge holding tank is dewatered in order for

volume reduction. A complete system contains:

- Sludge transfer pump;

- Flocculation;

- Reactor tank with mixer;

- Polymer dosing set;

- Sludge dewatering unit (screw type);

- Interconnects pipes, valves, instruments and control panel.

The dewatering system function manually based on the accumulation rate of sludge and the stored quantity.

Today current system is working with low efficiency.

We suppose that the up-grade and maintenance work of the pretreatment system should have good

influence on the biological system.

In any case the existing Eflosaf system, Line 1 and Line 2, have to be verified and calibrate in every step,

especially the following parts of the system:

- Biological functionally (biozone, sedimentation, sludge holding tank, disinfection tank);

- Multimedia filters, that shows some issues and needs of maintenance work;

- Dewatering system, that shows some issues and needs of maintenance work.

With these actions the current WWTP should be fully efficient for 2.000 PE, like original design.

This is insufficient for the current population into the Kabul HQ (about 2.500 PE), and for the next future (until

3,000 PE), but it is necessary for the transition period during the third line and sludge line construction, to

minimize the environmental and logistics problems (too many accesses to HQ).

6.3. Up-grade of the existing biological system (to 3.000 pe)

The current situation (2,500 PE circa) and the progressive increase expected for the future (3.000 PE), are

managed through an up-grade of the existing biological system.

The new plant will be located near the existing plant, in order to keep running the current plant until the

complete construction of the new one.

The new plant is based on a biological purification process. This choice has been made since the polluting

components of the sewage sludge are predominantly organic and nitrogenous, predominantly

biodegradable. The treatment process chosen is a biological treatment process based on submerged

aerated biofilter (a type of attached growth biological oxidation process) with technology similar to existing

Eflosaf WWTP; it allows achieving the quality standards required for the purified effluent.

Furthermore this choice can respect the guidelines of the project because:

- the technical solution EFLOSAF system guarantees an efficient and safe operation, integrating the

existing EFLOSAF biological line (Lines 1 and 2), easy O&M phases, in compliance with the current

procedures, and fast realization because the EFLOSAF system is composed by preassembled modules.



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- the technical solution EFLOSAF system guarantees the full functionality of the existing EFLOSAF

biological line (Lines 1 and 2) throughout up-grade construction.

The chosen technical solution must have an efficient and safe operation, easy O&M phases, and fast

realization.

The third line (Line 3) will be necessarily built similar to the existing Line1 and Line2; it will be composed by

the following parts:

1. Lift pumping station;

2. Autoscreen;

3. Biozone;

4. Settlement tank;

5. Disinfection tank;

6. Mutimedia filters;

7. Air blowers;

8. Sludge retention tank;

9. Sludge transfer pumps (n.1+1R);

10. Interconnects pipes, valves, instruments and control panel.

The dewatering system, instead, will be realized in the new sludge section (Line 1 and Line 2), only one for

the entire WWTP (see 3.5).

The biological design of the third line (Line 3) will be responsibility of process patent owner (for example

Eflosaf). We can suppose, base on previous design (current WWTP), that the following outputs (effluent

parameters) are expected:

- BOD5 < 10 mg/L

- TSS < 10 mg/L

- NH3-N < 2 ppm

- pH 6-9

6.4. Maintenance of the current disinfection system

The attached growth biological oxidation process is capable to significantly reduce the microbial charge of

the treated effluent. Anyhow, in order to prevent any sanitary hazard, a disinfection section is provided.

Current WWTP is equipped with a hypochlorite chlorination system in aqueous solution. The chlorate effluent

is conveyed in the effluent accumulation tank from where it will be released to the final filtration, or directly

discharged if the quality of the effluent is deemed suitable.

6.5. Up-grade of the sludge treatment system

With this section dedicate to sludge treatment we will reduce:

1. Movements of trucks inside the Camp: finally will be needed a truck (10 m3) every 20-30 days, based

on the accumulation rate of sludge in WWTP, and the storage volume.

2. Costs for transport of sludge to landfill: current waste removal transportation costs about 264.000

€/year (more if we suppose up-grade with third line but without specific sludge line); we suppose that

this value will be in the range 10.000€ - 25.000€ /year.

From analysis of the existing WWTP design and with the data from literature, we suppose that in the worst

case the WWTP will produce about 100 kg/day of total solids (TS), which will be extracted from the Sludge

retention tank of three lines of WWTP.



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Because the current dewatering system seems not efficiency and safety for eventually malfunctioning (no

more volume to accumulate untreated sludge) we suggest to implement a new and unique sludge treatment

sector near the new line (Line 3) and close pretreatment area and access gate. In this way we can improve

the layout of WWTP and the movements of the trucks into the Camp, for the transportation of wastes, grits

and sludges to landfill.

The new sludge sector will be composed by two lines (Line 1 and Line 2), for back-up and emergency

conditions, everyone with:

1. Sludge pumping station for SHT (SHT1, 2 and 3);

2. Dynamic pre-thickening sludge section;

3. Flocculation;

4. Reactor tank with mixer;

5. Polymer dosing set;

6. Aerobic stabilization / Storage tank (about 60 m3 );

7. Air blowers for aerobic stabilization;

8. Sludge pumping station to dewatering system (only one for the entire treatment sludge sector);

9. Flocculation;

10. Reactor tank with mixer;

11. Polymer dosing set.

In this way, we can extract a maximum daily volume of sludge (estimated about 10 m3

/d a 1% DS), which is

conveyed into the dynamic pre-thickening, by conditioning the flow with addition of synthesis cationic

flocculants (polyelectrolytes). They will work for 5 days on 7 days for about 2h every day, based on the

accumulation rate of sludge and the stored quantity.

Dynamic pre-thickening system

After this step the sludge (estimated about 2,5 m3

/d a 4% DS) is conveyed for gravity into the aerobic

stabilization tank.

In the aerobic stabilization tank the solid inside the sludge will be reduce with endogenous biological activity

and the outlet flow (estimated about 2,5 m3

/d a 2,6% DS) is conveyed into the dewatering system (type

decanter).



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Dewatering decanter system

The endogenous biological reaction needs of the process air; it is supply to the system by specific air

blowers (1+1R) and spec if piping and air diffusing system.

To prevent problems with humidity and ice the equipment will be shelter into containers or under covers.

Every Sludge Line has an aerobic stabilization tank with 30 m3

of effective volume, and this volume can be

used also like storage tank, for every event.

From dewatering system the sludge (estimated about 0,5 m3

/d a 18% DS) will be brought to landfill (or

reuse). The dewatering equipment we suppose will work for 5 days on 7 days for about 1h every day, based

on the accumulation rate of sludge and the stored quantity.

Many hydraulic connections will allow to use alternatively the equipments and tanks (Line 1 and Line 2) to

optimize the functionally system based on the needs of the WWTP.

Finally, to prevent unpleasant smells, the container with the Dewatering decanter system will be equipped

with an exhausted air treatment (type activated carbon).

Air exhausted treatment system

In the next design step, after acquisition of the real or theoretical rate production sludge of the biological

specific system, it could be confirmed or specified exactly the equipments that we need.



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7. CONSTRUCTION DETAILS

7.1. Area -preliminary operations

The area identified for the up-grade of WWTP is located near to the existing WWTP, as described in drawing

#210.

Before proceeding to the construction of the plant, some of the existing containers and devices shall be

relocated.

7.2. WWTP discharge

The WWTP existing discharge system should be adequate to receive the new design flow.

7.3. Water line treatment

The water treatment features the following stages:

7.3.1. Pre-treatment section

A - LIFT SYSTEM FROM EXISTING SEWAGE TANK

A new pumping unit will be installed inside the arrival of the sewage tank (Tank#1).

The lifting station will have the following characteristics:

- N° 2 (1+1 redundancy) not-clogging pumps;

- Single Flow: 35 m3/h;

- Hydraulic head: 7 m;

- Single engine power: 2.0 kW

Subsequently, from the distribution pipe, will lead to the solid separation system.

The lift station will be completed with regulation floats.

B - SOLID SEPARATION SYSTEM (Rotoscreen)

The filtration section will consist in a fine drum screen unit (rotoscreen), with the following features.

- N° 1 unit drum fine grid 3 mm;

- Total Flow max: 750 m3/h

- Engine power: 1.10 kW

The filtered water will be sent to the degreaser system; the solids will be mechanically filtered, and moved

periodically to special conveyor that reduce theirs volume.

C - SOLID CONVEYOR SYSTEM

The conveyor and squeeze section will consist in an endless screw inside a cylindrical chamber, with the

following features.

- N° 1 unit Diameter: 185 mm – Total length: 2.910 mm;

- Total Flow max: max 2 m3/h of waste


The squeezed waste will be sent to the storage tank and from here to landfill.

D – TANK #2 – EQUALIZZATION AND HOMOGENEIZATION TANK

The water from degreaser and grit removal system will be conveyed by gravity to Tank#2. To adequate, this

tank to Equalization and homogenization section will be added a Jet Aerator, which will make easier the

oxidation of the wastewater and prevent septic conditions:

- N° 1 radial jet airing unit

- Air flow: 44.5 Nm3/h



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- Water flow: 230 m3/h


An existing lift station will transfer the accumulated sewage to the biological treatment (Eflosaf Line1 and

Line2). New pumps will be added for transferring wastewater to new Line 3.

7.3.2. Biological reactor system

The treatment process chosen is a biological treatment process based on submerged aerated biofilter (a

type of attached growth biological oxidation process) with technology similar to existing Eflosaf WWTP.

The third line (Line 3) will be necessarily built similar to the existing Line1 and Line2; it will be composed by

the following parts:

1. Lift pumping station;

2. Autoscreen;

3. Biozone;

4. Settlment tank;

5. Disinfection tank;

6. Mutimedia filters;

7. Air blowers;

8. Sludge retention tank;

9. Sludge transfer pumps (n.1+1R);

10. Interconnects pipes, valves, instruments and control panel.

The dewatering system, instead, will be realized in the new sludge section (Line 1 and Line 2), only one for

the entire WWTP.

The biological design and details of the third line (Line 3) will be responsibility of process patent owner (for

example Eflosaf).

7.3.3. Disinfection system

After the multimedia filters the water flow will be conveyed to sampling manhole, where free chloride’s

samplings and measurings will be made using a free chlorine analyzer with the following properties:

Accuracy: ± 5 % or ±0.03 mg/L (ppm) as CL2, whichever is greater

Air Purge: 0.1 cfm (0.17 m³/h) instrument quality air at max. 20 psig (ca. 1.4 bar) with 1/4-inch

OD tube, quick disconnect fitting

Alarm: Two alarms selectable for sample concentration alarm, analyzer system warning, or

analyzer system shut-down alarm. Each is equipped with an SPDT relay with

contacts rated for 5A resistive load at 230 V AC.

Cycle Time: 2.5 min

Dimensions: Weight:23.13 lbs. (10.49 kg)

Dimensions (H x W x D):454 mm x 314 mm x 179 mm

Display: LCD, 3-1/2 inch digit measurement readout and six-character alphanumeric scrolling

text line

Drain: 1/2-inch ID flexible hose, hose barb

Enclosure Construction:ABS plastic, two clear polycarbonate windows, IP62-rated with the gasketed door

latched.

Enclosure Rating: IP62



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Inlet: 1/4-inch OD polyethylene tube, quick-disconnect fitting

Inlet Pressure: 1 to 5 psi (0.07 to 0.34 bar), 1.5 psi (1.03 bar) is optimum

Lower Limit of Detection (LOD): 0.03 mg/L (ppm)

Mounting: Wall mount

Operating Humidity: Up to 90 % at 40 °C (104 °F) maximum

Operating Temperature Range: 5 to 40 °C (41 to 104 °F)

Power Requirements (Amps): 2.5 A

Power Requirements (Hz): 50/60 Hz

Power Requirements (Voltage): 100 - 115/230 V AC

Pressure Range: Inlet Pressure to Sample Conditioning: 1.5 to 75 psi (0.1 to 5.2 bar)

Range: 0 - 5 mg/L free or total residual chlorine

Sample Flow Rate: 200 to 500 mL per minute minimum

Sample Temperature: 5 to 40 °C (41 to 104 °F)

SLUDGE TREATMENT SYSTEM

Sludge from SRT (Line 1, Line 2, Line 3) will be conveyed to dynamic pre-thickening equipment by sludge

pumping station.

A – SLUDGE PUMPING STATION (Line1 – Line 2)

- N° 2 unit for line – pumps type mohno (progressive cavity pump)

- Flow: 7-8 m3/h

- Pressure: 2 bar

- Engine power: 1 kW

B – DYNAMIC PRE-THICKENING (Line1 – Line 2)

- N° 2 unit Width: 750 mm – Height: 1.345 mm – Total length: 3.160 mm;

- Flow: 10-15 m3/h - 0,8-1 % DS


1. FLOCCULANT STATION

- N° 2 mixing unit single engine power 0,37 kW

- N° 1 flocculent hopper lt.60 capacity

- N° 2 (1+1 redundancy) dispensing pumping

C – AEROBIC STABILIZATION SECTOR (Line1 – Line 2)

After the dynamic pre-thickening step the sludge is conveyed for gravity into the aerobic stabilization tank.

Aerobic stabilization will be realized into two parallel iron tanks:

- N° 2 unit Width: 2200 mm – Height: 2.800 mm – Length: 6.000 mm

- Total volume: 60 m3

D – AIR BLOWERS

Aerobic stabilization need of air for treatment (biological endogenous reactions):

- N° 2 unit (1+1 redundancy)

- Flow (air): 230 m3/h

- ΔP: 400 hPa

- Engine power: 7.50 Kw



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E – SLUDGE PUMPING STATION TO DEWATERING SYSTEM

- N° 2 unit (1+1 redundancy) – pumps type mohno (progressive cavity pump)

- Flow: 1-3 m3/h

- Pressure: 2 bar


F – DEWATERING SYSTEM (DECANTER)

- N° 1 unit Width: 780 mm – Height: 930 mm – Total length: 2.936 mm;

- Flow: 1-3 m3/h - 3-4 % DS


FLOCCULANT STATION

- N° 2 mixing unit single engine power 0,37 kW

- N° 1 flocculent hopper lt.60 capacity

- N° 2 (1+1 redundancy) dispensing pumping

8. ELECTRICAL PROVISIONS

The WWTP upgrade will include the following electrical works:


- realization of a new electrical connection for the pre-treatment system from the main power line or the

next MV/LV transformer. Cables, trenches and refill will be included;

- installation of a new QEG (new main panelboard), IP65, with all switches for new and existing devices.

The cables, type FG7OR, will be placed in dedicated cable ducts or metallic cable trays with cover.

8.1.2. WWTP upgrade

- realization of a new electrical connection for the pre-treatment system from the main power line or the

next MV/LV transformer. Cables, trenches and refill will be included;

- installation of a new backup Diesel generator (power required, 125 kVA), which will be operational in

case of supply system general failure. The backup generator will power the entire pretreatment, the

biological systems and the new sludge line. The back-up unit will be located in the place shown in the

drawing #210;

- installation of a new QEG (main panelboard) IP65 with all switches for new and existing devices, for the

new biological modular section and for the new sludge line.

9. CIVIL WORKS

The WWTP upgrade will include the following civil works:


- intervention of the filtration tanks’ structure reinforcement for the new screen remover installation.

9.1.2. WWTP upgrade

- New steel reinforcement for the modular biologic WWTP and new sludge line basement installation, over

existing tanks;

- Installation of a shelter to protect the sludge thickening system;



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- Installation of new technical rooms for the placement of the following equipment:

- Free chorine analyzer

- New sludge thickening system

- New air blowers and polyelectrolyte installation

- New dewatering system

- The structure of these technical rooms will be realized with metallic profiles. Walls and roof will be

realized with metallic sandwich panels.



23 / 25

10. TIME SCHEDULE

As depicted in the Gantt chart below (better detailed in the document #030, time schedule) the new WWTP

will be operational in circa 210 days after the work commencement. This time is calculated for the only

realization of the works. Lead times between equipment’s order and delivery are not included.

LEGEND: M month; S week

The technical solution EFLOSAF system guarantees the full functionality of the existing EFLOSAF biological

line (Lines 1 and 2) throughout up-grade construction.



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ANNEX 1 - Operation & Maintenance, Monitoring Sheet

Inside EFLOSAF WWTP, a Supervisory Control And Data Acquisition (SCADA) metering system is provided

concerning outlet flowmeter, pressure gauge and level gauge into tanks.

It is important to note that the SCADA system shall be adopted accordingly with the Producer, as producer

O&M manual mentions. However; it is assumed that the skilled operator shall attend the plant.

The company operating the new plant shall undertake a programme of measurements based on the

following scheme, on a weekly basis:

WEEKLY BIOLOGICAL MONITORING SHEET

HQ KABUL

DATE…….……………….ESTIMATED PE………..….…..……

MAIN PROBLEM …………………………………………….…………….....

IN OUT

SCREEN EQUAL. REACTOR CHLORINE SYSTEM

DISINFECTION

MAIN PARAMETERS OF WASTE WATER TO BE MONITORED:

FLOW (m3/h) FLOW (m

3/d)

IN

OUT

COD (mg/l) BOD5 (mg/l) TKN (mg/l) N-NH4 (mg/l) N-NO3 (mg/l) N-NO2 (mg/l)

NO NO IN

OUT

P Tot. (mg/l) Oil & Grease

(mg/l) TDS (mg/l) pH

Non Ionic & Anionic

Surfactants (mg/l)

Hydrocarbon

s (mg/l) Chloride (mg/l)

IN

OUT



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Sulphate

(mg/l)

Faecal

Coliforms

Total

Coliforms

IN

OUT

MAIN PARAMETERS OF BIOLOGICAL PROCESS TO BE MONITORED:

This section will be implemented by the manual of selected patient biological process

(Eflosaf/Corodex).

MAIN PARAMETERS OF SLUDGE LINE TO BE MONITORED:

Level of sludge

holding tank

(Line1) (m)

Level of sludge

holding tank

(Line2) (m)

Level of sludge

holding tank

(Line3) (m)

Polymer

storage (kg)

O2 (mg/l)

In the aerobic

stabilization

reactor (Line1)

(mg/l)

O2 (mg/l)

In the aerobic

stabilization

reactor (Line2)

(mg/l)

Level of sludge

aerobic

stabilization

reactor (Line1)

(m)

Level of sludge

aerobic

stabilization

reactor (Line2)

(m)

Work time of

dynamic pre-

thickening

equipment

(Line1) (h/week)

Work time of

dynamic pre-

thickening

equipment

(Line2) (h/week)

Work time of

dewatering

equipment

(h/week)

Sludge

extraction

(m3/week)

Note………………………………………………………………………………………………………………………

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