vhm solutions transportable stp...

13 CHULLORA BEND, JANDAKOT,

WESTERN AUSTRALIA 6164

Phone: +61 (0) 8 9414 9111

Email: [email protected]

VHM SOLUTIONSSEWAGE TREATMENT SYSTEMS

V H M S o l u t i o n s P t y L t d Page 1

Introduction

VHM Solutions is proud to deliver in Australia and the Asian region a suite of fit-for-purpose

technologies focused the real need for process equipment in the waste treatment and water

purification for government infrastructure organisation’s, developers, mining companies and the

general public. Waste water treatment plants are custom designed for each client’s application, with

inbuilt flexibility for handling large changes in flows. These adaptable systems are supported by our

strong commitment to after sales service and maintenance.

What is a Sewage Treatment Plant?

Sewage Treatment Plant (STP) is a facility designed to receive the waste from domestic, commercial

and industrial sources and to remove materials that damage water quality and compromise public

health and safety when discharged into water receiving systems.

Objective: - The Principal objective of waste water treatment is generally to allow human and

industrial effluents to be disposed of without danger to human health or unacceptable damage to

the natural environment.

Conventional wastewater treatment processes consists of a combination of Physical, chemical, and

biological processes and operations to remove solids, organic matter and, sometimes, nutrients from

wastewater.


Preliminary treatment

The objective of preliminary treatment is the removal of coarse solids and other large materials

often found in raw wastewater. Removal of these materials is necessary to enhance the operation

and maintenance of subsequent treatment units. Preliminary treatment operations typically include

coarse screening, grit removal and, in some cases, communication of large objects.

Secondary treatment

The objective of secondary treatment is the further treatment of the effluent from primary

treatment to remove the residual organics and suspended solids. In most cases, secondary

treatment follows primary treatment and involves the removal of biodegradable dissolved and

colloidal organic matter using aerobic biological treatment processes. Aerobic biological treatment is

performed in the presence of oxygen by aerobic microorganisms (principally bacteria) that

metabolize the organic matter in the waste water, thereby producing more microorganisms and

inorganic end-products (principally CO2, NH3, and H2O). Several aerobic biological processes are

used for secondary treatment differing primarily in the manner in which oxygen is supplied to the

microorganisms and in the rate at which organisms metabolize the organic matter. Common high-

rate processes include the activated sludge processes, trickling filters or bio filters, oxidation ditches,

and rotating biological contractors (RBC). A combination of two of these processes in series (e.g. bio

filter followed by activated sludge) is sometimes used to treat municipal wastewater containing a

high concentration of organic material from industrial sources.


MICRO AND/OR NANO-BUBBLE AERATION

Principals of Operation

The principal process used in our sewage treatment plants (STP) is Continuous Flow / Activated

Sludge / Fixed Film process, a combination and modification of the well-known extended aeration -

activated sludge process. This process serves situations in which short-term variations in biochemical

oxygen demand (BOD) loading are great, and secondarily to minimize the production of excess

sludge, namely to only 0.1 to 0.2 pounds per pound of biochemical oxygen demand removed by the

process, when compared to other activated sludge processes with shorter retention times where

waste solids are produced at the rate of 0.35 to 0.55 pound per pound of biochemical oxygen

demands removed.

Experience with other similar treatment plants has shown that biochemical oxygen demand

removals of better than 98% can be achieved with minimal excess sludge production.

VHM Solutions can design and supply these compact package plants with a variety of treatment

options including: flow equalization, digestion, disinfection, and tertiary filtration. VHM Solution Pty

Ltd can offer a turnkey package plant which will be custom designed to the specific effluent

requirements. We are not fixed to any particular process equipment manufacturer and/or

technology supplier and design our plants specifically to the optimum benefit of the client’s needs.

The sewage treatment method (STM) - Aeration package plant delivers the proper wastewater

treatment to customers that are not able to connect with a municipal sewer. These package plant

applications have unique challenges that must be understood and accommodated with the correct

design. For example, a mining camp facility will experience large fluctuations in flow based on

attendance. The ability to easily adjust the plant to these variable loads is critical. The required

operator attention becomes another concern for any system. The process stability and mechanical

simplicity of a fine bubble generator (FBG) makes it the equipment of choice.

Process Description

The type of wastewater treatment process for the Sewage treatment plant is the Continuous Flow /Activated Sludge / Fixed Film process, a combination and modification of the well-known extendedaeration - activated sludge process. This process serves situations in which short-term variations inBOD loading are great, and secondarily to minimize the production of excess sludge, namely to only92 to 180 grams per 1000 grams of BOD removed by the process, when compared to other activatedsludge processes with shorter retention times where waste solids are produced at the rate of 316 to498 grams per 1000 grams of BOD removed.

This process is simple to operate, requiring minimum operator attention when compared to themore equipment intensive treatment processes. In the initial phase, all unit processes are controlledmanually, needing no adjustment during the normal operating day. Once a suitable procedure hasbeen established, the system operates fully automatic. The aeration system is controlled by thevolume and timing of the Bubble Generator, governed by the DO (Dissolved Oxygen) reading of thesensor in the aeration tank.


The wastewater from the building enters the influent channel of the STP and passes through amanually raked bar screen. Subsequently, after passing through an oil and grease interceptor, thewastewater discharges into the aerated equalization tank. Two sets of transfer pumps (submersiblesewage pumps) convey the raw sewage at a constant rate into the adjacent aeration tank. Here theraw influent is combined with the Returned Activated Sludge (RAS) collected from the hopper pit ofthe clarifier.For the aeration process we have the choice of the following technologies for options of standardsize bubbles (>1mm), micro or ultra-fine bubbles (0.001 - 1mm), or Ultra-Fine/Nano-bubbles:

Aeration Wheels (>1mm)

Aeration by pumped air membrane type diffusers (0.001 - 1mm)

Aeration by in flow media cavitation (<0.001mm)

Aeration by in flow carbon media activation (<0.001)

Here is an example STP description using a mechanical Wheel Aeration process:

The aeration tank diagram below shows it’s equipped with two STM aeration wheels in order tofacilitate thorough aeration. The two Aerotor wheels are equipped with a gear motor of 4 HP each,operating 24 hours/day and consuming 144 kWh. The STM aeration wheel captures with everyrotation atmospheric air, draws it down into the mixed liquor and releases it as coarse bubbleaeration. The amount of aeration can be controlled using a variable speed drive connected to therotor, causing it to rotate faster or slower based on the actual oxygen demand. This feature reducespower consumption up to 40% during periods of low flow. During the rotation, additional cascadeaeration elevates the dissolved oxygen in the upper layer of the tank. The combination of the slowrotation of the STM aeration, intense air is released and addition of peripheral mixing paddle insurea thoroughly mixed system.

In addition to aeration, the STM aeration includes a large surface area for fixed film growth. Theinterior and exterior of the special polypropylene discs provide the perfect environment for a varietyof attached growth organisms. The fixed film component increases the “effective” sludge age andimproves the sludge settling characteristics. Compared to the suspended growth in the tank, thefixed film organisms will supply between 15 to 25% of the total treatment based on the availablefood supply. The fixed film will react quickly to an increased food supply or shock load, to eliminatedischarge violations during peak or diurnal fluctuations.

From the aeration tank the now air-saturated mixed liquor flows via a gated overflow box into theinclined plate type clarifier, where the solids are allowed to settle out of the mixture to the bottomof the clarifier, accumulate in the sludge hoppers and being returned to the aeration tank via twosludge airlift pumps installed in the hopper pits of the clarifier. The operation of these sludge airliftpumps is controlled by adjustable airflow valves.

The sludge pumped out by the sludge pumps is discharged into the Sludge Flow Selector , where aset of gates direct the flow either to the aeration tank as Return Activated Sludge (RAS) or to thesludge holding tank as Waste Activated Sludge (WAS).

The clear supernatant underflows a scum baffle and passes over a saw tooth weir plate (launderbox) into the chlorination tank and is subsequently pumped out into the receiving body of water(storm drain). A permanent skimmer shall be installed in the clarifier upstream of the saw tooth weiroverflow (launder box) to collect floating scum and return it to the aeration tank. The skimmer isoperated by means of an airlift pump.


Continuous Flow / Activated Sludge / Fixed Film process Flow ChartSludge is wasted periodically when the MLSS concentration in the aeration tank has reached around4,500 mg/l. The excess sludge is wasted into the aerated sludge holding tank (aerobic digester) for

disposal.

Aeration Tanks


Bar Screen

A manual raked bar screen with an opening width between bars of 20 mm. It is constructed of mildsteel, hot dip galvanized after fabrication. A drip tray is connected to the bar screen top.

Bar screen

Equalization Tank

The equalization tank serves as a buffer storage tank between inflow and aeration. The equalizationtank is equipped with an aeration system, consisting of 12 membrane-type fine bubble diffusersmounted on a 3” PVC pipe grid. The grid is fixed to the tank floor by means of adjustable gridsupports made of hot dip galvanized mild steel.

Equalization TankAeration Air Blowers

A set of two lobe-type aeration air blowers (1duty, 1 stand-by) is installed for the aeration of theequalization tank. The blowers also deliver air for the aeration of the sludge holding tank (aerobicdigester), the two airlift pumps and the skimmer in the clarifier.


Equalization Pumps

Two equalization pumps are installed in the equalization tank, one pump operating and one pumpinstalled spare. These pumps discharge the contents of the equalization tank at a steady rate to theadjacent aeration tank and eliminate any flow fluctuations between high flow and low flow periods.Pump operation is controlled by level sensors located in the equalization tank.

The pumps would be submersible sewage non-clog type with fixed discharge elbow, guide pipes andlifting chain. The pumps can be withdrawn for maintenance without draining the tank. .

Aeration Tanks

Aeration is accomplished in this example by the Aerator wheel installed in the Aeration Tank.Polypropylene disk media bundles provide area for fixed film growth.

The rotation velocity of the aerator is governed by a variable speed drive, controlled by a dissolvedoxygen metering system. During high DO values, the rotation velocity will be decreasedautomatically and hereby reducing power consumption.

Clarifier

One inclined plate type clarifier with dual hopper would be provided, equipped with two sludgeairlift pumps for sludge recirculation. The mixed liquor enters the clarifier via a gated overflow boxlocated on the dividing wall between aeration tank and clarifier. A stainless steel chute directs theincoming flow in the clarifier towards the hopper bottom.

The existing clarifier area requires the installation of an inclined plate system to increase theclarification area. A set of 48 PVC sheets 6 mm thick (Versa board), 1.2 x 2.4 m in size, shall beinstalled at a distance of 6 cm between sheets and suspended in a stainless steel frame. Thisincreases the projected clarification area to 70 square meter, more than sufficient for the requiredoverflow rate of 11 m3/m2*day

They would be installed in each of the two clarifier hopper bottoms an airlift pump, operated by theair blower of the equalization tank. A discharge pipe shall transfer sludge to the sludge flow selector,


where the flow adjustment can be visually checked. From here, the sludge joins the raw influent anddischarges by gravity into the head end of the aeration tank. A gate installed in the sludge flowselector allows for diverting the sludge into the sludge holding tank (aerobic digester) for wasting.The sludge return lines shall be made from schedule 20 steel pipes.

The supernatant underflows a scum baffle end enters the launder box with the adjustable saw toothweir. The scum baffle serves also as a skimmer. The floating scum enters the slot of the scum baffle,collects in a small holding tank and is returned via an airlift pump to the aeration tank. Scum returnflow can be controlled manually or automatic.

Chlorination Tank

Chlorine solution is injected into the supernatant coming from the launder box directly at the headend of the chlorination tank.

A complete set of chlorine mixing and metering equipment would be installed for disinfection of thesecondary effluent before it is discharged into the drain. The system consists of a metering pumpand a solution storage tank.

Number of pumps: 2Maximum capacity: 15 GPDMaximum pressure: 100 PSIMaterial of construction: PolyethyleneMixer type: Manual

Effluent pump

A set of two effluent pumps shall be installed in the chamber downstream of the chlorination tank,one pump operating and one pump installed spare. These pumps discharge the treated wastewaterinto the street drain (storm drain). Pump operation is controlled by level sensors located in thepump chamber.

The pumps shall be submersible sewage non-clog type with fixed discharge elbow, guide pipes andlifting chain. The pumps can be withdrawn for maintenance without draining the tank.

Sludge Holding Tank (Aerobic Digester)


Waste sludge is diverted by the sludge flow selector box and collected in the aerated sludge holdingtank. A set of 4 fine bubble diffusers mounted on a 3” PVC pipe grid would be installed at the bottomof this chamber. Air supply comes from the aeration air blower of the equalization tank.

A decanting system operated by an airlift with floating suction head would be installed to reduce thesludge volume.

Aerobic Digester

Electrical Control

Two separate electrical control panels shall be installed, one serving the equalization pumps, theeffluent pumps and the air blowers, the second panel for the Aerotor wheel with its control systems.

Control Room

Sewage Treatment Plant Membrane bioreactor (MBR)

Principals of Operation

Membrane Bioreactors processes can produce effluent of high quality enough to be discharged to

coastal, surface or brackish waterways or to be reclaimed for urban irrigation. Other advantages of

MBRs over conventional processes include small footprint, easy retrofit and upgrade of old

wastewater treatment plants. The extended aeration process makes use of biological processes to

remove the organic matter from wastewater, thereby purifying it before it is returned to the

receiving body of water. There are two basic components in any extended aeration system, an

aeration tank and a clarification tank. In addition to these two basic components the treatment plant

is equipped with a chlorination contact chamber and an aerobic sludge digester.


The aeration tank, outfitted with a bar screen, receives the raw wastewater from the intended site.

If gravity flow from the source to the STP is not possible, a lift station needs to be constructed.

The return activated sludge, settled out in the clarifier, is pumped out from the clarifier hopper

bottom continuously using an airlift pump and returned to the aeration tank, where it is intimately

mixed with the incoming sewage in the presence of oxygen.

In the aeration tank the ‘mixed liquor’ is aerated to provide conditions suitable for the growth of

aerobic organisms. In the clarifier these organisms are allowed to settle out in the bottom of the

clarifier hopper. These organisms are the means by which purification of the wastewater is

accomplished. Upon contact with wastewater they absorb the organic matter into their system and

form more organisms.

Since the organisms upon which the process depends are aerobic in nature, there must be present in

their environment a sufficient quantity of oxygen in solution (Dissolved Oxygen) in order to maintain

life. They use this oxygen much the same human beings use it in their life cycle.

The aeration system is a full grid fine bubble system, which provides the highest oxygen transfer rate

when compared to other aeration system. The AIRFLEX fine/micro bubble diffusers are state of the

art maintenance-free diffusers made from non-corrosive materials.

It must be understood that in any well-operated plant, no matter how small the food supply, there is

always some sludge produced and the level of sludge in the system will always rise. It will

accumulate until there will be an inadequate supply of oxygen to sustain it, or the quantity will be


too great for the return sludge system. It will then be necessary to remove some of the surplus

sludge in order to maintain a satisfactory level of treatment. This is called “sludge wasting” and

carried out by transferring some of the sludge into the aerobic digester compartment for further

treatment.

FAST® Sewage Treatment System

The FAST (Fixed Activated Sludge Treatment) is wastewater treatment process that employs a

unique hybrid combination of attached and suspended growth in an aerobic, packed bed bioreactor.

FAST System can be used for new construction, existing tanks or renovation of failed systems,

including those in nitrogen sensitive areas or limitations with distance to groundwater and/or

smaller dispersal field size requirements.

Natural separation and settling processes occur prior to entering the FAST® treatment module. An

above-ground blower, the system’s only moving part, introduces air (oxygen) into the treatment

module to facilitate a robust circulation of wastewater through the media. Clear, odorless, treated

water is ready for standard or innovative dispersal.


Target market

Commercial

Environmental Engineers, Work camps for mining and construction projects, Off Shore, Shipping,

Remote communities, Resorts and hotels, Farms, Caravan parks, Islands, High density living, Schools,

Emergency relief projects, Shopping malls, Military Facilities, Recreational Facilities.

Marine

Fishing, Tug and work boats, Luxury yachts, Commercial Vessels, Research Boats, Offshore vessels,

Tankers, LNG Ships, Container Ships, Navy Boats, Cruise Ships, and Offshore Platforms

Sewage Treatment Plant Features

Turnkey setup

No noise or odor issues

Light weight

Square or rectangular footprint

50 year design life

Fully conductive for hazardous zones

Capacity up to 30,000 liters

Lower Energy usage

vhm solutions transportable stp...

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