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Technical and Engineering Details

- Basis of Design

This proposal is based on the following design values to

be used for design MBR system.

- Influent Quality

The design solution proposed is based on the values as

presented in Table 3.1. All concentrations refer to max

concentrations to be used for the system's design.

Fluctuations in feed composition and hydraulics will be

appropriately equalized to allow for optimum biologicaltreatment.

Table 3.1: Influent Quality to MBR

Parameter Unit Design Concentration

pH NU 6 - 8

Oil & Grease mg/L < 10Chemical Oxygen Demand (COD) mg/L 600

Biological Oxygen Demand - 5-day mg/L 300

Total Suspended Solids mg/L 200

Ammonia, as NH3 mg/L < 40

TKN, as N mg/L < 70

Total Phosphorous mg/L 10

Total Alkalinity mg/L 400

Total Dissolved Solids mg/L 1500 2100

Note (1) All solids are assumed to be < 2 mm in any dimension;

otherwise, larger solids, such as hair and fibrous material, have to

be removed by others prior to entering the MBR to avoid any

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harm to the membranes.

3.3 Influent Flow DataFlow rate at the inlet to the proposed MBR as well as the resultingbioreactor temperature is shown in Table 3.2.

Parameter Unit Design

Max. flow rate, both membranetrains in operation

m3/d 2500SeeNote1 (Total

Phase) 1000 (Phase I)1750 (Phase II) 2500(Phase III)

Assumed Feed Temperature C 20-28

Design Bioreactor Temperature C 20-28 See Note 2

Note (1) It is required that feed flow be properly equalized

by others and during N-1 condition the flow will be

produced with subsequent trains. For the Phase I, the

flow has to be equalized during cleaning.

Note (2) Biological and membrane process is designed for

a temperature operating range of 20 to 28 C. Higher

temperatures > 35 C have to be avoided as they

exceed the tolerance for the biology and membranes;

otherwise appropriate cooling (by others) will be

required.

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3.4 Operation Basis

Hours Per Day of 24 hrs

Days Per Year of Operation 365 days NOTE: Consider Maintenance Time

3.5 Expected Effluent Quality

Table 3.4 shows the expected effluent quality upon

equipment start-up based on the data listed in section 3.1 and

3.2.

Parameter Unit ExpectedChemical Oxygen Demand (COD) mg/L < 100 SeeNote1

Biological Oxygen Demand - 5-day (BOD5) mg/L < 5

Total Suspended Solids mg/L < 3

Turbidity NTU < 1

Ammonia, as NH3 mg/L < 1

TKN mg/L < 2

TP mg/L < 1

PH NU 6 - 8

Note (1) Expected effluent quality assumes soluble fractions of COD are

biodegradable to this degree.

Note (2) Since "3" is the minimum detection limit of TSS measurement

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by Standard Methods, there is a potential for analytical error of TSS

at such low levels. is able to provide TSS guarantees of < 3 mg/L

95% of the time, provided that the TSS measurement is performed

by a certified lab approved by with < 3 mg/L TSS measuring

capabilities. Any samples with results greater than 2 will be

retested to confirm that the accuracy of the analytical method.

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4 MBR Plant General Scope Of Equipment

Process Description

The following sections describe additional equipment that is

required for the system and will be supplied by GEWPT and

Customer.

1 Equalization Tank

Equalization is required for any system with variable flow

rates. An equalization (EQ) tank is normally installed upstream

of the biological tank. The required equalization volume can

also be incorporated into the biological tank under certain

circumstances. A minimum equalization capacity of 10 hours

is recommended.

2 Equalization Transfer Pumps

Transfer Pumps transport wastewater from the equalization

tank or lift station to the process tank. The transfer pumps are

automatically activated by the Level Switch in a lead/lag

arrangement according to the level in the tank.

3 Screening System

Trash and non-biodegradable solids, such as hair, lint, grit and

plastics may foul or damage the membranes if allowed to pass

into the membrane chamber.

An internally-fed screen with mesh or punched-hole openings

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less than or equal to 2 mm in diameter with no possibility of

bypass or carryover is absolutely required to maintain both

membrane warranty, and optimal MBR operation.

4 Process Mixers

Process mixers can be used to mix the anoxic and post-

anoxic chambers (if included) to prevent solids from settling in

the anoxic chamber.

5 Process Aeration System

The process aeration blowers provide air for the biological tank

and ensure that sufficient oxygen is available to maintain the

biological processes in the tank. The aeration compartments

will be fully aerated and mixed by a fine bubble aeration grid.

Dissolved oxygen will be monitored in each aerobic tank to

achieve a desired set point of 2 mg/L. For the Phase I, there

will be One (1) duty blower and one standby blower providing

process air to the aerobic zone of the bioreactor and for the

Phase II & Phase III, there will be additional One (1) duty blower

per Phase to provide process air to the aerobic zone of the

bioreactor.

6 Fine Bubble Diffusers

A fine bubble diffused aeration system delivers air from the

aeration blowers to the aerobic zone of the process tank.

7 Permeate/Backpulse Pump Equipment

One permeate pump is employed to draw water through the

membranes. The permeate pump, associated valves and

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piping for the system are mounted on a factory assembled,

epoxy-coated carbon steel skid. Treated water flows from the

permeate skid to the final disposal point.

Under normal operation and average day flow conditions,

permeation is stopped for a specific period of time at regular

intervals. This membrane relaxation period, combined with air

scouring, effectively removes solids that have accumulated on

the membrane surface or within the fibers and reduces

electrical costs.

Same permeate pump is provided for backpulsing the

membranes. Under increased flow or adverse sludge

conditions, the operator is able to select a "backpulse" mode.

In this instance, the Backpulse pump will reverse the flow of

permeate through the membrane fibers to dislodge solids that

have accumulated on the membrane surface or within the

fibers.

From membrane tanks, Permeate pump draws treated

effluent through the pores of the membrane fibers and into the

backpulse tank. Once full, the treated effluent is automatically

diverted away from the backpulse tank to a final disposal

point. Clean water (permeate) is suctioned through ZW500D

membranes by variable-speed centrifugal permeate pumps.

Permeate flow rate is controlled to keep up with the demand

placed on the system by influent flow.

8 Membrane System

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In Phase I, One train1 with 46 modules will produce permeate

of 1MLD, The Cassette is Consisting of Modules 4-50 quantity

9 Membrane Scour Aeration System

The membranes are air scoured with one duty membrane

aeration blowers for Phase I and additional One-duty

membrane aeration blowers for Phase II and additional One-

duty membrane aeration blowers for Phase III. The membrane

blower capacity for the respective phases can be adjusted by

pulley arrangement.

10 Mixed Liquor Recirculation Equipment

Recirculation pumps are used to transfer mixed liquor from

the Membrane Tank to Bioreactor at the rate of 4 x ADF. The

effluent overflows by gravity from Bio-Reactor tank to the

Membrane tank at a rate of 5 x ADF.

The sludge recirculation transfers solids away from themembranes and provides proper distribution within the

bioreactor.

The mixed liquor is pumped from the Bioreactor Splitter by

Three (3) duty and one common standby to Membrane Tank

Splitter. Any of the membrane trains can be isolated from the

others to allow for cleaning or maintenance.

11 Sodium Hypochlorite Dosing System

The Sodium Hypochlorite Dosing system is used during

membrane cleaning applications to remove organic fouling

from the membrane surface.

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12 Citric Acid Dosing System

The Citric Acid Dosing system is used during membrane

cleaning applications to remove inorganic scaling from the

membrane surface.

13 Effluent Turbidity Analyzer

An effluent turbidity analyzer can monitor effluent water quality

and alert operators if effluent turbidity rises beyond acceptable

parameters. For optimal performance monitoring, one turbidity

analyzer per train is recommended.

14 Sludge Wasting System

Sludge wasting is accomplished by periodically diverting

mixed liquor from the recirculation return line, via manual

control or by pulling directly from the bioreactor. The

frequency of wasting is a function of influent characteristics,

reactor design and operator preference. In certain operating

circumstances, bioreactors can be designed to accommodate

client preferences with regards to wasting frequencies

15 Coagulant dosing System

The Coagulant Dosing system will be used to feed a metal salt

(Ferric Chloride) to assist in precipitating phosphorus in the

mixed liquor. This precipitate is then filtered by the

ZeeWeed 500 ultrafiltration membranes, preventing

phosphorus from entering the effluent.

16 Control Equipment

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Programmable Logic Controller (PLC) and Panel HMI with a

Human Machine Interface (HMI), installed in the main NEMA

12 control panel, monitors and manages all critical process

operations.

The control panel includes all motor control hardware for the

equipment.

17 Backpulse or Backwash

Under certain fouling conditions or when experiencing poor

sludge characteristics, the ability to ackpulse is essential to

maintaining clean membranes. This feature allows for flexibleand reliable system performance during unexpected influent

or process operating scenarios. Applying the ackpulse

cleaning option is one of the simplest methods to ensure

that immersed membranes retain optimum permeability

throughout all operating conditions.

Backpulsing involves reversing the flow through the

membranes to slightly expand the membrane pores and

dislodge any particles that may have adhered to the

membrane fiber surface. Permeate used for backpulsing is

taken from the ackpulse tank.

An optimized ackpulse-cleaning schedule can ensure that the

plant benefits from:

High membrane permeability;

Efficient plant operation with minimal downtime;

Reduced frequency of chemical cleans;

Lower consumption of cleaning chemicals.

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For this project system design, dedicated ackpulse pumps

will provide the reverse flow at low pressures.

When operating in Backpulse mode the system backpulses

for 30 seconds at 34 lmh, every 12 to 15 minutes. No

chemicals are used during a Backpulse.

In addition to the normal filtration cycle, regular chemical

cleaning is essential to maintain the performance of the

membrane. philosophy is to always maintain the membrane in

state of readiness to effectively handle peak events when they

occur. This is achieved by using automatic in-situ maintenance

cleans as described below.

18 Maintenance Clean

Sodium hypochlorite is used to oxidize organic foulants and

citric acid is used to remove inorganic scaling.

For this project, maintenance cleaning is recommended up to

twice per week using sodium hypochlorite and once per week

using citric acid.

The maintenance cleaning procedure incorporates the

following features;

fully automated and the frequency is set by the operator;

Performed with full membrane tank (i.e. no tank drain

required);

(1) Hour duration per clean per train

Based on the site-specific requirements, cleaning procedures

can be modified to obtain effective cleaning and maximize

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chemical savings.

19 Recovery Clean

Recovery cleaning is required to restore the permeability of

the membrane once the membrane becomes fouled. A

recovery clean should be initiated when permeability declines

to less than 50% of initial stable permeability. This will

generally occur when the trans-membrane pressure (TMP)

consistently exceeds 4-5 psi (vacuum) under normal flow

conditions. The recovery cleaning procedure consists of a

chemical ackpulse sequence, followed by a chemical soak

period. The cleaning chemical concentrations typically used to

soak the membranes are 1,000-mg/L sodium hypochlorite

(NaOCl) for the removal of organic foulants and 2,000-mg/L

citric acid for the removal of inorganic foulants.

Key features of the recovery cleaning procedure for

ZeeWeed membrane filtration

system are:

Fully automated and initiated by the operator;

Cleans all membrane cassettes in a train at the same time;

Recommended two times per annum

Requires moderate chemical concentration Spent cleaning chemicals can be neutralized if required

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Estimated Cleaning Chemical ConsumptionTable provides the estimated yearly chemical consumptionrelated to maintenance cleans. The chemical consumption isbased on installed number of membranes.

Table 4.1: Maintenance Cleaning Su mmary

Parameters (for N Operating Trains) NaOCl Citric Acid

Phase I TotalPhas

e

Phase I Total

PhaseFrequency 2/week 1/week

Dosing Concentration of Chemical 200 200 2000 2000

Concentration (% by weight) 10.3 10.3 50 50

Average Volume ofChemical Required(liters/Train/Clean)

7.4 10.53 14.36 20.43

Estimated Volume of ChemicalConsumed Per Year in the Plant forMaintenance Cleans (L)

374 936 363 603

Preliminary Biological Process Design

The biological design is based on the design parameters as

described in Sections 3.1 and 3.2 of this proposal.

Table 4.1 presents GEWPT's recommended

biological process design parameters.

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Table 4.1: Preliminary Biological Process DesignParameter

Design Parameters Unit Values

Design Flow m

3

/d 2500Number of Biological Train - 3

Working Volume of each Anoxic m3 200

Working Volume of each Aerobic m3 270

Number of Membrane Tank - 3

Volume of Each Membrane Tank m3 23.2

Total bioreactor volume including m3 1480

Design HRT hr 14

Design SRT at min. design Temperature d 20

Design MLSS in Bioreactor g/L 8000

Aerobic Tank Working Depth (a minimum

of 0.5 meter is recommended to address

m 4.5

Oxygen requirements at max Temperature kg/d 1190Air required for process Note1 m3/hr 2170

Total Sludge Wasting per day @ max

Temp and MLSS (10 g/L) (wasting from

m3/d 50

Note (1) Air quantity mentioned above are approximate needs

confirmations from diffuser manufacturers

One membrane filtration train will be provided for each

phase. The membrane system design is summarized in

Parameter Values

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T e of Membrane ZW 500DNumber of Membrane 1Number of Cassettes 1Total No of cassettes in the 1Number of Membrane

modules installed per train

48

Total No of modules in the 48% free S are s ace -Surface area of each 34.37 m2

Net Flux N condition 25.25 lmhMembrane Tank

Dimensions per Train

(Preliminary dimensions)

L 2.57 x W 3.05 x TD 3.96

: MBR Operating Parameters

Parameter DesignValue

AcceptedOperating Range Units

Membrane tank MLSS 10,000 8,000 - 10,000 m /LBioreactor MLSS 8,000 6,000 - 8,000 mg/L

Bioreactor MLVSS 67 > 70 % MLSSDissolved oxygen 2.0 1.5 - 3.0 mg/LBioreactor H 7 6.5 - 7.5 SUTotal solids retention time 20 20-25 da sTotal time to filter of 200 2mm in size 0

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Table 2A: Guaranteed Membrane Permeate Quality forMembrane Warranty Duration

Parameter Guaranteed Values

Maximum MBR Treatment 2500 m3/day for all

Turbidity < 1 NTU,100% of theTotal Suspended Solids

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TKN < 3 mg/L

Total Phosphorus < 1 mg/L

GENERAL NOTES:1. The guaranteed effluent quality is based on a non-toxicand non-inhibitory wastewater composition in the inflow.The presence of such material in the wastewater will inhibitor kill the bacteria seriously impeding the efficiency of theMBR, and in this case the limits cannot be guarantEEd

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