calculation stp mbr 50kld

8/22/2019 Calculation STP MBR 50KLD

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FLOW SHEET OF SEWAGE TREATMENT PLANT

MBR pre Collection tankInflow

Sludge digester

Bar Screen Equalization Recycle

Filter Press

Final water tank ChlorinationDual Media Filter

(PSF & ACF)


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SPECIFICATION FOR 50 KLD STP (Membrane Bio Reactor System)

Details of STP units

It is proposed to install STP of capacity 50,000 litres/day. Following is the

scheme for treating 50,000 Litres/day capacity sewage. The treated water can be

utilized for gardening, etc. Various treatment units which have been envisaged in

this sewage treatment plant are explained below.

Characteristics considered:

Flow : 50KL/day

PH : 6 - 8

TSS : 600 mg/l

BOD : 350 mg/l

COD : 600 mg/l

Oil & Grease : 50 to 75 mg / Ltr.

No. of Hrs. operation: 24

1. Bar Screen

2. Collection Sump cum Equalization unit

3. Raw Sewage Pump

4. Membrane Bio Reactor system

5. Sludge Recycling Pump

6. Sludge collection tank7. Sludge Dewatering

8. Pre collection tank

9. Filter feed pump

10. Pressure sand filter

11. Activated carbon filter

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12. Chlorine Doser

13. Final Collection Tank

14. Treated water transfer pump

15. Blower Capacity

16. Inter Plant Piping

17. Electrical

1. Bar Screen

* Size of the Unit : 0.5m x 0.5m x 2.4m long

* Function : To separate coarse matter

from the raw sewage.

2. Equalization tank

* Size of the unit : 2.4m x 3.5m x 3.5m SWD

* Volume of the Tank : 25m3* Detention time available : 12 Hr.s during Average flow

* Function : Equalizing the flow dampen

the possible variation in the

characteristics of the sewage and

also to reduce initial organic load.

3. RAW SEWAGE PUMP

The equalised and neutralised waste together with return sludge shall be

pumped at a uniform rate of 5.0 Cu.m / Hr. into the Membrane bio-reactor

tank.

*Quantity : 2 no. (1w + 1s)

*Duty : To transfer Raw effluent from Equalisation tank to

Membrane Bio Reactor Tank

*Type : Vertical submersible pump.

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*Motor : TEFC Motor with IP-55 protection and suitable for

400 / 440 V, 50 HZ A/c supply of Kirloskar.

*Material : CI Body and impeller in Bronze.

*Accessories : Air cock with priming funnel, Flexible Coupling with

guard, Base frame, foundation bolts etc.

*Flow rate : 5.0 Cu.m / hr

*Head : 15 mtr

*Solids : 35 mm maximum

*Temperature: Ambient

4. Membrane Bio Reactor tank

* Flow : 50 m3 / day or 2.0833 m3/Hr

* F/M : 0.08

* MLSS : 13,000 mg/ Litre

* MOC : RCC

(i) Calculation of volume of the tank:

BOD X Flow rate

Volume = --------------------------------

F/M X MLSS

Assume F/M = 0.08 & MLSS = 13,000 mg/l

350 x 50

* Therefore Volume of the Tank required: -----------------=16.83m3 say 17m3

0.08 x 13,000

Assume SWD to be 3.0m

Therefore plan area required = 17/3.0 m = 5.66 m2 say 5.7m2

* Size of Aeration Tank required = 2.387m x 2.387 m x 3.0m SWD

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(ii) Calculation of total organic load :

* Average BOD of sewage at the inlet of Aeration tank neglecting BOD

Reduction with pre-aeration: 350 mg/lit

* Total organic load with 10% BOD reduction considered.

: 315mg/lit.

315 x Flow rate

Organic load : ----------------------

1000

* Total organic load in the system : 315 X 50/1000 = 15.75 Kgs/day.

* Total oxygen required assuming that

2 Kgs of O2 /Kg of BOD Removed : 2 X 15.75 = 31.5 Kg/day

(iii) Calculation of diffuser required:

Assume alpha = 0.6 & =0.7

Consider oxygen transfer at 3.0 SWD depth = 0.15%

Density of Air: 1.2 Kg/m3

Percentage of Oxygen in Atmospheric air 2331.5

Actual Air required for pre aeration : ------------------------------------

1.2x0.23x0.6x0.7x0.15x20

Assuming duration of air supply as 20 hours per day

Air required = 90.579 m3/hr

(iv) Calculation of diffuser required:

Consideration 10 m3/hour diffusion of air through the diffuser 1 /m length.

Number of diffusers required = 90.579 /10

= 9.0579 or Say 9 diffusers.

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* Type of aeration = Membrane fine pore

diffused aeration system.

* Function = to aerate the contents of the

MBR tank and to sustain the

biological activity so as to reduce

the organic load.

* Size of the unit : 2.387m x 2.387 m x 3.0m SWD

2.387m x 2.387 m x 3.5m

(Actual Size)

* Volume of the Tank : 19.94m3* Detention time available : 9.57 Hr.s during Average flow

* Function : to aerate and filter the sewage

through the membrane hollow fibre modules

and hold the contents of the MBR tank and to

sustain the biological activity so as to reduce

the organic load.

Hollow-fibre modules used are characteristically 4 inch (10cm) in diameter and 6

(1.83 m) feet long. Hollow-fibre units are almost always run with the feed streamon the outside of the fibre. Water passes through the membrane into the inside or

"lumen" of the fibre. A number of hollow-fibres are collected together and "potted"

in an epoxy resin at both ends and installed into an outer shell. The equivalent

hollow-fibre module filled with fibres of 100-mm diameter X 5 No.s in each set

(total 3 sets); with 0.08m Gap between each will provide an approximately 3000

m2 X 3 of membranearea.

5. SLUDGE RECYCLE PUMP

* Volume of Sludge : 17.5 m3/Day

* Discharge rate : 2 m3/Hr @ 8-10m head

(25 mm pipe dia)

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* Function : To re-circulate the return

Sludge to MBR tank to

maintain the required MLSS

& transfer excess sludge to

filter press.

The wastewater after biological treatment still contains some solids,

colour, odour and harmful micro-organisms. The pressure sand filter and

activated carbon filter are used to remove the solids and colour. The disinfection

process is used to remove the micro-organisms and odour.

6. SLUDGE HOLDING TANK

Flow x BOD

Bio-sludge produced /day : ------------------------------

Sludge concentration

50 x 350

= ------------------------------

10,000

= 1.75 cum/day @ 1.0% concentration

20% of the sludge to be wasted

Excess sludge to be wasted : 0.35 m3/day @ 1%

Volume of sludge holding tank : 2 m3

Size of the tank : 0.9 m x 0.9 m x 2.5 m SWD

7. SLUDGE DEWATERING

Flow x BOD

Bio-sludge produced /day : ------------------------------

Sludge concentration

50 x 350

= ------------------------------

10,000

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= 1.75 cum/day @ 1.0% concentration

20% of the sludge to be wasted

Excess sludge to be wasted : 0.35 m3/day @ 1%

Total sludge to be dewatered : 350 Lts/day @ 1%

Filter press of size 14 x 14 x 8 chambers provided.

Filter press feed pump provided = 2 m3/hr @ 6.0 Kilogram/Sq.Cms (KSC)

8. TREATED SEWAGE COLLECTION / PREFILTRATION TANK

* Size of the unit : 3.0m x 3.0m x 3.0m SWD* Volume of the unit : 27 m3

* Detention time available : 13 hours

* Function : To collect & store the settled

supernatant / treated sewage from

the tank.

9. FILTER FEED PUMP 2 Nos. (1W + 1 SB)

* Pumping Rate : 6 m3/hr

* Pumping Head : 23-25m

* Function : To pump the output water of MBR tank

through Pressure sand & carbon

filters.

* Type : Horizontal centrifugal non-clog Self

priming, open impeller pumps of

Kirloskar, Beacon make.

* Motor : TEFC Motor, with IP-55 protection and

suitable for 400 / 440 V, 50 HZ A/c

supply of Kirloskar make.

* Material : CI Body and impeller in Bronze

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* Accessories : Air cock with priming funnel, Flexible

Coupling with guard, Base frame,

foundation bolts etc.

10. PRESSURE SAND FILTER

Vertical down flow type with graded gravel with polystyrenes strainers.

* Diameter : 600 dia

* Depth of media : 600 mm

* Test Pressure : 5 Kg. / Sq.cm

* Velocity of filtration : 8 cum / Sq. m / Hr.

* Flow rate : 6.0 Cu.m / hr

* Quantity : 1 no

* Duration of pumping considered : 8.2 hr / day

* Make : Ion exchange or equivalent

* Material : Shall made out of 6 mm thick MS plate and

dish end made out of 8 mm thick end plate

whole unit shall be given 2 Coats for internal

and external with epoxy/enamel-based paint

over a coat of epoxy based primer.* Under drain : Perforated bottom plate with plastic

strainers or central headers and laterals.

* Media : Graded River sand and Gravel

* Flow direction : Down flow.

11. CARBON FILTER

Vertical down flow type with graded gravel with polystyrenes strainers.

* Diameter : 600 dia

* Depth of media : As per requirements

* Test Pressure : 5 Kg. / Sq.cm

* Velocity of filtration : 8 cum / Sq. m / Hr.

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* Flow rate : 6.0 Cu.m / hr

* Quantity : 1 no

* Duration of pumping considered : 8.2 hr / day

* Make : Ion exchange or equivalent

* Material : Shall made out of 6 mm thick MS plate and

dish end made out of 8 mm thick plate, whole

unit shall be given 2 Coats for internal and

external with epoxy / enamel - based paint over

a coat of epoxy based primer.

* Under drain : Perforated bottom plate with plastic

strainers or central headers and laterals.

* Media : Ionized Activated carbon with Gravel support

* Flow direction : Down flow.

12. CHLORINE DOSER

In order to disinfect the treated effluent various disinfection methods like

chlorination, ozonation, etc can be used. However chlorination is proved to be

cheaper and relatively effective. Hence the same system is adopted. The

Chlorine can be administered in the form of liquid or solid (bleaching powder) into

the treated effluent channel. An automatic electronic metering system can be

adopted. The chlorine demand is calculated based on the break point

chlorination and to allow residual chlorine of more than 1 mg/l in the treated

effluent.

* Quantity : 1 no.

* Make : Asia LMI / Ion exchange

* Flow : 0 4 Litres / Hour

* Material : FRP

* Accessories : Foot valve with strainer, Electronic diaphragm typemetering Pump

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Detention time = 30 minutes

Volume required = 17.5 X (0.5/24) = 0.365m3

Provide chlorine contact tank of size, Length= 1.0 m & width of the tank= 0.456m

and depth of 1.0m (1m including a free board of 0.2 m)

* Total flow : 17.5 m3/day

* Duration of pumping considered : 24 hr / day

* Pumping rate : 0.729 m3/hr

13. TREATED WATER SUMP

* Stone of the unit : 4.16 m x 4.16 m x 3.0m SWD

4.16 m x 4.16 m x 3.5m (Actual Size)

* Volume of the unit : 52 m3

* Detention time available : 25 Hours

* Function : To collect & store the final

treated (after disinfection) water

to pump to either garden or

toilet flushing.

14. TREATED WATER TRANSFER PUMP

* Volume of Treated water : 50 m3/day

* Discharge rate : 10.0 m3/Hr @ 10-12m head

(50mm pipe dia)

* Function : To pump the treated water from

the treated water collection sump

to Garden and also to toilet

flushing over head tank.

15. BLOWER CAPACITY :

Blower capacity required : 76 x 1.25

(For MBR tank) = 95 m3/hr (4.5% extra)

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Blower capacity required : 60.5 x 1.25

(For equalization + Sludge Holding Tank + Treated Water tank) = 75.625m3/hr.

Note: The capacity of twin lobe roots air blower suitable to discharge about

85m3/hr @ 0.5 KSC 2 Nos. (1W + 1SB) is provided for MBR. The common

blower of twin lobe roots air blower suitable to discharge about 68m3/hr @ 0.5

KSC 2 Nos. (1W + 1SB) is provided for supply of the air required for other

primary, intermittent & final storage units of the treatment plant (Equalisation

Tank, Pre-filtration & Filtered Water tank+ Sludge Holding Tank).

16. INTER PLANT PIPING

Provide PVC pipes of 4-6 Kilogram/sq.cm.s pressure rating including necessary

specials like tees, bends, elbows, flanges etc.

17. ELECTRICALS:

Provide & install motor control centre with necessary cabling, earthing etc.

complete.

CIVIL STRUCTURE WITH DIMENSION

Sl.

No.

Civil Structure Dimension Units

1. Bar Screen 0.5m x 0.5m x 2.4m long 1

2. Equalization tank 2.4m x 3.5m x 3.5m SWD 1

3. MBR Tank 2.387m x 2.387 m x 3.0m SWD 1

4. Sludge holding tank 0.9 m x 0.9 m x 2.5 m SWD

5. Prefilteration tank 3.0m x 3.0m x 3.0m SWD 1

6. Pressure sand D =0.6m, Ht= 0.6m 1

7. Carbon filter D =0.6m, Ht= 0.6m 1

8. Treated Water tank 4.16m x 4.16m x 3.5m 1

9. Filter press 14x14x7 1

18. Characteristics of treated effluent

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As the design includes tertiary treatment units also, the treated sewage

characteristics will be well within the standards prescribed by Karnataka State

Pollution Control Board specified norms for sewage as follows.

BOD(5 day 200 C) < 10 mg/l

Turbidity < 2 NTU

pH = 6.5 to 7.5

E-coli = Absent

Residual chlorine > Min 1 or >1, but

calculation stp mbr 50kld

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