LWORA STP Tech details

8/14/2019 LWORA STP Tech details

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Submitted to :Laughing Waters Owners and Residents Assoc iation

Ram ag onda nahalli

Design of DTS for Laughing Waters

Residentia l c olony


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R-ADEPT-2007-1/ V2 DTS-LWORA, White field i

Doc um ent No: R-ADEPT-2007-1/V2

Date of sub mission: 070218

Ap proved by: Pravinjith K.P

Client: Laughing Waters Owners and Residents Assoc iat ion (LWORA)

Internal Document Control

Sl. No. Doc ument Numbe r & Date Prp Chk App Rem arks

1. R-ADEPT-2007-1/ V2 & 070218 PKP PB PKP Copy Ed ited

2. R-ADEPT-2007-1/ V2 & 070218 PKP PB PKP Ready fo r sub mission

External Doc ument Control

Sl. No. Doc ument Numbe r & Date Subm itted on No & type of

copies

Distribution

list

Purpose

1. R-ADEPT-2007-1/ V2 & 070218 18th Feb 2007 1 - soft LWORA For approva l

2.

3.

4.


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R-ADEPT-2007-1/ V2 DTS-LWORA, White field ii

Contents

1 Introduction ............................................................................. 12 Background.............................................................................. 13 Project Design .......................................................................... 14 Sources of wastewater ............................................................... 25 Design characteristics of the Wastewater generated ....................... 26 Wastewater Treatment System ................................................... 27 What is DTS?............................................................................ 7

7.1 Description of Treatment Modules............................................. 7

7.2 Sludge generation and disposal ................................................ 98 Design computations of Treatment Modules ................................ 119 Project Implementation Chart ................................................... 17


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R-ADEPT-2007-1/ V2 DTS-LWORA, White field iii

List of acronyms:

Sl.No. Ac ronym Expansion

1. ADEPTAppropriate Decentralized Environment

Protec tion Tec hni ues

2. BOD Biolog ica l Oxygen Demand

3. BWSSB Banga lore Water Sup p ly and Sew erage Board

4. COD Chemic al Oxygen Demand

5. DTS Dec entralized wastewater Trea tment Systems

6. FBR Fluid ized Bed Reac to r

7. FFR Fixed Film Reac tor

8. HRT Hydraulic Rete nt ion Time

9. KLD Kilo Litres per Day

10. LWORA Laughing Wate rs Owners & Residents Assoc iat ion

11. m Meters

12. mg / l Millig ram per litre

13. PGF Planted Gravel Filte r

14. Q Disc harge Qua ntity

15. Sq.m Squa re Me ters

16. STP Sewage Trea tm ent Plant


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R-ADEPT-2007-1/ V2 DTS-LWORA, White field iv

List of Tables:

Tab le 1 Wastewa ter stream c harac te ristics 2Tab le 2 Design d eta ils of T1 2

Tab le 3 Design d eta ils of T2 3Tab le 4 Design d eta ils of T3 3


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R-ADEPT-2007-1/ V2 DTS-LWORA, White field v

List of figures:

Figure 1 Water Balance Cha rt for LWORA 5Figure 2 Wastewater treatment process flow chart LWORA 6

Figure 3 Settler 7Figure 4 Fluidized Bed Rea c tor 8

Figure 5 Fixed Film Rea c tor 9Figure 6 Planted Gravel Filter 9


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R-ADEPT-2007-1/ V2 DTS-LWORA, White field 1

1 Introduction

The residents of 214, Laughing Waters Ramagondana ha lli, Banga lore

560 066 represented by their Association LWORA, wish to integrate an

environmenta l friend ly and low ma intena nc e Waste Water Trea tme nt

plant for trea ting the do mestic blac k and grey wate r ge nerate d within

the c olony. The trea ted effluent is p rop osed to b e utilized for sec ond ary

use like irriga tion of the landsc ape.

The fund amenta l criteria for choosing the DTS is tha t it is an

environment friendly and low maintenance waste water treatment

op tion for trea ting the dom estic b lac k and grey water. The system is

not dep end ant on e lec tric ity for its trea tme nt a nd its insta lla tion c ost is

c om parab le to c onvent iona l STP. The trea ted effluent sha ll c onfo rm to

the KPSCB norms and will be utilized for secondary use like toilet flushing

and irriga tion of the landsc ape.

2 Background

Laughing Waters (LW) is a residential colony located at

Rama go ndanahalli, Whitefield on Airport Roa d . The c olony wa s

deve lop ed by Prestige Builders in 1994. It c onsists of 360 househo lds. The

developers had provided for four independent sewer network with

eac h co nnected to a de dica ted septic tank and soak pit.

Of late, the residents have experienced overflowing septic tanks and

hea d ing up of sew age within the d ra in. The freq uenc y of cleaning a nd

de-sludging septic tanks has also increased. Besides creating

unsanitary conditions near certain sites and ground water

conta mina tion, it is a lso p rov ing to b e c ostly.

LWORA a pproa c hed M/ s. Pa rad igm Environm enta l Strateg ies (P) Ltd .,

who has expertise in Appropriate Decentralized Environmental

Protec tion Tec hniques (ADEPT) , to p rov ide a viab le solution for

managing their waste water. LWORA has conducted a preliminary


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4 Sources of wastewater

Wastewater is generated from cooking, washing of utensils, clothesand floo r etc , ba thing a nd to ilet flushing. The q uantity is assumed to b e

100 lpcd and the total quantity of wastewater from 345 households

would be 180 KLD.

5 Design c harac teristic s of the Wastewa ter generated

The c harac teristic s of ea c h wa stew ater strea m a re b ased on the da tasubmitted by LWORA . The q uantities indica ted a re o f those a t the end

of the four existing strea ms.

The water ba lanc e c hart is show n in Figure 1.

Tab le 1 Wastewater stream c harac teristics

Stream

No

Nos. of

households

Qty KLD Peak flow COD mg/ l BOD mg/ l

1. 100 HH 50 5.0 800 400

2. 225 HH 115 11.5 800 400

3. 10 HH 5 0.5 800 400

4. 10 HH 5 0.5 800 400

Tota l 345 HH 175 17.5 800 400

6 Wastewater Trea tment System

The d esign c onc ep t is as per the a nnexed flow c ha rt (Refe r:Wastewater treatment Process Flow chart - Figure 2). Each of the

strea ms is app lied with a trea tme nt a pprop ria te to it.

Stream 1

The Stream 1 co mprising o f do me stic wastewater gene ra ted from 100


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Dime nsions of the t rea tment mo dules a re

1. Set tler - (4.2m +2.1m) Length x 2.5m Wid th x 2.0 m Depth2. Fluidized bed rea c to r -0.9m Leng th x 6.2m Width x 1.8m Dep th

6 Nos.

3. Fixed film rea c to r 1.5m Length x 6.2m Wid th x 1.8m Dep th 4

Nos.

4. Planted gravel filter 10m Length x 16m Width x 0.6m Depth

1 Nos

Stream 2

The Stream 2 co mprising o f do me stic wastewater gene ra ted from 225

households is c onveyed to a Set tler-Fluid ized Bed Reac to r (T1) linked to

an Fixed Film Reac to r. The to ta l HRT is 69 hours. The trea ted wa te r is sent

into the p lanted gravel filter (PGF)

The design deta ils of T2 is as g iven in ta b le below:

Table 3 Design deta ils of T2

Tota l wa ste wa ter 115 KL/ day Pea k hours 10

Inlet CO D 800mg / l Inlet BOD 400 mg/ l

Outlet COD-< 60 mg / l Outlet BOD


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Dime nsions of the t rea tment mo dules a re

1. Set tler - (1.2m +0.6m) Length x 1.2m Wid th x 2.0 m Depth2. Fluidized bed rea c to r -0.8m Leng th x 1.0m Width x 1.8m Dep th

6 Nos.

3. Fixed film rea c to r 1.2m Length x 1.0m Wid th x 1.8m Dep th 4

Nos.

4. Planted gravel filter 3.2m Length x 1.8m Width x 0.6m Depth

1 Nos

Reuse o f trea ted wa ter

About 30% of the treated wastewater is lost by evapotranspiration by

the p lants in the PGF. The out flow from the p lanted gravel filte rs is

routed to individual underground sumps and pumped for irrigationpurposes. Thus a to ta l of 120 KLD would be ava ilab le for land sc aping

purposes.

Sludge

The DTS units (T1, T2 and T3) a re d e-sludged onc e in 24 months and the

sludg e d isposed off throug h BWSSB. The c ha rac te ristics of the sludg ewill simila r to the sep tic tank sludge. The to ta l volume of sludge

ge nerated is estima ted a t a bout 30KL per annum.


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Paradigm Environmental Strategies (P) Ltd.,

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Figure 1 Water Balanc e Cha rt for LWORA


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Figure 2 Wastewater trea tment proc ess flow chart LWORA

Inlet outlet

Inlet Outletinlet

outlet

20

inlet

outlet

20

Inlet outlet

Inlet Outletinlet

outlet

20

inlet

outlet

20

Inlet outlet

Inlet Outletinlet

outlet

20

inlet

outlet

20

longitudinal section

plantation,preferably phragmites

inlet outlet

rhizomes

h= 0.60 1.0%

bottomslope

0.50 7.00 0.50



inlet outlet

rhizomes

h= 0.60 1.0%

bottomslope

0.50 7.00 0.50



inlet outlet

rhizomes

h= 0.60 1.0%

bottomslope

0.50 7.00 0.50


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7 What is DTS?

DTS sta nd s for Dec entra lized wastewater Trea tment Systems. It qua lifies

as an Appropriate Decentralized Environmental Protection

Tec hnique (ADEPT). All ADEPT app lic a tions a re based on the p rinc iple

of low-maintenance since most of the important parts of the system

wo rk with zero o r minima l externa l energy input . ADEPT app lica tion

provides state of the art technology at affordable prices becausema terials/ inputs used for co nstruct ion are loc a lly ava ilab le.

DTS is suitab le for wastewater for both, dom estic and industria l

sources

DTS c an c a te r to w astewater flow s of 1-1000 KLD

DTS are reliab le, long lasting and resista nt to shoc k loads

DTS do not warrant skilled ma intenanc e.

All ADEPT design enab les ma ximum reuse of the trea tment p rod uc ts.

ADEPT app lica tions a re designed to mee t requirem ents stipulated in

environm enta l laws and reg ula tions

7.1 Desc ription of Treatment Mod ulesSettler:

The Set tler is simila r to a sep tic ta nk but w ith low hydraulic rete ntion

times. The key p roc esses a re physic a l trea tment whic h reta ins

contaminants by sedimentation/flotation and biological treatment

whereby the remaining organic pollutants in the clarified wastewater

a re p artly dec om posed by microo rganisms. The d igestion proc ess

ensures that the accumulated sludge is reduced and stabilised.

Sto rage vo lume for sludge is p rovided for 18 to 24 mo nths, de fining thedesludg ing p eriod .

Ave rag e red uc tion o f BOD is between 20 and 40%. The Set tler is

resista nt to shoc k loa d and va riab le inflow .


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Fluidized Bed Reactor

The Fluid ized Bed Reac to r consists of a series of c hambers, in w hich the

wa stew a ter flow s up-strea m. Ac tiva ted sludge is loc a ted a t the b ottomof each c hamb er. The inflow ing effluent is intensively mixed up with the

sludge, whe rein it is inoc ula ted with bac teria l mass which d ec om pose

the contained pollutants. In the first chambers the easily degradable

substances are broken down. In the following chambers,

dec om position of less dec om posab le substanc es takes p lac e.

The BOD reduc tion rate of the Fluidized Bed Reac to r is 90 %. Thepatho gens reduc tion is in the range b etwee n 40 75 %. The Fluid ized

Bed Reactor is resistant to shock load and variable inflow, the

op eration a nd ma intena nc e is simp le and virtua lly no spac e is req uired

since it is an und erground construct ion.

Figure 4 Fluidized Bed Reactor

Fixed Film Reactor

The Fixed Film Reac to r (FFR), a lso kno wn as fixed bed or Anaerob ic

Filter Reac to r is ve ry simila r to the Fluidized Bed Reac to r (FBR). Thebac terial ma ss is lodged on filte r ma teria ls suc h as gravel, roc ks, cinder

or specially formed plastic pieces which provides additional surface

area for bacteria to settle. Non-settleable and dissolved solids are

treated by bringing them in close contact with a surplus of active

bac terial ma ss fixed on filter ma terial

gas

manholes

inflow

scum outflow

sludge

sedimentation inoculation of fresh wastewater with active sludge final settler


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Figure 5 Fixed Film Rea c tor

Anaerobic Filtergas release

Septic Tank gas release Anaerobic Filter

inlet outlet

scum

liquid filter

sludge grill

Planted Gravel Filter

The Planted Gravel Filte r (PGF) a lso know n a s Root Zone trea tment

system is made of reed planted filter bodies consisting of fine gravel.Bottom slop e is 1 %. The flow d irec tion is mainly horizonta l. The filte r is

p lanted with helophytes. The m a in remova l mec hanisms are b iologica l

conversion, physical filtration and chemical adsorption. Mechanisms of

BOD rem ova l a re ma inly ae rob ic a nd anoxic .The func tion of the PGF is

mainly post treatment. Reduction rate of BOD is between 75 - 90 %.

Reduction of infective organisms is over 95 %. Operation and

maintenanc e o f the system is simp le. The spa tia l req uirem ents a rec om pensa ted by integ ra ting it with the landsc apes.

Figure 6 Planted Gravel Filter

internal water level

inflow manhole

upper sand layer central outlet shaft

final outlet

O2O2O2O2


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Disposa l: Regular d isposa l throug h BWSSB every 18 to 24 mo nths. An

onsite processing through the installation of drying beds attached to

the DTS c ould b e a n alterna tive op tion d ue to the fac t tha t the sludgeprod uc ed will be ha rmless and rich in plant nutrients.


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8 Design c om putations of Treatment Modules

The c harac teristic s of ea ch wa stew ater strea m a re b ased on the da ta

submitted by LWORA.

Stream

No

Qty

KL/day

Peak

flow

pH TSS

mg/ l

TDS

mg/ l

COD

mg/ l

BOD

mg/ l

1. 50 5 7- 7.5


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Fluidized bed reactor (FBR):

Hydraulic retent ion time= 28 hours

Correspond ing COD rem ova l ra te= 80%BOD remova l ra te = 83%

Outlet CO D = (1-0.80) x 592 = 119 mg / l

Outlet BOD = (1-0.83) x 290=49 mg / l

Volume of FBR required =50 /24 x 28= 58.3 KL

Provid e a FBR of d imensions: 0.9 L x 6.2 W x 1.8 D 6 Nos; ac tua l vo lume

provided is 60 KL.

Fixed film reactor (FFR):

Hydraulic retent ion time= 24 hours

Correspond ing COD rem ova l ra te= 59%

BOD remova l ra te = 64%

Outlet C OD = (1-0.59) x 119 = 49 mg/ l


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Provide a Planted Gravel Filte r of d imensions 10 L x 16 W x 0.6 D 1Nos

with filter of porosity 35%.

About 30% of the trea ted wa stew ater is lost b y eva potransp ira tion by

the p lants in the PGF. The effec tive outflow of 35 KL from the p lanted

gravel filte r is c ollec ted in a c ollec tion ta nk for irriga tion p urposes.

T2- Dec entralized Trea tm ent System for Stream 2

Trea tment sc hem e:

The stream 2 is c onveyed to a DTS unit (T2) comprising a sett ler

integrated with an a nae rob ic upflow fluidized be d rea c tor and a fixed

film rea c tor with co mb ined hydraulic rete ntion time (HRT) of 54 hours

The d esign p arameters assumed a re

Tota l waste wate r 120 KLD Peak hours 10


Out let COD


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Fixed film reactor (FFR):

Hydraulic retent ion t ime= 24.3 hoursCorrespond ing COD rem ova l ra te= 59%

BOD remova l ra te = 64%

Outlet C OD = (1-0.59) x 117 = 48 mg/ l


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T3- Dec entra lized Trea tm ent System fo r Strea m 3 and 4

Trea tment sc hem e:

The strea m 3 and 4 are ind ividua lly conveyed sep ara te ly to DTS unit (T3)

c om prising a settler integ ra ted with an a nae rob ic upflow fluid ized bed

rea c tor and a fixed film rea c tor with com bined hydraulic retention time

(HRT) of 74 hours

The d esign p arameters assumed a re

Tota l waste wate r 5 KLD Peak hours 10


Out let COD


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Volume of FFR req uired = 5/ 24 x 31= 6.5KL

Provide an FFR of d imensions: 0.8 L x 1 W x 1.8 D 4 Nos with filte r of

porosity 35% and dep th 0.75m with effec tive volume 6.5 KL. The w aste

wa ter treatment p roc ess flow c hart is g iven in figure 2.

Planted Gravel Filter

The anae rob ic a lly trea ted wa stew ater is routed to a p lanted grave lfilte r p lanted with selec ted spec ies- Canas Ind ica , Colac asia, Papyrus,

Reed

Hydraulic c ond uc tivity o f filter ma teria l=500m/ day

Hydraulic g rad ient =1%

Ma x. BOD loa d on c ross sec tion =150g/ Sqm

Ma x. surfac e BOD loa d=10g/ sqmHydraulic retent ion t ime= 16.5 hours

Correspond ing COD rem ova l ra te= 5%

BOD remo va l ra te = 5%

Outlet COD = (1-0.05) x 47 = 45 mg/ l

Outlet BOD =(1-0.05) x 17 = 16 mg / l

Cross sec tiona l area is the ma ximum of5x17/150= 0.6 Sqm, and

5/ 500/1% =1 Sqm

Adop t d ep th 0.6m, Wid th required 1.8m

Surfac e a rea req uired is the m aximum o f

5x(17-16)/ 10= 0.5 sqm, and

5x16.5/24/0.6= 2 Sqm

Provide a Planted Gravel Filte r of d ime nsions 3.2 L x 1.8 W x 0.6 D

1Nos with f ilte r of p orosity 35%.

About 30% of the treated wastewater is lost by evapotranspiration by

the p lants in the PGF The effec tive outflow of 3 5 KL from the p lanted


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9 Project Implementation Chart

Documents

LWORA STP Tech details