o m Manual Dewat Technology

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Operational Tasksfor the Upkeep of Decentralised WastewaterTreatment System(DEWATS)



O erational Tasksfor the U kee of Decentralised WastewaterTreatment System(DEWATS)

220, 4 h A Cro , 3rd BlockH R B R La ouKal an NagarBangalor 560 043Telefax00 91 80 25431772/ 25431773E-mailcdd nd a@ h.n /bangalor @cdd nd a.orgwww.cddindia.orgwww.borda-sa.org



OpeRAtiONAL tAsKs fOR tHe UpKeep Of DeCeNtRALiseD WAsteWAteR tReAtmeNt system (DeWAts)

Around 300 D c n ral z d Wa wa r tr a n s (DeWAts) hav b ncon ruc d n ind a ov r h a 7 ar , w h h n n on o rov d ng wa wa r g n ra d ro var ou c or l k ho al , ho l , n u

d u cal n r r , co un ba d an a on co l x , nd v dual

hou ng colon . in o o h DeWAts un , r u n ra ruc ur rov do n ur a hol c a roach o nv ron n al an a on. A DeWAts ha omaintained ef ciently has the potential to be productive and sustainable economically,

nv ron n all and oc all .th da - o-da o ra onal a k ar ado d or oo h unc on ng and u k

DeWAts. th a k ar l and r qu r ba c ra n ng. How v r, h ar crn ur ng h con nu ng h gh r or anc o h r a n .

th manual n nd d or u b h o ra or /car ak r and a n nancpersonnel, to facilitate them to carry out the routine speci c and critical tasks.

AbbreviationsBORDA Br n Ov r a R arch and D v lo n A oc a onCBS Co un Ba d san a onCDD Con or u or DeWAts D na on socDEWATSD c n ral z d Wa wa r tr a n sO & M O ra on and ma n nanc

Contents1.0 Introduction ........................................................................................................... 52.0 Task 1. Check for free wastewater ow ................................................................ 6

Task 2. Check for grease formation ...................................................................... 7Task 3. Check for water seal level in the biogas settler ...................................... 8Task 4. Check for gas leakages at the water seal in biogas settler .................... 9Task 5. Check for release of condensed water in the biogas supply pipeline .. 10Task 6. Cleaning biogas stove burner ................................................................. 11

Task 7. Check for biogas leakage at biogas supply pipeline ..............................12Task 8. Check for swivel pipe level in the planted gravel lter ...........................13Task 9. Weeding, removal of dead leaf litter and other litter .............................14

3.0 Appendix 15

Foreword




DeWAts d gn d uch ha b ax z ng h r l anc on na ural roc , oa k ar n z d. How v r, h n al a k ar cr cal o n ur ha DeW

operate ef ciently. A properly operated DEWATS is a productive system economically,nv ron n all and oc all or 20 ar or or .

i u b born n nd ha n ur ng h gh r or anc o DeWAts r qu r a wrange of site speci c tasks that go beyond the activities outlined in this Manual. Forxa l , n a Co un Ba d san a on (CBs) roj c , h a k o ng a du

r gularl n ur ha o l do no hrow garbag n o h o l hu r v n nblockages in the DEWATS modules. Although there may be a longer list of site speci co ra onal a k , h manual d al onl w h a k , wh ch hav o b r or d

ha h DeWAts odul unc on ro rl .

How to use this manual, and by whom?This Manual is intended for use by the bene ciaries of DEWATS, in particular caretakers

and o ra or . each o ra onal a k addr d n r o wh r and wh n woccur, how h a k hould b r or d and wh n d d. s l n or a onDeWAts odul and how h unc on ou l n d n h A nd x 1.0. for ur h

n or a on wh ch a b b ond h co o h manual, on a d r c l conCon or u or DeWAts D na on (CDD) soc .

for h ajor o DeWAts, h gu d l n g v n h r w ll k h weffectively. However, changes in quantity or quality of the wastewater owing into theun and dra c chang n h cl a a al o a c h ’ r or anc

x nd ng or hor n ng h n rval o h o ra onal a k .your DeWAts ha b n cu o z d or our c al r qu r n . th r or ou

no hav all h odul or wh ch o ra onal a k ar r n d n h anua

1.0 Introduction




Cleaning of inspection chambersRemoval of obstacle from the sewer pipeline

Where should this task be done?• s w r 1

• inl , ou l and a d r bu on chann l o all DeWAts modul (modul xA nd x 1.0).

When should this task be done?• Onc n 30 da , dur ng ak u ag (nor all n h orn ng)• Or, n h ollow ng ca

—There is over ow in the inspection chamber(s)—There is over ow in the inlet or outlet of DEWATS modules—There is no wastewater ow in the inspection chambers or DEWATS modules.

Why should this task be done?• to d n o bl ob ruc on n and DeWAts odul• To allow required free ow of wastewater through the entire system (all DEWATS

odul )• to d n o bl da ag or l akag .

How should this task be done?STEp 11. O n h anhol cov r o n c on cha b r2. Open the manhole cover at inlet and outlet of each DEWATS module (settler, baf e

r ac or c.).STEp 2

1. Check for obstructions like solid materials, oating materials, deposition at all theo n

2. Check if the wastewater has its usual ow (compare with what was observed in earliern c on ).

STEp 31. R ov ob ruc on an , u ng an a ro r a ool. ( g. hov l, ck, broo2. If no ow is observed, check whether the system is in use and if so, report to CDD

Society or its certi ed service provider3. If an unusual ow (extremely low, high or much dirtier than usual) is observed, repeat

Step 1 and Step 2 for 3 days. If unusual ow continues during observation for 3 daysreport to CDD Society or its certi ed service provider.

NOTES

ta k 1.Check for free wastewater ow

1. Sewer system:p l n u d

o carr hwa wa rand n c oncha b r

rov d d a c r a nn rval or

r gular ch ck u .




NOTES

1. Grease tra s ar u uall onl

n all d acan n , ho land n u onw h lar

rv c(b g k ch n).

Grease formation Removal of grease

Where should this task be done?• in h n c on cha b r( ) and b or h gr a ra1

• A h nl , ou l and n d gr a ra cha b r( ).

When should this task be done?• ev r da or a l a onc n 7 da ( or ho l , can n, ho l c.)• Or, n h ollow ng ca

—th r larg quan o gr a ob rv d n h gr a ra cha b r or n hDeWAts odul

—There is a bad odour and over ow from the top of the grease trap chamber—There is back ow at source or in the inspection chamber before the grease trap

chamber or no ow of wastewater into the next treatment module

Why should this task be done?• To allow the required free ow (to avoid clogging) of wastewater through the treatment and o avo d gr a n r ng ub qu n ag o r a n

• to avo d bad odour n and around h gr a ra cha b r

How should this task be done?STEp 11. O n h anhol cov r o h gr a ra cha b r and n c on cha b r b

and a r h gr a ra cha b r.STEp 21. Ch ck or h r nc o xc gr a n h cha b r

2. Check if the wastewater has its usual ow in the grease trap chamber and subsequentinspection chambers (compare the ow with what was observed in the earlier

n c on ).STEp 31. R ov h gr a ro h cha b r and ro h nl and ou l o h g

ra cha b r u ng an a ro r a ool ( g. hov l, ck, broo )2. R ov all gr a ro h n c on cha b r and r or and a r h g

ra cha b r3. D o h gr a and o h r wa a l n o a , wh ch a l a 30

dug or bor w ll4. If an unusual ow is observed, report it to CDD Society or its certi ed service provider.

ta k 2.Check for grease formation




Where should this task be done?• in d h n ck (c rcular o cha b r) cha b r o h b oga l r.

When should this task be done?• Onc n 15 da• in h ollow ng ca

—th r l han 2 nch (d h) o wa r n h n ck cha b r—th r l or no b oga u l—th r bad odour or bubbl ng ound n ar h b oga l r.

Why should this task be done?• to k h cla al1 w• to avo d crack n h cla al.

How should this task be done?STEp 11. in r a wood n cal or ck hrough h n c on hol rov d d n h

ll ouch h ba o h n ck cha b r.STEp 21. m a ur h wa r l v l on h cal or ck a nd ca d b h wa r ark

or on).STEp 31. i h w or on on h cal or ck ound o b l han 2 nch ,

ll h wa r l v l r ach or han 4 nch

2. If the water level recedes frequently, report it to CDD Society or to its certi ed servicerov d r.

Biogas settler neck chamber

B oga valvcha b rB oga l r

n ck

Cla al

ta k 3.Check for water seal level in the biogas settler

Checking the level of water seal

in c onhol

NOTES

1. Clay seal: i h x ur o

cla and wa rwh ch u d o

al h vo d haa b r nn h n ck o h

cha b r.




Filling water to required depth

Where should this task be done?• in d h n ck cha b r (c rcular o cha b r) o h b oga l r.

When should this task be done?• Onc n 60 da• Or, n h ollow ng ca

—th r l or no b oga u l—th r bad odour or bubbl ng ound n ar h b oga l r.

Why should this task be done?• to d n o bl l akag o b oga n h n ck cha b r.

How should this task be done?STEp 11. Clo h a n b oga valv n ar h b oga l r2. A r wo hour ro h o clo ng h valv , o n h anhol cov r o

b oga l r n ck cha b r.STEp 21. Ch ck or an bubbl on h wa r ur ac .STEp 31. i no wa r ound n h b oga l r n ck cha b r, our wa r ll

around 4 nch ro h ba and ch ck or bubbl or a on on h wa r ur2. If bubbles are observed on the water surface, report to CDD Society or to its certi ed

rv c rov d r.

Bubbles indicating gas leakage in the water seal

Bubbl

Wa r al

ta k 4.Check for gas leakages at the water seal in biogas settler




10

Release of condensed water

Where should this task be done?• A h wa r ra rov d d or our b oga l n .

When should this task be done?• Onc n 7 o 15 da• Or, n h ollow ng ca

—th r l l or no b oga u l—th r wa r bubbl ng ound h ard n h b oga u l l n or a h

a l anc ( ov , la c.).

Why should this task be done?• To avoid blockage or slowing down of biogas ow to the biogas appliance (stove, lamp

c) du o coll c on o cond n d wa r1 n h b oga l n• Cond n d wa r or a on n b oga l n nor al, bu n d o b

How should this task be done?STEp 11. Loca wa r ra ( ) w h cond n d wa r r l a valv (nor all low

our b oga l n )2. O n anhol o cov r h wa r ra rov d d n d h cha b r.STEp 21. Ensure that there is no re or any other sparking device nearby. (No smoking!)2. O n cond n d wa r r l a valv or 5 cond and clo aga n3. R a h abov onc aga n.STEp 31. If the water bubbling sound persists and / or less biogas pressure or unusual ame

qual ro h b oga ov wa ob rv d con nuou l or 2 da , r or Society or to its certi ed service provider.

Condensed water release valve

B oga

NOTES

ta k 5.Check for release of condensed water in the biogas su ly i e

1. Condensedwater formation:th b oga co ng

ro h d g r a ura d w h

wa r va our. thwa r va our w llcond n andcoll c on h wallo h l n .




11

Where should this task be done?• A h b oga ov burn r( ) or o h r b oga a l anc ( g. la ).

When should cleaning be done?• Onc n 30 da• in h ollow ng ca

—There is inconsistent ame—th r corro on ound on h ov burn r—th r ar gn o corro on.

Why should cleaning be done?• To keep the stove in ef cient usage condition by eliminating depositions• To use the biogas ef ciently.

How should this task be done?STEp 11. Clo h b oga u l valv n ar h b oga ov2. mak ur wa r ro wa r ra ( ) ar r l a d (R r ta k 5 “Ch ck or r l a

cond n d wa r”).STEp 21. D an l h burn r( ) o h ov or o h r b oga a l anc a r a l an

anual2. Cl an h burn r( ) r ng and hol u ng a bru h and r qu r d a n dl3. Cl an h j hol w h a n dl

4. Some times you may also have to dismantle and clean the gas ame regulator valve if itdo no urn a l

5. i corro on no ar ound, r ov h w h bru h6. A r co l on o all h abov , ak ur ha v r ar ro rl

og h r aga n7. Open the biogas supply valve near the biogas stove and check for the ame.STEp 31. If you are not satis ed with the performance of the stove, then contact the stove

provider or CDD Society or to its certi ed service provider.

Cleaning of burner ring holes

Burn r r ng

Cleaning of Jet holes

ta k 6.Cleaning biogas stove burner




12

Material required for preparation of soap solution Application of soap solution

Where should this task be done?• A h b oga l n , ro h b oga lan o h a l anc .

When should this task be done?• Onc n 4 on h a a rou n• Or, n h ollow ng ca

—There is no steady pressure and ame in the biogas appliances—th r l l or no b oga u l—th r b oga odour n ar h b oga l n .

Why should this task be done?• to n ur o u u o b oga• to avo d l akag o b oga

• to avo d odour o b oga• To avoid outburst of re.

How should this task be done?STEp 11. pr ar a oa olu on b x ng wa r and l qu d oa (3 : 1 x ur ) or w

d rg n owd r (1 cu wa r : 1 a oon d rg n owd r)2. Ch ck

a. or ava lab l o ga b l gh ng h a l anc ( ov c.)b. wh h r h a n valv a b oga un o nc. or h ga r ur n h ga

3. A l h olu on on x o d and jo n u ng a a n bruwh r h ga l akag1 u c d.

STEp 21. Ch ck or h bubbl or oa or a on dur ng h a l ca on o h oa

nd ca h loca on o ga l akag .STEp 31. If bubbles or foam formation is observed, contact a plumber for recti cation work

d a l2. If biogas leakage continues after recti cation, report it to CDD Society or its certi ed

rv c rov d r.

ta k 7.Check for biogas leakage at biogas su ly i eline

NOTES

1. Gas Leakage:th o n all akag o n n ab oga u l l n ar h jo n

uch a t jo n ,nor al jo n ,b nd , n ar hvalv c.




13

Swivel pipe chamber/ Outlet chamber Measuring the level of swivel pipe top

Where should this task be done?• sw v l (L- ) n d h ou l cha b r.

When should this task be done?• Onc n 30 da• Or, n h ollow ng ca

—The water level is observed above the upper surface of the lter material (coarseaggr ga )

—There is dampness on the lter material—th r no lan grow h—th r xc o qu o grow h.

Why should this task be done?• To ensure ef cient usage of lter media for wastewater treatment• To avoid ooding• to avo d d a h o lan• To avoid mosquito growth due to ooding.

How should this task be done?STEp 11. O n h cov r lab o h ou l cha b r.STEp 21. Ch ck h w v l o a 50c ro h bo o o h ou l cha bSTEp 3

1. i h w v l o no a h d r d l v l, low r or ra un l hw v l 50c ro h bo o o h ou l cha b r

2. If there is no water ow from top of the swivel pipe1, ch ck or l akag a h w v l jo n a h bo o . i an l akag ound, n or h con rac or o r c immediately. If the condition prevails even after recti cation, report it to CDD Society orits certi ed service provider.

ta k 8.Check for swivel pipe level in the planted gravel lter

50 c

NOTES

1. Swivel i e:th a d v cwh ch can b u d

o r gula hwa r l v l n h

lan d grav llter.




1

Weeding and cleaning of litter

Where should this task be done?• In side the planted gravel lter• On h ur ac o ol h ng ond• Around all h r a n odul .

When should this task be done?• Onc n 30 da• or, n h ollow ng ca

—th r xc w d or/and l r.

Why should this task be done?• To avoid rotting of dead leaf litter in the planted gravel lter and polishing pond• To avoid clogging of lter material in the planted gravel lter• to avo d alga bloo1 n h ol h ng ond• to x o r a d wa r n h ol h ng ond o h a o h r and o h • to a n a n h cl anl n and o ncr a a h c n ar h r a n

How should this task be done?STEp 11. Check for presence of dead leaf litter or/and weed inside the planted gravel lter and

ol h ng ond2. Ch ck or w d and o h r l r around all h r a n odul3. Ch ck or xc ( or han 60% cov rag o wa r ur ac ) alga n d h

ond.

STEp 21. i h d ad l a l r or o h r l r r n , r ov anuall or u n

tool (garden rake, sh net and sieve)2. W d hould b r ov d b x rac ng h roo al o3. Remove excess algae in the polishing pond using a sh net.

Pond with algae growth

Alga grow h

ta k 9.Weeding, removal of dead leaf litter and other litter

NOTES

1. Algae bloom:exc v grow ho alga n a wa rbod du o h ghnu r n con n .




1

1.0 DEWATS modules descri tion

1.1 primary Treatment (pre treatment)1. Grease traps are used as pretreatment steps to retain oil and grease by otation, while

cl ar r wa r und rn a h d charg d n o h ollow ng r a n odul . th wa r a n d n h un or 2 o 4 nu .

2. s l r ar d n a on ank or r a n ng all ha nk n a g v n . organ c a r r a n d n h ank , wh l all h r (d olv d and u nd

a un r a d o h ollow ng r a n odul . th wa wa r r a n d or 1.5 o 2 hour .

3. B oga l r ar d n a on ank or r a n ng all ha nk ( l. B oga or d du o h d co o on (d g on) o l d organ c

call d ana rob c d g on. All h r (d olv d and u nd d ar cl ) a uo h ollow ng r a n odul . th wa wa r r a n d n h un or 12

A endix

Grease + Oil

Sand/ Silt

OutletInlet

Floating material(plastic, organicmatters etc)Biogas

OutletInlet

Retained material(sand/ slit, organicmatters, papers etc)

Retainedmaterial(sand/ silt,organicmatters,papers etc.)

Inlet

Gas release Floating material (plastics, organicmatters etc.)

Outlet




1

1.2 Secondary treatment1. Baf e reactors ensure anaerobic degradation of suspended and dissolved solids by

x ng wa wa r w h ac v ludg blank – h ar na urall occurr ng that accumulate in the bottom of each chamber. The baf e reactor is suitable for all kinds

of organic wastewater and its ef ciency increases with more organics in the water (thed r r h b r). th wa wa r r a n d n h un or 1 o 2 da .

2. Anaerobic xed bed lters make use of anaerobic digestion process with xed bedlter—these are stones or other material in chambers. Active bacterial mass grows on thelter material (carrier). These units treat whatever is dissolved in the wastewater by bringing

it in close contact with active bacteria mass. The lter media can be cinder, rock aggregates,lag, or c all d gn d la c a r al c. th un ar d al or wa

con n o u nd d ol d . th wa wa r r a n d n h un or 1.5

Plants

Gravel/Pebbles

InternalWater Level

ManholeInlet

Outlet

O2 O2 O2 O2

1.3 Tertiary treatment1. Horizontal Planted Gravel Filter: The horizontal gravel lter is a shallow tank lled with

Inlet Outlet

Gas release

Fixed BedFilter

A endix

Inlet

Gasrelease Floating Material (Scum)

Outlet

Sludge blanket




1

graded gravel or pebbles, and special plants are planted in this gravel lter. The normald h 60c . th a n r oval chan ar b olog cal conv r on, h cal

ltration and chemical adsorption. Plants commonly used are canas indica, reed juncas,phragmites etc. The lters clean the wastewater by retaining particles and digesting them

w h h h l o bac r a grow ng na urall on h grav l/ bbl . i or an of air (oxygen) into the lter body. The plants help with transporting oxygen through theirroo . Wa wa r r a n d n h un b w n 5 o 10 da .

Inlet

Sun radiation

Outlet

Sinking material(mainly algae)

1. post Treatment1. pol h ng pond: th ol h ng ond a hallow ond wh r a hog n r oval ak

lac . th a n ur o o ond ox g n nr ch n and l na on o a hoghrough un’ rad a on. floa ng aqua c lan can h l con rol algal grow h and akl a an land ca a ur d r d. Wa wa r r a n d n h un or

A endix



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This publication of BORDA was prepared with the nancial assistance of G r an f d ral m n r or econo c Coo ra on and D v lo nth euro an Co on andth fr Han a c C o Br n

publ h d n ind a bCon or u or DeWAts D na on (CDD) soc#220, 4 h A Cro , 3rd Block, H R B R La ou , Kal an Nagar, Bangalor 560 043,Karna aka, ind a, 2008

G r an f d ral m n ror econo c Coo ra on

and D v lo n

D

i g n

d b y

D e s

i g n

D i f f e r e n c e

C o c h

i n

o m Manual Dewat Technology

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