Need of tertiary treatment for anaerobic wastewater treatment

1. LLeeccttuurree oonn
Need of tertiary treatment for
anaerobic wastewater treatment
by
Dr. Arvind Kumar Mungray
B. Tech., M. Tech., Ph.D.
CHEMICAL ENGINEERING DEPARTMENT
SARDAR VALLABHBHAI NATIONAL INSTITUTE OF TECHNOLOGY,
SURAT 395 007

2. Municipal wastewater
Components.
Sewage

3. Point sources
 Wastes tthhaatt aarree ccoolllleecctteedd iinn ppiippeess oorr
cchhaannnneellss aanndd ddiisscchhaarrggeedd ttoo aa ssuurrffaaccee wwaatteerr
wwiitthh oorr wwiitthhoouutt ttrreeaattmmeenntt
 DDiissttiinngguuiisshheedd bbyy ssoouurrccee
mmuunniicciippaall sseewwaaggee oorr wwaasstteewwaatteerr
iinndduussttrriiaall wwaassttee wwaatteerrss
ccoommbbiinneedd sseewweerrss aanndd ccoommbbiinneedd sseewweerr
oovveerrfflloowwss

4. Nonpoint sources
 Storm water runoff ddiisscchhaarrggeedd aatt mmuullttiippllee
ppooiinnttss
 VVaarriieess ssuubbssttaannttiiaallllyy wwiitthh uussee ooff tthhee llaanndd rruunnooffff
oorriiggiinnaatteess ffrroomm
aaggrriiccuullttuurraall
uurrbbaann
ccoommmmeerrcciiaall
ssppeecciiaall ((ee..gg.. ggoollff ccoouurrsseess))

5. Municipal Wastewater

6. IMPORTANT WASTEWATER
CONSTITUENTS
 Dissolved ssoolliiddss ((TTDDSS//SSaallttss)) :: lleessss IImmppoorrttaannccee
 SSuussppeennddeedd ssoolliiddss:: ((SSSS))
 BBiiooddeeggrraaddaabbllee oorrggaanniiccss:: OOrrggaanniicc mmaatttteerr ((BBOODD))
 NNuuttrriieennttss –– NNiittrrooggeenn && PPhhoosspphhoorruuss.. ((IImmppoorrttaanntt
iiff ttrreeaatteedd wwaasstteewwaatteerr iiss ddiisscchhaarrggeedd iinnttoo llaakkeess))
 HHeeaavvyy mmeettaallss –– CCrr,, CCdd,, HHgg,, PPbb :: lleessss iimmppoorrttaannccee
 RReeffrraaccttoorryy oorrggaanniiccss:: CCFFCC,, BBeennzzeennee eettcc..:: lleessss
iimmppoorrttaannccee,,
 PPaatthhooggeennss –– TTrraannssmmiitt ddiisseeaassee

7. T O W N
CREMATORIA
RFD
LCS
R I V E R
FOR
IRRIGATION
TREATED
EFFLUENT
SEWER
RFD
NALLAS
INDUSTRY
ETP
STP
PUMPING
STATION

8. Significance of Wastewater
Contaminants
 Dissolved ssoolliiddss –– iinntteerrffeerree wwiitthh rreeuussee
 SSuussppeennddeedd ssoolliiddss –– ccaann ccaauussee sslluuddggee ddeeppoossiittss
aanndd aannaaeerroobbiicc ccoonnddiittiioonnss iinn tthhee eennvviirroonnmmeenntt
 BBiiooddeeggrraaddaabbllee oorrggaanniiccss –– ccaann ccaauussee aannaaeerroobbiicc
ccoonnddiittiioonnss iinn tthhee eennvviirroonnmmeenntt
 PPaatthhooggeennss –– ttrraannssmmiitt ddiisseeaassee
 NNuuttrriieennttss –– ccaann ccaauussee eeuuttrroopphhiiccaattiioonn
 HHeeaavvyy mmeettaallss –– ttooxxiicciittyy ttoo bbiioottaa aanndd hhuummaannss

9. What we can Do ?
AAnnyy SSoolluuttiioonn

10. - Wastewater Treatment -

11. Objectives of Wastewater
Treatment
 Removal of Suspended SSoolliiddss bbyy CCllaarriiffiiccaattiioonn (( IInn
SSeeddiimmeennttaattiioonn TTaannkk))&& DDeeccoommppoossiittiioonn ((BByy pprroovviiddiinngg
SSuuiittaabbllee ccoonnddiittiioonnss ffoorr bbaacctteerriiaa))
 RReemmoovvaall ooff OOrrggaanniiccss bbyy DDeeccoommppoossiittiioonn ((BByy
pprroovviiddiinngg SSuuiittaabbllee ccoonnddiittiioonnss ffoorr bbaacctteerriiaa)) && PPrroovviiddee
ccoonnddiittiioonnss ffoorr sseeppaarraattiioonn ooff tthhee wwaasstteewwaatteerr ffrroomm tthhee
BBaacctteerriiaa..
 RReemmoovvaall ooff RReessiidduuaall bbaacctteerriiaa pprreesseenntt iinn sseeppaarraatteedd
wwaasstteewwaatteerr bbyy aaddddiinngg ppoowweerrffuull ooxxiiddaannttss ssuucchh aass
CChhlloorriinnee..

12. Treated Quality Standards
IINNTTOO WWAATTEERR BBOODDYY OONN LLAANNDD
BBOODD ((mmgg//ll))
CCOODD ((mmgg//LL))
TT SS SS ((mmgg//ll))
FFAAEECCAALL ((MMPPNN//110000 mmll))
CCOOLLIIFFOORRMMSS
3300
225500
110000
11000000
1100000000
110000
220000
((DDeessiirraabbllee))
((MMaaxxiimmuumm))

13. To Bring the River Water to Bathing Quality
( River Bathing Standards)
PPAARRAAMMEETTEERRSS PPEERRMMIISSSSIIBBLLEE LLIIMMIITT
BBOODD 33 mmgg//LL ((MMAAXXIIMMUUMM))
DDOO 55 mmgg//LL ((MMIINNIIMMUUMM))
CCOOLLIIFFOORRMM ((FFAAEECCAALL)) 550000 ((DDEESSIIRRAABBLLEE))
22550000 ((MMAAXX.. PPEERRMMIISSSSIIBBLLEE))
BBOODD - BBIIOO-CCHHEEMMIICCAALL OOXXYYGGEENN DDEEMMAANNDD
DDOO - DDIISSSSOOLLVVEEDD OOXXYYGGEENN
MMPPNN - MMOOSSTT PPRROOBBAABBLLEE NNUUMMBBEERR
MPN
100 ml

14. Treatment of wastewaters
• Aerobic
• Anaerobic
S.V. National Institute of Technology, Surat

15. AAeerroobbiicc MMeetthhooddss
– AAccttiivvaatteedd SSlluuddggee PPrroocceessss
– TTrriicckklliinngg FFiilltteerrss
– EExxtteennddeedd AAeerraattiioonn SSyysstteemm
– SSttaabbiilliizzaattiioonn PPoonnddss
– OOxxiiddaattiioonn DDiittcchheess
– LLaaggoooonnss
AAnnaaeerroobbiicc MMeetthhooddss
– UUAASSBB PPrroocceessss
– AAnnaaeerroobbiicc PPoonnddss
– AAnnaaeerroobbiicc FFiilltteerrss

16. AEROBIC PROCESS
Organic
Pollution
Nutrients
O2
Aerobic
Micro-organisms
CO2+H2O+New Cells

17. ANAEROBIC PROCESS

18. AEROBIC METHOD

19. ANAEROBIC METHOD
(UASB PROCESS)

20. Sewage Treatment
Plant

21. Anaerobic degradation process
Step General process Description Notes
1
HHyyddrroollyyssiiss
Acid
production
Methane
production
Carbohydrates, lipids, proteins
broken down to low molecular weight
compounds by enzymes.
Acidogenesis – amino acids
converted to volatile fatty acids
(VFAs)
Acetogenesis – VFAs, lactic acid etc
converted to acetic acid, H2, CO2
Acetotrophic methanogensis – Acetic
acid converted to CO2 and CH4
Hydrogenotrophic methanogensis –
H2 and CO2 converted to CO2 and CH4
2
3
Rate limiting.
Temperature
dependant
Not rate
limiting
Rate
limiting.
Temperature
dependant

22. Overview Anaerobic Biodegradation
Polymers
(proteins, polysaccharides)
h
Monomers
(sugars, amino acids, peptides)
propionate
butyrate
H2 + CO2 acetate
4 4
CH4 + CO2
h
1
1 1
1
2 2
2
3
3
4
Hydrolytic enzymes
Fermentative bacteria
Syntrophic acetogenic bacteria
Homoacetogenic bacteria
Methanogens
Methanogenic
Consortium

23. Types of anaerobic reactors
Low rate anaerobic reactors High rate anaerobic reactors
Anaerobic pond
Septic tank
Imhoff tank
Standard rate
anaerobic digester
Slurry type bioreactor, temperature,
mixing, SRT or other environmental
conditions are not regulated. Loading
of 1-2 kg COD/m3-day..
Anaerobic contact process
Anaerobic filter (AF)
Upflow anaerobic slugde
Blanket (UASB)
Fluidized bed Reactor
Hybrid reactor: UASB/AF
Anaerobic Sequencing Batch
Reactor (ASBR)
Able to retain very high concentration of
active biomass in the reactor. Thus
extremely high SRT could be maintained
irrespective of HRT. Load 5-20 kg COD/m3-d
COD removal efficiency : 80-90% .

24. Up-Flow Anaerobic Sludge Blanket Reactor (UASB)
S.V. National Institute of Technology, Surat

25. Granules

26. Effluent
Influent
UASB Reactor
biogas

27. Physical:
Microbial:
Anaerobic Sludge Granules
dense compact biofilms
high settleability
high mechanical strength
balanced microbial community
syntrophic partners closely associated
high methanogenic activity
(0.5 to 2.0 g COD/g VSS.d)
protection from toxic shock
(30-80 m/h)

28. Anaerobic Sludge Granules (close up)

30. Anaerobic Sludge Granules (settling)
granular flocculent dispersed

32. Who Discovered the UASB?
Gatze Lettinga

33. raw
wastewater
screens
grit trap
to grit disposal
splitter box
UASB
reactor
gas
holder
excess
flared
facultative lagoon
effluent to reuse or disposal
sludge to agriculture
sludge drying beds
UASB
reactor

34. struvite
precipitation
reuse
discharge
black
water
kitchen
waste
gray water
biogas
UASB-septic
nutrient rich
product
Nirogen
removal
Removal
micro-pollutants
(ozone)
sludge
hygienisation
treatment
Landbouw?

35. UASB Reactor

36. Side Views of UASB Reactor

37. Top View of UASB Reactor

38. Salient Features of UASB
LLooww EEnneerrggyy CCoonnssuummppttiioonn ((AAllmmoosstt NNiill))
CCoommppaarraattiivveellyy LLooww CCaappiittaall CCoossttss
GGoooodd rreemmoovvaall EEffffiicciieenncciieess
GGeenneerraattiioonn ooff MMeetthhaannee GGaass ((EEnneerrggyy RReeccoovveerryy))
SSmmaallll LLaanndd AArreeaa RReeqquuiirreemmeennttss
LLooww SSlluuddggee PPrroodduuccttiioonn
NN,,PP,,KK CCoonncc.. aarree RReettaaiinneedd iinn TTrreeaatteedd EEffffiicciieennccyy
SSiimmppllee CCoonnssttrruuccttiioonn,, OOppeerraattiioonn MMaaiinntteennaannccee

39. Removal Efficiencies
 TTSSSS 7700--8855%%
 BBOODD 6655--7755%%
 CCOODD 7700--8800%%
 FFeeaaccaall CCoolliiffoorrmm 9999%%

40. Development of UASB
Technology in India
Bilateral cooperation between India and Netherlands in 1985 led to
the design and construction of first successful full scale UASB reactor
for domestic sewage at Kanpur. This demonstration plant was designed
to treat 5 ML/d of raw sewage at 6 h HRT with influent BOD and COD
of 200 and 500 mg/L respectively.
One more UASB based treatment plant (36 ML/d) built in Kanpur to
treat the wastewater of approximately 180 tanneries after dilution with
domestic wastewater in a ratio of 1:3 is in operation since April 1994.

41. UASB TREATMENT PLANTS
under Ganga Action Plan
5 MLD UASB Demonstration PPllaanntt aatt
KKaannppuurr
1144 MMLLDD UUAASSBB SSTTPP aatt MMiirrzzaappuurr
3366 MMLLDD UUAASSBB CCEETTPP aatt KKaannppuurr

42. Up-Flow Anaerobic Sludge Blanket (UASB)
Reactors
 The UASB reactor iiss tthhee mmoosstt wwiiddeellyy uusseedd hhiigghh rraattee aannaaeerroobbiicc
ssyysstteemm ffoorr ttrreeaattmmeenntt..
 WWoorrlldd wwiiddee mmoorree tthhaann 550000 aallrreeaaddyy iinnssttaalllleedd..
 MMoorree tthhaann 3355 UUAASSBB bbaasseedd iinn IInnddiiaa

43. More than 900 UASB units are
currently operating all over the
world.
16 full scale UASB based STP (598 ML/d)

44. UASB
UASB
ASP
ASP
OP
OP
Roorkee
Locations of STPs selected for the study with
their treatment capacities.

45. (a) COD
600
500
400
300
200
100
0
27 34 38 56 70
COD (mg/L)
Total Filterable
COD: Discharge standard = 250 mg/L
CODt = 100- 159 mg/L
CODs = 70 – 90 mg/L
(BOD/COD)eff = 0.29

46. (b) BOD
250
200
150
100
50
0
27 34 38 56 70
BOD (mg/L)
Total Filterable
Mean unfiltered BOD (3d, 270 C) = 33 – 43 mg/L
Discharge limit = 30 mg/L
Marginal improvement required
Mean filterable BOD (3d, 270C) = 25.6 – 28.7 mg/L

47. (c) TSS, VSS
600
500
400
300
200
100
0
27 34 38 56 70
TSS, VSS (mg/L)
TSS VSS
TSS = 124 – 155 mg/L
TSS 100 mg/L

48. Main advantage: Energy can be generated
11 kkgg CCOODD == 00..3355 mm33 CCHH44
ccoommpplleettee aannaaeerroobbiicc ddeeggrraaddaattiioonn ooff 11 KKgg
CCOODD pprroodduucceess 00..3355 mm33 CCHH44 aatt SSTTPP

49. Table: UASB Based Sewage Treatment Plants in India
Town Capacity
(ML/d)
Town Capacity
(ML/d)
Town Capacity
(ML/d)
Kanpur 5 Panipat 35 Ghaziabad 70
Kanpur 36 Sonipat 30 Ghaziabad 56
Mirzapur 14 Faridabad 20 Noida 27
Yamuna
25 Faridabad 45 Noida 34
Nagar
Yamuna
Nagar
10 Faridabad 50 Agra 78
Karnal 40 Gurgaon 30 Hydrabad 50
Panipat 10 Saharanp
ur
38 Kabitkhadi 78
Kapurthala 25 Mohali 45 Jalandhar 25
Vadodara 43 Surat 100

50. Review of UASB process removal efficiency in India
Place V
(m3)
T
(ºC)
Influent concentration
(mg/L)
COD BOD
TSS
HRT
(h)
Removal efficiency (%)
COD BOD
TSS
Reference
India 1200 20-
30
563 214 418 6 74 75 75 Draaijer et al.,1992
India 12000 18-
32
1183 484 1000 8 5 1
63
53 69 46 64 Haskoning, 1996; et al., 1997
India --- -- 387 195 360 -- 57 64 66 Hammad 1996
India 6000 18-
32
404 205 362 8 62 72 65 71 70 78 Haskoning, 1996b;
Tare et al., 1997
India 36000 -- 1180 480 1000 -- 56 61 55 Wiegant et al., 1999
India 36000 -- 838 398 846 --- 52 50 56 Tare et al., 2003
India -- -- 315
403
-- 162
836
4.49
5.49
45 78 -- 45 76 Ghangrekar and
Kahalekar, 2003
India
(15-
UASBs)
(10-
78) x
106
18.8-
23.8
754 258 410 8.4
10.7
46.5 49.6 7.31 Sato et al., 2006
India
(5
UASBs)
(27-
70) x
106
--- 373
452
159
175
324
419
9.4
10.3
42 55 55 69 30 43 Mungray , 2007

51. SSTTAANNDDAARRDDSS FFOORR TTRREEAATTEEDD SSEEWWAAGGEE
IINNDDIIAANN SSTTAANNDDAARRDDSS
FFOORR DDIISSCCHHAARRGGEE
IINNTTOO WWAATTEERR BBOODDYY PPUUBBLLIICC SSEEWWEERRSS
BBOODD (mmgg//LL))
CCOODD (mmgg//LL))
TT SS SS (mmgg//LL))
FFAAEECCAALL (MMPPNN//110000 mmll))
CCOOLLIIFFOORRMMSS
3300
225500
110000
11000000
1100000000
550000
660000
(DDeessiirraabbllee))
(MMaaxxiimmuumm))
pH 5.5-9
Oil Grease 10 100
Temp 40 45

52. Main limitations of anaerobic systems
(1) Limitations regarding organic matter
Does not follow the discharge standards in terms of BOD, COD
Requires post treatment step.
UASB Effluent BOD: 60-120 mg/L
BOD removal Efficiency: 55 - 75%

53. (2)Limitations regarding nitrogen and phosphorous
Discharge of nutrients in to surface water may caused
increased algal biomass = eutrophication
1.0 Kg of phosphorous can result in the reconstruction of
111 Kg of biomass = which corresponds to approx. 138 Kg of COD
1 Kg of Nitrogen can result in the reconstruction of Approx.
20 Kg COD under the form of dead algae

54.  (3) Limitations regarding
microbiological indicators
 Pathogens = 10,000 MPN/100 ml
(Maximum)
 = 1000 MPN/100 ml
(Desirable)

55. Post-Treatment Options
 FFiinnaall PPoolliisshhiinngg PPoonnddss
 AAeerraatteedd LLaaggoooonnss
 OOvveerrllaanndd ffllooww ssyysstteemm
 AAccttiivvaatteedd sslluuddggee
 TTrriicckklliinngg ffiilltteerr
 CCoonnssttrruuccttiioonn wweettllaannddss
 CCoommbbiinnaattiioonn ooff AAeerraatteedd LLaaggoooonn PPoonnddss
 DDoowwnn HHaannggiinngg SSppoonnggeedd MMeeddiiaa SSyysstteemm

56. Post treatment of UASB effluents
TThhee mmaaiinn rroollee ooff tthhee ppoosstt--ttrreeaattmmeenntt iiss ttoo ccoommpplleettee
tthhee rreemmoovvaall ooff oorrggaanniicc mmaatttteerr,, aass wweellll aass ttoo
rreemmoovvee ccoonnssttiittuueennttss lliittttllee aaffffeecctteedd bbyy tthhee
aannaaeerroobbiicc ttrreeaattmmeenntt,, ssuucchh aass nnuuttrriieennttss ((NN aanndd PP))
aanndd ppaatthhooggeenniicc oorrggaanniissmmss ((vviirruusseess,, bbaacctteerriiaa,,
pprroottoozzooaannss aanndd hheellmmiinntthhss))..
LLiimmiittaattiioonnss iimmppoosseedd bbyy eennvviirroonnmmeennttaall aaggeenncciieess
ffoorr eefffflluueenntt ddiisscchhaarrggee ssttaannddaarrddss..

59. Treatment plant with UASB reactor Overland flow system

60. Treatment plant with UASB reactor Submerged ABF

61. Treatment plant with UASB reactor and Anaerobic filter

62. Treatment plant with UASB reactor and Trickling filter

63. Treatment plant with UASB reactor and polishing ponds
Raw
sewage
Screen chambers
Polishing Ponds (PP)
Grit channels
UASB reactors
Sludge drying beds (SDB)
Screenings Grit
Wet UASB
sludge
Final effluent
Dried sludge
1 2
3
4 5
SCHEMATIC FLOW-DIAGRAM OF UASB BASED STP

64. PPoolliisshhiinngg ppoonnddss

65. Down Hanging Sponged Media (DHS)

66. Top View of DHS

67. Effluent from UASB
Raw sewage
Effluent from PP
Effluent from DHS

68. Post treatment process efficiency
CCoouunnttrryy HHRRTT UUAASSBB eefffflluueenntt ((mmgg//LL))
CCOODD BBOODD SSSS
PPoosstt
TTrreeaattmmeenntt
HHRRTT EEfffflluueenntt ccoonncceennttrraattiioonn ((mmgg//LL))
CCOODD BBOODD SSSS
BBrraazziill 77hhrr 112266 4422 5511 OOzzoonnaattiioonn 5500mmiinn 5533 2200 1133
IInnddiiaa ---- 117700 7700 112244 FFPPUU ------ 8833 3366 5566
BBrraazziill ------ 111122 ------ 1144 AAFF 2244 6600 ------ 2299
BBrraazziill 44--66 hhrr 2233..33 1100 3377 BBFF 44hhrr 3366 99 1100
BBrraazziill 88hhrr 111122 3366 3377 SSuubbmmeerrggeedd
AABBFF
11..55mm33//mm22..
hh
3388 3366 1100
IIssrraaeell 55 ddaayyss 112266±±8811 2233±±1133 3355±±3300 DDWW 44..77 ddaayyss 4499±±2200 88±±1155 1111±±44
BBeellggiiuumm 1100 hhrr 5533±±2288 2255±±66 3355±±44 ZZeeoolliittee ---- 4455±±66 ---- ----
IInnddiiaa 55ddaayyss 660000 ---- 7700 SSBBRR 88 ddaayyss 110000 ---- ----
BBrraazziill 77..55hhrr ------ 4466 6600 PPPP 44..22hhrr ---- 4400 110088
JJaappaann 88hhrr 117788 6677 4477 DDHHSS 22..77 4433 22..33 1122
JJaappaann 66hhrr 222266..88 113366 4400..99 DDHHSS 22..55hhrr 6622 1166..55 1177..55
IInnddiiaa 99..44--1100..33hh ------ 220000 4400 PPPP 11--11..66dd ------ -------- ----------
DHS = Down Flow Hanging Sponge, RBC = Rotating Biological Contactor, FPU = Final Polishing unit, AF = Aerated Filter, BF = Biofilters, ABF =
Aerated Biofilters, PP = Polishing ponds, DW = Duckweed.
S.V. National Institute of Technology, Surat

69. ¨ INDIA
D UASB, Vadodara
¨ UASB, Surat
D
Locations of STPs selected for the study with their treatment capacities.
43 ML/d UASB, Vadodara
100 ML/d UASB, Surat

70. Fig. Flow diagram in UASB + post treatment unit

71. Surface
Aeration
System
Fig. Photograph of Surface Aeration Tank at 43
ML/d UASB based STP at Vadodara

72. Diffusion
Aeration
System
Fig. Photograph of Diffusion Aeration Tank at 100 ML/d UASB
based STP at Surat

73. Parameters for 43 ML/d and 100 ML/d STP.
Sampling
Parameters
Sampling Points
UASBR + Surface Aeration
( Vadodara)
UASBR + Diffused Aeration
( Surat)
Raw
Sewage
UASB
Effluent
Final
Effluent
Raw
Sewage
UASB
Effluent
Final
Effluent
pH 7.33 7.18 7.58 7.12 6.78 7.18
Dissolved oxygen
0.11 0.12 2.66 0.12 0.08 4.31
(mg/L)
Total COD (mg/L) 878.47 514.93 124.00 726.87 405.00 128.47
Filtered COD (mg/L) 336.47 186.53 55.07 330.73 160.60 52.60
Total BOD (mg/L) 229.67 115.33 15.87 256.60 153.27 16.40
Filtered BOD (mg/L) 88.47 58.80 7.07 78.40 52.67 9.40
Suspended solids (mg/
214.6 113.07 84.267 261.4 167.267 93.8
L)
Total Coliform
( MPN/100 ml )
8x1012 5x107 5.71 x105 2.7 x1012 1.9 x107 6.7 x105
Fecal Coliform
( MPN/100 ml )
3x1012 1.93x1
07
3.67 x105 1.0x1010 6.8 x106 2.2 x105

74. Feed Tank
( FT)
Gas
Collection
Chamber
Peristaltic
Pump
UASB
Reactor
Cascade Sponge Reactor (CSR)
Final
Effluent
FIG.16
Schematic flow-diagram of Experiment.

75. FIG.17 FIG.18
Prior to start up of CSR
(Cascade Sponge Reactor)
After accumulation of biomass on
CSR (Cascade Sponge Reactor)

76. SEM images of clean
Sponge at 7 x.
SEM images of accumulation
of biomass on Sponge at 7 x.

77. SEM images of measurement of pore size of Sponge at 50 x.

78. y = 0.9971x - 0.1533
R2 = 0.9926
3
2.5
2
1.5
1
0.5
0
0 1 2 3
OLR (KgCOD/m3.d)
COD Removal
Rate(KgCODm3.d)
FIG.68
Variation of COD removal rate according to OLR (Organic
Loading Rate)

79. (A) (B) (C)
Appearance of (A) Raw sewage (B) UASB effluent (C) CSR effluent

80. Conclusions
Of all the anaerobic wastewater treatment process
currently being used, the UASB process has excellent potential to
become highly competitive for municipal wastewater treatment.
However treated effluent from UASB contains significant
amounts of organics, nutrients, sulphide and fecal coliform. When
discharge to the environment creates risk to aquatic and terrestrial
region. So there is a need of post treatment for the UASB effluent
before discharging it to the surface water or terrestrial region. It
can be concluded that all these technologies are feasible for the
post treatment of UASB effluents for satisfying the discharge
standards in surface waters.

81. THANK YOU