www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986www.ecotech-india.com
PIONEERS & LEADERS IN WASTEWATER TREATMENT
Dr. Ananth S Kodavasal
Director
Sewage Treatment Eye
Openers
www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
An assessment of various technologies
March 2019Presented for ADDA Water Workshop

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
THREE CARDINAL
LAWS FOR A
GOOD STP
PROPER
DESIGN
PROPER
ENGINEERING
PROPER
OPERATION &
MAINTENANCE

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
THE ZEROTH LAW
SELECTION OF THE APPROPRIATE
TREATMENT TECHNOLOGY

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
wrong technology
2500 STPs
IN BANGALORE
350 MLD SEWAGE
80% STPS ARE DEFUNCT
incorrect design
poor engineering
huge operation & maintenance

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
wrong technology
600 STPs
IN PUNE
100 MLD SEWAGE
80% STPS ARE DEFUNCT
incorrect design
poor engineering
huge operation & maintenance

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Bangalore suffers from SBR itis
Pune suffers from MBBR itis
STP diseases – the Dr.’s diagnosis

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
typical naïve STP tender from architect
“The vendor may select any
process as per their area of
expertise and proprietary
design…”

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
typical naïve STP tender from architect
“…acceptable technologies include
Extended Aeration, SBR, FAB,
SAFF, FBBR, RBC, MBR…”

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
typical naïve STP tender from architect
“…anaerobic systems like UASB,
Septic tank…physical/chemical like
enzyme activated …electrolysis…”

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
An Experienced Consultant must :
Specify the most appropriate
technology, and not the one the
vendor is “comfortable” with

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
huge fresh water
savings potential
over Rs. 1600 crore
in STP assets in
Bangalore 20-25% investment
enough to revamp
2000 defunct STPs
protect waterbodies

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
COMMUNITIES CAN BE 60%
SELF-SUFFICIENT IN WATER
BEYOND 100 KLD, STP
MAKES MONEY
PAYBACK PERIOD
IS MONTHS

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Classic EAAS
Anaerobic
CAACO
EADOX
SBR
MBBR/Fixed
MBR
STP TECHNOLOGIES
PREVALENT IN BANGALORE

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
CLASSIC, CONVENTIONAL
EXTENDED AERATION ACTIVATED SLUDGE
IS BEST

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
1 | Extended Aeration Activated Sludge
(EAAS)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
sludge
recirculation
1. bar
screen
2. grease
trap
3. equalisation
tank
(aerated)
4.
aeration
tank
5. settling
tank
filtratio
n
treated
water
excess sludge
Stages 3 & 4 allow for
extended aeration
sludge recirculation – activated sludge
EAAS SYSTEM

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
EAAS WITHIN
72 HOURS

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
2 | Moving Bed Biofilm Reactor (MBBR)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MOVING BED
BIOREACTOR
(MBBR)
PRIMARY SEDIMENTATION ISSUES
SLUDGE HANDLING ISSUES
POORLY DESIGNED & ENGINEERED
NOT APPROPRIATE FOR SMALL STPS
PLASTIC MEDIA TO INCREASE
SURFACE AREA

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
PROF. HALLVARD ODEGAARD OF NORWAY
INVENTED MBBR IN LATE ‘80S (NOT NEW TECH)
PROPER PRIMARY SEDIMENTATION IS A MUST
UNDER ALL CIRCUMSTANCES
THE MBBRS WE HAVE INSPECTED SKIP THIS AND JUST END UP
TANKERING OUT THE SLUDGE (BAD !)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Original Genuine MBBR
▪ Originally developed by Norwegian University of
Science & Technology with M/S Anox Kaldnes of
Norway (Now Veolia)
▪ Every treatment flowsheet requires primary
solids removal – Crux of an MBBR System

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Typical issues with MBBRs in India
▪ No primary sedimentation
▪ Primary sewage solids (faeces) cannot be
digested in small MBBRs in less time
▪ Generic plastic carrier media used (Density,
Roughness, Surface Area - not tailor made )
▪ Cannot transfer more Oxygen in less time using
Coarse Bubble Diffusers

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MBBR issues (cont’d)
▪ Fine Bubble Diffuser cannot be used due to
media interference (have to use less efficient
coarse bubble diffuser)
▪ Shallow MBBR tanks – less efficient oxygen
transfer
▪ Primary solids (faeces) slip out of MBBR tank
▪ Dead microbes slough off from MBBR tank

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MBBR issues (cont’d)
▪ Plate/tube settler cannot be used for Biomass
settling ( This is WTP legacy for chemical sludge)
▪ Sludge/solids adhere to plate/tubes and then
become septic and escape out
▪ Thin slurry from plate settler difficult to dewater
▪ Sludge requires thickening, digestion,
conditioning before dewatering

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Plastic Carrier Media for MBBR
developed by
Anox Kaldness

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Fig. 1 – What is
actually used in
MBBRs in India
Fig. 2 – What should be used:
Anox Kaldness MBBR media
with microbial coating

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
The Big Question then?
Question #1
If dead or dying microbes along with some living
microbes on the outside can float out of any
MBBR tank, why can they not do the same in the
settling tank? MBBR Tank Cross Section is much
larger!

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
The Big Question then?
Question #2
If microbes can attach to plastic media under
turbulent conditions in the MBBR tank, why will
they not attach to the plastic tube/plate in the
secondary settler under calm, quiescent
conditions?

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MBBR sludge difficult to handle
▪ Without primary settling, human faeces slip out
of MBBR tank
▪ Solids slipping out of MBBR tank are inherently
difficult to settle, fluffy, light, do not dewater
▪ Need thickening, digestion, conditioning

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MBBRs we have seen in recent times
▪ No primary sedimentation
▪ Less than 50% treatment
▪ Filter press never used
▪ Sludge tankered out (ILLEGAL!)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MBBRs we have seen in recent times
▪ Not one MBBR STP working per design
▪ Have converted many MBBRs to EAAS
▪ In Pune-Hinjewadi 220 KLD, and 435 KLD in
Kharadi

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
EAAS versus MBBR

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Lifecycle of microbes

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
A genuine, well-engineered MBBR

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
A genuine, well-engineered EAAS

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
EAAS : SUSPENDED GROWTH REGIME
SLUDGE RECIRCULATION
MBBR : ATTACHED GROWTH REGIME
PRIMARY SEDIMENTATION
NO SLUDGE RECIRCULATION
Key differences EAAS vs MBBR

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
3 | Sequencing Batch Reactor (SBR)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
1
fill wastewater
2
react
3
settle
4
decant
5
idle
waste
sludge
treated
water
aeration
aeration
NO ISSUES WITH TECHNOLOGY
AIMS TO SAVE SPACE & ENERGY
SEQUENCING BATCH REACTOR (SBR)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MOTORISED DECANTERS NEEDED
SLUDGE ENTERS
DECANT WATER
BUT RUDIMENTARY DECANTERS USED
FOULS TERTIARY FILTERS & OPERATOR WILL JUST
BYPASS
DECANT TANK WITH SLUDGE GOES SEPTIC

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Motorised
Decanter
required for proper
treatment, but never
used

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
DECANT
VELOCITY
3000
TIMES
SETTLING
VELOCITY
DECANT ISSUES

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
AREA AND POWER MYTHS
OVERSIZED COLLECTION TANK FOR SMALL STPS TO
DEAL WITH 8 HOURS OF EFFLUENT
POWER SAVINGS ONLY WITH
TWO SETS OF AIR BLOWERS
AREA & POWER BENEFITS ONLY FOR
LARGE PLANTS BEYOND 10 MLD

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
INAPPROPRIATE FOR SMALL STPS – RESIDENTIAL,
COMMERCIAL
DISTINCT PEAK FLOWS REQUIRE LARGER
EQUALISATION TANK
DECANT ONLY 33% OF AT VOLUME →LARGER
AERATION TANK NEEDED
ODOUR NUISANCE, MORE ENERGY, LARGER
FOOTPRINT, MORE EQPTS

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
EAAS versus SBR (qualitative)
Sl. Existing SBR Proposed EAAS Remarks
1
Inappropriate Technology for
res. complexes
Most suitable for Mini, Small STP* See PPT*
2 Large Footprint Smaller footprint
3 High energy Less energy
4 Unscientific decant system* N.A See PPT*
5 Very thin sludge Thick Sludge * Easy to dewater *
6 High Solids carryover * Clear water Filters Stressed *
7 Frequent Backwash filters Less Frequent Operators will bypass
8 Large Collection tank Smaller collection tank Collection tank receiving raw sewage generates max. odour
9 Very High failure rate Almost NIL if designed well * Robust performance 24/7 for decades *
10 3 Nos. Air blower 400 Derate to 275cmh each * Less noise, less vibration *
11 Membrane life Short* Membrane life longer Cyclic air flux rates *
12
Long stabilisation period after
upset
Short recovery period * Less downtime * Loss Minimised
13
Does not deliver quality water
24/7 for in sustained manner
Our first EAAS for ITC – Frazer town still delivering after 30
years
Least life cycle cost
14 N.A.
Converted Several SBR to EAAS with 100 % success* - Latest
500 KLD Phoenix market City
Yet to see a good SBR working to 100 % design capacity*

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
EAAS versus SBR (quantitative)
Sl. Item Existing Proposed SBR Larger by Remarks
SBR EAAS
1 Footprint, Sqm 315 250 0.26
Could have been less if designed from
scratch
2
Tank
constructed
volume, cum
1200 770
56% (140 % if EAAS
designed from scratch)
Could have been less at 500 cum if
designed from scratch
3
Connected
load
43 KW 42 KW --
Could have been less @ 35 KW if
designed from scratch
4
Energy Used,
Units
526 338 0.56
Energy can be reduced further with new
1.5 HP pump
5
No. of
equipment
10 9 0.11
Could have been less if designed from
Scratch
6 Filters size 1.3m Dia 1.3 m Dia
1.3 dia is undersized for SBR since
filtration hours must be shorter

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
SLUDGE HANDLING ISSUES
FLAT BOTTOM SBR
THIN EXCESS SLUDGE
CONVENTIONAL EAAS
THICK EXCESS SLUDGE

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
EAAS IN ACTION
TREATED WATER SAMPLE FROM
BANGALORE’S BIGGEST MALL
AFTER HEAVY SATURDAY NIGHT RUSH
SBR STP UPGRADED TO EAAS BY US IN OCT 2017.
ECOTECH HAS BEEN PERFORMING O&M OF
THIS STP SINCE THEN

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
4 | Anaerobic Treatment

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
not suitable for urban
residential & commercial
buildingsanaerobic
treatment
unfit for urban reuse
foul odour
black colouration
black solid particles
3 STPs modified by us
200 KLD, 350 KLD, 500 KLD

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
6 | Anaerobic Bio-Reactor (ANBR) for
micro STPs

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
DEWATS of Ludwig Sasse

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
50 KLD ANBR
HDFC SCHOOL
HADAPSAR

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
60 KLD ANBR
KUNDALAHALLI
BANGALORE

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
7 | Electrocoagulation (EADOX)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
similar to chemical
coagulation
EADOX
electrocoagulation
removes only solids and
colloids
six STPs studied by us – all defunct
does not remove dissolved organics
unsustainable electrode costs
tertiary filters
overload costs

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
6 | Membrane Bio-Reactor (MBR)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
NO PROBLEM WITH
TECHNOLOGY
MEMBRANE
BIOREACTOR (MBR)
GOOD FUTURE PROSPECTS
RELIABILITY & COST ISSUES:
NOT MATURE FOR SMALL
STPS

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
MBR Flowsheet

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Typical Membrane Cassettes

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
Key Takeaways
▪ From a long-term perspective, EAAS is still the
best available, practicable, and most appropriate
technology
▪ Anaerobic, CAACO, EADOX are unsuitable
▪ SBR, MBBR inappropriate for micro & mini STPs
▪ MBR is for the future but only when all current
issues are resolved

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
But isn’t Modern Technology
always better?

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
METRO (CONVENTIONAL TECHNOLOGY)
MOST APPROPRIATE FOR WITHIN TOKYO
BULLET TRAIN (MODERN TECHNOLOGY)
GREAT FOR TOKYO TO OSAKA (INTER-CITY)

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
EAAS is the best technology
for mini and small STPs
10-80 KLD Micro
100 – 1000 KLD Mini
1000 – 5000 KLD Small

www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986www.ecotech-india.com
THANK YOU
for patiently listening
Dr. Ananth S Kodavasal, Ecotech