Slide 1Anaerobic Baffled Reactor
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Contents
Concept
Design principals
Treatment efficiency
*
Background and working principal (adapted from U.S. EPA 2006, SASSE
1998)
1. Concept
Source: SANIMAS (2005), MOREL & DIENER (2006)
physical and biological (anaerobic) treatment of wastewater
integrated sedimentation chamber for pre-treatment of
wastewater
alternating standing and hanging baffles
wastewater passes through the sludge to move to the next
compartment
solid retention time (SRT) separated from hydraulic retention time
(HRT)
high treatment rates due to enhanced contact of incoming wastewater
with residual sludge and high solid retention
low sludge production
Anaerobic Baffled Reactor
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Source: BORDA 2009
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Biogas settler as settlement compartment (near completion) at
Pestalozzi School, Zambia
Source: http://www.germantoilet.org/
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The ABR under construction, down pipes and perforated slabs to
support filter media in the Anaerobic Filter (AF) sections, pouring
ABR’s concrete slab at Pestalozzi School, Zambia
Source: http://www.germantoilet.org/
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ABR (part of DEWATS) at Adarsh Vidyaprasarak Sanstha’s College of
Arts & Commerce, India
Source: N. Zimmermann
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ABR (part of DEWATS) at Sunga Wastewater Treatment Plant,
Kathmandu, Nepal
Source: N. Zimmermann
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2. How it can optimize SSWM
treatment of all wastewater (grey-, black- and/or industrial
wastewater) that it is fit (after secondary treatment) for reuse
and/or safe disposal
allows for recovery of biogas, which can be used as a substitute to
e.g. LPG or fuel wood in cooking
Anaerobic Baffled Reactor
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3. Design principals
ABRs start with settling chamber for larger solids and impurities
(SASSE 1998) followed by series of at least 2 (MOREL & DIENER
2006), sometimes up to 5 (SASSE 1998) up-flow chambers
Hydraulic Retention Time (HRT) is relatively short and varies from
only a few hours up to two or three days (FOXON et al. 2004; MOREL
& DIENER 2006; TILLEY et al. 2008)
up-flow velocity is the most crucial parameter for dimensioning,
especially with high hydraulic loading. It should not exceed 2.0
m/h (SASSE 1998; MOREL & DIENER 2006).
organic load <3 kg COD/m3/day. Higher loading-rates are possible
with higher temperature and for easily degradable substrates (SASSE
1998)
Anaerobic Baffled Reactor
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4. Treatment efficiency
Treatment performance of ABRs is in the range of (SASSE 1998; MOREL
& DIENER 2006; BORDA 2008)
Chemical Oxygen Demand (COD) removal: 65% to 90%,
Biological Oxygen Demand (BOD) removal: 70% to 95%,
Total Suspended Solids (TSS) removal: up to 90% (SINGH 2008)
Pathogen reduction: low
Superior to BOD-removal (30% to 50%) of conventional septic tank
(UNEP 2004).
Anaerobic Baffled Reactor
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5. Operation and maintenance
inoculate („seed“) ABR with active anaerobic sludge from e.g.
septic tank to speed up start-phase
allow bacteria to multiply, by starting with 1/4 of daily flow, and
then increasing loading rates over 3 months
long start-up time do not use ABRs when need for treatment is
immediate
check for water-tightness regularly and monitor scum and sludge
levels
remove sludge every 1 to 3 years (preferably by vacuum truck or
gulper to avoid that humans get in direct contact with
sludge)
leave some active sludge in each compartment to maintain stable
treatment process
take care of advanced treatment and/or safe disposal of
sludge
Source: adapted from SASSE 1998, TILLEY et al. 2008, EAWAG/SANDEC
2008
Anaerobic Baffled Reactor
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Use of “straight handle” (left) and “Z-handle” (right) brushes for
cleaning of down-ward pipes
Source: K.P. Pravinjith
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6. Applicability
be installed in every type of climate, although efficiency is
affected in colder climates (TILLEY et al. 2008)
suited for household level or for small neighbourhood as DEWATS
(Decentralized Wastewater Treatment System) (EAWAG/SANDEC
2008)
suited for industrial wastewaters
be designed for daily inflows in a range of some m3/day up to
several hundreds of m3/day (FOXON et al. 2004; TILLEY et al.
2008)
in general, installed underground and therefore appropriate for
areas where land is limited
been pre-fabricated from e.g. fibreglass and used as final step for
emergency sanitations (BORDA 2009)
Anaerobic Baffled Reactor
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effluent requires secondary treatment and/or appropriate
discharge
clear design guidelines are not available yet
low reduction of pathogens
high treatment performance
no electrical requirements
low capital and operating costs, depending on economy of
scale
low sludge generation
*
BORDA (2009): EmSan - Emergency Sanitation. An innovative &
rapidly installable solution to improve hygiene and health in
emergency situations (Concept Note). Bremen: Bremen Overseas
Research and Development Association (BORDA)
EAWAG/SANDEC (2008): Sanitation Systems and Technologies. Lecture
Notes. (=Sandec Training Tool 1.0, Module 4). Duebendorf: Swiss
Federal Institute of Aquatic Science (EAWAG), Department of Water
and Sanitation in Developing Countries (SANDEC)
FOXON, K.M., PILLAY, S., LALBAHADUR, T., RODDA, N., HOLDER, F.,
BUCKLEY, C.A. (2004): The anaerobic baffled reactor (ABR)- An
appropriate technology for on-site sanitation. In=Water SA Vol. 30
No. 5 (Special edition)
MOREL A., DIENER S. 2006. Greywater Management in Low and
Middle-Income Countries. Review of different treatment systems for
households or neighbourhoods. Duebendorf: Swiss Federal Institute
of Aquatic Science and Technology (Eawag).
SANIMAS (2005): Informed Choice Catalogue. PPT-Presentation. BORDA
and USAID
SASSE, L. (1998): DEWATS Decentralised Wastewater Treatment in
Developing Countries. Bremen: Bremen Overseas Research and
Development Association (BORDA)
Anaerobic Baffled Reactor
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8. References
SINGH, S., HABERLA, R., MOOG, O., SHRESTA, R.R., SHRESTA, P.,
SHRESTA, R. (2009): Performance of an anaerobic baffled reactor and
hybrid constructed wetland treating high-strength wastewater in
Nepal- A model for DEWATS. In: Ecological Engineering 35.
654-660
TILLEY, E., LUETHI, C., MOREL, A., ZURBRUEGG, C., SCHERTENLEIB, R.
(2008): Compendium of Sanitation Systems and Technologies.
Duebendorf and Geneva: Swiss Federal Institute of Aquatic Science
(EAWAG) & Water Supply and Sanitation Collaborative Council
(WSSCC)
U.S. EPA (2006): Emerging Technologies for Biosolids Management.
(=EPA 832-R-06-005). United States Environmental Protection Agency,
Office of Wastewater Management
Anaerobic Baffled Reactor
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