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{{santable_new|
sys1=[[(Semi-) Centralized Treatment Single Pit System |71]]|sys2=[[Blackwater Treatment System with Infiltration|6]]|sys3=[[Blackwater Treatment System with Effluent Transport|7]]|sys4=[[Blackwater Transport to (Semi-) Centralized Treatment System|8]]|sys5=[[Sewerage System with Urine Diversion|9]]|
sys6=|
sys7=|
sys8=|
pic=Waste_stabilization_ponds.png|
ApplHousehold=XXX|
ApplNeighbourhood=XX|
ApplCity=|
ManHousehold=XXX|
ManShared=XX|
ManPublic=XX|
Input1=Blackwater|Input2=Greywater |Input3= Brownwater | Input4= Effluent |Input5=|Output1= Faecal Sludge | Output2=Effluent | Output3= | Output4= | Output5=
|english_link=Semi_centralised_Anaerobic_Baffled_Reactor
|french_link=Réacteur_anaérobie_à_chicanes_(semi-)_centralisés
[[Image:Icon_waste_stabilization_ponds.png |right|80px]]
'''An Anaerobic Baffled Reactor anaerobic baffled reactor (ABR) is an improved septic tank because of the Septic Tank (S.9) with a series of baffles over under which the incoming wastewater is forced to flow. The increased contact time with the active biomass (sludge) results in improved treatment.'''
The majority of settleable solids are removed in thesedimentation chamber at the beginning of the ABR,which typically represents 50% of the total volume.The up-flow upflow chambers provide additional enhanced removal anddigestion of organic matter: . BOD may be reduced byup to 90%, which is far superior to that of its removal in a conventionalSeptic Tank. ===Design Considerations=== septic tankThe majority of settleable solids are removed in a sedimentation chamber in front of the actual ABR. Small-scale, stand-alone units typically have an integrated settling compartment (as shown in S.10), but primary sedimentation can also take place in a separate [[Settler]] (T.1) or another preceding technology (e.g., existing [[Septic Tank|Septic Tanks]]). As sludge is accumulatingDesigns without a settling compartment are of particular interest for (Semi-) Centralized Treatment plants that combine the ABR with another technology for primary settling, or where prefabricated, desludgingis required every modular units are used. Typical inflows range from 2 to 3 years200 m3 per day. Critical design parametersinclude a hydraulic retention time (HRT)between 48 to 72 hours, up-flow upflow velocity of the wastewaterless than below 0.6m6 m/h and the number of up-flowupflow chambers (2 3 to 6). The connection between the chambers can be designed either with vertical pipes or baffles. Accessibility to 3all chambers (through access ports)is necessary for maintenance. Usually, the biogas produced in an ABR through anaerobic digestion is not collected because of its insufficient amount. The tank should be vented to allow for controlled release of odorous and potentially harmful gases.
! style="background:#f0f8ff;" | Disadvantages
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| valign="top" |- Resistant to organic and hydraulic shock loads. <br>- No electrical energy is required. <br>- Greywater can be managed concurrently. <br>- Can be built and repaired with locally available materials. Low operating costs <br>- Long service life. <br>- No real problems with flies or odours if used correctly. <br>- High reduction of organics. BOD <br>- Low sludge production; the sludge is stabilized- Moderate capital costs, moderate operating costs depending on emptying; area requirement (can be low cost depending on number of users.built underground)| valign="top" | - Requires constant source of water. <br>- Effluent require secondary treatment expert design and/or appropriate discharge. construction <br>- Low reduction of pathogens. and nutrients <br>- Requires expert design Effluent and sludge require further treatment and construction. /or appropriate discharge <br>- Pre-treatment is required to prevent clogging.
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===AdequacyAppropriateness===This technology is easily adaptable and can be applied at the household level, in small neighbourhoods or even in bigger catchment areas. It is most appropriate where a relatively constant amount of blackwater and greywater is generated. A (semi-) centralized ABR is appropriate when there is a pre-existing Conveyance technology, such as a [[Simplified Sewer]] (C.4).
This technology is easily adaptable andcan be applied at the household level or for a small neighbourhood. A (semi-) centralized ABR is appropriate when there isan already existing Conveyance technology, such as a[[Solids-free Sewer]]. This technology is also appropriatesuitable for areas where land may be limited since thetank is most commonly installed underground and requires a small area.It However, a vacuum truck should not be able to access the location because the sludge must be regularly removed (particularly from the settler). ABRs can be installed where there is a high groundwatertable as infiltration will affect in every type of climate, although the treatment efficiencyis lower in colder climates. They are not efficient at removing nutrients and contaminate the groundwaterpathogens. The effluent usually requires further treatment.
This technology can be efficiently designed for a daily===Health Aspects/Acceptance=== inflow of up to 200Under normal operating conditions,000L/day. The ABR will users do not operateat full capacity for several months after installationbecause of come in contact with the long start up time required for theanaerobic digestion influent or effluent. Effluent, scum and sludge must be handled with care as they contain high levels of the sludgepathogenic organisms. The effluent contains odorous compounds that may have to be removed in a further polishing step. Therefore, the ABRtechnology Care should not be used when taken to design and locate the need for atreatment system is immediatefacility such that odours do not bother community members.
Because ===Operation & Maintenance=== An ABR requires a start-up period of several months to reach full treatment capacity since the slow growing anaerobic biomass first needs to be established in the reactor. To reduce startup time, the ABR must can be emptied regularlyinoculated with anaerobic bacteria, a vacuumtruck should be able e.g., by adding fresh cow dung or Septic Tank sludge. The added stock of active bacteria can then multiply and adapt to access the locationincoming wastewater.ABRs can be installed in every type Because of climate althoughthe efficiency will delicate ecology, care should be affected in colder climatestaken not to discharge harsh chemicals into the ABR.
===Health Aspects/Acceptance===Scum and sludge levels need to be monitored to ensure that the tank is functioning well. Process operation in general is not required, and maintenance is limited to the removal of accumulated sludge and scum every 1 to 3 years. This is best done using a [[Motorized Emptying and Transport|Motorized Emptying and Transport]] technology (C.3). The desludging frequency depends on the chosen pre-treatment steps, as well as on the design of the ABR. ABR tanks should be checked from time to time to ensure that they are watertight.
Although the removal===References===of pathogens is not high* Bachmann, A., Beard, the ABR is contained sousers do not come in contact with any of the wastewateror disease causing pathogensV. L. Effluent and sludge must be handled with care as they contain high levels ofpathogenic organismsMcCarty, P. L. (1985).To prevent the release Performance Characteristics of potentially harmful gases, thetank should be ventedAnaerobic Baffled Reactor. Water Research 19 (1): 99-106.
===Maintenance===* Barber, W. P. and Stuckey, D. C. (1999). The Use of the Anaerobic Baffled Reactor (ABR) for Wastewater Treatment: A Review. Water Research 33 (7): 1559-1578.
ABR tanks should be checked toensure that they are watertight * Foxon, K. M., Buckley, C. A., Brouckaert, C. J., Dama, P., Mtembu, Z., Rodda, N., Smith, M., Pillay, S., Arjun, N., Lalbahadur, T. and the levels Bux, F. (2006). Evaluation of thescum and sludge should be monitored to ensure thatthe tank is functioning wellAnaerobic Baffled Reactor for Sanitation in Dense Peri-urban Settlements. Because of the delicateecologyWRC Report No 1248/01/06, Water Research Commission, Pretoria, care should be taken not to discharge harshZA.chemicals into the ABR:Available at: [http://www.wrc.org.za wrc.The sludge should be removed annually using a vacuumtruck to ensure proper functioning of the ABRorg. ===References===za]
* BachmannFoxon, AK. M., Pillay, S., Lalbahadur, T., Rodda, N., BeardHolder, VLF. and McCartyBuckley, PLC. A. (19852004). Performance Characteristics of the The Anaerobic Baffled Reactor(ABR): An Appropriate Technology for on-Site Sanitation. Water Research 19 SA 30 (5) (1Special Edition).:Available at: 99–106[http://www.wrc.org.za wrc.org.za]
* FoxonStuckey, KMD., et alC. (20042010). The anaerobic baffled reactor Anaerobic Baffled Reactor (ABR)for Wastewater Treatment. In: An appropriate technology for on-site sanitationEnvironmental Anaerobic Technology. Applications and New Developments, H. Water SA 30 (5) (Special edition)H. Available: wwwP.wrcFang (Ed.org), Imperial College Press, London, UK.za
* Ulrich, A. (Ed.), Reuter, S. (Ed.), Gutterer, B. (Ed.), Sasse, L., Panzerbieter, T. and Reckerzügel, T. (19982009). DEWATS: Decentralised Wastewater Treatment Systems (DEWATS) and Sanitation in Developing Countries. BORDAA Practical Guide. WEDC, Bremen. Overseas Research and Development AssociationLoughborough University, BremenLeicestershire, GermanyUK. (Design summary including and Excel®-based design program.)
===Acknowledgements===
{{:Acknowledgements Sanitation}}
