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<!{|style="float: left;"|{{Language-- table at top of page with logo, picture, Application level, Management level, and input-output tables -->box|english_link=Biogas_Reactor|french_link=Réacteur_anaérobie_à_Biogaz|spanish_link=Reactor_Anaerobico_de_Biogas|hindi_link=coming soon|malayalam_link=coming soon|tamil_link=coming soon | korean_link=coming soon | chinese_link=Coming soon | indonesian_link=Coming soon | japanese_link=Coming soon }}|}{|width="100%"|style="width:50%;"|{{santablesantable_new|sys1=[[Pour Flush Single Pit System with Twin Pits|31]]|sys2=[[Blackwater Treatment System with SewerageInfiltration|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]]|

Input1=Faecal Sludge|Input2=Organics |Input3=Blackwater| Input4= Brownwater |Input5=|Output1=Treated Sludge|Output2=Effluent Biogas | Output3=Biogas | Output4= | Output5=|english_link=Anaerobic_Biogas_Reactor|french_link=Réacteur_anaérobie_à_Biogaz

[[Image:Icon_anaerobic_biogas_reactor.png |right|95px80px]]'''An Anaerobic Biogas Reactor A biogas reactor or anaerobic digester is an anaerobic treatment technology that produces (a) a digested slurry to (digestate) that can be used as a soil amendment fertilizer and (b) biogas which that can be used for energy. Biogas is a mix of methane, carbon dioxide and other trace gasses that gases which can be easily converted to heat, electricity, or light and heat (see [[Biogas as source of energy]]).'''

An Anaerobic [[Image:Anaerobic_digestion.PNG|thumb|right|200px|Biogas Reactor is a chamber or vault that facilitates the anaerobic degradation of blackwater, sludge, and/or biodegradable waste. It also facilitates the separation and collection of the biogas that is produced. The tanks can be built above or below ground. Prefabricated tanks or brick-constructed chambers can be built depending on spacereactor in Vietnam (for credits, resources and click the volume of waste generated.picture)]]

[[Image:Anaerobic_digestionA biogas reactor is an airtight chamber that facilitates the anaerobic degradation of blackwater, sludge, and/ or biodegradable waste.PNG|thumb|right|150px|Biogas It also facilitates the collection of the biogas produced in the fermentation processes in the reactor . The gas forms in Vietnam (for creditsthe slurry and collects at the top of the chamber, click mixing the picture)]]slurry as it rises. The digestate is rich in organics and nutrients, almost odourless and pathogens are partly inactivated.

The residence time ===Design Considerations=== Biogas reactors can be brick-constructed domes or prefabricated tanks, installed above or below ground, depending on space, soil characteristics, available resources and the volume of waste generated. They can be built as fixed dome or floating dome digesters. In the fluid in fixed dome, the volume of the reactor should is constant. As gas is generated it exerts a minimum of 15 days in hot climates pressure and 25 days in temperate climatesdisplaces the slurry upward into an expansion chamber. For highly pathogenic inputsWhen the gas is removed, the slurry flows back into the reactor. The pressure can be used to transport the biogas through pipes. In a residence time floating dome reactor, the dome rises and falls with the production and withdrawal of 60 days should be consideredgas. NormallyAlternatively, Anaerobic Biogas Reactors are not heated, but to ensure pathogen destruction it canexpand (i.e. like a sustained temperature over 50°Cballoon) . To minimize distribution losses, the reactor reactors should be heated (although in practice, this is only found in installed close to where the most industrialized countries)gas can be used.

Once waste products enter the digestion chamber, gases are formed through fermentation. The gas forms hydraulic retention time (HRT) in the sludge but collects reactor should be at the top least 15 days in hot climates and 25 days in temperate climates. For highly pathogenic inputs, a HRT of the reactor60 days should be considered. Normally, mixing the slurry as it rises. Biogas biogas reactors can be built as fixed dome or floating dome reactors. In are operated in the fixed dome reactor the volume mesophilic temperature range of the reactor is constant30 to 38 °C. As gas is generated it exerts a pressure and displaces the slurry upward into an expansion chamber. When A thermophilic temperature of 50 to 57 °C would ensure the gas is removedpathogens destruction, the slurry will flow back down into the digestion chamber. The pressure generated but can only be used to transport achieved by heating the biogas through pipesreactor (although in practice, this is only found in industrialized countries).

In a floating dome reactor, the dome will rise and fall with the production and withdrawal of gas. AlternativelyOften, the dome can expand (like a balloon). Most often biogas reactors are directly connected to indoor (private or public) toilets with an additional access point for organic materials. At the household level, reactors can be made out of plastic containers or bricks and can be built behind the house or buried underground. Sizes can vary from 1,000L 000 L for a single family up to 100,000L 000 L for institutional or public toilet applications. The slurry that Because the digestate production is produced is rich in organics and nutrientscontinuous, but almost odourless and partly disinfected (complete pathogen destruction would require thermophilic conditions). Often, a biogas reactor is used as an alternative to a conventional septic tank, since it offers a similar level of treatmentthere must be provisions made for its storage, but with the added benefit of biogas. Depending on the design use and /or transport away from the inputs, the reactor should be emptied once every 6 months to 10 yearssite.

- Generation of a renewable, valuable energy source. <br> - Low capital costs; low operating costs. <br> - Underground construction minimizes Small land use. area required (most of the structure can be built underground) <br> - Long life span. No electrical energy required <br> - Can be built and repaired with locally available materials. Conservation of nutrients <br> - No electrical energy required. Long service life <br> - Small land area required (most of the structure can be built underground). Low operating costs| con=- Requires constant source of water. <br> - Requires expert design and skilled construction. <br> - Gas production below 15°C is not economically feasible. Incomplete pathogen removal, the digestate might require further treatment <br> - Digested sludge and effluent still requires treatment Limited gas production below 15 °C

==Adequacy=Appropriateness=== This technology is easily adaptable and can be applied at the household level , in small neighbourhoods or for the stabilization of sludge at large wastewater treatment plants. It is best used where regular feeding is possible. Often, a small neighbourhood biogas reactor is used as an alternative to a [[Septic Tank | Septic Tank]] (refer S.9), since it offers a similar level of treatment, but with the added benefit of biogas. However, significant gas production cannot be achieved if blackwater is the only input. The highest levels of biogas production are obtained with concentrated substrates, which are rich in organic material, such as animal manure and organic market or household waste. It can be efficient to Technology Information Sheet T15: Anaerobic Biogas Reactor for information about applying it at co-digest blackwater from a single household with manure if the latter is the community level)main source of feedstock.

Greywater should not be added as it substantially reduces the HRT. Wood material and straw are difficult to degrade and should be avoided in the substrate. Biogas reactors are best used less appropriate for concentrated products (i.e. rich in colder climates as the rate of organic material)matter conversion into biogas isvery low below 15 °C. If they are installed for a single household that is using a significant amount of waterConsequently, the efficiency of the reactor can HRT needs to be improved significantly by also adding animal manure longer and biodegradable organic wastethe design volume substantially increased.

===Health Aspects/Acceptance=== The digestate is partially sanitized but still carries a risk of infection. Depending on the soilits end-use, location, and size further treatment might be required, . There are also dangers associated with the reactor can be built above or below ground (even below roads). For more urban applicationsflammable gases that, small biogas reactors can be installed on the rooftops or in a courtyard. To minimize distribution lossesif mismanaged, the reactors should could be installed close harmful to where the gas can be used. Biogas reactors are less appropriate for colder climates as gas production is not economically feasible below 15°Chuman health.

==Health Aspects/Acceptance=Operation & Maintenance=== If the reactor is properly designed and built, repairs should be minimal. To start the reactor, it should be inoculated with anaerobic bacteria, e.g., by adding cow dung or Septic Tank sludge. Organic waste used as substrate should be shredded and mixed with water or digestate prior to feeding. Gas equipment should be carefully and regularly cleaned so that corrosion and leaks are prevented. Gritand sand that have settled to the bottom should be removed. Depending on the design and the inputs, the reactor should be emptied once every 5 to 10 years.

The digested slurry is not completely sanitized ===References and still carries a risk of infection. There are also dangers associated with the flammable gases that, if mismanaged, could be harmful to human health.external links===

The Anaerobic Biogas Reactor must be well built and gas tight for safety* CMS (1996). If the reactor is properly designed, repairs should be minimal[http://www. To start the reactor, active sludge (efao.gorg/3/ae897e/ae897e00. from a septic tank) should be used as a seedhtm Biogas Technology: A Training Manual for Extension. The tank is essentially selfFAO/TCP/NEP/4451-mixingT]. Consolidated Management Services, Kathmandu, but it should be manually stirred once a week to prevent uneven reactionsNP.

Gas equipment should be cleaned carefully * GTZ (1998). Biogas Digest. [https://www.susana.org/en/knowledge-hub/resources-and regularly so that corrosion -publications/library/details/525?pgrid=1 Volume I], [https://www.susana.org/en/knowledge-hub/resources-and leaks are prevented-publications/library/details/526 Volume II], [https://www.susana. Grit org/en/knowledge-hub/resources-and sand that has settled to the bottom should be removed once every year-publications/library/details/1717 Volume III], [https://energypedia. Capital costs for gas transmission infrastructure can increase the project costinfo/images/1/17/Biogas_gate_volume_4. Depending pdf Volume IV]. Information and Advisory Service on the quality of the outputAppropriate Technology (ISAT). Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH, the gas transmission capital costs can be offset by long-term energy savingsEschborn, DE.

==Acknowledgements=={{* Mang, H.-P. and Li, Z. (2010). [https:Acknowledgements //www.susana.org/en/knowledge-hub/resources-and-publications/library/details/877 Technology Review of Biogas Sanitation}}. Draft – Biogas Sanitation for Blackwater, Brown Water, or for Excreta Treatment and Reuse in Developing Countries]. Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, Eschborn, DE.

==References * Ulrich, A. (Ed.), Reuter, S. (Ed.), Gutterer, B. (Ed.), Sasse, L., Panzerbieter, T. and external links==Reckerzügel, T. (2009). [https://wedc-knowledge.lboro.ac.uk/resources/books/DEWATS_-_Chapter_01.pdf Decentralised Wastewater Treatment Systems (DEWATS) and Sanitation in Developing Countries. A Practical Guide]. WEDC, Loughborough University, Leicestershire, UK.

* Food Vögeli, Y., Lohri, C. R., Gallardo, A., Diener, S. and Agriculture Organization Zurbrügg, C. (FAO) (19962014). Biogas Technology[https: A Training Manual for Extension//www. Consolidated Management Services, Kathmandueawag. Available: http:ch/fileadmin/Domain1/Abteilungen/sandec/publikationen/SWM/Anaerobic_Digestion/wwwbiowaste.pdf Anaerobic Digestion of Biowaste in Developing Countries. Practical Information and Case Studies].faoEawag (Department Sandec), Dübendorf, CH.org

* ISAT (1998). Biogas Digest Vols. I–IV. ISAT and GTZ, Germany. Available: http://www.gtz.de * Koottatep, S., Ompont, M. and Joo Hwa, T. (2004). Biogas: A GP Option For Community Development. Asian Productivity Organization, Japan. Available: http://www.apo-tokyo.org * Rose, GD. (1999). Community-Based Technologies for Domestic Wastewater Treatment and Reuse: options for urban agriculture. IDRC, Ottawa. pp 29–32. Available: http://idrinfo.idrc.ca===Acknowledgements===* Sasse, L. (1998). DEWATS{{: Decentralised Wastewater Treatment in Developing Countries. BORDA, Bremen Overseas Research and Development Association, Bremen, Germany.Acknowledgements Sanitation}}