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Biogas Reactor

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sys2=[[Blackwater Treatment Biogas System with Sewerage|65]]|

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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|80px]]

'''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]]).''' <br>An Anaerobic 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 space, resources and the volume of waste generated.

[[Image:Anaerobic_digestion.PNG|thumb|right|200px|Biogas reactor in Vietnam (for credits, click the picture)]]

The residence time A biogas reactor is an airtight chamber that facilitates the anaerobic degradation of blackwater, sludge, and/ or biodegradable waste. It also facilitates the collection of the fluid biogas produced in the fermentation processes in the reactor should a minimum of 15 days . The gas forms in hot climates the slurry and 25 days in temperate climates. For highly pathogenic inputs, a residence time collects at the top of 60 days should be considered. Normallythe chamber, Anaerobic Biogas Reactors are not heated, but to ensure pathogen destruction (imixing the slurry as it rises.e. a sustained temperature over 50°C) the reactor should be heated (although The digestate is rich in practiceorganics and nutrients, this is only found in the most industrialized countries)almost odourless and pathogens are partly inactivated.

Once waste products enter the digestion chamber===Design Considerations=== Biogas reactors can be brick-constructed domes or prefabricated tanks, installed above or below ground, depending on space, soil characteristics, gases are formed through fermentation. The gas forms in available resources and the sludge but collects at the top volume of the reactor, mixing the slurry as it riseswaste generated. Biogas reactors They can be built as fixed dome or floating dome reactorsdigesters. In the fixed dome reactor , the volume of the reactor is constant. As gas is generated it exerts a pressure and displaces the slurry upward into an expansion chamber. When the gas is removed, the slurry will flow flows back down into the digestion chamberreactor. The pressure generated can be used to transport the biogas through pipes. In a floating dome reactor, the dome rises and falls with the production and withdrawal of gas. Alternatively, it canexpand (like a balloon). To minimize distribution losses, the reactors should be installed close to where the gas can be used.

In a floating dome The hydraulic retention time (HRT) in the reactor, the dome will rise and fall with the production should be at least 15 days in hot climates and withdrawal of gas25 days in temperate climates. AlternativelyFor highly pathogenic inputs, the dome can expand (like a balloon)HRT of 60 days should be considered. Most often Normally, biogas reactors are directly connected operated in the mesophilic temperature range of 30 to indoor (private or public) toilets with an additional access point for organic materials38 °C. At A thermophilic temperature of 50 to 57 °C would ensure the household levelpathogens destruction, reactors can be made out of plastic containers or bricks and but can only be built behind achieved by heating the house or buried underground. Sizes can vary from 1reactor (although in practice,000L for a single family up to 100,000L for institutional or public toilet applicationsthis is only found in industrialized countries).

The slurry that is produced is rich in organics and nutrients, but almost odourless and partly disinfected (complete pathogen destruction would require thermophilic conditions). Often, a biogas reactor is used as reactors are directly connected to private or public toilets with an alternative to a conventional septic tankadditional access point for organic materials. At the household level, reactors can be made out of plastic containers or bricks. Sizes can vary from 1, since it offers 000 L for a similar level of treatmentsingle family up to 100, but with the added benefit of biogas000 L for institutional or public toilet applications. Depending on Because the design digestate production is continuous, there must be provisions made for its storage, use and /or transport away from the inputs, the reactor should be emptied once every 6 months to 10 yearssite.

<br>

{{procontable | pro=

- 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

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===AdequacyAppropriateness=== This technology is easily adaptable and can be applied at the household level , in small neighbourhoods or a small neighbourhood (refer to Technology Information Sheet T15: Anaerobic Biogas Reactor for information about applying it the stabilization of sludge at the community level)large wastewater treatment plants. Biogas reactors are It is best used for concentrated products where regular feeding is possible. Often, a biogas reactor is used as an alternative to a [[Septic Tank | Septic Tank]] (i.eS. rich in organic material9). If they are installed for , since it offers a single household that is using a significant amount similar level of watertreatment, but with the efficiency added benefit of biogas. However, significant gas production cannot be achieved if blackwater is the reactor can be improved significantly by also adding only input. The highest levels of biogas production are obtained with concentrated substrates, which are rich in organic material, such as animal manure and biodegradable organic market or household waste. Depending on the soil, location, and size required, the reactor can be built above or below ground (even below roads). For more urban applications, small biogas reactors It can be installed on the rooftops or in efficient to co-digest blackwater from a courtyard. To minimize distribution losses, single household with manure if the reactors should be installed close to where latter is the gas can be used. Biogas reactors are less appropriate for colder climates as gas production is not economically feasible below 15°Cmain source of feedstock. ===Health Aspects/Acceptance===

The digested slurry is Greywater should not completely sanitized be added as it substantially reduces the HRT. Wood material and straw are difficult to degrade and still carries a risk of infectionshould be avoided in the substrate. There Biogas reactors are also dangers associated with less appropriate for colder climates as the flammable gases thatrate of organic matter conversion into biogas isvery low below 15 °C. Consequently, if mismanaged, could the HRT needs to be harmful to human healthlonger and the design volume substantially increased.

===Health Aspects/Acceptance=== The Anaerobic Biogas Reactor must be well built and gas tight for safetydigestate is partially sanitized but still carries a risk of infection. If the reactor is properly designedDepending on its end-use, repairs should further treatment might be minimalrequired. To start There are also dangers associated with the reactorflammable gases that, active sludge (e.g. from a septic tank) should be used as a seed. The tank is essentially self-mixingif mismanaged, but it should could be manually stirred once a week harmful to prevent uneven reactionshuman health.

===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 cleaned carefully and regularly cleaned so that corrosion and leaks are prevented. Grit and sand that has have settled to the bottom should be removed once every year. Capital costs for gas transmission infrastructure can increase the project cost. Depending on the quality of design and the outputinputs, the gas transmission capital costs can reactor should be offset by long-term energy savingsemptied once every 5 to 10 years.

===References and external links===

* Food and Agriculture Organization (FAO) CMS (1996). Biogas Technology: A Training Manual for Extension. FAO/TCP/NEP/4451-T. Consolidated Management Services, Kathmandu, NP. :Availableat: [http://www.fao.orgfao.org]

* ISAT GTZ (1998). Biogas Digest Vols. I–IVVolume I-IV. Information and Advisory Service on Appropriate Technology (ISAT and ). Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH, Eschborn, GermanyDE. :Availableat: [http://www.gtzsusana.deorg/library susana.org/library]

* KoottatepMang, SH., Ompont, M-P. and Joo HwaLi, TZ. (20042010). Technology Review of Biogas: A GP Option For Community DevelopmentSanitation. Draft – Biogas Sanitation for Blackwater, Brown Water, or for Excreta Treatment and Reuse in Developing Countries. Asian Productivity OrganizationGesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, JapanEschborn, DE. :Availableat: [http://www.apo-tokyosusana.org/library susana.org/library]

* RoseUlrich, GDA. (1999Ed.), Reuter, S. (Ed.), Gutterer, B. (Ed.), Sasse, L., Panzerbieter, T. and Reckerzügel, T. (2009). Community-Based Technologies for Domestic Decentralised Wastewater Treatment Systems (DEWATS) and Reuse: options for urban agricultureSanitation in Developing Countries. A Practical Guide. IDRCWEDC, Loughborough University, Leicestershire, Ottawa. pp 29–32. Available: http://idrinfo.idrcUK.ca

* SasseVögeli, LY., Lohri, C. R., Gallardo, A., Diener, S. and Zurbrügg, C. (19982014). DEWATS: Decentralised Wastewater Treatment Anaerobic Digestion of Biowaste in Developing Countries. BORDA, Bremen Overseas Research Practical Information and Development AssociationCase Studies. Eawag (Department Sandec), BremenDübendorf, GermanyCH.:Available at: [http://www.sandec.ch sandec.ch]

===Acknowledgements===

{{:Acknowledgements Sanitation}}

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