Clearly WaSH facilities are essential in densely populated refugee camps. Ideally toilet blocks would be connected to a sewer to take human waste away. However, often pit latrines are the only facility and these must be carefully positioned away from potable water sources. The concept of connecting latrines to anaerobic digesters is not new. But, it is only more recently that there has been a growing acceptance of the possibilities it offers for treating human waste and providing gas for cooking that is more efficient to use and does not pose the risks of smoke and other air pollutants associated with cooking with wood, dung or charcoal.
An example of an operation combining sanitation and biogas comes from a refugee camp in Bangladesh . Unfortunately, Rohyingya refugees are much in the news but they have been arriving in Bangladesh for over 20 years. In 2013 at a UNHCR camp near Cox’s Bazaar pilot biogas systems were set up. The main reason, as is often the case, for doing this was to treat the sewage sludge with the bonus of producing biogas and the potential to use the treated solid residue as a fertilizer. Two fixed-dome masonry constructed biodigesters were built connecting to latrine blocks each serving around 700-750 people. In both cases it was found the faecal sludge was significantly reduced by the anaerobic digestion process. This was by about 90%, thus reducing the handling requirements that would have been associated with latrine pit emptying. Following on from the pilot stage, a further 22 digesters have been constructed at the camp.
The advantages for the use if biogas in refugee camps include: reducing handling/volume/space needed for human waste disposal; providing a clean source of cooking fuel with a higher heat to pot efficiency; the digestate can potentially be used as a fertiliser or for other uses adding value to the process; and the biodigesters are underground saving space . However, it is important to consider the need to have good construction of the latrine-biodigester system . This requires management of the construction and commissioning phase as well as management of expectations. This is because biogas is only produced at meaningful amounts when the system reaches operational capacity, possibly 4 weeks after first use. A trained operator is also required to monitor and maintain the systems in a camp.
Other examples of latrines to biogas, from a non-humanitarian perspective, can be found. In Malawi, a biogas digester has been built at a primary school in Muzuzu and provides biogas to cook meals for the children. Practical Action have produced a wealth of supportive materials  and a guide for the disposal of latrine waste has been produced by WEDC .
 Eyrard, J. et. Al. (2016) Biogas production in refugee camps: when sustainability increases safety and dignity. 38th WEDC International Conference. https://wedc-knowledge.lboro.ac.uk/re... (Accessed 30-11-2017).
 Fox, S., & Blanchard, R.E. (2017). Cost benefit analyses for small scale biogas systems in Ethiopia. International ... (more)
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