This technical short looks at the alternative of applying biogas units to lessen the waste generated by pit latrines. Waste is transported to a biogas plant where treatment is taken.

As populations rapidly grow and urban migration puts further strain on cities, issues around applicability of the on-site sanitation facilities like pit latrines and how these were originally supposed to work are increasing.

Utilizing a pit to preserve the feces underground for around two years to make it less harmful needs space, which heavily populated areas like slum areas are not present, and there are implications of cost of repeated construction. So users must clear their latrines and use again them whenever feasible. This has been the topic of much study over the last few years, but then what is done with the waste has received little consideration.

It is needed to accumulate waste from an on-site system, carry it to a management facility and dispose of them safely. The first step to resolve disposal problems is to apply a structured process that defines how sludge should be handled. Without it contamination of the environment will take place earlier (i.e. in the time of a transportation stage).

Biogas is the result of anaerobic digestion, breaking down of organic matter in absence of the air. This gas is rich in methane gas and can be utilized as a fuel for generating electricity, cooking and lighting. Anaerobic digestion occurs in what is familiar as a digester. Conventionally digesters have been directly connected to the pit latrine so fresh feces are needed to digestion instantly. Little effort has been done to watch if using mature, incompletely digested waste from a latrine is possible in making biogas.

The waste will be incompletely degraded upon clearing consequently decreasing the highest methane production. This indicates, to make the system realistic the frequency of pit clearing will have to raise. Pit clearing rate is inversely proportional to the active life of the latrine. Dismantling often required when clearing a latrine. A solution proposed is to set up an in-situ pipeline to the latrine that has an outlet outside the super system. This addition will reduce the trouble caused by clearing as well as formulating the whole practice safer because the pipe will no longer have got to be fallen into the feces. The accumulation will also assist deal with the issues with regard to viscosity and soiling up in latrines because clearing will happen from the base and water can be added with the pipe to reduce the viscosity.

These technologies are more realistic in urban areas where access is a concern for vacuum pumps. While using these systems it is not the space from the pits to the dumping point that is the important factor but the moment it takes. In this circumstance a cost or time advantage calculation should be applied working backwards from the expenses that have to be covered for the process to work which will provide the required quantity of empties per day. Using this date and the average operational day an appropriate haulage length can be calculated.

There are basically two main problems regarding waste treatment. The first is issues surrounding pressure of the biogas. One answer would be to make sure that digester is properly maintained. Another physical solution is the use of a detached gas holder. The other treatment concern that requires to be evaluated is the concentration of nitrogen gas in the feedstock.

The first thing of concern with regard to social and cultural problems is dealing with issues regarding the community's enthusiasm to apply this technology. There are three most important areas that have to be dealt with to make sure a successful implementation.

Firstly, the implementers have to keep the people of the community well informed. The lack of understanding can cause an unwillingness to utilize the by-products, the second concern. When evaluating the willingness to utilize the left over as a soil conditioner the important factor is land to apply the conditioner on. If public do not have areas or gardens to utilize compost, such as in urban areas and then they are not willing to want it. The final concern when managing willingness to apply the technology is the religious issues over excreta. This leads to cleaning happening at night as there is less possibility they will be beaten or robbed. The thought is to make the procedure as possible as less obtrusive, which implementing physically operated methods will do.

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