8. Discussion
Access to energy resources, economic development and environmental pollution, which in turn
threaten human health, are major challenges facing developing countries today [207]. Economically
feasible and efficient small scale biogas digesters could be the answer of solving some of these
problems and needs. By enhancing energy availability and simultaneously protect the surrounding
environment such as soil, water and air, a lots of benefits could be gained. Most of small-scale
digesters are concentrated in developing countries with India and China as leading countries
accounting for the highest share.
More or less, every biodegradable organic waste can be treated in a biogas digester, providing
energy for cooking, lighting and heating along with increased of dissolved nutrient concentration in the
digestate, thus, providing farmers with an improved organic fertilizer. Many of small scale digesters do
not require high maintenance and are more or less adaptable to the climate and condition of many of
developing countries [73]. However, adopting of biogas digesters is low in many countries despite the
great potential to gain a wide verity of benefits, both from socioeconomic and environmental point of
View. Possible negative impacts are suggested such as the potential for pathogens, limitation of
economic and material resources, and pollution through losses from damaged digesters, and possible
leakage of incomplete combustion of methane to CO2. Additionally several practical problem have
also been suggested as limiting the uptake of small-scale digesters including unaffordable initial
investment costs, accessibility of proper materials to avoid leakage in digester construction, lack of
efficient functioning digesters in different climate condition, sufficient production of fuel to meet the
needs, social acceptability of the fuel produced, etc. [208].
Studies showed that political measures are required to suppo