Keywords: human excreta, resource recovery, plant nutrients, biogas, pollution control, resource recovery, water conservation, eco–sanitation, flush toilets, grey water recycling, anaerobic digestion, black water, sustainable development, sustainability
Is human excreta a waste?
Every day a huge amount of excreta is being produced by human society and it is also considered one of the most unwanted waste/refuse of the society because of its nuisance and diseases causing characteristics. However, it is also utilised as a fertiliser and soil conditioner in several countries such as India and China. Presently most common sanitation concept is centralised treatment of human excreta containing wastewater, in which a small volume of excreta is being mixed with large volume of water, and transport the mixture to the centralised treatment site employing a costly and complicated sewer network. Disadvantage associated with this process are loss of valuable resource in terms of plant nutrient, energy and water. Therefore, a holistic approach is warranted for human excreta management, which could lead to pollution control, resource recovery and water conservation. Eco–sanitation (separate collection of faeces and urine employing urine diverting toilet) is good option at least for rural setting. In urban areas, flush toilet with recycling facilities of grey water for flushing purpose and subsequently separate decentralise anaerobic digestion of resulting black water would be an optimal compromise for sustainable development.