Review on Dehydration and Various Applications of Biogas Slurry for Environmental and Soil Health

Anaerobic digestion has been considered as a highly suitable technology to treat organic waste and yield biogas, a renewable source of energy. In this process, besides biogas, the undigested substrate is generated as byproduct in the form of slurry. Although the slurry being rich in plant nutrients (N,P,K,C and micro-nutrients) is very much useful for plant growth and soil fertility, its transportation from the production site to the farms becomes difficult due to its high water content (>90 per cent). Generally the slurry is deposited in the vicinity of biogas plants and creates environmental pollution problems i.e., breeding of mosquitoes, houseflies, etc., and foul smell. To achieve the maximum benefits of biogas technology, the optimal utilisation of biogas slurry is important. This paper discusses the various methods for slurry treatments/dehydration to facilitate its effective utilisation and the potential applications and value addition of slurry for various purposes.