Use of night soil in agriculture and fish farming.

The use of untreated night soil as a fertilizer in agriculture or as a source of nutrients in fish farming presents a considerable health hazard in the form of pathogens and parasites. A pilot study is reported in which night soil was placed in an anaerobic digester, producing biogas and residual organic matter. The latter was introduced into biostabilization ponds, and nutrients were thus obtained for the rearing of fish. Fish ponds receiving nutrients derived from treated night soil were less contaminated than ones to which untreated night soil was applied, and the fish reared in them were of superior quality.