Is bio-solid fertilizer safe?
In appreciation of Engr. S. A. Mansoor’s notion, I would like to say that fertiliser known as ‘night soil’ or ‘night manure’ made from bio-solids, or human waste has yet to get a safety certificate for application in food crop production or in agriculture. Because such fertiliser even after strict treatment may contain heavy metals, pathogens or chemicals which might contaminate crops and enter into the human food chain. In some advanced countries, fertiliser made from human wastes or bio-solids are used but after killing dangerous bacteria either with heat or anaerobic digestion in treatment plants. But such type of fertiliser is not allowed in organic agriculture. In fact more epidemiological research is needed to determine the health effects of using this fertiliser in growing food crops.
Professor M Zahidul Haque
SAU, Dhaka
