Treatment of piggery wastewater using an acti-zyme (Bio-catalyst) and papermill biochar compound co-capturing biogas

Abstract

The world is facing formidable challenges in meeting rising demands of clean water as the available supplies are depleting due to extended droughts, population growth, more stringent health based regulations and competing demands from a variety of users. At the same time, wastewater treatment plants are using energy from the national grid rather than generating their own energy. Piggery farms and paper mills make use of a lot of water and thus contribute towards water shortage. The piggery farms produce a significant amount of wastewater which water can be effectively treated via anaerobic routes to harness biogas. On the other hand, paper mills are generate excessive amounts of sludge during paper making process. Secondary treatment of wastewater can therefore be used to make sludge based activated biochar which can be used in wastewater treatment. This work assessed the feasibility of using a compound from activated carbon from paper mill sludge (PMS) and Acti-zyme (a digestion bio-catalyst) to treat piggery wastewater anaerobically and co-capturing the biogas produced for energy usage. A piggery wastewater treatment plant generating 6000 m3 /day of wastewater was considered and the change in the wastewater physicochemical properties was determined using standard methods. The amount of biogas produced was determined using a water displacement method for retention periods of 30 days at 37 °C. The use of Acti-zyme and PMS biochar compound at 50 g/m3 reduced the piggery wastewater contaminants properties such as total solids, colour, pH and BOD5 by >70%. The treated effluent met the set standards for effluent water disposal. Biogas was produced at a rate of 2.3 m3 /m3 .day with a bio-methane composition of about 78%.