Ultrasonication as a pre-treatment method for the enhancement of the psychrophilic anaerobic digestion of aquaculture effluents

The effectiveness of ultrasonication as a pre-treatment method for the psyc hrophilic anaerobic treatment of aquaculture effluents was assessed using a 4 l solids digester. Ultrasonication of aquaculture wastewater was found t o enhance the removal of chemical oxygen demand by anaerobic digestion by a lmost 10%. There was also a concurrent increase in total biogas production from 0.29 l day(-1) to 0.45 l day(-1) with a corresponding 10% increase in methane concentration. Furthermore, there was an increase of 60% in effluen t total ammonia nitrogen concentration as a result of sonication in compari son with a 45% increase for untreated digester waste.