A New Process to Treat Strong Biological Waste

Abstract

Strong brewery waste was trickled through a vertical curtain consisting of two 3mm layers of reticulated Polyurethane foam bonded to a reinforcing nylon cloth core. A filamentous fungus, Geotrichum fragrans adhered to the curtain and provided a matrix for other yeasts and aerobic bacteria which include Kloeckera lindneri and a Candida sp., a Bacillus sp. and a Corynebacterium sp. The organisms grew as a lawn. To avoid anaerobiosis the lawn was harvested periodically by passing the curtain through rollers leaving a viable representative residue of the population. Passage through 6m of curtain reduced a TOD of 55,000 mgL−1 to 3,300 mgL−1 (94%). Probably the length of the curtain could be reduced to 4m with a residence time of 9.6h. One m2 of curtain with a 4m fall can treat 15Ld−1. A further waste from pigs (2% solids) was acidogenically fermented to produce organic acids. The acids during clarification were used to kill the bacterial pathogens in the waste. The liquor was run through a curtain inoculated with suitable organisms. These removed the unpleasant odour and 88% of the TOD in a 4m passage through the curtain. Treatment time: fermentation 5d, clarification and removal of pathogens 2d, treatment in curtain 0.3d, total 7.3d.