EFFECT OF FREE PHOSPHINE ON ANAEROBIC-DIGESTION

Gaseous phosphine was found to inhibit biogas formation during the ana erobic fermentation of swine manure. A logarithmic dose-response corre lation was obtained with 50% inhibition at a phosphine concentration o f approximately 150 ppm. Anaerobic fermentation of acetate and yeast e xtract measured by biogas formation were not affected at concentration s up to 1000 ppm. Despite the relative tolerance of anaerobic bacteria , phosphine may obviously inhibit the degradation of manure constituen ts. (C) 1997 Elsevier Science Ltd.