Fungal degradation of anaerobically digested sewage sludge

Fifty isolates of fungi were screened for their ability to grow on and degrade sludge. Cunninghamella elegans was selected for further study of degradation as affected by moisture, nutrients, time and temperature. Maximal sludge degradation (total dry weight basis) was 5.8% by Rhizopus oligosporus, 5.4% by C. elegans and 5.3% by Myrothecium verrucaria, representing approximately 11% degradation of the organic matter present. Added nutrients had little or no effect on sludge degradation. Maximal sludge degradation by C. elegans occurred in three weeks at 30-35 C or four weeks at 25 and 40 C.