Heat Treatment of Organics for Increasing Anaerobic Biodegradability. Annual Progress Report, June 1, 1977-May 31, 1978. Civil Engineering Technical Report No. 233

摘要

This report contains the results of the last and final 12 months of study under this portion of the grant on the heat treatment of organics to increase biodegradability by methane producing anaerobic bacteria. The purpose of this study has been to develop a means for increasing the yield and reducing the cost of methane gas, which can be used as an energy source. The procedures evaluated were heat treatment at temperatures up to 300 exp 0 C, generally under alkaline conditions (300 to 400 meq/1 NaOH). Included in this report are results of a study on the effects of alkaline heat treatment on lignocellulosic materials, the bioconversion of nitrogenous organic residues to methane under various chemical heat treatment conditions, and the microbiological examination of the biodegradability of selected lignoaromatic compounds and their conversion to methane. The results obtained on lignin indicate that alkaline treatment at 200 exp 0 C of the wood sample would yield around 20% conversion of the lignin material. Results obtained on cellulosics indicate about 80% bioconversion of this fraction in the softwood. The data suggest that the effect of heat treatment on WAS is to promote hydrolysis, splitting complex nitrogen polymers into simpler constituent molecules. At temperatures over 175 exp 0 C, however, decreased bioconversion of both the soluble and insoluble fractions was observed. Results suggest that refractory materials are being formed, accounting partially for the decreased biconversion. In addition, toxic compounds are also being formed, with this effect being more pronounced as treatment conditions become more severe. Data suggest that anaerobic degradation of aromatic ring compounds with the production of methane may be fairly widespread phenomenon among microorganism populations in anaerobic environments. (ERA citation 05:037794)