Studies on the Treatment of Night Soil. VI. Degradation on Treatment Plant of Non-diluted Night Soil by Aerobic Digestion

Abstract

In order to investigate the degradation mechanism of treatment plant of non-diluted night soil, changes in the composition of the contents at each treatment process wers measured. Each sample was separated into three fractions (soluble, fine particles, and coarse particles) by centrifugation and component of each fraction was analyzed. BOD, COD, Kjeldahl-N, NH₃-N, albumin-N, andvola tile fatty acids were greatly removed in the 1st digestion tank, especially in the soluble and fine-particle fractions. BOD removal was well related to the removal of volatile fatty acids. It became clear that gel-filtration on Sephadex G25 was a useful method to observe the effect of removal. On the comparison of elution diagram at OD₂₈₀ of the supernatant from each sample (centrifugation at 1200×g), the peakhights decreased well in the 1st digestion tank. Almost all the peaks of low molecules disappeared.