Prodn. of humus-like substrate from purified sewage - comprises using solid sewage residue to condition sewage and reduce incandescence

摘要

Prodn. of a depositable, humus-like substrate comprises treating purified sewage, prior to mechanical dehydration, with a solid purified sewage residue ground to a size below 1 mm in order to physically condition the sewage and to reduce its incandescence loss by 10%. The added solid sewage residue is obtd. by the fermentation of mechanically dehydrated, purified sewage either aerobically, e.g. for 5-10 days at 50-90 deg.C, and/or without aeration, e.g. for several weeks at 10-90 deg.C, esp. in the presence of fungi. Further, the purified sewage contains added organic and/or inorganic additives to increase its solid content as well as synthetic flocculants, is mechanically dehydrated to at least 20% solid content and is then fermented in the same manner. USE/ADVANTAGE - The finished substrate is used as an agricultural fertiliser. The finished substrate complies with legal regulations and the method is simpler and more cost-effective than known processes. In addition, prod. with a solid content above 40% can be obtd., compared with 25% usually achieved.