Research On Effectiveness Of Aerobic Sludge Composting With Functional Membrane Coverage

With the rapid development of economy and significant improvement of sewage treatment, water requirement and sewage production increase year by year. Therefore, sewage treatment plants have explosively grown in recent 20 years, In municipal sewage treatment a large amount of sludge is produced. The sludge disposal has become a key problem in China. Aerobic composting is widely used in the sludge disposal with advantages of fast organic decomposition, high resource utilization and low operating cost. Although aerobic sludge composting technology has been greatly improved, the problems of odor emission and high nitrogen loss still exist. How to effectively reduce the odor emission has important significance for the development and application of sludge composting.Waterproof and breathable membrane is widely used in industry and life because of their excellent characteristics, such as waterproof, breathable, economical and practical. Functional membrane is normally made of waterproof and breathable membrane and fabric. The research on sludge composting system with functional membrane coverage has just started in China. The effect of functional membrane coverage and adding zeolite to sludge composting system with functional membrane coverage on odor emission has few reported.In this research, municipal sludge was used as the main material for composting, and leaves, sawdust and corn straw were used as conditioners. The sludge composting was carried out in batch pile with a forced aeration. Through covering the composting pile with functional membrane and adjusting the operation parameters, the effects of functional membrane coverage on composting process were studied. With the functional membrane coverage, zeolite of 10% was added to the substracts to study how the zeolite addition effected the odor emission. The results showed that ammonia emission reduced by 60% through functional membrane coverage on the composting pile. The pH of composting system increased by 0.2-0.4, and the rotten compost contained higher nitrogen content. When the composting system with functional membrane coverage was supplied with sufficient oxygen, the ammonia emission was of positive relevance with the ventilation rate, but the higher ventilation rate did not lead to an intense increase of ammonia emission. The ammonia emission reduced by 32% through adding zeolite in the sludge composting system with functional membrane coverage, and the pH decreased by 0.05-0.2 in the composting process. With the combined functional membrane coverage with zeolite addition, the ammonia emission reduced by 70%, compare with control, which greatly reduced the influence of composting odor on surrounding environment.