粪便与生活垃圾混合堆肥过程控制

Night-soil/municipal solid waste co-composting process control

采用强制通风静态仓进行粪便和生活垃圾混合堆肥,以玉米秸为调理剂,石灰调节pH,考察正压鼓风和负压抽吸2种通风方式对不同堆料配比堆肥过程的控制效果。试验结果表明,5种堆料配比的中层温度都达到了50℃,并保持了5 d以上,达到了堆肥无害化和稳定化的要求。正压鼓风堆料底部温度较低,负压抽吸堆料底部热量容易聚集,但是后者堆体温度分布相对均匀。负压抽吸对水分的去除效果差于正压鼓风。对于温度未达到50℃的堆料应回流处理保证无害化。粪便有机物含量高,堆肥初期易酸化,添加石灰调节pH,使堆肥顺利升温,缩短发酵期,石灰合理添加量为2%(质量分数)。采用负压抽吸的通风方式,散除堆肥初期的挥发性有机酸,再经过冷凝除臭器脱酸除臭后排放,是一种可取的方式。

Static composting vessel with active ventilation was set to investigate the process control of night- soil/municipal solid waste co-composting with maize straw as amendments and lime as pH controller. Results showed that mixtures prepared with different ratios of composting material all reached ceiling temperature of higher than 50 ~C and maintained more than 5 days, which met the requirement for the innocuity and stabilization of composting. Venti- lation methods affected temperature distribution of piles. Blow ventilation had the effects of driving heat to the apex of the pile whilst the base remained cool, while the suck ventilated pile presented relatively uniform temperature distri- bution with base temperature easy to gather than that of blow ventilated pile. Blow ventilation showed positive effects to moisture volatilization than suck ventilation. The mixture residues with temperature lower than 50 ℃ should be re- cycled to composting process in order to keep the innoeuity. Acidification at start-up stage causing by the high organic content of night-soil could be reduced by adding lime at dosage of 2 % weight ratio, leading to rapid rising of tempera- ture and short eomposting period. To dispel volatile acid by suck ventilation and controlled by condensation was also an alternative.