污泥的高温微好氧消化-厌氧消化工艺研究

Study of sludge stabilization for dual processes of thermophilic micro-aerobic and anaerobic digestion

城市污泥含有大量有机物和病原菌,需要稳定化处理。采用新型工艺高温微好氧与中温厌氧两级消化工艺(ATMD-MAD)处理城市污泥,与全程厌氧消化工艺(MAD)相比,不仅回收能源气体甲烷,而且缩短稳定化停留时间。55℃高温微好氧消化停留时间为2 d,后接35℃中温厌氧消化共运行24 d。结果表明,在ATMD-MAD系统中污泥的挥发性悬浮固体VSS去除率能在22 d时达到污泥稳定化要求的40%以上。ATMD-MAD工艺的单位VSS甲烷产量最高为496 m L/g VSS高于MAD工艺。在消化的前14天,可溶性挥发有机酸VFA在ATMD-MAD系统中的总量比MAD高出20%;在消化的第2天,ATMD-MAD系统中可溶性COD(SCOD)高出MAD工艺43.8%。ORP的变化反映了ATMD-MAD工艺保持了较好的厌氧状态,消化开始时的头2天限量曝气并没有给厌氧带来冲击。

The sewage sludge with a significant amount of organic matters and pathogen is treated to achieve stabilization. A novel combined process of auto thermophilic micro-aerobic and mesophilic anaerobic digestion（ ATMD-MAD） was applied to treat sewage sludge. Compared with conventional anaerobic digestion process（ MAD）,ATMD-MAD process can produce bio-gas methane and shorten stabilization retention time. Thermophilic aerobic digestion with a 2 d HRT and 55℃ reaction temperature was followed by a mesophilic anaerobic process. This process run for 24 d. Results indicate that sludge could achieve stabilization during the 22 d digestion process with a removal VSS rate of over 40%. The maximum methane yield of per unit VSS of ATMD-MAD process up to 496 mL/g VSS was higher than that of the MAD process. At the start of the digestion period,total concentrations of VFA at 14 d and soluble COD at 2 d were 20% and 43. 8% higher in ATMD-MAD than in MAD,respectively. Results of ORP values implied that the sludge of ATMD-MAD process could be maintained under anaerobic condition during the digestion period. At the first two days of beginning,limited aeration had no impact on anaerobic digestion process in ATMD-MAD system.