预热自热高温好氧消化工艺处理市政污泥的研究

Research on municipal sludge disposal by preheated autothermal themerphilic aerobic digestion

用自行设计的预热自热高温好氧消化工艺系统处理市政污泥,采用间歇式运行方式,对不同的进泥浓度、搅拌速率、曝气量、固体停留时间条件下的污泥稳定化效果进行了单因素分析研究,获得最佳工艺参数,在此基础上,对污泥稳定化和无害化效果进行了评价,同时对消化后污泥的脱水性能、总氮、总磷、氨氮、总有机碳和pH值进行了测试分析。结果表明,当进泥含固率为4%～6%、进泥挥发性有机物浓度为(31.9～42.1)g/L、搅拌速率为(90～100)r/min、曝气量为(0.06～0.08)m3/h、固体停留时间为10d时,污泥稳定化效果最好,反应器内温度可维持在55～57℃,对挥发性有机物的去除率平均达到52.8%,此时,病原菌的灭活率达到100%,出泥达到了美国环保局规定的A级生物固体(污泥)的标准;在此最佳工艺条件下发现消化后的污泥脱水性能变差,而总氮、总磷、氨氮、总有机碳和pH值升高,这是由于在消化过程中产生的溶胞现象所致。

The municipal sludge was disposed by self-designed technology of preheated autothermal themerphilic aerobic digestion. With the intermittent operating method, the influence of different feeding sludge concentration, agitation velocity, aeration and solid retention time （SRT） on sludge stability were researched by single-factor experiment, the best operating parameters were obtained. In this basis, the effectiveness of sludge stability and harmlessness was evaluated, the dewatering functional, total nitrogen （TN）, total phosphorus （TP）, ammonia （NH3-N）, total organic carbon （TOC） and pH were detected and analyzed. The results showed that when the total solid and VSS of feed sludge was 4%～6% and （31.9～42.1）g/L,respectively the agitation velocity was （90～100）r/ min, the aeration was （0.06～0.08）m^3/h, the SRT was 10 d, the sludge digestion efficiency was the best, the temperature of inner tank was sustained 55 ～57 ℃, the average removal rate of VSS was reached to 52.8%, the inactivation rate of pathogens bacteria was 100%, the digested sludge was accorded to the class A biomass standard of USEPA. At this best process conditions, the sludge dewatering functional was worse, while the TN, TP, NH3-N, TOC and pH were increased, this phenomenon was caused by cell lysis in digestion process.