城市污泥与稻草混合堆肥氧气消耗的通风量优化研究

The research of optimal ventilation:the oxygen consumption study of urban sewage sludge composting with rice straw

对城市污泥和稻草秸秆混合物料进行好氧堆肥试验,研究不同通风量堆肥过程氧气浓度的变化特征和差异性,分析了耗氧速率与温度和含水率之间的相关性。结果表明:(1)温度的变化经历4个时期:升温期、高温期、降温期和稳定期,最高温度达到74.20℃;含水率先升高,后降低,然后趋于稳定;(2)不同时期氧气浓度逐渐下降,高温期下降最明显;(3)氧气浓度在高温期与稳定期之间差异性达到极显著水平(P<0.01);(4)各处理耗氧速率最大值的大小顺序为:3号箱>2号箱>1号箱>4号箱,耗氧速率下降为0.11%/min,可以作为堆肥的腐熟评价指标,3号箱耗氧速率和温度与含水率的相关性达到极显著水平(P<0.01)。当通风量为1.00 m^3/h时,堆肥历时共16 d,高温期最长(6 d),氧气浓度超过17%,耗氧速率最大(0.75%/min),最适合污泥好氧堆肥发酵。

In order to analyze the correlation between oxygen consumption rate with temperature and water content in the aerobic composting of urban sewage sludge with rice straw,the oxygen concentration variation and fluctuation were analyzed in different aeration rates of composting process.Our results indicated that:(1)The change of temperature in each treatment showed four periods:raising-temperature period,high-temperature period,cooling-temperature period and constant-temperature period,and the maximum temperature was 74.20℃.The water content was increased at first,then decreased and trended to stable at last.(2)The oxygen concentration decreased gradually in different periods and descended obviously in the high-temperature period.(3)The difference of oxygen concentration between the hightemperature period and the constant-temperature period had significant difference(P<0.01).(4)The regularities of the maximum oxygen consumption rate was treatment 3>treatment 2>treatment 1>treatment>4 treatment.The compost would be matured when the oxygen consumption rate dropped to 0.11%/min.The correlation between oxygen consumption rate with temperature and moisture content of treatment 3 had significant difference(P<0.01).In addition,when the aeration flowrate was 1.00 m^3/h,the oxygen concentration exceed 17%,the high-temperature stage(6 d)was the longest in the whole composting stage(16 d)and the maximum oxygen consumption rate was able to achieve(0.75%/min).The aeration rate of 1.00 m3/h was the best flow-rate for urban sewage sludge composting.