辅料及工艺参数对干旱地区污泥堆肥物理指标动态变化的影响

针对我国西北干旱地区污泥堆肥过程中存在升温速度慢和缺少适宜堆肥技术参数的问题，通过大型条垛式污泥堆肥正交实验，研究堆肥过程中堆体的温度、pH、电导率、含水率的动态变化过程，以期明确适宜该地区的污泥堆肥技术参数。结果表明，当玉米秸秆配比为15%时，堆体的升温速度达17.3 ℃∙d⁻¹，最高温度可达75 ℃以上；当秸秆粒径为5 cm时，高温持续时间最长，达22 d；堆体的电导率随着秸秆配比的增加呈增加的趋势，堆肥结束后以秸秆配比15%的电导率值最大。从水分变化来看，堆肥10 d后，污泥先静置6 d后翻抛的堆体上层含水率高，而常规翻抛的堆体各层含水率在15 d后呈现下层>上层>中层的垂直空间分布。总体而言，玉米秸秆粒径对堆体温度影响最大，而玉米秸秆配比对堆体含水率影响最大。西北干旱区污泥条垛式堆肥最优技术参数为添加5 cm粒径的玉米秸秆15%，完全混合先静置6 d后进行翻抛。本研究结果可为我国西北干旱地区生活污泥高效堆肥提供参考。

Effects of auxiliary materials and pile-turning technique on the dynamical changes of some physical index of sludge composite in northwest arid region

The objectives of this research were to clarify the influence of auxiliary materials and pile-turning technique on the dynamic change of physical index of sludge composting in northwest arid region, and to provide suitable technical parameters for organic fertilizer production with domestic sludge. The temperature, pH value, electrical conductivity, moisture content and its dynamic change in the upper, middle and lower layers of the windrow were studied by a large windrow composting system with an orthogonal experiment of 9 strips including 3 factors (ratio of auxiliary materials, particle size of auxiliary materials and turning-over process) and 3 levels. Results showed that the rate of temperature increase of compost was as fast as 17.3 ℃·d−1 and the highest temperature reached over 75 ℃ with 15% straw ratio. The duration of high temperature period got 22 days with the straw particle size of 5 cm. The electrical conductivity (EC) of the compost increased with the increase of the straw ratio, and the maximum value of EC at the end of experiment was achieved with 15% straw ratio. The moisture content at upper layer was higher with the treatment of conventional turning-over after standing for 6 d within composting 10 days and then gradually tended to be consistent among different layers after composting 30 days. However, the moisture content of each layer showed a vertical gradient of lower layer > upper layer > middle layer with conventional turning-over after composting 15 days. The maximum affecting factor on sludge composting temperature was corn straw particle size, while the maximum affecting factor on sludge composting moisture content was corn straw ratio during sludge composting. In a word, the optimal composting parameters for the sludge composting system in the northwest arid region are 15% corn stalks, 5 cm particle size of the stalks, and conventional turning-over after standing for 6 days. The results of this study can provide a reference for sludge window composting in the arid region of northwest China.