生物炭添加对污泥堆肥腐殖化和氨气排放的影响

近年来，市政污泥产量及无害化处置量均呈增加趋势，污泥堆肥技术成为研究与关注的热点，但传统堆肥中存在许多问题。为提高市政污泥堆肥腐殖化程度并减少氮素损失，通过好氧堆肥方法研究了添加生物炭对市政污泥堆肥腐殖质组分及氨气排放的影响。结果表明，在37 d堆肥中，对照（C1）、添加5%生物炭（C2）、添加10%生物炭（C3）3个处理均达到腐熟标准。与对照相比，生物炭添加延长了堆体高温时间1~4 d，提高了堆体pH和EC，对总有机碳、水溶性有机碳、富里酸分解更彻底；堆肥结束时，C2堆体腐殖化指数、胡敏酸占有率和胡富比均高于对照，腐殖化效果最好。氨气释放主要在高温期，累计释放量C1（178.43 g/m2）＞C3（151.28 g/m2）＞C2（134.97 g/m2），堆肥结束C1、C2和C3总氮含量分别为11.67 g/kg 、13.48 g/kg和13.03 g/kg，添加生物炭有利于氮素保留。可见，生物炭在提高堆肥腐殖质稳定和减少氨气排放中具有良好效果，且5%添加量优于10%。

Effects of biochar addition on humification and ammonia emission of sludge compost

In recent years, the output of municipal sludge and the proportion of harmless disposal are increasing. Sludge composting technology has become the focus of research and attention, but there are many problems in traditional composting. In order to improve the humification degree of municipal sludge compost and reduce nitrogen loss, the effects of adding biochar on humus composition and ammonia emission of municipal sludge compost were studied by aerobic composting method. The results showed that control (C1), addition of 5% biochar (C2) and addition of 10% biochar (C3) all reached the standard of maturity in 37 d compost. Compared with the control, biochar addition prolonged the high temperature time for 1 to 4 days, increased the pH and EC of the reactor, and decomposed the total organic carbon, water-soluble organic carbon and fulferic acid more thoroughly. At the end of composting, the humification index, humic acid occupancy rate and hu fu ratio of C2 were higher than those of the control, and the humification effect was the best. Ammonia release mainly occurred in high temperature period, and the cumulative release amount was C1 (178.43 g/m2) > C3 (151.28 g/m2) > C2 (134.97 g/m2). The total nitrogen contents of C1, C2 and C3 after composting were 11.67 g/kg, 13.48 g/kg and 13.03 g/kg, respectively. The addition of biochar is beneficial to nitrogen retention. It can be seen that biochar has a good effect on improving humus stability and reducing ammonia emissions in compost. Moreover, the addition amount of 5% is better than 10%.