通风条件对城市污水厂污泥好氧堆肥过程的影响

本文选择堆肥熟料作为添加剂与城市污水厂污泥混合进行好氧堆肥。通过对温度、耗氧速率、有机物、含水率、pH值和氨氮等指标的分析,重点研究了不同通风条件对堆肥过程的影响。实验结果表明,污泥与熟料混合后,有机物含量较低,堆肥速率较快,对通风条件的改变比较敏感。当通风量低于0.025m3/(m3.min)时,堆肥前期系统供氧不足,堆肥速率较慢,耗时长,同时堆体内变为厌氧环境,pH值变低,臭气产生量高;当通风量高于0.05m3/(m3.min)以及采用变风量通风时,在保证供氧量充足的同时,具有较长的高温期,具有臭气产生量小、堆肥速率快的优点,但采用变风量通风更加节能。

Effect of Ventilation on Aerobic Compost of Sludge from Domestic Sewage Treatment Plant

In this paper, the sludge from domestic sewage treatment plant was treated by aerobic compost mixed with eomposted materials as additive. By analysis of the parameters including temperature, oxygen consumption rate, organic matters, moisture content, pH value and ammonia nitrogen, the effect of ventilation on composting process was studied. The results showed that the mixture of the sludge and composted materials contained low organic matters, so the eomposting rate became fast and sensitive to the ventilation condition. At the condition with ventilation rate lower than 0. 025m3/ （m3 . min）, it resulted in effects such as shortage of oxygen for composting during the initial period, low eomposting rate, long time needed, becoming anaerobic environment inside the composting pile, decreasing of pH value and more production of odors. On the contrary, the condition with ventilation rate higher that 0. 05m3/ （m3 . min） and changing the rate had advantages such as sufficient air supply, long thermophilic period, little stink gas produced and high composting speed. With variable ventilation rate, the process would save more energy.