Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, China.
Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, China.
J Environ Sci (China). 2018 May;67:145-153. doi: 10.1016/j.jes.2017.08.016. Epub 2017 Aug 30.
Dehydrating large amounts of sludge produced by sewage treatment plants is difficult. Microwave pretreatment can effectively and significantly improve the dewaterability and hydrogen production of sludge subjected to anaerobic digestion. The aim of this study was to investigate the effects of different microwave conditions on hydrogen production from anaerobic digestion and dewaterability of sludge. Based on an analysis of the electric field distribution, a spiral reactor was designed and a continuous microwave system was built to conduct intermittent and continuous experiments under different conditions. Settling Volume, Capillary Suction Time, particle size, and moisture content of the sludge were measured. The results show that sludge pretreatment in continuous experiments has equally remarkable dehydration performance as in intermittent experiments; the minimum moisture content was 77.29% in the intermittent experiment under a microwave power of 300W and an exposure time of 60sec, and that in the continuous experiment was 77.56% under a microwave power of 400W and an exposure time of 60sec. The peak measured by Differential Scanning Calorimeter appeared earliest under a microwave power of 600W and an exposure time of 180sec. The heat flux at the peak was 4.343W/g, which is relatively small. This indicates that microwave pretreatment induced desirable effects. The maximum yield of hydrogen production was 7.967% under the conditions of microwave power of 500W, exposure time of 120sec, and water bath at 55°C. This research provides a theoretical and experimental basis for the development of a continuous microwave sludge-conditioning system.
处理污水处理厂产生的大量污泥是困难的。微波预处理可以有效地显著改善污泥的脱水性能和厌氧消化产氢性能。本研究旨在探讨不同微波条件对厌氧消化产氢和污泥脱水性能的影响。基于电场分布分析，设计了一种螺旋式反应器，并建立了连续微波系统，在不同条件下进行间歇和连续实验。测量了污泥的沉降体积、毛细吸水时间、粒径和含水率。结果表明，连续实验中污泥预处理具有与间歇实验同样显著的脱水性能；在间歇实验中，微波功率为 300W、暴露时间为 60s 时，污泥的最低含水率为 77.29%，在连续实验中，微波功率为 400W、暴露时间为 60s 时，污泥的最低含水率为 77.56%。在微波功率为 600W、暴露时间为 180s 的条件下，差示扫描量热仪测量的峰值出现最早。峰值时的热通量为 4.343W/g，相对较小。这表明微波预处理产生了理想的效果。在微波功率为 500W、暴露时间为 120s、水浴温度为 55°C 的条件下，氢气的最大产率为 7.967%。本研究为连续微波污泥调理系统的开发提供了理论和实验基础。
