2.上海大学土木工程系, 上海 200444
1.Shanghai Geological Construction Co. Ltd., Shanghai 200331, China
2.Department of Civil Engineering, Shanghai University, Shanghai 200444, China
针对药剂真空预压法处理填埋污泥通常存在污染的问题,利用更加环保高效的冻融-真空预压法进行处理,并采用室内模型箱实验,探究了排水板类型 (分离式和整体式) 对冻融污泥真空固结效果的影响。结果表明,当原始污泥含水率为86%,经冻融联合真空预压处理后,含水率最低可降至59.5%,这一含水率可达到我国填埋污泥的规范要求;整体式排水板与分离式排水板最终出水量差别不大,但整体式排水板的含水率沿径向分布更均匀。整体式排水板与分离式排水板孔径分布差异明显,分离式排水板主要以小孔分布为主,而整体式排水板主要以微孔和介孔为主,整体式排水板结构更加致密,固结程度高;整体式排水板的减量比为63.6%,分离式排水板的减量比为61.9%,总体上整体式排水板的减量比略优于分离式排水板。本研究结果可为冻融真空预压原位处理填埋污泥提供参考。
Many cities in China are facing severe problems of in-situ sludge reduction from landfills. In view of the shortage of chemical preconditioning combined with vacuum preloading method in treating landfill sludge, a more environmental friendly and efficient freeze-thaw vacuum preloading method was proposed, and the indoor model box test was used to explore the influence of plastic drainage plate type (separate type and integral type) on the vacuum consolidation effect of freeze-thawed sludge. The results showed that the water content of the original sludge was 86%, after freeze-thaw combined with vacuum preloading treatment, the water content was reduced to 59.5%, which meets the requirements of China's landfill sludge specification. The final water discharge of the integral plastic drainage board (IPVD) and the separate plastic drainage board (SPVD) had little difference, but the water content of the IPVD was more evenly distributed along the radial direction. The pore size distribution of the IPVD was significantly different from that of the SPVD. The pore size distribution of the SPVD was mainly small pores, while the IPVD was mainly micropores and mesoporous. The structure of the IPVD was more compact and had a higher degree of consolidation. The volume reduction ratio of IPVD was 63.6%, and that of SPVD was 61.9%. On the whole, the volume reduction ratio of IPVD was slightly better than that of SPVD. The research results had certain guiding significance for in-situ treatment of landfill sludge by freeze-thaw combined with vacuum preloading.
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Particle size distribution curve of original sludge and sludge after freeze-thaw
Schematic diagram of radial vacuum preloading model box
Physical drawing of different types of plastic drainage boards
Change curve of cumulative water discharge of different PVD types
Variation curve of cumulative settlement of different PVD types
Change of water content of different PVD types
Pore size distribution curves of different PVD types
Percentage change of pores with different sizes under different PVD types
SEM diagram of different PVD types
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