EFFECTS OF PROPERTIES AND STRUCTURE OF POLYACRYLAMIDE ON SLUDGES CONDITIONING AND DEWATERING PERFORMANCE BEFORE AND AFTER ANAEROBIC DIGESTION
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摘要: 为研究聚丙烯酰胺(PAM)性质和结构对污泥脱水性能的影响,选取10种常用阳离子PAM对消化进泥(初沉污泥和剩余污泥)和消化出泥进行调理。通过测定PAM调理后的污泥比阻(SRF)、毛细吸水时间(CST)、粒径和脱水后泥饼含水率的变化,并结合流变学特性进行调理效果评价和机制解析。结果表明:不同PAM对2种污泥脱水性能的影响迥异,但大多数PAM调理后消化出泥的脱水性能更优,两者均适合采用大分子、高离子度、支链结构的PAM调理。在优选PAM的最佳投加量为4.0 kg/t下,调理后消化出泥的SRF、CST和粒径分别为0.64×1012 m/kg、18.6 s和400.5 μm,脱水后泥饼含水率可降低至74.8%。流变学分析结果表明,优选PAM调理后污泥的触变性显著,絮体更大更密实,弹性模量更大,絮体抗剪切能力更强,脱水性能更优。研究结果可为污水处理厂消化污泥调理脱水药剂的选择提供理论依据与技术参考。
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关键词:
- 厌氧消化污泥 /
- 聚丙烯酰胺(PAM) /
- 污泥调理 /
- 污泥脱水 /
- 流变学
Abstract: In order to investigate the effects of the property and structure of polyacrylamide (PAM) on sludge dewatering performance, 10 types of common cationic PAM were chosen for the conditioning of mixed sludge (primary and waste sludge) and anaerobically digested sludge. Changes in sludge specific resistance (SRF), capillary water absorption time (CST), particle size, and moisture content of dewatered sludge cake were determined for PAM-conditioned sludge, and then they were coupled with the rheological property to evaluate the conditioning performance and elucidate governing mechanisms. The results showed that the effects of different types of PAMs on the dewaterability of waste sludge and digested sludge were distinct, and the conditioned digested sludge generally obtained better dewatering performance. Both waste sludge and digested sludge achieved the best dewaterability after being conditioned by the PAM with high molecular weight, high charge density and branched chain PAM. At the optimum dosage of 4.0 kg/t DS for the chosen PAM, the SRF, CST, and particle size of the conditioned digested sludge were 0.64×1012 m/kg, 18.6 s, and 400.5 μm, and the moisture content of dewatered sludge cake was reduced to 74.8%. Rheological analysis showed that sludge conditioned by the chosen PAM had more obvious thixotropy, larger and denser flocs, higher elasticity modulus, stronger shear resistance, and thus better dewatering performance. The results of this study can provide a theoretical basis and technical reference for conditioner selection for the anaerobically digested sludge in wastewater treatment plants.-
Key words:
- anaerobically digested sludge /
- polyacrylamide (PAM) /
- sludge conditioning /
- dewaterability /
- rheology
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