堿解預處理改善污泥與煤共成漿特性的研究

王睿坤 劉建忠 胡友瑞 周俊虎 岑可法

摘 要：將污水污泥與煤粉摻混制備成漿體燃料是一種經濟有效的污泥資源化方法。由于污泥中含有豐富的胞外聚合物和極強的持水性能，由其制備的污泥水煤漿往往具有很高的粘度，不利于工業應用。該文研究了CaO對污泥有機物、持水性能、絮體結構等的影響，以及CaO改性污泥與煤共成漿性能。研究發現，CaO有促進污泥絮體有機物破解的作用。上清液中分子量大于5000 Da （Mn>5000 Da）的有機物含量下降，而Mn<5000 Da的含量升高。污泥顆粒的可溶性化學需氧量SCOD增加，揮發分含量VSSC降低。原污泥SCOD為16.2 mg O2/g DS，VSSC為58.19%。當加入20 wt.%CaO處理24 h后，SCOD增加至153.6 mg O2/g DS，VSSC降為45.61%。CaO對污泥有機物的水解作用和改性作用降低了污泥的持水性能，原污泥具有較強的持水性能，飽和持水率SMC為84.71%，當加入20%的CaO處理24 h后，SMC降為79.10%。這都是有利于成漿的。與原污泥水煤漿相比，改性污泥水煤漿具有較低的特征粘度。原污泥水煤漿的特征粘度為1 635.3 mPa·s，當加入20%的CaO調理24 h后，特征粘度降為1 082.2 mPa·s。

關鍵詞：污泥處理 污泥堿解 成漿性能 胞外有機物 漿體燃料

Abstract：Municipal wastewater sludge （denoted as sludge hereafter） can be economically and effectively utilized by mixing it with coal to prepare slurry fuels.However，the abundant extracellular polymeric substances （EPSs） and strong water-holding capacity of raw sludge causes the viscosity of slurry fuel to increase remarkably， which is disadvantageous for industrial applications.The slurrying properties of sludge can be improved by alkaline hydrolysis. This study examined the effects of calcium oxide （CaO） on EPSs，water-holding capacity，floc structure of sludge， and co-slurrying properties of sludge with coal.Results showed that after CaO modification，the relative amount of EPSs with a number-average molecular weight（Mn） >5000 Da noticeably decreased， whereas the relative amount of EPSs with Mn< 5000 Da increased. Moreover， the soluble chemical oxygen demand （SCOD） of sludge increased， and its volatile suspended solid （VSS） content decreased. Raw sludge had an SCOD of 16.2 mg O2/g dry sludge （DS） and VSS of 58.19%. After treatment with 0.2 g CaO/g DS for 24 h，SCOD increased to 153.6 mg O2/g DS，VSS decreased to 45.61%，the water-holding capacity of the sludge decreased，and the saturated water content of raw sludge decreased from 84.71% to 79.10%.The characteristic viscosity ηc of raw sludge–coal slurry was 1 635.3 mPa·s， which decreased to 1 082.2 mPa·s after treatment with 0.2 g CaO/g DS for 24 h.These findings strongly suggested that sludge solubilization can help improve slurrying.

Key Words：Municipal Wastewater Sludge；Alkaline Hydrolysis；Slurrying；Extracellular Polymeric Substances （EPS）；Slurry Fuels

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