热处理和pH调节协同作用下污泥调质过程研究
Synergy effects of pH adjustment and thermal treatment on sewage sludge disintegration process
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摘要: 采用单因素实验和正交实验相结合的方式，考察了不同实验条件参数（温度、pH和反应时间）下，热处理和pH调节对污泥细胞溶出过程的影响。结果表明，污泥溶解性化学需氧量（SCOD）与反应温度、溶液pH、反应时间成正相关，其中pH对SCOD的影响最为显著，反应时间对其影响最小。污泥溶胞的最优条件：反应温度120℃，pH=11，反应时间为15 min，经过处理，SCOD可达14 810 mg/L，与总化学需氧量（TCOD）之比为49.29%，总有机碳（TOC）达4 560 mg/L，总氮（TN）则增加27%，总悬浮固体（TSS）和挥发性悬浮固体（VSS）去除率分别达22.85%和40.93%。热碱处理后污泥上清液分子量分布（MWD）状况结果显示：>1 000 KDa MW物质含量随pH和温度的增加而增加，当pH=11时，该部分物质可从原污泥的20.94%增加到31.70%；当温度为120℃时，该部分物质可达49.83%。Abstract: The sludge cells could be disintegrated greatly under the thermal conditions cooperating with appropriate pH range. To investigate the optimal operation conditions for sludge disintegration processes， single factor experiments and orthogonal experiments were applied in this work. The results showed that the disintegration process of sludge was influenced significantly by the reaction time， pH value and temperature， and the optimum conditions were as follows: pH of 11， thermal temperature of 120℃， and the reaction time of 15 min. The SCOD， SCOD/TCOD and TOC in supernatant of the treated sludge were 14 810 mg/L， 49.29% and 4 560 mg/L， respectively， TN increased by 27%， and the removal rates of TSS and VSS were about 22.85% and 40.93%， respectively. Meanwhile， the molecular weight distribution (MWD) in sludge supernatant was analyzed by GPC (gel permeation chromatography) after alkaline thermal hydrolysis treatment. It was found that the percentage of the fraction >1 000 KDa MW in supernatant increased from 20.94% to 31.70% as pH value changed from the origin to 11， and from 20.94% to 49.83% as temperature increased to 120℃， respectively.
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Key words:
- sewage sludge /
- alkaline thermal treatment /
- SCOD /
- molecular weight distribution
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