Abstract:

In view of the problem of difficulty in floc structure destruction and cell lysis of waste activated sludge (WAS), the impact and mechanism of cation exchange resin (CER) treatment on carbon source release in waste activated sludge was investigated. The results showed that the addition of CER had the greatest impact on the cracking of WAS, and the interaction between CER dosage, treatment time, and stirring speed was significant. At the optimal dosage of 2.8g CER/g TS, the ratio of TB-EPS to S-EPS decreased from the value of 9.61 to 0.95, and the maximum release of intracellular DNA and LDH was 3.04 times and 13.53 times that of the original sludge, respectively. At the dosage of 3.4g CER/g TS, Ca, Mg, and K elements in the sludge were removed by 58.39%, 52.00%, and 63.75%, respectively, while Na content in the sludge was 30.30 times that of the original sludge. Mechanism analysis showed that, CER induced the extensive removal of metallic elements such as Ca and Mg in the sludge system, and the formation of high osmotic pressure environment, which caused EPS structure cracking and cell lysis in sludge. The particle size of sludge flocs was reduced, and the apparent morphology of sludge became looser, which was beneficial for the effective dissolution of internal and external carbon sources in sludge flocs. When the exchange capacity of CER in the sludge system reached saturation, metal ions in the sludge liquid phase are re-adsorbed by the sludge flocs, resulting in a decrease in the release efficiency of SCOD in WAS.

Key words: waste activated sludge, cation exchange resin, carbon source, cell lysis, metallic elements

摘要：

针对剩余污泥絮体结构破坏和污泥溶胞困难问题，研究了阳离子交换树脂（CER）预处理对剩余污泥细胞内外碳源溶出的影响及作用机制。结果表明：CER投加量对剩余污泥破解的影响最大，且CER投加量与处理时间、搅拌速度之间的交互作用较显著。CER处理增强了污泥细胞内外碳源的有效溶出，CER为2.8g/g TS时，污泥TB-EPS与S-EPS比值由初始的9.61降至0.95，胞内DNA和LDH最大释放量分别是原泥的3.04倍和13.53倍；CER为3.4g/g TS时，污泥中金属元素的去除率最大，CER能去除污泥中58.39%、52.00%和63.75%的Ca、Mg和K元素，同时污泥中Na含量增加了30.30倍。机理分析表明，CER对污泥体系中Ca、Mg等元素的大量去除和高渗透压环境造成污泥絮体结构严重破解和细胞裂解，污泥颗粒粒径减小，污泥表观形态更加松散，有利于污泥絮体中内外碳源的有效溶出；CER在污泥体系中交换容量达到饱和后，金属离子从污泥液相中重新被污泥絮体吸附，导致污泥中SCOD的溶出效果变差。

关键词: 剩余污泥, 阳离子交换树脂, 碳源, 溶胞, 金属元素