电化学预处理污泥的机制研究

Mechanism of electrochemical pretreatment for enhancement of sludge aerobic digestion

采用电化学方法对含固率为2%(质量分数)的污泥进行预处理,不仅可去除污泥中10.5%的挥发性悬浮固体(VSS),而且还可使后续的污泥好氧消化时间由20 d缩短为16 d。为了探讨电化学预处理提高污泥好氧消化性能的机制,对预处理前后的污泥性质进行了研究,发现污泥经电化学预处理后,上清液中可溶性有机物(SCOD)、TN、TP和NH4+-N含量均升高,其中SCOD由原来的202 mg/L升至2 191 mg/L;污泥固体的热稳定性有所降低。污泥的扫描电镜和红外光谱分析表明,电化学预处理提高污泥好氧消化性能的机制在于其可以破解污泥中的微生物细胞、溶解蛋白质和多糖物质。

Electrochemical technology was applied to pretreat sludge before its aerobic digestion.Results showed that the volatile suspended solids（VSS） of sludge was removed by 10.5% after electrochemical pre-treatment,and in the subsequent aerobic digestion,the solids retention time（SRT） was decreased from original 20 days to 16 days.The sludge before and after electrochemical pretreatment were investigated and characterized by thermogravimetric analysis（TGA）,scanning electron microscope（SEM） images and infrared（IR） spectra to reveal the enhancement mechanism of electrochemical pretreatment.The results indicated that soluble chemical oxygen demand（SCOD）,total nitrogen（TN）,total phosphorus（TP） and ammonia nitrogen（NH＋4-N） of pretreated sludge was significantly increased,while its thermal stability of pretreated sludge was relative poor;SEM image and IR spectra showed electrochemical pretreatment could rupture sludge cells,remove and solubilize intracellular substances,especially protein and polysaccharide,and consequently enhance the aerobic digestion.