超声与碱预处理对剩余污泥磷及有机物释放的影响

为了回收污泥所含的磷,采用碱和超声波对3种剩余污泥进行预处理以释放磷,考察了处理前后PO3-4-P(正磷酸盐)、TP(总磷)、SCOD(可溶性COD)、TOC(总有机碳)、TS(总固体)、VS(挥发性固体)的释放规律及溶解性有机物的三维荧光特性变化.结果表明,碱和超声波处理均能有效破解污泥,释放磷和有机物;城市污泥比制药污泥更容易破解;城市污泥无机磷的释放高于有机磷,而工业污泥的有机磷释放高于无机磷;采用生物脱氮除磷工艺的城市污泥释放磷最多,释放有机物最少,有利于磷的进一步回收.碱处理和超声处理都不会从根本上改变污泥上清液中有机物的组分,但碱处理能促进污泥蛋白质类、腐殖酸类和富里酸类有机物的释放.

Phosphorus and DOM releasing from different surplus activated sludge by ultrasonic and alkaline pretreatment

To recover the phosphorus from surplus activated sludge, three types of sludge were pretreated by alkali treatment or combination of alkali treatment and ultrasonic technique to release phosphorus. The characteristics of PO₄^3--P, TP, SCOD, TOC, TS, VS before and after pretreatment were investigated. The fluorescence properties of dissolved organic matter in supernatant were analyzed via fluorescence regional integration based on the observation of excitation-emission matrix (EEM) spectroscopy. The results showed that phosphorus and organic matter could release into supernatant by both alkali and ultrasonic treatment. The decomposition of surplus activated sludge from municipal wastewater treatment plant was easier than that from pharmaceutical wastewater treatment plant. The concentration of inorganic phosphorus released from municipal sludge was higher than that of organic phosphorus, while the concentration of organic phosphorus released from industrial sludge was higher than that of inorganic phosphorus. The activated sludge from denitrification and dephosphorization process could be selected for further phosphorus recovery since it emitted the largest quantity of phosphorus and the lowest organic matter among the three types of surplus activated sludge. Alkaline pretreatment can obviously promote the release of protein-, humic- acid and fulvic-like matters. Alkaline and ultrasonic pretreatment could not change the composition of the organic matter in the supernatant.