畜禽养殖废水生物处理剩余污泥臭氧减量过程中的重金属释放

采用臭氧氧化污泥减量法对畜禽养殖废水SBR中的剩余污泥进行处理。当臭氧反应时间控制在30min时，污泥的溶解比例在30％左右（以MLSS计）。上清液中一定量的SCOD溶出可为生物处理单元提供充足的碳源，同时在上清液中，TN、TP及水相重金属浓度增加有限，臭氧氧化后的污泥液回流污水处理系统后造成的N、P处理负荷较小，重金属对污泥微生物的活性抑制风险较低。若继续延长臭氧的反应时间，上清液SCOD、TN、TP以及重金属cu、Pb的释放速率明显增加，同时上清液的C／N降低，臭氧化后的污泥液回流反而不利于生物单元的脱氮处理。综合考虑TN、TP及水相重金属浓度增加的危害性，臭氧反应时间应控制在30min，臭氧实际投加量应为123．1mg O3／gSS。

Release behavior of heavy metals in the ozonation of sludge from swine wastewater biological treatment process

The sludge ozonation process was investigated in reducing the excess sludge of livestock wastewater treatment by SBR. When the ozonation time was controlled in 30 mins, the sludge dissolution ratio in MLSS was about 30%. The soluble COD （SCOD） releasing to the supernatant could provide enough carbon sources for biological treatment unit. The increment of total nitrogen （TN）, total phosphorus （TP） and heavy metals in the liquid phase was limited under this condition, which could decrease the nitrogenous and phosphor- ous loading when the sludge mixture became the system backflow after ozonation, and reduce the risk of heavy metals inhibition to the sludge microbial activity. If the ozonation time was extended, the release rate of SCOD, TN, TP, Cu, Pb in the supernatant showed a rapid increase trend. At the same time, the reduction of C/N in the supernatant was harmful to the denitrification of biological treatment unit. Considering the harmfulness of the increment of total nitrogen （TN）, total phosphorus （TP） and heavy metals in the liquid phase, the ozonation time should be controlled in 30 mins, the actual ozone dose was controlled at 123.1 mg O3/g SS.