pH值对微气泡臭氧释放剩余污泥内碳源的影响

Influence of pH Value on Release of Internal Carbon Source from Excess Activated Sludge by Microbubble Ozone

针对我国部分城镇污水处理厂进水缺乏碳源的问题,拟以富含有机碳的污泥为碳源回收对象,展开微气泡臭氧这一新型工艺释放剩余污泥内碳源的研究。试验发现,pH值为10时,剩余污泥释放的SCOD浓度高于pH值为4和7时,且pH值为7和10时细胞破裂比例和VFA释放量高于pH值为4时。上清液中,包括TN、NH4^+-N、NO3^--N和ON在内的各组分氮浓度均随反应进行而上升。基于SCOD和TN浓度数据,pH值为4时,SCOD/TN持续下降,而pH值为7和10时SCOD/TN呈现先上升后下降的趋势,SCOD/TN最高点出现在pH值为10时的第48 min,这可能是释放剩余污泥内碳源并用于强化反硝化时适宜选用的工况。

In order to solve the problem of low carbon source concentration in the influent of wastewater treatment plant,a new technology of using microbubble ozone to release inner carbon source from excess activated sludge(WAS)was introduced.Influence of pH value on treatment efficiency was investigated.It was found that the released SCOD concentration was higher when the pH was 10 than that with the pH value of 4 and 7.The percentage of broken cells and released VFA concentration were also higher under the pH value of 7 and 10 than that of 4.In the supernatant,concentrations of various nitrogen compounds,including TN,NH4^+-N,NO3^--N and ON were increased along with reaction time.Based on the data of SCOD and TN concentration versus reaction time,the SCOD/TN ratio was decreased with the pH value of 4 while it showed an inverted-V tendency with the pH value of 7 and 10.The SCOD/TN ratio was the highest at the reaction time of 48 min when the pH value was 10,which might be a proper choice when releasing inner carbon source from WAS to enhance biological denitrification.