Hg^(2+)对剩余污泥厌氧消化过程中物质释放的影响

Effect of Hg^(2+) on Materials Release during Anaerobic Digestion of Phosphorus-rich Waste Sludge

以某采用A/O生物除磷工艺的污水处理厂排出的富磷剩余污泥为研究对象,设计两组厌氧消化比较试验,考察了Hg2+的毒性对剩余污泥厌氧消化过程中SCOD、VSS、SOP等相关指标的影响,藉此讨论相关物质的释放机制。结果发现,Hg2+的投加可以促进剩余污泥的水解,造成了短期内VSS的快速下降以及SOP的快速释放。当HgCl2投加量为0.25 g/L时,这个短期的时间尺度持续4 d左右;4 d以后,由于HgCl2对产甲烷菌、产酸菌以及聚磷菌均会产生不利影响,HgCl2开始抑制消化过程的进行,导致SCOD积累,VSS、SOP等释放速度减缓。这表明HgCl2可以促进水解释磷,抑制生物释磷。总体而言,投加HgCl2对剩余污泥中磷的释放是不利的。

Effect of toxicity of HgCl2 on SCOD, VSS and SOP during anaerobic digestion of phosphona, s-rich waste sludge were studied. The sludge was obtained from a wastewater treatment plant in which A/O process was used. Results indicated that VSS in sludge declined and SOP increased fast in short time because the hydrolyzing of waste sludge was promoted by addition of HgCl2. The short time scale were about 4d if the addition quantity HgCl2 was 0.25 g/L. After that, due to sterilizing of HgCl2 to methane production bacteria and phosphate accumulating organisms, the decline of VSS and increase of SOP in digestion liquids were resisted by the addition of HgCl2 for the entire experimental period. Therefore the presence of Hg^2＋ was disadvantage to the release of phosphate.