Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA.
Sci Total Environ. 2011 Jun 15;409(14):2852-7. doi: 10.1016/j.scitotenv.2011.03.022. Epub 2011 May 6.
The release of nanoparticles (NPs) into the environment, including wastewater treatment plants, is expected to increase in the future. Therefore, it is important to understand the potential effects of these NPs on activated sludge treatment processes. A pulse-flow respirometer was used to study the toxicity of nano-ZnO on activated sludge endogenous respiration, BOD biodegradation, and nitrification. In addition, toxicities of bulk ZnO particles and Zn ion (e.g. soluble Zn) were also studied. All three Zn forms were found to adversely impact the activity of activated sludge, with soluble Zn exhibited the greatest toxicity. The effects of nano-ZnO and bulk ZnO on activated sludge were caused by soluble Zn resulting from ZnO particle dissolution. The IC(50) values of soluble Zn on activated sludge endogenous respiration, BOD biodegradation, ammonia oxidation, and nitrite oxidation were 2.2, 1.3, 0.8, and 7.3 mg-Zn/L, respectively. Therefore, the first step of nitrification was most sensitive to Zn.
纳米颗粒（NPs）被释放到环境中，包括污水处理厂，预计未来还会增加。因此，了解这些 NPs 对活性污泥处理过程的潜在影响非常重要。本文采用脉冲流呼吸计研究了纳米 ZnO 对活性污泥内源呼吸、BOD 生物降解和硝化的毒性。此外，还研究了块状 ZnO 颗粒和 Zn 离子（如可溶性 Zn）的毒性。三种 Zn 形态均对活性污泥的活性产生了不利影响，其中可溶性 Zn 的毒性最大。纳米 ZnO 和块状 ZnO 对活性污泥的影响是由于 ZnO 颗粒溶解产生了可溶性 Zn。可溶性 Zn 对活性污泥内源呼吸、BOD 生物降解、氨氧化和亚硝酸盐氧化的 IC（50）值分别为 2.2、1.3、0.8 和 7.3mg-Zn/L。因此，硝化的第一步对 Zn 最敏感。
