碳纳米管降低生物脱氮除磷效率的机制探究  

Mechanism of Carbon Nanotubes Reducing the Efficiency of Biological Nitrogen and Phosphorus Removal

作　　者：阙添进 王胤 李光倜 QUE Tianjin;WANG Yin;LI Guangti(China Southwest Municipal Engineering Design and Research Institute Co.,Ltd.,Chengdu 610081,China)

机构地区：[1]中国市政工程西南设计研究总院有限公司,四川成都610081

出　　处：《水处理技术》2022年第7期125-130,共6页Technology of Water Treatment

基　　金：四川公益性科研院所基本科研项目(2018YSKJ0158)。

摘　　要：为了探究碳纳米管(CNT)对生物脱氮除磷效率及活性污泥特征的影响,以实际生活废水为探究对象,构建了序批式反应器,探究了中温环境下不同剂量CNT(0、1.0、10.0、20.0和30.0 mg/L)长期暴露下活性污泥特征及脱氮除磷效率的变化规律。结果表明低浓度CNT(1.0 mg/L)对污泥特征及脱氮除磷影响不明显,而高浓度CNT降低了污泥内混合液悬浮固体浓度和污泥体积指数(SVI)分别至3 165~3 450 mg/L和111~116 mL/g。在生物脱氮除磷方面,CNT显著降低脱氮除磷效率,尤其当CNT为30.0 mg/L时,出水COD约为66.9~71.7 mg/L,COD去除效率75.6%~76.6%,氨氮去除效率80.6%~81.3%,磷酸盐去除效率75.5%~76.3%,均显著低于初始状态。机制探究表明CNT降低了生物脱氮除磷涉及的关键酶活性并降低了聚羟基脂肪酸酯(PHA)的合成量,促进了糖原质在典型周期内的代谢。毒性测定分析表明CNT存在促进了活性氧(ROS)产率及乳酸脱氢酶(LDH)释放量ROS释放,尤其当CNT浓度为30.0 mg/L时,ROS的相对产量高达294%,LDH的相对释放量高达289%。本研究结果可对评估CNT对污水生物处理的影响提供一定参考依据。To explore the effect of carbon nanotubes(CNT) on the efficiency of biological nitrogen and phosphorus removal and the characteristics of activated sludge, a sequencing batch reactor was constructed to investigate the characteristics of activated sludge and the change of nitrogen and phosphorus removal efficiency under different doses of CNT(0, 1.0, 10.0, 20.0 and 30.0 mg/L) in a medium temperature environment. The results showed that the low concentration of CNT(1.0 mg/L) had no significant effect on sludge characteristics and nitrogen and phosphorus removal, while the high concentration of CNT reduced the concentration of suspended solids and sludge volume index(SVI) to 3 165~3 450 mg/L and 111~116 mL/g,respectively. In the aspect of biological nitrogen and phosphorus removal, CNT significantly reduced the nitrogen and phosphorus removal efficiency.Especially when CNT was 30.0 mg/L, the effluent chemical oxygen demand(COD) concentration was about 66.9~71.7 mg/L, the COD removal efficiency was 75.6%~76.6%, the ammonia nitrogen removal efficiency was 80.6%~81.3%, and the phosphate removal efficiency was 75.5%~76.3%,which were significantly lower than those in the initial state. The mechanism showed that CNT reduced the key enzyme activities involved in biological nitrogen and phosphorus removal, reduced the synthesis of polyhydroxyfatty acid esters(PHA), and promoted the metabolism of glycogen in a typical cycle. The results of toxicity analysis showed that the presence of CNT promoted the production of reactive oxygen species(ROS) and the release of lactate dehydrogenase(LDH). Especially when the concentration of CNT was 30.0 mg/L, the relative production of ROS was as high as294%, and the relative release of LDH was as high as 289%. The results of this study can provide some references for evaluating the impact of CNT on wastewater biological treatment.

关 键 词：碳纳米管 脱氮除磷 污泥特征 污泥体积指数 乳酸脱氢酶 

分 类 号：X703.1[环境科学与工程—环境工程]