UV/TiO2光催化过程对二级处理出水多重生物效应的削减特性研究

为了考察复杂体系的二级处理出水在UV光解及UV/TiO_2光催化反应过程中生物效应的变化,本文探究了反应前后发光细菌的荧光抑制毒性、SOS/umu遗传毒性、小球藻光合抑制效应3种生物效应的变化,并分析了物化指标的变化与生物效应之间的关系.结果表明,UV光降解过程并不能高效削减二级处理出水的荧光抑制毒性,但可以高效削减遗传毒性和光合抑制效应,其削减率分别达到61%和81%;在低辐照强度下,UV/TiO_2光催化过程对3种生物效应的削减率分别为38%、84%和80%.增大辐照强度后,3种生物效应的削减率进一步提高,尤其是荧光抑制毒性,其削减率可提高至62%.在UV光降解条件下,二级处理出水的遗传毒性、光合抑制效应与荧光强度、UV_(254)之间存在很好的线性关系;在UV/TiO_2光催化条件下,二级处理出水的3种生物效应都与荧光强度、UV_(254)之间具有很好的线性关系.这为二级处理出水生物效应的控制及生态安全的保障提供了一定的依据.

The reduction of multiple biological effects of secondary treatment effluent by UV/TiO2 photocatalysis

To investigate the variation of biological effects of secondary treatment effluent by UV/TiO₂ photocatalysis process, the fluorescence inhibition toxicity based on luminescent bacteria, genotoxicity using SOS/umu test, and photosynthetic inhibition effect based on Chlorella vulgaris were conducted on the secondary treatment effluent before and after treatment. The relationships between physicochemical indices and biological effects were analyzed. The results show that UV photolysis process could not decrease the fluorescence inhibition toxicity, but could effectively decrease the genotoxicity and photosynthetic inhibition effect. The removal could reach 61% and 81%, respectively. At low irradiation intensity, the removal of three biological effects were 38%, 84% and 80%, respectively, during UV/TiO₂ photocatalysis process. When the irradiation intensity increased, the removal of three biological effects were all improved, especially for fluorescence inhibition toxicity whose removal could achieve 62%. During UV photolysis process, genotoxicity and photosynthetic inhibition effect had good correlation with physicochemical indices (fluorescence intensity and UV₂₅₄). While, during UV/TiO₂ photocatalysis process, the three biological effects had obvious liner relationship with physicochemical indices (fluorescence intensity and UV₂₅₄). This could help to control the biological effect posed by secondary treatment effluent and to guarantee the ecological safety.