Disinfection of reclaimed water prior to reuse is important to prevent the transmission of pathogens. Chlorine is a widely utilized disinfectant and as such is a leading contender for disinfection of reclaimed water. To understand the risks of chlorination resulting from the potential selection of pathogenic bacteria, the inactivation, reactivation and regrowth rates of indigenous bacteria were investigated in reclaimed water after chlorine disinfection. Inactivation of total coliforms, Enterococcus and Salmonella showed linear correlations, with constants of 0.1384, 0.1624 and 0.057 L/(mg·min) and R2 of 0.7617, 0.8316 and 0.845, respectively. However, inactivation of total viable cells by measurement of metabolic activity typically showed a linear correlation at lower chlorine dose (0-22 (mg·min)/L), and a trailing region with chlorine dose increasing from 22 to 69 (mg·min)/L. Reactivation and regrowth of bacteria were most likely to occur after exposure to lower chlorine doses, and extents of reactivation decreased gradually with increasing chlorine dose. In contrast to total coliforms and Enterococcus, Salmonella had a high level of regrowth and reactivation, and still had 2% regrowth even after chlorination of 69 (mg·min)/L and 24 hr storage. The bacterial compositions were also significantly altered by chlorination and storage of reclaimed water, and the ratio of Salmonella was significantly increased from 0.001% to 0.045% after chlorination of 69 (mg·min)/L and 24 hr storage. These trends indicated that chlorination contributes to the selection of chlorine-resistant pathogenic bacteria, and regrowth of pathogenic bacteria after chlorination in reclaimed water with a long retention time could threaten public health security during wastewater reuse. 相似文献
In this work, hexadecyltrimethylammonium-bromide (HTAB)-modified polythiophene (PTh)/TiO2 nanocomposite (HTAB/PTh/TiO2) was applied to remove uranyl ions (UO22+). FT-IR, XRD, ζ potential, TGA, SEM, and XPS were utilized to obtain the chemical and physical properties of HTAB/PTh/TiO2. The effects of HTAB content, preparation temperature, and adsorption conditions on UO22+ removal were investigated comprehensively. And the UO22+ adsorption process on HTAB/PTh/TiO2 was fitted to the Sips model with a saturated adsorption capacity of 234.74 mg/g, which was 6 times over TiO2. The results suggested that the surfactant of HTAB can significantly improve the adsorption ability of TiO2 for UO22+ ions. This work provides a strategy of surfactant modification for enhancing the separation and recovery ability of adsorbent toward UO22+ in the radioactive wastewater.
Environmental Science and Pollution Research - Little is known on the potential impact of temperature on respiratory morbidity, especially for children whose respiratory system can be more... 相似文献
Environmental Science and Pollution Research - Agricultural non-point source pollution is one of the important reasons for rural water pollution, and it is also an important source of water... 相似文献
This paper begins by analysing the mutual influence between international trade and the environment, and then proceeds to explore the environment and trade conflicts. On the basis of sustainable development theories and the above discussion, the article suggests taking sustainable trade as a solution to the existing conflicts. This paper aims to find the way to strike a balance between international trade and environment based on the present situation in China. 相似文献