Effect of catalyst type on the kinetics of the photoelectrochemical disinfection of water inoculated with E. coli

The rates of the photoelectrochemical disinfection of Escherichia coli at TiO₂ electrodes were measured as a function of concentration and applied potential. Two different TiO₂ photoelectrodes were used: a thermally treated titanium plate and a porous film prepared by a sol–gel hydrolysis technique. The kinetics of the disinfection process were found to depend upon the nature of the electrode material. For the thermal film they were first order, and half order for the sol–gel film. It was also found that the catalytic activity per unit surface area of catalyst is many orders of magnitude greater than that observed using TiO₂ slurries; this was attributed to the reduced rate of electron-hole recombination afforded by the application of a small potential bias (1 V vs Ag/AgCl), and hence the exploitation of the electric field enhancement (EFE) effect.     

水处理工程的消毒方法比较

在水处理中,消毒工艺的目的主要是杀死对人体健康有害的病原微生物,常用的方法有氯消毒、次氯酸钠消毒、二氧化氯消毒、臭氧消毒、紫外线消毒和活性氧消毒剂法等。文章重点分析以上消毒方法的机理及各自的优缺点,为工程选择提供理论依据。     

污水处理厂利用次氯酸钠消毒实验研究

粪大肠菌群是污水处理厂出水的一个重要指标,次氯酸钠是一种真正的高效、广谱、安全的强力灭菌、杀病毒药剂。固戍污水处理厂通过实验投加不同量的次氯酸钠溶液,使出水水质粪大肠菌群数不超过最高允许排放浓度,并得出最佳的投加量。     

饮用水消毒副产物生物毒性与调控策略的研究

饮用水消毒可以有效除去病毒、细菌等有害微生物,但消毒剂会与水中的有机物反应生成多种消毒副产物(DBPs),危害人类健康。基于对消毒副产物种类、生成及污染现状的探讨,归纳总结了DBPs的典型生物毒性及其毒性作用机制。为有效防控DBPs环境风险,深入探讨了针对去除DBPs前体物、优化消毒剂及消毒过程、DBPs毒性的调控策略。最后对DBPs生物毒性作用机制及调控策略的研究进行了展望,为DBPs污染防治提供理论与技术支持。     

Modeling heterogeneous photocatalytic inactivation of E. coli using suspended and immobilized TiO2 reactors

A study was carried out to develop a kinetic model of the photocatalytic inactivation of Escherichia coli using different TiO₂ catalysts. The model developed is based on a reaction scheme that involves effectively coupling mass‐transfer fluxes between bacteria and catalyst surface on one hand and bacterial degradation reaction on the other. The photocatalytic results were derived from experiments led in a batch reactor under both dark and Ultra Violet (UV) irradiation conditions. Using a reference catalyst, the robustness of the developed model was tested under solar conditions. The experimental data validated the model as successfully able to reproduce evolutions in the viable bacteria concentration in the range of parameters studied without any further adjustment of the kinetic parameters. The model was used to simulate the bacterial degradation kinetics under different working conditions to describe the partitioning of both bacterial adhesion and photocatalytic reaction in the solution to be treated © 2015 American Institute of Chemical Engineers AIChE J, 61: 2532–2542, 2015     

污水处理厂消毒方式探讨

针对国内城市污水处理厂出水消毒的现状,分别介绍了紫外线消毒、液氯消毒和二氧化氯消毒工艺的原理、优点和缺点,影响消毒效果的因素,以指导相关人员合理选择消毒工艺,提高污水消毒效率。     

复合二氧化氯的制备及其用于城市污水回用消毒

在酸性环境中通过NaCl电解协同NaClO2化学氧化方法制备的复合二氧化氯溶液中ClO2和自由氯浓度分别达到70%和20%左右,系统地研究了电流密度(A)、NaClO2与NaCl质量比(B)、电解时间(C)对复合溶液中组分浓度和质量百分数的影响,并将复合溶液用于城市污水二级处理出水的消毒。结果表明,复合溶液中自由氯的浓度主要受因素C和A的影响,ClO2的浓度主要受因素C和B的影响,而A对副产物ClO2-和ClO3-的影响最大。总大肠菌群数在105~108个.L-1的城市污水二级处理出水采用复合溶液消毒时,当其中ClO2投加量为4 mg/.L-1,自由氯含量不低于1.20mg.L-1,经30min接触后出水生物学指标满足GB/ T18920-2002 的要求。既降低了消毒剂的使用量,又减少了消毒副产物ClO2-的生成。     

水解酸化/生物接触氧化/ClO2消毒处理中小型医院废水的效果分析

采用水解酸化/生物接触氧化/ClO2消毒处理某中小型医院废水,当进水COD、BOD5、SS、氨氮质量浓度分别为190～300 mg/L、80～150 mg/L、42～56 mg/L、≤14.87 mg/L粪大肠菌群(MPN)≥25 000 L-1时,去除率分别为74%～83%、89%～93%、71%～81%、≥32.7%和99.6%～99.7%,工程出水达到国家医疗机构水污染物排放标准(GB18466-2005)排放标准。因此,该工艺处理中小型医院废水具有较好的实际运用价值和明显的经济效益。     

医疗机构废水处理研究与应用

文章通过对南昌市某医疗机构废水处理工程运行特性进行研究,工程运行结果表明:采用水解酸化+生物接触氧化+ClO2消毒工艺对医疗废水进行处理,工艺运行稳定,出水水质可以达到《医疗机构水污染物排放标准》(GB18466-2005)中的浓度限值,吨水处理费用仅为1.35元。