Comparison of the effects of aluminum and iron(Ⅲ) salts on ultrafiltration membrane biofouling in drinking water treatment

Coagulation plays an important role in alleviating membrane fouling, and a noticeable problem is the development of microorganisms after long-time operation, which gradually secrete extracellular polymeric substances(EPS). To date, few studies have paid attention to the behavior of microorganisms in drinking water treatment with ultrafiltration(UF)membranes. Herein, the membrane biofouling was investigated with different aluminum and iron salts. We found that Al_2(SO_4)_3·18 H_2O performed better in reducing membrane fouling due to the slower growth rate of microorganisms. In comparison to Al_2(SO_4)_3·18H_2O,more EPS were induced with Fe_2(SO_4)_3·x18H_2O, both in the membrane tank and the sludge on the cake layer. We also found that bacteria were the major microorganisms, of which the concentration was much higher than those of fungi and archaea. Further analyses showed that Proteobacteria was dominant in bacterial communities, which caused severe membrane fouling by forming a biofilm, especially for Fe_2(SO_4)_3·x18H_2O. Additionally, the abundances of Bacteroidetes and Verrucomicrobia were relatively higher in the presence of Al_2(SO_4)_3·18 H_2O,resulting in less severe biofouling by effectively degrading the protein and polysaccharide in EPS. As a result, in terms of microorganism behaviors, Al-based salts should be given preference as coagulants during actual operations.     

Are current Chinese national ambient air quality standards on 24-hour averages for particulate matter sufficient to protect public health?

With rapid economic development and urbanization in recent decades, China has experienced the worsening of ambient air quality. For better air quality management to protect human health, Chinese government revised national ambient air quality standards(NAAQS) for particulate matter(PM) in 2012(GB3095-2012). To assess the effectiveness of current NAAQS for PM on public health in Chinese population, we conducted a metaanalysis on published studies examining the mortality risk of short-term exposure to PM with aerodynamic diameters less than 10 and 2.5 μm(PM_(10) and PM_(2.5)) in China. The reported24-hour concentrations of PM_(10) and PM_(2.5) in studies ranged from 43.5 to 150.1 μg/m~3 and 37.5 to 176.7 μg/m~3. In the pooled excess, mortality risk estimates of short-term exposure to PM.In specific, per 10 μg/m~3 increase in PM_(10), we observed increases of 0.40%(95%CI: 0.33%,0.47%), 0.57%(95%CI: 0.44%, 0.70%) and 0.49%(95%CI: 0.40%, 0.58%) in total, respiratory and cardiovascular mortality, per 10 μg/m~3 increase in PM_(2.5), we observed increases of 0.51%(95%CI: 0.38%, 0.63%), 0.62%(95%CI: 0.52%, 0.73%) and 0.75%(95%CI: 0.54%, 0.95%) in total,respiratory and cardiovascular mortality. Finally, we derived 125 μg/m~3 for PM_(10) and 62.5 μg/m~3 for PM_(2.5) as 24-hour recommendation values based on the pooled estimates. Our results indicated that current Chinese NAAQS for PM could be sufficient in mitigating the excess mortality risk from short-term exposure to ambient PM. However, future research on longterm exposure cohort studies in Chinese population is also essential in revising annual averages for PM in Chinese NAAQS.     

强化生物絮凝＋生物接触氧化除磷效果分析

通过单因素试验研究了强化生物絮凝＋生物接触氧化组合式一体化工艺对城市污水悬浮物SS、化学需氧量COD、氨氮NH3-N、总氮TN、总磷TP的去除效能和机理。试验结果表明：在组合工艺的较优运行条件下,装置对SS、COD、NH3-N、TN、TP的平均去除率分别为88．7％、89．3％、87．9％、73．4％、58．8％。组合工艺对污染物的总体去除效果良好,且稳定可靠,其中生物絮凝吸附段对总磷的去除率为32．4％,生物接触氧化段对总磷的去除率为39．1％,并对装置的除磷效果进行了分析。     

外循环厌氧反应器的工艺特征与运行性能研究

将UASB反应器多点进水装置进行改造,设计独特的变速旋流配水装置,具有配水均匀,混合效果好,不会产生短流的特点。研究结果表明,旋流配水装置容积利用率高,外循环能耗小,布水均匀性良好;中温条件下外循环反应器处理模拟啤酒配水,进水COD浓度为2000mg／L～3000mg／L,容积负荷可以达到22．7kgCOD／m^3·d,COD去除率最高可达92．46％。     

乡镇环境规划指标体系研究——以扬州市瓜洲镇为例

从经济发展、生态环境、社会进步三方面构建乡镇环境规划指标体系,并引入“可持续发展度”、“因子贡献度”、“指标偏离度”、“制约度”,对瓜洲镇的现状进行了综合评价,对限制瓜洲镇可持续发展的因素进行识别。研究结果表明：规划基准年（2006年）瓜洲镇的可持续发展度为0.759,处于较强可持续发展阶段;影响瓜洲镇可持续发展的制约因素主要集中于环境质量及污染物治理方面（占36.75%）,其次为经济结构方面（占25.65%）,接着为发展支持（占24.21%）、生态环境与资源利用（占9.42%）、生活质量（占2.62%）、经济效益（占1.34%）。     

厌氧膨胀颗粒床（EGSB）反应器在有机废水治理中的研究进展

厌氧膨胀颗粒床（EGSB）反应器作为第三代高效厌氧反应器代表工艺之一,它通过增大反应器的高径比和采用出水回流技术,使反应器内的水力上升流速远远高于UASB反应器,强化了传质效果,提高了处理效率。适用于超高浓度和含有毒物质的工业废水,也特别适用于低温低浓度有机废水的处理。还展望了EGSB反应器未来的发展前景。     

西宁及邻区地震活动特征研究

对西宁及邻区1900年以来M≥5.0、1970年至今ML≥3.0地震进行了分析,得到了该区5级以上中强地震的活动规律,认为研究区近2～3年内地震活动处于相对平静期,具备发生M5～6级中强地震的条件,发生6级以上地震的可能性不大.     

石油化工企业定量风险评价程序探讨

介绍了定量风险评价的风险可接受准则和石油化工企业定量风险评价的一般程序。基本程序主要包括准备、资料数据收集、危险辨识、失效频率分析、失效后果分析、风险计算、风险评价及建议和风险评价报告和结论。此外,提出了评价过程中应注意的事项。     

上海南区污水输送干线世博期间排水安全保障

上海世界博览会将于2010年5月至10月召开,会展期跨越上海市夏季主汛期。届时如何保障世博园区的排水安全和水质安全,对接纳园区污水的已建干线排水系统是一个极大的考验。通过建立上海市南干线排水管网系统的数学水力集成模型,对世博园区污水接入后南干线的水力状态进行模拟,预测世博园区的排水风险,提出世博期间南干线的排水安全保障方案,为世博会期间的防洪保安奠定基础。     

石油炼制业污染防治与清洁生产

石油炼制业是国民经济的支柱行业,直接关系到整个国民经济的发展,它不仅提供各种石油产品,同时也为石油化工、化纤、化肥等工业提供原料。同时,石油炼制业也是污染物排放大户,在生产过程中产生大量废水、废气、固体废物,对人体健康和环境造成了一定潜在的影响。石油产品和中间产品多为易燃、易爆、有毒、有害的化学物质,在生产、储运和使用过程中,会对大气、水域、湖泊、土壤、环境造成危害,必须采取有效的方法加以预防和治理。而实施清洁生产可以有效的帮助石油炼制业节能资源、减少排污。