苯并三唑在土壤中的吸附特性

为了解苯并三唑(BTA)在水-土系统中的迁移转化,通过批实验方法研究了BTA在华北平原土样(GSS13)中的吸附,考察了平衡时间、土壤投加量、溶液初始p H以及共存阳离子对吸附的影响。结果表明,在初始阶段,土壤对BTA的吸附速率较快,之后随着吸附点位的减少,吸附逐渐变慢;吸附过程符合准二级反应动力学方程。土壤对BTA的平衡吸附为非线性吸附,吸附等温线为Freundlich型;随着土壤投加量的增大,单位质量土壤吸附BTA的量减少,可能原因是所选土壤对BTA的吸附存在"固体浓度效应"。溶液的p H通过改变BTA的存在形式和土壤表面的带电性而影响吸附,当溶液p H在BTA的p Ka2(8.6)附近时,土壤对BTA的吸附效果最好。此外,溶液中共存阳离子对土壤吸附BTA有不同的影响,Na+对吸附影响不明显,而不同浓度Ca2+对BTA的吸附有不同程度的促进作用。     

Investigation of PM2.5 pollution during COVID-19 pandemic in Guangzhou, China

The COVID-19 pandemic has raised awareness about various environmental issues,including PM_2.5 pollution.Here,PM_2.5 pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM_2.5 in Guangzhou,with an emphasis on heavy pollution.The lockdown led to large reductions in industrial and traffic emissions,which significantly reduced PM_2.5 concentrations in Guangzhou.Interestingly,the trend of PM_2.5     

铁矿石对脱除烧结废气中NOx的催化效应

向混合料中加添加剂能够在烧结过程中脱除烧结废气中的NO。实验研究了铁矿石对NO脱除反应的催化效应。在900℃下,分别以5种不同铁矿石作为填料层,用2种标准气体和压缩空气配制的混合气体模拟烧结废气。试验结果表明,铁矿石种类对铁矿石的催化能力有重要影响。D型铁矿的催化能力最强而且不会发生弱化,NO转化率接近100%;其它几种铁矿石的催化能力较差,随着反应时间的延长有明显的弱化现象,但很快即基本趋于稳定状态,NO转化率达到了60%~70%。     

张家港河凤凰段水质达标整治方案研究

张家港河凤凰段位于张家港市凤凰镇,受上游、支流水质以及区域生活污染源等影响,河道出入境断面水质达标率较低,主要超标因子为氨氮和总磷。本文通过水质现状分析和现场调研,总结了水质难达标的主要原因,提出了针对性较强的水质提升整治方案,对改善张家港河水环境具有非常重要的意义。     

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

• The SRAO phenomena tended to occur only under certain conditions. • High amount of biomass and non-anaerobic condition is requirement for SRAO. • Anammox bacteria cannot oxidize ammonium with sulfate as electron acceptor. • AOB and AnAOB are mainly responsible for ammonium conversion. • Heterotrophic sulfate reduction mainly contributed to sulfate conversion. For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. SRAO was considered an autotrophic process mediated by anammox bacteria, in which ammonium as electron donor was oxidized by the electron acceptor sulfate. This process had been attributed to observed transformations of nitrogenous and sulfurous compounds in natural environments. Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. Thus, the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible. In this study, continuous reactor experiments (with working volume of 3.8L) and batch tests were conducted under normal anaerobic (0.2≤DO<0.5 mg/L) / strict anaerobic (DO<0.2 mg/L) conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion. Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition, while absent under strict anaerobic conditions for same anammox consortia. Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed. Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could, in fact, be a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes.     

异波折板水解酸化-A~2O一体化反应器实验研究

设计了异波折板水解酸化-A2O一体化反应器,进行生活污水处理的实验研究。10个月的实验结果表明,系统的最佳水力停留时间(HRT)为8 h时,最适COD进水浓度为240~600 mg/L,最佳混合液回流比(r)-污泥回流比(R)为250%~100%。控制反应器于以上运行参数下,25±2℃所对应的COD、TN和TP去除率分别为96.84%、67.55%和81.92%。当温度降至7℃时,其COD、TP和TN分别降至86.35%、50.25%和65.68%。基于实验分析结果,阐明了一体化反应器高效性的机理在于异波折板水解酸化段具有高效传质特性和A2O段具有复合式活性污泥-接触氧化好氧池的特点。     

厌氧发酵系统中回流沼液的产甲烷活性研究

为确定两阶段厌氧发酵系统合理的污泥回流时段,对厌氧发酵系统排出沼液产甲烷活性进行了研究。通过对这些沼液在后储罐放置的不同天数(0~5 d)测定其不同的活性,用间歇实验方法测定最大比产甲烷活性(Um ax.CH4)作为厌氧污泥的产甲烷活性指标。结果表明,排出的沼液产甲烷活性在不同的时间段有所不同,经实验得出沼液放置第2 d时的产甲烷活性最高,从而确定该两阶段厌氧发酵系统排出污泥合理的回流时段应该是沼液进入后储罐的第2 d。进而为在线活性污泥与后储罐最佳活性时段污泥混合的污泥回流工艺提供理论依据。     

Comprehensive assessment of toxic metals in urban and suburban street deposited sediments (SDSs) in the biggest metropolitan area of China

A set of toxic metals, i.e. As, Hg, Pb, Cd, Cu, Zn, Ni and Cr, in urban and suburban SDSs were investigated comparatively in the biggest metropolitan area of China, Shanghai. Results showed that all of the metals except As were accumulated greatly, much higher than background values. Geo-accumulation index indicated that metal contamination in urban SDSs was generally heavier than that in suburban SDSs. Potential ecological risk index demonstrated that overall risks caused by metals were considerable. Cd contributed 52% to the overall risk. Multivariate statistical analysis revealed that in urban SDSs, Zn, Ni, Cd, Pb, Cu and Cr were related to traffic and industry; coal combustion led to elevated levels of Hg; soil parent materials controlled As contents. In suburban SDSs, Pb, Cu, As and Cd largely originated from traffic pollution; Zn, Ni and Cr were associated with industrial contaminants; Hg was mainly from domestic solid waste.     

Cost-effectiveness of two operational models at industrial wastewater treatment plants in China: A case study in Shengze town,Suzhou City

The widespread illegal discharge of industrial wastewater in China has posed significant challenges to the effective management of industrial wastewater treatment plants (IWTPs) and caused or exacerbated critical social issues such as trans-boundary environmental pollution. This study examines two operational strategies, decentralized model and an innovative integrated model, that have been used in the industrial town of Shengze (located in Suzhou City) over the past two decades at IWTPs handling wastewater from the city’s dyeing industry. Our cost-effectiveness analysis shows that, although the operational cost of IWTPs under the integrated model is higher than under the original decentralized model, the integrated model has significantly improved IWTP performance and effectively reduced illegal discharge of industrial wastewater. As a result, the number of reported incidents of unacceptable pollution in local receiving water bodies had declined from 13 in 2000–1 in 2008. Key factors contributing to the success of the innovative integrated model are strong support from municipal and provincial leaders, mandatory ownership transfer of IWTPs to a centralized management body, strong financial incentives for proper plant management, and geographically-clustered IWTPs.     

强化循环厌氧反应器处理印染废水的中试启动研究

应用自主研制的强化循环厌氧反应器(SCAR)中试规模处理实际印染废水,研究反应器的启动特性。反应器接种厌氧颗粒污泥后启动运行83 d,形成连续内循环并实现了对印染废水处理的高效稳定运行。在进水COD浓度1 000~3 650 mg/L、系统容积负荷0.7~6.4 kg/(m3·d)条件下,废水COD和色度平均去除率分别达到55%和73%。反应器内较高浓度的NH+4-N保证了系统pH的稳定性,350~600 mg/L的NH+4-N浓度没有对强化循环厌氧反应器产生抑制作用,系统内也没有出现VFA(以乙酸计)积累。启动过程中,厌氧颗粒污泥的粒径增大、沉降性能变好。启动实验完成时,反应器内微生物的脱氢酶活性(以TF计)和辅酶F420浓度分别为3.4973 mg/(g·h)和0.1872μmol/g。