Observed and modeled seasonal trends in dissolved and particulate Cu, Fe, Mn, and Zn in a mining-impacted stream

North Fork Clear Creek (NFCC) in Colorado, an acid-mine drainage (AMD) impacted stream, was chosen to examine the distribution of dissolved and particulate Cu, Fe, Mn, and Zn in the water column, with respect to seasonal hydrologic controls. NFCC is a high-gradient stream with discharge directly related to snowmelt and strong seasonal storms. Additionally, conditions in the stream cause rapid precipitation of large amounts of hydrous iron oxides (HFO) that sequester metals. Because AMD-impacted systems are complex, geochemical modeling may assist with predictions and/or confirmations of processes occurring in these environments. This research used Visual-MINTEQ to determine if field data collected over a two and one-half year study would be well represented by modeling with a currently existing model, while limiting the number of processes modeled and without modifications to the existing model's parameters. Observed distributions between dissolved and particulate phases in the water column varied greatly among the metals, with average dissolved fractions being >90% for Mn, approximately 75% for Zn, approximately 30% for Cu, and <10% for Fe. A strong seasonal trend was observed for the metals predominantly in the dissolved phase (Mn and Zn), with increasing concentrations during base-flow conditions and decreasing concentrations during spring-runoff. This trend was less obvious for Cu and Fe. Within hydrologic seasons, storm events significantly influenced in-stream metals concentrations. The most simplified modeling, using solely sorption to HFO, gave predicted percentage particulate Cu results for most samples to within a factor of two of the measured values, but modeling data were biased toward over-prediction. About one-half of the percentage particulate Zn data comparisons fell within a factor of two, with the remaining data being under-predicted. Slightly more complex modeling, which included dissolved organic carbon (DOC) as a solution phase ligand, significantly reduced the positive bias between observed and predicted percentage particulate Cu, while inclusion of hydrous manganese oxide (HMO) yielded model results more representative of the observed percentage particulate Zn. These results indicate that there is validity in the use of an existing model, without alteration and with typically collected water chemistry data, to describe complex natural systems, but that processes considered optimal for one metal might not be applicable for all metals in a given water sample.     

Biological treatment of Mn(II) and Fe(II) containing groundwater: kinetic considerations and product characterization

In the present article, the treatment of groundwater containing Mn(II) and Fe(II) has been investigated. The biological oxidation of Mn(II) and Fe(II) in upflow filtration units comprised the applied experimental technique. The oxidation processes were mediated by specific bacteria, namely the Leptothrix ochracea and Gallionella ferruginea, which belong to the general category of manganese and iron oxidizing bacteria. This work was focused on the characterization of the products of biological oxidation and to the examination of the kinetics of Mn(II) removal as compared with Fe(II) removal from groundwaters. The products of biological oxidation were characterized using the spectroscopic techniques XRD, XPS and SEM-EDS and comprised a mixture of biogenic hydrous manganese and iron oxides. The oxidation state of manganese in the precipitates was found to be between 3 and 4. Iron oxides were mainly in the form of amorphous ferrihydrite. The kinetic results indicated that the rates of manganese and iron oxidation were several orders of magnitude greater than the respective for abiotic oxidation. The bacterially mediated oxidation of iron was faster than manganese oxidation, presenting half-lives of reaction 0.9 and 3.98 min, respectively.     

The risks associated with wastewater reuse and xenobiotics in the agroecological environment

Treated wastewater reuse for irrigation, landscape and surface or groundwater replenishment purposes is being widely implemented. Although the reuse practice is accompanied by a number of benefits relating to the enhancement of water balances and soil nutrition by the nutrients existing in the treated effluents, a number of unanswered questions are still related to this practice. Besides the lack of knowledge in respect to possible elemental interactions that may influence the accumulation of heavy metals and other elements in the soil and the subsequent uptake by plants and crops, during the last several years, the technological progress in respect to analytical chromatographic methods has enabled the identification and quantitation of a number of organic xenobiotic compounds in treated wastewater. Therefore it is now known that the effluents' remaining organic matter most usually expressed as Chemical Oxygen Demand consists of a number of biorecalcitrant organic xenobiotic compounds including potential endocrine disrupting compounds (EDCs), pharmaceuticals, etc. It is also widely accepted that the currently applied treatment processes for urban wastewater abatement fail to completely remove such contaminants and this lead to their subsequent release in the terrestrial and aquatic environment through disposal and reuse applications. The number of studies focusing on the analysis and the toxicological assessment of such compounds in the environment is constantly increasing the aim being to bridge the various knowledge gaps associated with these issues. The existing knowledge in respect to the relevant existing legislation framework, the types of elements and chemicals of concern, the uptake of xenobiotic pollutants and also that of other neglected chemical elements along with their potential environmental interactions constitute the focus of the present review paper.The review addresses the problems that might be related to the repeated treated wastewater release in the environment for reuse applications in respect to the wastewater residual load in heavy metals, accumulating in soil and plants and especially in their edible parts, in xenobiotic compounds, including EDCs, pharmaceuticals and personal care products, drugs' metabolites, illicit drugs, transformation products, and also genes resistant to antibiotics.     

小型污水处理站污水处理及回用工程工艺设计探讨

以罗源金港工业区宝钢德盛污水处理站为例,分析介绍了处理站生活污水处理及回用工程的工艺设计内容,提出了类似工程设计的细节和重点,以保证出水水质稳定、可靠。     

Mn oxide coated catalytic membranes for a hybrid ozonation-membrane filtration: Comparison of Ti, Fe and Mn oxide coated membranes for water quality

In this study the performance of catalytic membranes in a hybrid ozonation-ceramic membrane filtration system was investigated. The catalytic membranes were produced by coating commercial ceramic ultrafiltration membranes with manganese or iron oxide nanoparticles using a layer-by-layer self-assembly technique. A commercial membrane with a titanium oxide filtration layer was also evaluated. The performance of the coated and uncoated membranes was evaluated using water from a borderline eutrophic lake. The permeate flux and removal of the organic matter was found to depend on the type of the metal oxide present on the membrane surface. The performance of the manganese oxide coated membrane was superior to that of the other membranes tested, showing the fastest recovery in permeate flux when ozone was applied and the greatest reduction in the total organic carbon (TOC) in the permeate. The removal of trihalomethanes (THMs) and haloacetic acids (HAAs) precursors using the membrane coated 20 times with manganese oxide nanoparticles was significantly better than that for the membranes coated with 30 or 40 times with manganese oxide nanoparticles or 40 times with iron oxide nanoparticles.     

Effect of PVC and iron materials on Mn(II) deposition in drinking water distribution systems

Polyvinyl chloride (PVC) and iron pipe materials differentially impacted manganese deposition within a drinking water distribution system that experiences black water problems because it receives soluble manganese from a surface water reservoir that undergoes biogeochemical cycling of manganese. The water quality study was conducted in a section of the distribution system of Tegucigalpa, Honduras and evaluated the influence of iron and PVC pipe materials on the concentrations of soluble and particulate iron and manganese, and determined the composition of scales formed on PVC and iron pipes. As expected, total Fe concentrations were highest in water from iron pipes. Water samples obtained from PVC pipes showed higher total Mn concentrations and more black color than that obtained from iron pipes. Scanning electron microscopy demonstrated that manganese was incorporated into the iron tubercles and thus not readily dislodged from the pipes by water flow. The PVC pipes contained a thin surface scale consisting of white and brown layers of different chemical composition; the brown layer was in contact with the water and contained 6% manganese by weight. Mn composed a greater percentage by weight of the PVC scale than the iron pipe scale; the PVC scale was easily dislodged by flowing water. This research demonstrates that interactions between water and the infrastructure used for its supply affect the quality of the final drinking water.     

Fate of carbamazepine and anthracene in soils watered with UV-LED treated wastewaters

Water disinfection technologies based on ultraviolet (UV) radiations emitted by Light-Emitting Diodes (LED), as a wastewater tertiary treatment, have been shown to be promising for water reuse. Here, we assessed the fate of two ubiquitous pollutants, carbamazepine and anthracene, in soil watered with either UV-LED treated wastewaters or irrigation water. After 3 months, anthracene and carbamazepine were transformed two and three times faster respectively, in soils watered with UV-LED wastewater than in soils watered with tap water (probably because of the addition of organic matter by the effluent). Laccase activity was induced in the presence of the pollutants and anthraquinone was found as anthracene product of oxidation by laccases. Moreover, the addition of these pollutants into soil did not affect the functional diversity of autochthonous microbial communities assessed by Ecolog plates. Cellulase, protease and urease activities increased in soils watered with UV-LED treated wastewaters (UV-LED WW), showing transformation of organic matter from the effluent and lipase activity increased by anthracene addition, confirming the potential role of these enzymes as indicators of hydrocarbon contamination.     

Simultaneous removal of Cu, Mn and Zn from drinking water with the use of clinoptilolite and its Fe-modified form

Zeolites have been widely used in water treatment and especially clinoptilolite, due to its low cost and high abundance. It has large cation-exchange capacity and is capable of removing large quantities of heavy metals from contaminated water samples. By loading the surface of clinoptilolite with amorphous Fe-oxide species, a total improvement in adsorption capacity could be achieved. Thus, the Clin–Fe oxide system is capable of adsorbing significantly higher heavy metal concentrations than untreated clinoptilolite with simultaneous noticeable decrease in water hardness. Batch adsorption experiments have shown that Clin–Fe system has very large Cu, Zn and Mn adsorption capacity and for most of the cases the treated water samples were suitable for human consumption or agricultural use. New experiments were conducted to study the effectiveness of clinoptilolite and of the Clin–Fe system in removal of Cu, Mn, Zn, present simultaneously in water samples, so that the study of metal–sorbent chemical behavior and of the adsorption selectivity would be feasible. Desorption of metals was also examined and an integrated approach of the effectiveness of such materials in drinking water treatment is presented.     

城镇污水生物处理新工艺及其应用

介绍了几种污水生物处理新工艺的工艺流程、特点及在国内的应用情况，包括将传统活性污泥法与氧化沟相结合产生的OOC、OCO、AOR、AOE及改进A^2／O工艺，特种形式的活性污泥法——VT工艺，将生物膜法与活性污泥法相结合产生的投料曝气、BIOFOR、BIOSTYR工艺。     

污水处理厂土建阶段施工要点及质量控制分析

通过总结多年施工经验和教训,针对污水处理厂土建阶段施工重点和难点,分析了砼构筑物防渗漏、预应力砼水池、沉井、异形砼构筑物等施工要点和施工过程中的质量控制关键点,提出了相应的管理措施,可对今后的污水厂建设提供很好的借鉴。     

水解酸化/悬浮滤料BAF一体化装置处理生活污水

水解酸化/悬浮滤料曝气生物滤池,是将水解酸化与曝气生物滤池结合为一体的新型污水处理工艺。在滤速为37.7 m/d、水力停留时间为3.98 h、进水pH平均值为7.69、平均水温为18.1℃的条件下,考察了该工艺对城镇污水的处理效果。试验结果表明,当BOD5容积负荷为2.14 kg/(m3.d)、NH3-N容积负荷为0.38 kg/(m3.d)、反冲洗周期为3 d、反冲洗强度为39.3m3/(m2.h)时,该工艺具有良好的除碳脱氮性能,对COD、BOD5、NH3-N、SS、TN、TP的平均去除率分别可达90.1%、96.0%、90.1%、92.8%、38.4%、75.5%。此外,该工艺还具有结构简单、占地面积小、运行稳定、出水水质好、管理简便的特点,适合于居住小区等小水量的生活污水处理工程。     

石马河流域污水处理厂提标改造技术路线分析

随着"十二五"污水排放标准的提高,国内大部分污水处理厂亟需进行提标改造,以东莞市石马河流域污水处理厂提标改造为例,通过调研现状污水处理规模、实际出水水质及运行状况,分析国内外现有的提标改造技术,提出了适用于石马河流域污水处理厂提标改造的技术路线和具体的工程措施,以供周边城镇污水处理厂升级改造工程参考。     

无锡市城镇污水处理厂提标改造措施及效果

2007年5月底太湖蓝藻暴发影响了无锡城市饮用水水质,无锡市开展了治理太湖、保护水源的"6699"行动,将城市污水处理厂提标改造作为治理太湖的行动纲要之一。介绍了"6699"行动中有关提标改造的相关措施,并对城市污水处理厂提标改造中需要重点考虑的问题、提标改造工程的运行效果进行了重点分析。     

城镇污水处理厂尾水中氮磷形态及光谱特征分析

为了进一步探究污水厂尾水排放对受纳水体的潜在影响,选取巢湖流域采用3种典型处理工艺(氧化沟、SBR、A²/O工艺)的7座污水厂为研究对象,分析了尾水中氮、磷的形态及水体中溶解性有机质(DOM)的光谱特征。结果表明,不同工艺对TN、TP、COD等指标均具有很好的去除效果且无明显差异。尾水中颗粒态总氮(PN)占比在13.4%以下,主要以溶解态总氮(DTN)形式存在,其中溶解态无机氮(DIN)占比高于溶解态有机氮(DON)。尾水中颗粒态总磷(PP)占比在10.1%~66.7%,磷主要以溶解态总磷(DTP)形式存在,其中溶解态无机磷(DIP)占比在60%以上。DOM的三维荧光光谱显示,不同工艺尾水中的DOM均具有4类荧光特征峰,其中腐殖酸类物质C峰与紫外区类富里酸物质A峰较为明显。根据DOM的荧光特性参数(HIX值<4、FI值>1.9、BIX值>1.0),各污水厂出水中的DOM主要为自生来源。由此表明,污水处理厂削减了大量的入河碳、氮、磷等负荷,其尾水可用于城市河道生态补水水源,实现城市污水资源再生利用。     

漂染工业园污水厂实际运行中出现的问题及其对策

某漂染工业园污水处理厂实际运行过程中存在的加酸系统容量偏小、预处理系统容易堵塞、氧化沟系统曝气不足、鼓风机曝气系统故障多、污泥SVI值偏高以及污泥脱水机滤带损耗大、效率低等问题,分析了其各自产生的原因,并提出了相应的对策.通过改造加酸系统、更换格栅与排泥泵等预处理设备、抬高表曝机、增加氧化沟曝气设备、改造污泥脱水系统和调整运行方式等措施使上述问题得到了有效解决.     

数学模拟在污水处理厂节能减排中的应用和发展

在国内外节能减排的大背景下,污水处理厂面临着巨大的提标改造和节能减排压力。基于活性污泥数学模型的数学模拟技术在国内外许多污水处理厂的模拟仿真、运行诊断与工艺优化、升级评估、节能减排等方面得到广泛的应用,文章主要介绍了数学模拟技术在污水处理厂节能减排方面的发展和应用情况,并提出今后国内的主要研究方向。     

ICA技术在污水厂的应用现状及发展

详细说明了仪表、控制和自动化（Instrumentation，Control and Automation，ICA）技术在污水处理系统中应用的限制性因素和发展动力，介绍了ICA技术在国内和欧洲部分国家的应用现状，给出了污水处理厂常用的实时控制方法，强调传感器已不是污水处理系统在线控制的主要瓶颈，指出污水处理厂的运行缺乏灵活性以及管理人员水平较低是难以实现在线控制的主要原因。     

水解酸化—生物接触氧化工艺处理小区污水

某城市居民小区污水处理站设计规模为 1 0 0m3/d ,采用水解酸化—生物接触氧化工艺 ,在进水BOD为 86mg/L、COD为 2 1 5mg/L、SS为 1 1 6mg/L、NH3-N为 2 8mg/L的条件下 ,处理后出水BOD <2 0mg/L、COD <60mg/L、SS<2 0mg/L、NH3-N <1 5mg/L ,达到《污水综合排放标准》(GB8978-1 996)一级标准     

西部小城镇污水厂、垃圾站的经济指标分析

在参考现有国内污水厂(站)经济指标及国内外经济指标费用模型的基础上,通过调查分析大量已建的西部城市污水处理厂的规模及投资情况,建立了适用于西部小城镇污水厂(站)的总的和分工艺的处理量一投资费用模型,并通过对运行成本构成的分析,构建了西部小城镇污水厂(站)的运行费用模型;同时,研究了全国采用卫生填埋工艺的城镇垃圾处理场的规模和投资情况,得出了西部小城镇垃圾处理设施的处理量一投资、单方库容投资费用模型及运行成本模型.     

生物活性炭法处理钢铁企业排水的微生物分析

为实现水资源的循环利用,采用生物活性炭(BAC)工艺对某钢铁企业的排水进行深度处理。在获得良好除污效果的基础上对BAC上的生物量及铁细菌进行了研究,以期为优化设计提供依据。结果表明,在显微镜下可清楚地观察到生物活性炭上成熟的生物膜,沿水流方向随着深度的增加,生物量由上层105cfu/g的数量级减少至下层103cfu/g的数量级;在一个反冲洗周期内,上层生物量每2d增加一个数量级;反冲洗后的生物量仍可保持在103cfu/g的数量级,保证了BAC滤柱在下阶段的稳定运行。对铁细菌的分离、纯化和鉴定表明,在近一年的运行中,已培养出高效除铁菌,上、下层的铁细菌数量分别为7.60×103和3.73×102cfu/g,比细菌总数平均低两个数量级,根据形貌特征和生长环境判别其为嘉氏铁柄杆菌。