Immobilization biological activated carbon used in advanced drinking water treatment

Bacteria separated from a mature filter bed of groundwater treatment plants were incubated in a culture media containing iron and manganese. A consortium of 5 strains of bacteria removing iron and manganese were obtained by repeated enrichment culturing. It was shown from the experiments of effect factors that ironmanganese removal bacteria in the euhure media containing both Fe and Mn grew better than in that containing only Fe, however, they were unable to grow in the culture media containing only Mn. When comparing the bacteria biomass in the case ofp （DO） ：2.8 mg/L andp （DO） ：9. 0 mg/L, no significant difference was found. The engineering bacteria removing the organic and the bacteria removing iron and manganese were simuhaneously inoculated into activated carbon reactor to treat the effluent of distribution network. The experimental results showed that by using IBAC （ Immobilization Biological Activated Carbon） treatment, the removal efficiency of iron, manganese and permanganate index was more than 98% , 96% and 55% , respectively. After the influent with turbidity of 1.5 NTU, color of 25 degree and oflbnsive odor was treated, the turbidity and color of effluence were less than 0.5 NTU and 15 degree, respectively, and it was odorless. It is determined that the cooperation function of engineering bacteria and activated carbon achieved advanced drinking water treatment.

Evaluation of copper removal efficiency using water treatment sludge

Large quantities of sludge are produced during water treatment processes. Recently, sludge has been treated as waste and disposed of in landfills, which increases the environmental burdens and the operational cost. Therefore, sludge reuse has become a significant environmental issue. In this study, adsorption of copper ions (Cu^2+) onto calcined sludge was investigated under various operational conditions (with varying temperature, Cu^2+ initial concentration, pH, and sludge dosage). The prepared sludge material was characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and Brunauer-Emmett-Teller (BET) surface area. The sorption capacity of sludge was directly proportional to the initial Cu^2+ concentration and inversely proportional to the sludge dosage. The optimum operational pH and solution temperature were 6.6 and 80℃, respectively. The experimental results followed a Langmuir isotherm and pseudo-first-order adsorption kinetics. Thermodynamic parameters such as activation energy, change in free energy, enthalpy, and entropy were calculated. Thermodynamic analyses indicated that the sorption of copper ions onto the calcined sludge was driven by a physical adsorption process. The prepared sludge was proven to be an excellent adsorbent material for the removal of Cu^2+ from an aqueous solution under optimum conditions.

Review on Optimization of Drinking Water Treatment Process

In the drinking water treatment processes, the optimization of the treatment is an issue of particular concern. In general, the process consists of many units as settling, coagulation, flocculation, sedimentation, filtration and disinfection. The optimization of the process consists of some measures to decrease the managing and monitoring expenses and improve the quality of the produced water. The objective of this study is to provide water treatment operators with methods and practices that enable to attain the most effective use of the facility and in consequence optimize the cubic meter price of the treated water. This paper proposes a review on optimization of drinking water treatment process by analyzing all of the water treatment units and gives some solutions in order to maximize the water treatment performances without compromising the water quality standards. Some practical solutions and methods are performed in the water treatment plant located in the middle of Morocco (Meknes).

Computer-Aided Design and Simulation of a Membrane Bioreactor for Produced Water Treatment

Membrane Bio Reactor (MBR) has been designed and simulation for the treatment of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Organic Carbon (TOC), Total Dissolved Solid (TDS) and Oil/ Grease in produced water at a capacity of 54.1778 kg/hr for removal of 95%-99% contaminants. The MBR design equations were developed using the law of conservation of mass to determine the dimensions and functional parameters. The developed performance equations were integrated numerically using fourth-order Runge-Kutta embedded in MATLAB computer program to determine the optimum range of values of the reactor functional dimensions and functional parameters. The effect of rate of energy supply per reactor volume and substrate specific rate constant on the capacity of the membrane bioreactor were investigated. Also, the effect of initial loading of substrate on Solid Retention Time (SRT) was also investigated. Results showed that kinetic parameters influenced the percentage removal of contaminants as Hydraulic Retention Time (HRT) and size of MBR decreased with increase in specific rate constant at fixed conversion of contaminants. Also, HRT and MBR size increased as the conversion of Chemical Oxygen Demand (COD) was increased, while increased in the ratio of energy supplied per volume resulted in decreased of MBR volume. The effect of initial loading of substrate on SRT showed that increased in substrate loading increased the retention time of the solid at fixed substrate conversion, while the conversion of substrate to microorganism increased as the solid retention time was increased. The increased in initial loading of substrate concentration increased the production of Mixed Liquor Suspended Solids (MLSS). Thus, the size of MBR required for the conversion of the investigated contaminants at the design percentage removal increased in the following order: oil/grease 3;0.98 and 4.68 m;and 1.38 and 6.62 at 95% and 99% respectively, while the SRT was 82.67 days.

PREPARATION AND APPLICATION OF COPOLYMERS OF 2-ACRYLAMIDO-2-METHYL PROPANE SULFO ACID AS WASTE WATER TREATMENT AGENTS

In this paper, the preparation and application of copolymers of 2-acrylamido-2-methyl propane sulfo acid (AMPS) were discussed. The results showed that the copolymers with molecular weight 18.10 million can be prepared. In treating waste water from deinked pulp, the dosage of copolymers was 0.75ppm, the optimum dosage of PAC was 100ppm; dosage of the amphoteric polyacylamide (AmPAM) with molecular weight 11.34 million was 0.75ppm, the optimum dosage of PAC was 75ppm. The removed rate of CODcr was above 70%.

Biodegradation of microcystin-RR and -LR by an indigenous bacterial strain MC-LTH11 isolated from Lake Taihu

The indigenous bacterial strain MC-LTH11 with the capability of degrading microcystin-RR MC-RR and microcystin-LR MC-LR was successfully isolated from Lake Taihu.The bacterium was identified as Stenotrophomonas sp. which possessed a mlrA gene. The MC-LTH11 thoroughly degraded MC-RR and MC-LR with the initial concentration of 37.13 mg/L and 18.49 mg /L respectively in the medium containing crude microcystins extract within 6 d.The degradation rates were affected by temperature pH initial MCs concentration and the kinds of media. Additionally the bacterial strain MC-LTH11 also degraded thoroughly microcystins in the water body of Lake Taihu within 1 d.These results suggest that the Stenotrophomonas sp.MC-LTH11 has the capacity to bioremediate water bodies contaminated by microcystins and may contribute to the degradation of microcystins after the outbreak of harmful cyanobacterial blooms in Lake Taihu.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

Removal of antibiotic-resistant genes during drinking water treatment:A review

Once contaminate the drinking water source,antibiotic resistance genes(ARGs)will propagate in drinking water systems and pose a serious risk to human health.Therefore,the drinking water treatment processes(DWTPs)are critical to manage the risks posed by ARGs.This study summarizes the prevalence of ARGs in raw water sources and treated drinking water worldwide.In addition,the removal efficiency of ARGs and related mechanisms by different DWTPs are reviewed.Abiotic and biotic factors that affect ARGs elimination are also discussed.The data on presence of ARGs in drinking water help come to the conclusion that ARGs pollution is prevalent and deserves a high priority.Generally,DWTPs indeed achieve ARGs removal,but some biological treatment processes such as biological activated carbon filtration may promote antibiotic resistance due to the enrichment of ARGs in the biofilm.The finding that disinfection and membrane filtration are superior to other DWTPs adds weight to the advice that DWTPs should adopt multiple disinfection barriers,as well as keep sufficient chlorine residuals to inhibit re-growth of ARGs during subsequent distribution.Mechanistically,DWTPs obtain direct and inderect ARGs reduction through DNA damage and interception of host bacterias of ARGs.Thus,escaping of intracellular ARGs to extracellular environment,induced by DWTPs,should be advoided.This review provides the theoretical support for developping efficient reduction technologies of ARGs.Future study should focus on ARGs controlling in terms of transmissibility or persistence through DWTPs due to their biological related nature and ubiquitous presence of biofilm in the treatment unit.

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges and opportunities

Drinking water source contamination poses a great threat to human health in developing countries.Point-of-use(POU)water treatment techniques,which improve drinking water quality at the household level,offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterbome diseases.Ceramic water filters(CWFs),fabricated from locally sourced materials and manufactured by local labor,are one of the most socially acceptable POU water treatment technologies because of their effectiveness,low-cost and ease of use.This review concisely summarizes the critical factors that influence the performance of CWFs,including(1)CWF manufacturing process(raw material selection,firing process,silver impregnation),and(2)source water quality.Then,an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs,including(1)simultaneous increase of filter flow rate and bacterial removal efficiency,and(2)removal of various concerning pollutants,such as viruses and metal(loid)s.To promote the application of CWFs,future research directions can focus on:(1)investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters;and(2)exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces.

Nitrogen Removal Efficiency of the Reclaimed Water by Land Treatment System

[Objective] The research aimed to study nitrogen removal effect of the land treatment process on reclaimed water. [Method] By using land treatment system, reclaimed water which reached one-level A standard was conducted advanced processing, and nitrogen removal efficiency of the effluent was inspected. [ Result] There was a positive correlation between organic matter content of the soil medium and nitrogen removal effect. With appropriate soil medium, TN and NH3-N could obtain the removal efficiency of more than 90% and 75% respectively, and they could be removed at 30 and 10 cm height of soil medium respectively with land treatment system to treat reclaimed water. [ Conclusion ] The research provid- ed theoretical basis for application of the land treatment system into nitrogen removal of the reclaimed water.

水环境中微塑料去除技术研究进展

首先概述了水环境中微塑料的来源、分布及对人体的危害,原生微塑料和次生微塑料可通过地表径流和污水厂出水进入引用水,从而被人类摄入体内,引发多种毒性作用。随后讨论了膜技术、磁分离、电絮凝、光催化降解与生物降解等新技术的处理原理、去除效果与优缺点,重点关注各项新技术研究进展及其有效性。最后据此提出了实验研究及后续处置方面的展望。归纳了水环境中微塑料去除技术研究进展,以期为未来进一步降低能耗、提高水环境中微塑料的去除率,形成稳定工艺提供参考。

长江大保护试点城市某污水处理厂尾水湿地净化效果研究

为探寻污水处理厂配套尾水湿地净化效果,以长江大保护试点城市某污水处理厂尾水湿地为例,通过现场调查与采样,分析湿地出水水质特征,探讨影响湿地污染物去除效率因素。结果表明:尾水湿地出水COD、NH_(3)-N及TP浓度满足设计目标,潜流湿地对COD去除率较高,表流湿地对氨氮及磷的去除率较高,优于涵养塘;湿地实际运行水力负荷、水力停留时间和污染物负荷与设计值不符,影响污染物去除效果;据此提出湿地运行优化建议,促进湿地深度脱氮除磷,提升尾水湿地效能;运行优化可提高潜流湿地污染物去除率,同时污水处理厂减少碳排放94.74 gCO_(2)m^(3)。研究结果可为该尾水湿地运行管理及长江大保护试点城市系列污水处理厂配套尾水湿地设计与运维提供参考。

黄河上游给水厂中微塑料的出现及去除效率

调查了位于黄河上游给水厂中>1μm的微塑料的丰度、物理形貌和组成,结果显示原水、混凝沉淀、过滤、紫外消毒和终端出水中微塑料的丰度分别为(1964.5±212.5)个/L、(795±136)个/L、(386±21)个/L、(377±20)个/L和(374.5±13.5)个/L,总体去除率达到80.97%.从原水到终端出水中微塑料以<10μm(89.60%~100%)的碎片状为主,且其去除效率与形状和大小有关.通过激光红外成像光谱仪和拉曼光谱进行定性分析发现了15种不同的聚合物类型,聚对苯二甲酸乙二醇酯、聚丙烯、聚乙烯及聚甲基丙烯酸甲酯最为常见.该研究结果为城市供水中存在微塑料提供了依据,并为给水处理过程中微塑料的去除提供参考.

Ti-Al水滑石的制备及吸附水中低质量浓度F-性能

以AlCl_(3)·6H_(2)O和TiCl_(3)为原料、Na OH为沉淀剂,采用共沉淀法制备了不同n(Ti)∶n(Al)的双金属氢氧化物(Ti-Al LDHs),考察了其对模拟废水中低质量浓度F-的吸附性能。采用SEM、BET和XRD对Ti-Al LDHs吸附F-前后的样品进行了表征,探究了Ti-Al LDHs的投加量、初始溶液pH对Ti-Al LDHs除氟容量的影响,测试了其循环再生能力。对Ti-Al LDHs吸附F-的机理进行了推测。结果表明,Ti-Al LDHs稳定性较好,呈现层状结构且均匀堆积,主要以分散的无定形态存在,具有较宽的孔径分布和较大的比表面积(108.34 m^(2)/g);当n(Ti)∶n(Al)=2∶8、介质p H=6时制备的Ti-Al LDHs-1对F-具有最佳的吸附性能,在Ti-Al LDHs-1投加量为0.1 g/L、25℃、200 r/min、水浴恒温振荡12 h的条件下,Ti-Al LDHs-1的除氟容量最高,为63.08 mg/g;常温下,初始溶液p H=4时,投加量0.2 g/L的Ti-Al LDHs-1平衡除氟容量为47.59 mg/g,F-去除率为86.53%;共存阴离子(0~10mmol/L)对F-吸附的影响高低排序为HCO_(3)->CO_(3)^(2-)>SO_(4)^(2-)>H_(2)PO_(4)^(-)>Cl^(-)>NO_(3)^(-)。Ti-Al LDHs-1对F-的吸附更符合拟二级动力学模型(R^(2)>0.99),吸附等温线更符合Langmuir模型。经过4次吸附-解吸循环后,Ti-Al LDHs-1除氟容量仍可达初始的73%。吸附过程为离子交换、静电吸引和表面络合3种类型共同作用。

饮用水处理工艺对微塑料的去除效果的研究进展

微塑料作为一种新型污染物,在世界各地区的饮用水源中广泛存在,饮用水处理厂通过多种处理工艺对饮用水源地的进水进行处理,从而生产供人类生活生产的饮用水。然而饮用水处理厂的一系列处理流程无法完全清除微塑料,同时,供水管网的运输、水箱水桶的蓄水存储等过程也可能会将微塑料引入水体中,导致微塑料在饮用水中不断被检出,对人类健康造成严重的威胁。文中针对微塑料在水体中的污染状况,阐述了近年来微塑料在饮用水源地和饮用水中的污染特征和可能的污染来源,分析了不同的常规饮用水处理工艺和深度处理工艺对于微塑料的去除效果和影响因素,以及对微塑料的去除过程中存在的问题,展望了饮用水处理技术的发展,对当前饮用水处理工艺对微塑料的去除问题提出了建议。

MBR技术与工艺在水产养殖尾水处理中的研究进展

膜生物反应器技术(MBR)被认为是水产养殖中先进水处理的潜在技术,在水产养殖尾水处理领域的应用还有很大进步空间。以已有的理论知识为基础,结合国内外文献,分别对养殖尾水的高效处理技术、膜污染控制技术、尾水回收技术以及MBR技术改进工艺的研究现状展开描述。然后对不同MBR脱氮除磷组合工艺进行优劣对比,最后提出MBR技术与工艺在水产养殖尾水处理研究中存在处理成本高、处理技术与养殖技术未很好融合的问题,并认为未来该技术可在集成模块化、膜材料和稳定工艺等方面深入研究。为后续MBR技术在水产养殖尾水处理中的高效化、经济化研究提供参考和方向。

低温对含盐食品污水深度处理性能与微生物群落的影响

固体碳源被广泛应用于污水深度处理,但是低温条件下对含盐食品污水的处理性能还缺乏评估,微生物特性也需要揭示。以聚丁二酸丁二醇酯为固体碳源,考察了不同温度条件下的脱氮性能、微生物群落结构以及基因富集特征。结果表明:常温(25~28℃)条件下的固体碳源反应器出水可以满足《污水综合排放标准》一级标准。低温(5~9℃)对脱氮性能抑制显著,NH_(4)^(+)-N、NO_(3)^(-)-N去除率仅为30.17%、73.51%,并且运行初期存在出水有机物超标的风险。固体碳源体系中unclassified_Comamonadaceae、Acidovorax分别是主要的硝化、反硝化菌属,但容易受低温影响而丰度降低。此外,温度降低还会导致硝化基因(amoA、amoB、amoC)和反硝化基因(narG、narH、narI)丰度降低。

长江下游典型城市水源水中农药分布及水厂工艺去除效果研究

建立了一种能同时分析水中190种农药的气相色谱-质谱联用(GC-MS/MS)方法,并选取长江下游5个城市13个饮用水厂,调查了农药在进水中的分布及水厂工艺的去除效果。结果表明,仪器检出限为0.01~7.2 ng/L,回收率为50.8%~130.1%。水源中共检出53种农药,总浓度为198.8~759.2 ng/L。其中,多效唑、γ-六六六、异丙甲草胺、环嗪酮和戊唑醇在水源水中检出率为100%,平均浓度为11.5~63.8 ng/L;多效唑、马拉硫磷、三硫磷、地茂散和γ-六六六为平均浓度最高的5种农药(30.4~101.2 ng/L)。γ-六六六作为一种被禁用的有机氯农药被广泛检出,表明有必要加强对农药生产过程的监管。水厂净水工艺对农药仅有部分去除效果,相对于4个仅采用常规处理工艺水厂(平均去除率30.0%±13.8%),9个采用臭氧-活性炭深度处理工艺水厂的农药平均去除率较高(54.4%±10.1%)。

多羟基单体调控分离层结构制备高性能净水用纳滤膜

为了制备高效净化水中微污染物的纳滤膜,在哌嗪(PIP)水相溶液中混入小分子的多羟基第二单体双(2-羟乙基)氨基(三羟甲基)甲烷(BIS-TRIS),两者同时与均苯三甲酰氯(TMC)发生聚合反应,利用BIS-TRIS的羟基与PIP的氨基产生竞争作用来调控纳滤膜的分离层结构,制备净水用纳滤膜.采用傅里叶红外光谱与Zeta电位研究了膜的化学结构及表面荷电性,并对膜的分离性能与抗污染性能进行了表征.结果表明,与纯PIP和TMC制备的聚酰胺膜相比,BIS-TRIS的加入将膜孔径分布从0.3~0.9 nm提升至0.4~1.0 nm,成膜截留分子量从223提高到267,分离层厚度由135 nm减小到115 nm,渗透通量从93.6 L/(m^(2)·h·MPa)增加为220 L/(m^(2)·h·MPa),Na_(2)SO_(4)截留率由最初的95.6%提升至98%,盐酸四环素截留率由94%提升至98.4%,并且膜的抗污染性能进一步得到改善.本研究提出利用水相溶液中羟基、氨基与TMC的竞争交联作用来调控分离层结构,为高效去除水中微污染物的纳滤膜制备提供了简便的策略.

硫自养-异养协同反硝化技术的研究进展

介绍了硫自养-异养协同反硝化技术的基本特性,传统的异养反硝化运行成本高、污泥产量大,而硫自养反硝化存在脱氮效率低、消耗碱度等缺点,将两种工艺耦合可以实现取长补短。硫自养-异养协同反硝化技术是处理低C/N比废水最具潜力和经济效益的工艺之一,具有成本低、SO_(4)^(2-)产量少、pH稳定、高效脱氮等优点,对其协同机理、微生物群落特征和影响因素进行阐述,例举了该工艺在城市尾水、地下水等低碳氮比废水等方面的实际应用,总结现阶段存在的问题并对未来研究方向进行展望,为该技术的推广和实际应用提供理论参考。