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.

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.

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.

Dyeing and printing wastewater treatment using fly-ash coated with chitosan

Printing and dyeing industry is a considerable source of environmental contamination.In this study treatment of printing and dyeing wastewater with a new type of sewage treatment agent,fly-ash coated with chitosan particles (FCCP),was examined.The effects of pH,stirring time,sedimentation time and temperature on color,COD,turbidity and NH3-N removal were determined.The optimum dosage of FCCP and the influence of individual factors on removal efficiency were tested.The optimum parameters determined using the L16 (45) orthogonal experiment were as follows:FCCP (weight ratio of chitosan to fly-ash 1:6) dosage,4 g·L-1;temperature,35°C;pH,4.The stirring time and sedimentation time were 20 min and 5 h,respectively.Under these optimum conditions,the color,COD and NH3-N removal ratios were 97%,80% and 75%,respectively.

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.

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 iron-manganese removal bacteria in the culture 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 of ρ (DO)=2.8 mg/L and ρ (DO)=9.0 mg/L, no significant difference was found. The engineering bacteria removing the organic and the bacteria removing iron and manganese were simultaneously 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 offensive 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.

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%.

Removal of VOCs from Sudden Polluted Raw Water by Air Stripping

Volatile organic compounds(VOCs) are widely used in various industrial processes and generate water pollutions.VOCs removal from raw water is an important task for waterworks to guarantee drinking water security.The removal of VOCs such as chlorobenzene(CB) and ethylbenzene(EB) from raw water by air stripping was investigated under various conditions,including the variation of temperature(5-30℃),pH(3.5-10.5),and air/water ratio(10-60).The air stripping removal efficiency of VOCs decreased with VOCs concentration declining in water.And Henry's law constant was demonstrated as an indicator of the estimation of VOCs removal efficiency for air stripping.The effects of temperature and the ratio of air and water were found to play a great role in VOCs removal,but the effect of pH seemed to be negligible.This study demonstrates that air stripping provides a promising opportunity in removing VOCs in drinking water treatment,especially for the relatively high concentration of VOCs.

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。

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.

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。

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。

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。

抗冻剂与浸渍冷冻协同处理对调理牛排冻藏期品质的影响

为阐明抗冻剂与浸渍冷冻协同处理对调理牛排冻藏品质的影响,以牛肉为原料,添加调味料或辅料,经加工制成调理牛排。调理牛排样品采用空气冻结、抗冻剂、浸渍冻结和抗冻剂与浸渍冻结联合处理进行冷冻处理。将牛排置于-30℃冰柜冻藏90 d,分别在0、30、60、90 d测定解冻损失率、汁液损失率、蒸煮损失率、质构特性、剪切力、色泽和硫代巴比妥酸反应物(thiobarbituric acid reactive substances,TBARS)值及观察牛排微观结构。结果表明:与其他处理组相比,抗冻剂与浸渍冻结联合处理组的调理牛排解冻损失率、汁液损失率、蒸煮损失率均明显降低,且TBARS值也明显低于其他处理组;此外,该处理组调理牛排的亮度值和红度值较高,组织结构中肌纤维排列整齐、最紧密。综上,采用抗冻剂与浸渍冻结联合处理调理牛排不仅能促使其组织结构紧密以保持较好的保水性,而且可保持其肉色稳定。

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。

海水养殖尾水中NH_(4)^(+)-N去除技术的机理与工艺研究进展

总结了海水养殖尾水中NH_(4)^(+)-N的来源及特点,NH_(4)^(+)-N去除技术的机理与功能微生物、工艺应用及其微生物分布等,重点对海水养殖尾水中NH_(4)^(+)-N去除技术的机理与工艺应用进行了阐述。好氧氨氧化微生物主要包括氨氧化细菌(AOB)、氨氧化古菌(AOA)及全程硝化菌(comammox),厌氧氨氧化微生物主要包括厌氧氨氧化细菌(AnAOB)。基于好氧氨氧化微生物原理去除NH_(4)^(+)-N的主要工艺技术包括移动床生物膜反应器(MBBR)、曝气生物滤池(BAF)、人工湿地和生态塘等;基于厌氧氨氧化菌处理海水养殖尾水的主要工艺技术有厌氧流化床、厌氧固定床等。指出工艺应用与微生物种群结构之间关系的研究不足。富集氨氧化微生物从而实现经济高效脱氮是未来工艺研究的重点方向。

自来水厂不同水处理工艺环节对全氟化合物浓度的影响

全氟化合物(perfluoroalkyl substances,PFASs)是一类具有毒性、积累性、持久性等特性的新型污染物。本文采集了成都某自来水厂水源水、末梢水以及不同工艺环节的水样进行分析,研究不同处理工艺对去除PFASs的影响。结果表明,在水源水、自来水厂各工艺段水以及末梢水中,全氟辛烷羧酸(perfluorooctanoic acid,PFOA)的含量最高,其次是全氟丁酸(perfluorobutanoic acid,PFBA),分别占12种全氟化合物的总浓度(Σ12PFASs)的26.7%~74.1%和12.0%~26.0%,说明PFOA和PFBA是主要污染物。经过水厂处理后,Σ12PFASs从水源水的2.22 ng/L下降到了出厂水的1.74 ng/L,下降了21.6%,说明自来水厂对PFASs的去除有一定效果。在自来水厂各处理环节中,折板反应池的Σ12PFASs浓度最高,为4.42 ng/L,其中PFOA的占比最高。混凝对PFASs的去除效果最为明显,去除率达到48.9%,说明在常规处理工艺中混凝对PFASs的去除起到重要作用。该自来水厂出水中的PFOA和全氟辛烷磺酸(perfluorooctane sulfonic acid,PFOS)的浓度远低于《生活饮用水卫生标准》(GB 5749—2022)的限值,符合日常安全用水要求。

金属有机框架材料对水体中重金属离子去除性能及机理的研究进展

工业化进程的加快导致全球环境污染日趋严峻,尤其是铬、砷、铅、汞、镉、锌、铜及镍等重金属污染极为显著。重金属在水体中多以离子态存在,难以生物降解,将对生态环境和人类健康构成巨大威胁,因此寻求经济、高效的重金属去除方法刻不容缓。水体中重金属去除的方法主要包括离子交换、混凝沉淀、氧化还原、吸附、膜过滤及电渗析等,其中吸附法具有成本低廉、操作简单和适应性强等诸多优点,被认为是去除水体中重金属的优选方法之一。金属有机框架材料(MOFs),因其比表面积大、孔隙率高、活性位点丰富、可调节性强及热/化学稳定性高等特性,被广泛应用于去除水体中的重金属。重点综述了MOFs及其复合材料对铬、砷、铅、汞、镉、锌、铜及镍重金属离子的去除性能,分析了MOFs初始浓度、重金属离子浓度、接触时间、pH值、温度及干扰离子等因素对重金属去除效果的影响。同时,明确了MOFs去除重金属离子的机理。其主要作用机理为吸附、沉淀及氧化还原,其中吸附分为物理吸附和化学吸附,物理吸附主要包括静电引力、扩散作用和范德华力,化学吸附主要包括开放金属位点/配位作用、酸碱作用及氢键作用,而沉淀或者氧化还原伴随在吸附过程中。此外,对今后MOFs材料在重金属污染防治领域的研究方向及潜在应用进行了展望,以期为MOFs材料在环境污染修复领域的研究和应用提供理论基础。