A full‐scale trickling filter for the simultaneous removal of ammonium,iron and manganese from potable water

Ammonium, iron, manganese and hydrogen sulfide are a serious problem for water reservoirs all over the world. The aim of this work was the design, construction and operation of a full‐scale trickling filter for the simultaneous removal of the above pollutants. The long‐term removal efficiency and the effect of environmental and operating conditions on filter performance were studied. Start‐up time of the filter was minimized using as inoculum backwash water from an existing pilot‐scale plant, while natural advection was adequate to provide sufficient aeration. Redox potential variation throughout the filter depth enhanced simultaneous removal of the pollutants. Under steady operating conditions the filter presented perfect performance, while under pollutant concentration and/or hydraulic loading shocks the filter retained high removal efficiency. Seasonal or daily temperature variations did not affect filter performance since raw water temperature was constant at 20 °C. The proposed system exhibited high pollutant removal rates for all hydraulic and pollutant loadings tested, under various environmental conditions. The simplicity of the installation and the minimal operating cost provide an effective solution to a serious environmental and social problem. Copyright © 2010 Society of Chemical Industry     

Removal of ammonium,iron and manganese from potable water in biofiltration units: a review

Ammonium, and trace metals such as iron and manganese are common inorganic pollutants present in waters. Several surface and groundwaters contain natural or increased concentrations of these pollutants that are observed either isolated or in pairs, or all three together. Although several processes have been established for the biological removal of one of the above‐mentioned pollutants, only recently have important studies been performed on the efficient and cost‐effective simultaneous biological removal of two or more substances. This paper reviews the variety of full‐ and pilot‐scale biological filters that have been used for combined or simultaneous biological removal, as well as factors and conditions that were found to affect the process. The main results regarding research progress on combined or simultaneous biological removal are evaluated. Finally, the kinetic models and simulation approaches used are discussed. © 2013 Society of Chemical Industry     

Catalytic denitrification: direct and indirect removal of nitrates from potable water

A nitrate removal process that drastically reduces salt consumption and waste discharge has been developed on a bench scale. Nitrate is removed by chloride ion exchange, and the strong-base anion resin is completely regenerated at mild reaction conditions (i.e., ambient temperature, atmospheric pressure) in a closed circuit containing a single-flow fixed-bed reactor packed with a Pd–Cu/γ-Al₂O₃ catalyst. The combined treatment system avoids direct contact between the denitrification reactor and the water to be treated, and minimizes operational problems associated with each separate technique. No dissolution of Pd and Cu metallic-phases was observed at the given operating conditions.     

矿井水除铁除锰的工程应用

煤矿矿井水富含悬浮物、铁离子和锰离子等物质,直接外排会污染水体,破坏环境。介绍了辽宁锦州某煤矿的矿井水除铁除锰工程。该工程针对矿井水中悬浮物与铁、锰离子含量过高的现状,采用"调节池(曝气)+絮凝沉淀+锰砂过滤器"工艺对其进行处理。结果表明,处理出水铁离子质量浓度≤0.3 mg/L,锰离子质量浓度≤0.1 mg/L。该工艺处理效果明显,运行稳定,处理出水24 h不返色。     

pH值对地下水除铁除锰影响机理的研究

以洞庭湖区地下水为水源,通过调节试验原水的pH值,考察不同pH值条件下铁锰去除效果的变化,试验结果表明：随着pH值的升高,铁的去除从最初没有效果（pH值小于6.5）到接触氧化除铁（pH值在6.5～7.5）,再过渡到空气氧化除铁法（pH值大于7.5）;锰的去除在pH值大于5.0时为生物除锰法,在pH值小于5.0时生物除锰丧失了除锰能力.     

Removal of iron and manganese from groundwater by oxidation and microfiltration

Iron and manganese can be removed from groundwater by a process which combines oxidation and microfiltration (MF), especially when the concentrations of these metals are high and variable. The present experimental work focused on the MF of iron and manganese oxide suspensions in order to study the effects of the operating variables (tangential flow rate, pressure, metal feed concentrations) on permeate quality and permeation flux decline, i.e., membrane fouling. Artificial and natural groundwaters in which iron and manganese were previously oxidized were used to perform laboratory-scale MF experiments. The results show that the oxide particles, with sizes ranging from 1.5 to 50μm, were efficiently microfiltered even at high concentrations. Within the experimental limits, the effect of operating pressure appeared to be much more significant than the those of tangential flow rate and feed concentration. A relatively high and constant permeation rate of 0.5 m/h was obtained at a pressure below 10 kPa, whereas rapid permeation flux declines were observed at higher pressure. Both artificial and natural groundwaters always exhibited very similar behavior.     

As(III) removal from drinking water using manganese oxide-coated-alumina: Performance evaluation and mechanistic details of surface binding

This paper describes the arsenite [As(III)] removal performance of manganese oxide-coated-alumina (MOCA) and its interaction with As(III) in drinking water. MOCA was characterized by XRD, SEM, EDAX, gas adsorption porosimetry, and point of zero charge (pH_pzc) measurements. Raman spectroscopy coupled with sorption experiments were carried out to understand the As(III) interaction with MOCA. As(III) sorption onto MOCA was pH dependent and the optimum removal was observed between a pH of 4 and 7.5. The Sips isotherm model described the experimental equilibrium data well and the predicted maximum As(III) sorption capacity was 42.48 mg g⁻¹, which is considerably higher than that of activated alumina (20.78 mg g⁻¹). The sorption kinetics followed a pseudo-second-order equation. Based on sorption and spectroscopic measurements, the mechanism of As(III) removal by MOCA was found to be a two-step process, i.e. oxidation of As(III) to arsenate (As(V)) and retention of As(V) on MOCA surface, with As(V) forming an inner surface complex with MOCA. The results of this study indicated that MOCA is a promising alternative sorbent for As(III) removal from drinking water.     

低pH下饮用水生物除铁试验研究

通过试验,探讨了低pH条件下饮用水生物滤池除铁的效果及其证据.结果表明,当pH为5.7～5.9,水温为25～28 ℃,DO为0.7～1.5 mg/L,EBCT为7.5 min时,生物滤池具有良好的除铁效果;在生物除铁滤池内,滤层除铁机理主要为生物氧化作用.     

生物法去除地下水中铁锰的研究进展

生物法除铁除锰是近年来提出的去除水中铁锰的新理论和新技术,为地下水中铁锰的去除开拓了新思路。阐述了生物除铁除锰理论的基本观点,重点介绍了该领域新的研究进展,主要包括生物除铁除锰的工艺优化、滤料选择、微生物研究和动力学研究4个方面,并指出深入研究生物除铁除锰的机理、动力学模型和高效除铁除锰工程菌的特性等是生物除铁除锰技术今后的主要研究方向。     

The removal of phosphorus from reject water in a municipal wastewater treatment plant using iron ore

BACKGROUND: Reject water (return liquor) from dewatering of anaerobically digested activated sludge in municipal wastewater treatment plants contains from 10 to 50% of the phosphorus load when being recycled to the aeration tank. Phosphorus removal from reject water could be an effective way to decrease phosphorus loads entering the aeration tank. An innovative approach involves the replacement of iron salts, which are commonly used for phosphorus removal, with ferrous ions produced by iron‐reducing bacteria from iron ore. The aim of the research was to examine the feasibility of phosphorus removal from return liquor using bioreduction of iron ore. RESULTS: Ferrous production, phosphate and organic carbon removal rates were determined as a function of different iron ore particle sizes in batch experiments. Iron‐reducing bacteria ensured the production of ferrous ions from iron ore up to concentrations of 550 mg L^?1. The ferrous production rate was linearly dependent on the calculated specific surface area of the iron ore particles. The phosphorus concentration in the reject water was reduced by 90% during bioreduction of iron ore. The phosphorus removal rate did not depend on specific surface area of iron ore particles when the particle size of iron ore was smaller than 7 mm. The organic carbon removal rate did not seem to be dependent on iron ore particle size. CONCLUSION: Removal of phosphate using iron ore can be more economical than conventional chemical precipitation of phosphate using iron salts because of the lower cost of iron ore. Copyright © 2008 Society of Chemical Industry     

地下水生物除铁、锰的影响因素试验研究

目的：研究锰砂滤层去除铁、锰过程中滤速、温度、溶解氧3个因素对去除效果的影响,为生物法除铁、锰的实际运行提供了参考依据。方法：在其他运行条件相同的情况下,只改变其中一项,进行去除率试验对比。结论：（1）当处理只有铁超标的地下水时,滤速可以适当提高,锰超标时,出水中的含锰量是选择过滤速度的主要的控制指标;（2）DO在一定范围内的变化对生物除铁除锰效率的提高无显著影响。从经济性和微生物角度考虑原水DO维持在3mg／L左右既可满足运行要求;（3）当铁锰共存时,最适宜的处理环境温度为20℃。     

Efficient technology for the removal of iron and manganese ions from artesian water using clinoptilolite

A method and technology for the deposition of strongly bonded high-disperse manganese dioxide onto the external surface of clinoptilolite grains is developed. The optimal conditions for the application of thus prepared material for the purification of artesian water are determined. A two-stage process of water purification is proposed, which involves usual clinoptilolite filter at the first stage to remove the main amount of iron, and the filter with modified clinoptilolite on the second stage to remove the residual iron and bivalent manganese ions. The proposed technology of preparation and application of modified clinoptilolite is tested in industrial conditions.     

Preparation and characterization of polyvinyl chloride based nanocomposite nanofiltration-membrane modified by iron oxide nanoparticles for lead removal from water

In this research (polyvinyl chloride-blend-cellulose acetate/iron oxide nanoparticles) nanocomposite membranes were prepared by casting technique to lead removal from wastewaters. The effect of blend ratio of polymer binder (PVC to CA) and Fe₃O₄ nanoparticles concentration on physico-chemical characteristics of membranes were studied. Water permeability and ionic rejection tests, water content and mechanical properties measurements and SEM analysis were carried out in membranes characterizations. Obviously, modified membrane containing 10 wt% CA and 0.1 wt% Fe₃O₄ nanoparticles showed better performance in lead removal compared to other modified membranes and also pristine ones.     

煤气净化过程中剩余氨水、富液除油新技术

针对山西焦化股份有限公司90万t/a焦炉易地改造工程中煤气净化车间剩余氨水、富液带油严重,造成蒸氨脱酸板式换热器频繁堵塞的现象,采用气浮除油技术和微孔陶瓷过滤技术对剩余氨水、富液系统进行了改造。改造后系统运行稳定,系统中压蒸汽消耗量减少2.0 t/h,剩余氨水脱油率达到80.0%以上;过滤器后含油质量浓度降至10 mg/L以下,除油率稳定在80.0%以上,过滤器后悬浮物质量浓度稳定在20 mg/L以下。     

MS2 removal from high NOM content surface water by coagulation ‐ ceramic microfiltration,for potable water production

MS2 bacteriophages removal from surface water, characterized by high natural organic matter (NOM) content, was investigated by inline coagulation/flocculation pretreatment followed by ceramic microfiltration (MF). MS2 and DOC removal increased with lower pH and higher coagulant dose. Lowering the coagulant pH from 6.5 to 5.5 for polyaluminum chloride (PACl), and to 5.0 for iron chloride (FeCl), respectively, along with doubling of the coagulant dose from 2 to 4 mg Al/L, and from 4 to 8 mg Fe/L, respectively, maximized the virus removal, resulting in more than six log unit reductions up to complete virus retention. However, high residual metal concentrations were found under such conditions. Comparison of conventional two‐stage coagulation pretreatment with simple inline coagulation did not show any significant performance differences. Both investigated coagulants showed virus inactivation about two log units after 60 min contact time, which is equivalent to a virus inactivation of 99%. This inactivation was only reversible to a small extend by chemical or physical floc destruction. The investigated process combination can comply with modern hygienic barrier standards. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

The distribution and transformation of iron and manganese in soil fractions in a savanna Alfisol under continuous cultivation

Data on the responses of micronutrients in definable soil fractions to cultivation and management are required to design judicious fertilization practices to improve soil fertility in the savanna. Iron and manganese fractions are particularly sensitive to cultivation and management practices. The objectives of this study were to determine the sizes and changes in Fe and Mn fractions in a savanna Alfisol cultivated for 50 years and fertilized with (i) NPK, (ii) farmyard manure (FYM), (iii) FYM + NPK, (iv) a control plot, and (v) a natural site adjacent to the experimental field. The mean concentration of total Fe (Fe_T) ranged from 9.4 g kg^–1 in the surface layer to 45 g kg^–1 in the subsurface layer, whereas total mangenese (Mn_T) concentration ranged from 79 mg kg^–1 in the surface layer to 279 mg kg^–1 in the subsurface layer. The distribution of Fe_T followed the distribution of clay in the soil profile across the field. The distribution of Mn_T did not, however, follow the characteristic depth distribution of clay as observed for Fe_T, suggesting that Mn movement and distribution in this soil might be independent of clay movement and distribution. The concentrations of DTPA extractable Fe and Mn were much higher than the critical levels delineated for soils. Application of FYM increased the concentration of amorphous oxide bound Fe over the natural site and reduced the concentration of residual or inextractable Fe in the soil. Similarly, fertilization with FYM reduced the concentration of residual Mn, and increased the exchangeable, amorphous oxide bound and reducible Mn compared to the natural site. It seems that sole application of FYM or application in combination with NPK rather than NPK alone can mobilize non-labile Mn and Fe sources into labile and plant available forms of Fe and Mn in a savanna Alfisol.     

高镁卤水中有机物去除的工艺研究

通过对混凝、臭氧氧化、活性炭吸附和树脂吸附等工艺处理有机物含量较高的卤水的试验研究,探索出了合理的卤水有机物处理工艺,在不损失卤水中有价值金属离子成分的基础上对卤水中的有机物进行有效去除。研究表明:XDA-1树脂吸附与催化氧化的组合工艺,可以达到预期目标,即金属镁离子的损失率控制在10%以内,有机物去除率不低于70%。     

气田采出水复合除铁、除钙工艺

由预处理环节水质及精馏塔垢分析可知,管线堵塞的主要原因是含铁、含钙量严重超标,导致结垢物堆积在输水设备及管线内部,同时引起垢下腐蚀,影响气田采出水处理设备的正常运行。鉴于绝大多数处理厂仅考虑铁离子的去除,而未考虑Ca²⁺的去除,本文首次在采出水预处理环节对除铁和除钙工艺进行复合,通过筛选适宜的除铁除钙剂,优化加药顺序、加药反应时间、静置时间等参数,开发出适用于气田采出水处理的复合除铁除钙工艺。结果表明,现场加药量为H₂O₂ 500mg/L、NaOH 500mg/L、PAC 50mg/L、PAM 4mg/L,除钙剂与Ca²⁺的摩尔比为1∶1,加药顺序为Na₂CO₃→H₂O₂→NaOH→PAC→PAM,反应时间7min以上,静置5h以上时,气田采出水中的总铁离子含量可由153.24mg/L降至0.3338mg/L,Ca²⁺由5495mg/L降至520mg/L,其中总铁离子降幅为99.8%,Ca²⁺降低了90.54%,矿化度大幅度降低可避免后续环节堵塞,从而保障气田采出水处理系统高效运行。     

窑法磷酸中铁、铅、砷的深度净化

对沉淀法深度净化窑法磷酸中的铁、铅和砷进行了研究。理论计算表明,采用亚铁氰化铁沉淀法除铁,可以将w(Fe)降低至≤1 mg/kg;采用硫化物沉淀法除铅、除砷,当净化液中c(S)≥9.46×10-5mol/L时,可以将w(Pb)和w(As)分别降至10 mg/kg、1 mg/kg。实验结果表明,当亚铁氰化钠加入量为理论量、反应温度为50℃时,w(Fe)降至0.001 9%(折合w(H3PO4)85%磷酸中);当五硫化二磷加入量为理论量4.6倍、反应温度为20~30℃以及反应时间为0.5 h时,w(Pb)和w(As)分别降至7.5 mg/kg、0.15 mg/kg(折合w(H3PO4)85%磷酸中)。上述净化指标均达到了工业级磷酸国家标准(GB/T 2091—2008)的要求。     

负载铁离子活性炭除砷的研究进展

砷污染是一个严重的世界问题,在其诸多的去除方法中,负载铁离子活性炭兼顾了活性炭和混凝沉淀的优势,可高效去除砷离子.作者对负载铁离子活性炭的制备方法、影响砷去除率的主要因素和吸附模型的研究现状进行了详细评述,其中负载铁离子活性炭的孔径结构、表面性质,负载铁离子的形貌、分布、种类和质量等决定着其吸附容量;通过调节搅拌时间、...