利用固相反硝化工艺去除饮用水原水中的硝酸盐

饮用水原水中的硝酸盐污染已成为世界范围内普遍而日益突出的问题,固相反硝化是有效去除原水中硝酸盐的一种新工艺,该工艺利用不溶于水的固体有机物（生物质、可生物降解聚合物等）同时作为反硝化微生物的碳源和附着生长的载体,其主要优点是避免了常规异养反硝化工艺中存在的甲醇、乙醇等液体碳源易投加过量而影响出水水质的风险。讨论了不同固体碳源对反硝化作用的影响,介绍了固相反硝化工艺的研究现状,并展望了该工艺的发展趋势。     

饮用水除氟技术的现状及进展

基于近年来除氟方法的研究进展，综述了近年来国内饮用水除氟方法，如混凝沉降法、吸附法、电凝聚法、电渗析法、反渗透法、离子交换法等，同时讨论了各种除氟方法的机理及进展，以促进饮用水除氟技术的发展。     

饮用水中动物性污染物及去除工艺的研究进展

通过收集整理国内外针对动物性污染物的报道及相关研究,总结了常见动物性污染物的分类、去除方法等内容,为今后此类问题的进一步研究奠定基础和提供借鉴。     

AutoPrep离子色谱法检测饮用水中痕量NO3-和NO2-

利用戴安公司全新的AutoPrep自动样品前处理技术,首次提出将OnGuard SPE前处理小柱在线使用的概念,对饮用水中的大部分氯离子进行在线去除的同时,还可对其中的亚硝酸盐和硝酸盐进行快速、准确的定量。该方法选用了自动在线水纯化装置CIRA和OnGuard Ag小柱,运用阀切换技术实现自动进样;适宜的色谱条件为：高容量氢氧化物选择性IonPac AS18阴离子交换色谱柱,淋洗液自动发生装置在线产生KOH进行梯度淋洗,抑制型电导检测;相关方法参数：对于自来水和瓶装水,亚硝酸盐和硝酸盐的检出限（S／N=3）分别为17．8μg/L和25．6μg/L,线性相关系数分别为0．9997和0．9999,RSD〈5％,加标回收率〉92％。该方法具有自动化程度高、操作简单、重现性好、节约时间、成本低廉和对环境友好的特点。此外,研究了前处理小柱的连续使用次数,并对在线和离线的除氯效果进行了比较,认为在线除氯可节约检测成本,且对除氯效果无太大影响。     

Design and Construction of an Ion-Exchange Denitrification Plant in South Staffordshire

Increasing concern about rising levels of nitrate in groundwater supplies and their subsequent removal to comply with EC drinking water standards has led to the construction of the first full-scale ion-exchange nitrate-removal plant in the UK by the South Staffordshire Waterworks Company.
This paper describes the development of the project from concept, through pilot-plant studies to final design, installation and commissioning. It explains the role of ion-exchange technologies, the use of recently developed nitrate-selective resins and the development of a novel dual regeneration system. The initial performance of the full-scale plant is discussed.     

电化学产氢自养反硝化去除水中硝酸盐的研究

随着硝酸盐氮的污染问题日益严重,人们对水质的要求也逐渐提高,寻求高效且经济的方法来去除水中的硝酸盐氮成为了一个重要的课题。本研究以此出发,研究了建立在电极生物膜反应器中的氢自养反硝化去除水中硝酸盐的方法。本实验采用碳棒作为阳极,活性炭纤维毡为微生物载体,水被电解后在阴极表面产生氢气,供固定在阴极表面的反硝化细菌直接利用进行氢自养反硝化作用。无需外加有机碳源,即可去除水中的硝酸盐氮,具有处理费用低、无二次污染、剩余污泥少等特点。     

生物除磷机理与新工艺

综述了生物除磷的PAO和DPB原理,介绍了PASF、Dephanox和A3N-SBR三种新的脱氮除磷工艺,从而达到提高脱氮除磷效果,消除水环境污染的目的。     

Wheat straw as substrate for water denitrification

Biological denitrification of drinking water was studied in up-flow laboratory reactors packed with wheat straw which served as the sole carbon source as well as the only physical support for the microorganisms. The highest rates of denitrification (0.053 g N removed l⁻¹ d⁻¹) were observed in fresh reactors during their first week of operation and the efficiency of the process declined thereafter. The addition of fresh wheat straw brought about a temporary improvement of the denitrification performance and a regime of one weekly addition prevented the deterioration of a reactor which was operated for 5 months. The rate of denitrification was affected by the water velocity and decreased at velocities above 0.054 m d⁻¹. Colour and soluble organic carbon associated with fresh straw were removed by adsorption on powdered activated carbon.     

氢自养反硝化去除水中硝酸盐的影响因素研究

研究了氢自养反硝化细菌在不同条件下的反硝化性能,结果表明：反硝化的适宜温度为30—40℃,35℃时的效果最佳;pH值为7．7～8．2时对硝酸盐的降解速率最快,随着pH值的升高,逐渐产生亚硝酸盐的积累,pH〈6．3或pH〉9．2时反硝化基本停滞;当硝酸盐〈100mg／L时,反应24h后对总氮的去除率〉95％,而当硝酸盐〉120mg／L时则会抑制反硝化过程;此外,随着硝酸盐的降解,菌体浓度和pH值都呈缓慢上升趋势。     

Comparison of two partially activated carbon fabrics for the removal of chlorine and other impurities from water

Experimental studies were undertaken at the University of Birmingham to investigate and compare the use of two partially activated carbon fabrics for the removal of chlorine and other impurities from potable water in domestic point-of-use water filters. Since the implementation of the EEC drinking water quality directive in July 1985, there has been a marketing surge in domestic water filters, generally aimed at improving taste (the taste of chlorine is frequently cited). The fabrics were observed to be very effective at removing chlorine from water; their dechlorinating powers were significantly superior to that of the granular activated carbon used for comparison. The fabrics were observed to be much less effective at removing phenol, methylene blue and colour.     

Metal ions removal from wastewater or washing water from contaminated soil by ultrafiltration-complexation

In the present paper a process for removal of ions from wastewater or from washing water of contaminated soil by using the weakly basic water-soluble polymer polyethylenimine (PEI) as chelating agent and the Cu(2+) ion as model in combination with an ultrafiltration process was investigated. The complexing agent was preliminarily tested to establish the best operative conditions of the process. Next, ultrafiltration tests by using five different membranes were realised to check membrane performance like flux and rejection. Finally, the possibility for recovering and recycling the polymer was tested in order to obtain an economically sustainable process. Obtained results showed that complexation conditions depends on pH: indeed, at a pH>6 PEI-Cu(2+) complexes are formed, while at pH<3 the decomplexation reaction takes place. Saturation condition is 0.333 mg Cu(2+)/mg PEI, meaning a ratio PEI/Cu(2+)=3(w/w). UF tests showed good results using the PAN 40 kDa membrane reaching an average copper concentration in the permeate of 2 mg/l and a flux of 135.4 and 156.5l/h.m(2) at 2 and 4 bar, respectively. Metal rejection, permeate flow rate, and possibility to regenerating and recycling the polymer makes the polymer-assisted ultrafiltration process (PAUF) very interesting for metal ion removal from waters.     

阴离子交换膜生物反应器反硝化性能的研究

考察了进水硝酸盐浓度对阴离子交换膜生物反应器反硝化性能的影响。试验结果表明,当进水NO3-为47.01～168.55mg/L时,流动池出水中的NO3-N浓度满足我国生活饮用水水质标准中小于10mg/L的要求(NO3-≤44.29mg/L)。厌氧生物反应器对硝酸盐具有较高的反硝化性能。流动池出水中的Cl-浓度随着进水NO3-浓度的增加而升高,但出水pH值稳定在6.8左右。出水总有机碳浓度与进水的保持一致,表明其未受到"二次污染"和"微生物污染"。     

Operating Experiences of Full-Scale Biological and Ion-Exchange Denitrification Plants in France

I n F rance , nitrate removal by biological means was authorized in 1981 and by ion exchange in 1985. To date, four installations use the biological process and six plants incorporate ion-exchange techniques. Details of the plant are explained. The first conclusions can now be drawn from the results of the startup period as well as from operation. The existing facilities produce water in compliance with laid-down regulations, and in a reliable manner throughout the year. The average capital costs of all the French facilities are given, together with typical operational costs.     

地下含水层储能和地下水源热泵系统中地下水回路与回灌技术现状

介绍了国内外有关技术发展现状及存在的一些技术和环境问题。就地质条件、回灌方式、地下水灌抽比、回扬和洗井次数等指标,比较了目前国内和荷兰的技术差异。指出解决地下水回灌的堵塞问题是地下含水层储能和地下水源热泵技术得以发展的关键。强调为避免出现地面沉降和地下水质污染等问题,必须采用回灌技术和密闭系统。对政府今后的管理工作提出了一些建议。     

Organic arsenic removal from drinking water

Arsenic occurs in both inorganic and organic forms in water. Although various methods have been adopted to remove inorganic species of arsenic from drinking water, not much emphasis has been given to the removal of organic species of arsenic. In the present study column studies were conducted using manganese greensand (MGS), iron oxide-coated sand (IOCS-1 and IOCS-2) and ion exchange resin in Fe³⁺ form, to examine the removal of organic arsenic (dimethylarsinate) spiked to required concentrations in tap water. Batch studies were conducted with IOCS-2, and the results showed that the organic arsenic adsorption capacity was 8 μg/g IOCS-2. Higher bed volumes (585 BV) and high arsenic removal capacity (5.7 μg/cm³) were achieved by the ion exchange resin among all the media studied. Poor performance was observed with MGS and IOCS-1.     

Hybrid anion exchanger for trace phosphate removal from water and wastewater

Throughout recent decades, the wastewater treatment industry has identified the discharge of nutrients, including phosphates and nitrates, into waterways as a risk to natural environments due to the serious effects of eutrophication. For this reason, new tertiary treatment processes have abounded; these processes generally utilize physico-chemical and biological methods to remove nutrients from secondary wastewaters. The disadvantages of such methods involve larger reactor volumes, operating costs, and waste sludge production; furthermore, complete nutrient removal is unattainable due to thermodynamic and kinetic limitations. The subject study presents the development and performance of a new phosphate-selective sorbent, referred to as hybrid anion exchanger or HAIX. HAIX combines durability and mechanical strength of polymeric anion exchange resins with high sorption affinity of hydrated ferric oxide (HFO) toward phosphate. HAIX is essentially a polymeric anion exchanger within which HFO nanoparticles have been dispersed irreversibly. Laboratory studies show that HAIX selectively removes phosphate from the background of much higher concentrations of competing sulfate, chloride and bicarbonate anions due to the combined presence of Coulombic and Lewis acid-base interactions. Experimental results demonstrate that HAIX's phosphate-sulfate separation factor is over two orders of magnitude greater than that of currently available commercial ion exchange resins. Additionally, optimal HAIX performance occurs at typical secondary wastewater pH conditions i.e., around 7.5. HAIX is amenable to efficient regeneration and reuse with no noticeable loss in capacity.     

Rapid column-mode removal of arsenate from water by crosslinked poly(allylamine) resin

Performances of crosslinked poly(allylamine) resin (PAA) as arsenate (As(V)) adsorbent were studied using a column packed with PAA in hydrochloride form. PAA has a high amino group content of 14.6 mmol/g in free amine form and a high chloride content of 10.2 mmol/g in hydrochloride form. Its wet volumes in water were 4.5 and 3.1 mL/g in hydrochloride and free amine forms, respectively, indicating its high hydrophilicity. Breakthrough capacities for As(V) were evaluated changing conditions of adsorption operations: pH of feeds from 2.2 to 7.0, concentration of As(V) in feeds from 0.020 to 2.0 mM, and feed flow rate from 250 to 4000 h⁻¹ in space velocity. Breakthrough capacities increased from 2.6 to 3.4 mmol/g with a decrease in pH from 7.0 and 2.2, and also from 0.81 to 2.8 mmol/g with an increase in As(V) concentration from 0.020 to 2.0 mM. When feed flow rate increased from 250 to 4000 h⁻¹, breakthrough capacities changed form 3.5 to 0.81 mmol/g. Because of non-Hofmeister anion selectivity behavior of PAA, the interference of chloride and nitrate was minor. Although PAA slightly preferred As(V) to sulfate, the latter more markedly interfered with uptake of As(V) than chloride and nitrate. Competitive uptake of As(V) and phosphate revealed that PAA slightly preferred phosphate to As(V). The adsorbed As(V) was quantitatively eluted with 2 M HCl and PAA was simultaneously regenerated into hydrochloride form. All results were obtained using the same column without change of the packed PAA and any deterioration in column performances for 4 months.     

Column-mode phosphate removal by a novel highly selective adsorbent

A phosphoric acid resin RGP was immobilized with zirconium(IV) (Zr(IV)) to investigate its applicability in phosphate removal. When loaded with Zr(IV), RGP was changed into an effective ligand exchanger with phosphate sorption capacity of 0.345 mmol/ml. Little metal leakage was observed. Breakthrough of phosphate sorption depended on solution acidity and phosphate concentration. An increase of solution pH greatly suppressed phosphate removal, but even at pH 8.21, about 56% of the added phosphate (2.8mM) in the feed solution could still be sorbed. Electrolytes in the aqueous solution did not interfere with phosphate sorption; on the contrary, an enhancement effect was observed. Due to the high sorption capacity of Zr(IV)-loaded RGP, low concentration of phosphate can be removed at high flow rate (100 h(-1) in space velocity). The sorbed phosphate on the Zr(IV)-loaded RGP could be quantitatively eluted with 0.5M sodium hydroxide solution. The Zr(IV)-loaded RGP is a promising ligand exchanger for treating wastewater containing trace amounts of inorganic phosphate.     

Enhanced trace phosphate removal from water by zirconium(IV) loaded fibrous adsorbent

This study was investigated for the trace phosphate removal at high feed flow rate by ligand exchange fibrous adsorbent. The zirconium(IV) loaded bifunctional fibers containing both phosphonate and sulfonate were used as a highly selective ligand exchange adsorbent for trace phosphate removal from water. The precursory fiber of the bifunctional fibers was co-grafted by polymerization of chloromethylstyrene and styrene onto polyethylene coated polypropylene fiber and then bifunctional fibers were prepared by Arbusov reaction followed by phosphorylation and sulfonation. Phosphate adsorption experimental work was carried out in column approach. Phosphate adsorption increased with decreasing the pH of feed solutions. An increase in the feeds flow rate brings a decrease in both breakthrough capacity and total adsorption. The effect of competing anions on phosphate adsorption systems was investigated. The experimental findings reveal that the phosphate adsorption was not affected in the presence of competing anions such as chloride and sulfate despite the enhancement of the breakthrough points and total adsorption. Due to high selectivity to phosphate species, low concentration level of phosphate (0.22 mg/L) was removed at high feed flow rate of 450 h⁻¹ in space velocity. The adsorbed phosphate on the Zr(IV) loaded fibrous column was quantitatively eluted with 0.1 M NaOH solution and then the column was regenerated by 0.5 M H₂SO₄ for the next adsorption operation. During many adsorption-elution-regeneration cycles, no measurable Zr(IV) was found in the column effluents. Therefore, the Zr(IV) loaded bifunctional fibrous adsorbent is to be an effective means to treat wastewater to prevent eutrophication in the receiving water bodies for long time without any deterioration.