Potable water treatment for some asbestiform minerals: optimization and turbidity data

A study has been undertaken to optimize conventional alum coagulation treatment of water for asbestos fibre removal. The results indicate that both the alum and polyelectrolyte concentrations significantly effect the quality of the treated water. Optimum results were obtained with alum concentrations of 30–50 ppm and polyelectrolyte concentrations of 0.3–0.6 ppm. Rapid coagulation/direct filtration has been evaluated and the results found to be comparable to conventional treatment employing flocculation and sedimentation. A survey of turbidities and fibre concentrations for several municipal water supplies indicate that no systematic relationship exists between these two parameters.     

强化常规工艺处理黄河原水的试验研究

天津在冬季、经长距离调用的黄河原水水质具有低温、低浊、微污染的特点，采用常规工艺处理时出水CODMn很难满足《城市供水水质标准》（CJ／T206-2005）的要求，为此开展了强化常规工艺的试验研究。结果表明，通过采取臭氧预氧化或高锰酸盐复合药剂（PPC）预氧化、高效絮凝刺HPAC强化混凝气浮、改性滤料强化过滤等措施，可显著改善常规工艺的出水水质，对有机物的去除率提高了10％以上，出水CODMn〈3mg／L。臭氧（或PPC）预氧化、HPAC混凝气浮、改性滤料过滤是改善常规工艺出水水质的有效手段。     

微砂强化混凝工艺处理微污染水库水研究

根据鹊山水库水低浊、微污染和高藻的水质特点，采用微砂强化混凝工艺对其进行处理，结果表明：微砂强化混凝的效果优于常规混凝，可使沉淀出水水质得到显著提高。当微砂、FeCl3及PAM的投量分别为1000、30、0．5mg／L时，沉淀出水浊度〈0．78NTU，色度〈2倍，对藻类、TOC、CODMn、UV254的去除率分别可达92．6％、85．6％、67．8％和68．8％以上，该方法为处理该水库水的工艺选择提供了泰者。     

BAF用作混凝沉淀工艺预处理单元的研究

采用传统的混凝、沉淀、过滤工艺处理有机污染比较严重的城市河流原水时．出水水质难以令人满意，且混凝剂投量较高。为此，考察了曝气生物滤池（BAF）作为混凝、沉淀工艺预处理单元的可行性。研究结果表明，在投药量相同的情况下，BAF-混凝沉淀工艺出水的浊度和CODMn比单独混凝沉淀工艺低得多；由于BAF能导致水中有机污染物的成分（或性质）发生改变，因而提高了混凝沉淀工段的除污效果；组合工艺对CODMn的去除率〉70％，并有效降低了混凝剂的投量。     

Laboratory study of electro-coagulation-flotation for water treatment

An electro-coagulation-flotation process has been developed for water treatment. This involved an electrolytic reactor with aluminium electrodes and a separation/flotation tank. The water to be treated passed through the reactor and was subjected to coagulation/flotation, by Al(III) ions dissolved from the electrodes, the resulting flocs floating after being captured by hydrogen gas bubbles generated at cathode surfaces. Apparent current efficiencies for Al dissolution as aqueous Al(III) species at pH 6.5 and 7.8 were greater than unity. This was due to additional reactions occurring in parallel with Al dissolution: oxygen reduction at anodes and cathodes, and hydrogen evolution at cathodes, resulting in net (i.e. oxidation + reduction) currents at both anodes and cathodes. The specific electrical energy consumption of the reactor for drinking water treatment was as low as 20 kWh (kg Al)(-1) for current densities of 10-20A m(-2). The water treatment performance of the electrocoagulation process was found to be superior to that of conventional coagulation with aluminium sulphate for treating a model-coloured water, with 20% more dissolved organic carbon (DOC) being removed for the same Al(III) dose. However, for a lowland surface water sample, the two processes achieved a similar performance for DOC and UV-absorbance removal. In addition, an up-flow electrocoagulator configuration performed better than a horizontal flow configuration, with both bipolar and monopolar electrodes.     

沸石生物滤池/混凝沉淀/超滤工艺处理微污染源水

微污染源水中的污染物以有机物和氨氮为主,采用传统工艺处理时其出水水质难以达到《生活饮用水卫生标准》(GB 5749—2006)的要求。将沸石作为生物滤池的填料,与混凝沉淀、超滤组合后用于处理微污染地表水,考察了其对污染物的去除效果。结果表明:该组合工艺对氨氮有较好的去除效果,出水氨氮在0.5 mg/L以下,去除率可达90%;对有机物也有较好的去除效果,出水CODMn在2 mg/L左右,去除率约为60%,出水水质达到了《生活饮用水卫生标准》(GB 5749—2006)的要求。该工艺对氨氮的去除主要由沸石生物滤池完成,而沸石生物滤池、混凝沉淀及超滤均能去除CODMn,贡献率分别为49.6%、30.9%、19.5%。     

Adsorption/complexation of organic micropollutants to aquatic humus influence of aquatic humus with time on organic pollutants and comparison of two analytical methods for analysing organic pollutants in humus water

In a laboratory study the influence of aquatic humus with time on low concentrations of alkanes, polycyclic aromatic hydrocarbons (PAH) and chlorinated hydrocarbons have been investigated. The feasibility of a liquid/liquid extraction method and a resin (XAD-2) adsorption method for analysing these pollutants in humus water has also been studied.The interaction between the organic pollutants and the humus were found to vary considerably between different classes of compounds as well as between compounds of the same class.None of the two analytical methods investigated were found feasible for determining the total amount of organic pollutants present in humus water.     

生物破乳剂对油田采出水处理系统的影响

从新疆克拉玛依油田某采油井附近长期受石油污染的土壤中筛选得到了生物破乳剂——TR-1，研究了该生物破乳剂对油田采出水处理系统的影响。结果表明，与化学破乳剂脱出水相比，生物破乳剂脱出水的COD浓度较低，而SS浓度较高。对排放系统而言，使用生物破乳剂具有优势，可使混齑乏／过滤工艺出水的COD降至150mg／L左右，同时其可生化性相对较好，再经生物法处理后有望实现达标排放；而化学破乳剂脱出水经混凝／过滤工艺处理后，其COD浓度仍维持在350mg／L以上。对回注系统而言，生物破乳剂脱出水无硫酸锶结垢趋势，对挂片的腐蚀速率也远低于化学破乳剂脱出水。该生物破乳剂有较好的应用前景。     

Disinfection of water by electrochemical treatment

Natural water, highly contaminated with coliforms, was electrochemically treated in a stirred batch system with the use of two Ti electrodes and direct current, the polarity of which alternated automatically in half cycles of 1 min. The process was found to be effective and the percentage of the initial concentration of bacteria which were destroyed was found to be proportional to both treatment time and the square of current density obeying the kinetic model = ki² t; consequently the time needed for complete disinfection was inversely proportional to the square of current density. The percentage above was found to be independent of the initial concentration of germs at least for the range of concentrations employed. The residual disinfection capacity, after completion of the electrochemical treatment, was also verified by mixing electrochemically treated, disinfected natural water with contaminated water.     

化学沉淀法强化常规工艺去除水中镍的应急处理

以模拟遭受突发性镍污染的水体为研究对象,考察了化学沉淀法强化常规水处理工艺对镍污染原水的应急处理效果.结果表明,该方法能有效去除饮用水水源中的镍,可作为突发性饮用水水源镍污染的应急处理措施;pH对除镍效果有较大影响,故在水厂现有常规工艺基础上,通过调整混凝前原水的pH值,保证滤后水的pH值在9.0以上,即可使出厂水水质满足《生活饮用水卫生标准》(GB 5749-2006)要求;聚合氯化铝在高pH值条件下存在铝超标风险,故化学沉淀法除镍时宜选用三氯化铁作为混凝剂.     

Occurrence and removal of pharmaceuticals and hormones through drinking water treatment

The occurrence of fifty-five pharmaceuticals, hormones and metabolites in raw waters used for drinking water production and their removal through a drinking water treatment were studied. Thirty-five out of fifty-five drugs were detected in the raw water at the facility intake with concentrations up to 1200 ng/L. The behavior of the compounds was studied at each step: prechlorination, coagulation, sand filtration, ozonation, granular activated carbon filtration and post-chlorination; showing that the complete treatment accounted for the complete removal of all the compounds detected in raw waters except for five of them. Phenytoin, atenolol and hydrochlorothiazide were the three pharmaceuticals most frequently found in finished waters at concentrations about 10 ng/L. Sotalol and carbamazepine epoxide were found in less than a half of the samples at lower concentrations, above 2 ng/L. However despite their persistence, the removals of these five pharmaceuticals were higher than 95%.     

Importance of speciation methods in analytical control of water treatment processes with application to fluoride removal from waste waters

Analytical methods of speciation for the control of water treatment processes, particularly for the removal of fluoride by aluminium hydroxide polymers as precipitant, have been discussed. It has been shown that combination of ultrafiltration with spectroscopic methods and fluoride ion-selective electrode offers a powerful means for the control of both the precipitant and pollutant, e.g. fluoride. ²⁷Al n.m.r. has been used for the identification of hydrolytic products of aluminium(III) and the ultrafiltration technique has been applied for the separation of the active polymer. The hydrolytic products were also characterized by timed spectrometric method. The interaction between aluminium hydroxide polymer and fluoride was studied by means of fluoride ion-selective electrode, ultrafiltration and atomic absorption spectrometry. The usefulness of these speciation methods for choosing the best conditions for water treatment process is discussed. By applying them for the removal of fluoride, it was found that the fluoride levels can be brought down to less than 10 mg l^?1, the limit set by Swiss regulatory body for discharge of waste water. The importance of using such speciation methods for evaluating the possible impact of the “products” of the water treatment (dissolved species in treated water, discharged solid) is also emphasized.     

Using a geotextile with flocculated filter backwash water and its impact on aluminium concentrations

The use of geotextiles (i.e. geotextile tubes) in wastewater treatment applications is ever increasing. This paper examines the potential of using a geotextile to improve upon the treatment of aluminium present in a filter backwash water that is generated from a water treatment plant in Halifax, Canada. A field investigation to ascertain the distribution of aluminium in the filter backwash water treatment process is provided and compared to regulatory guidelines at the environmental compliance point. It is shown that aluminium is undergoing incomplete treatment at various times throughout the year. To examine a potential corrective action, the results of bench scale studies are presented in which cationic additives (i.e. CaO, MgO, and Fe₃O₄) are combined with a polymer to remove aluminium from solution and flocculate particulate matter from the filter backwash water. A geotextile is utilized to retain particulate matter generated from this process. It is shown that the combined use of the cationic additive with polymer can successfully reduce aluminium concentrations in the filter backwash water and that filtration via a geotextile can retain the aluminium particulate in the filter backwash water to levels close to regulatory requirements. Further optimization with the flocculation process is recommended prior to pilot testing.     

强化常规给水处理工艺研究

分析了辛安水厂原水水质问题及常规水处理工艺的运行效果,通过在常规混凝单元增加投药量、投加高锰酸盐复合药剂、预氯化以及在过滤单元投加助滤剂等强化措施,探讨了强化常规水处理工艺的运行效果。结果表明,通过各种强化措施可以提高常规水处理工艺对有机物和藻类的去除效果,进一步提高常规工艺的处理效能,保证出厂水水质满足《生活饮用水卫生标准》(GB 5749—2006)要求。     

不同条件下低温低浊水混凝试验研究

为了保证饮用水水质并实现节能降耗,宁夏宁东水厂采用调节原水pH值,投加高锰酸钾的方式来强化常规处理工艺。结果表明,调节pH值对于处理偏碱性的低温低浊水具有良好的净化效果。当原水pH值调节为中性时,混凝效果达到最优;适当使用聚丙烯酰胺可以优化混凝效果,但由于聚丙烯酰胺具有毒性,在实际运行中要慎重使用;高锰酸钾预氧化可有效提高低温低浊水的处理效果,对于提高冬季低温低浊水处理效果具有重要影响;通过滤池反冲洗水回流的方法．可以提高原水中颗粒物的数量．有助于提高水处理过程中颗粒碰撞效率,改善混凝效果。     

新型浮滤池处理微污染源水的研究

常规工艺对高藻、低浊微污染源水的处理效果较差,为了解决这个问题,将气浮与混凝、过滤技术相结合,开发出了一套新型浮滤池工艺（DAFF）,并以济南玉清湖水库水为处理对象进行中试,考察了对藻类及有机物的去除性能.试验结果表明：DAFF的处理效果明显优于常规工艺,对叶绿素a、高锰酸盐指数、UV254、浊度及氨氮的平均去除率分别为84.24%、59.76%、58.62%、85.2%、20.83%.该工艺结构紧凑、操作简便、占地面积小,适合新建的小水厂及老水厂的改造.     

强化混凝工艺处理滦河低温低浊水的试验研究

结合现有的中试试验系统,开展了强化混凝工艺的试验研究,结果表明,在该水质期,混凝剂PAC对浊度和CODMn的去除效果较优于混凝剂FeCl3;然而在满足出水浊度和CODMn要求的情况下,每处理单位水体PAC混凝药剂费用远高于FeCl3;使用NaSiO3与FeCl3混合液作为混凝剂时,适当增大混合液中NaSiO3的比例有利于提高常规工艺处理效率。     

Combined use of calcium salts and polymeric aluminium hydroxide for defluoridation of waste waters

The combined use of calcium salt and polymeric aluminium hydroxide, P, for treatment of fluoridated waste water has been described. In the proposed method of treatment the calcium ions acts as the precipitant and polymeric aluminium hydroxide as the coagulant. At low fluoride concentrations (2 × 10⁻³ M) the precipitation reaction of calcium fluoride is a slow process. The residual fluoride concentrations found experimentally approached the theoretically predicted values only at high calcium concentrations (| F | _t/ | Ca | _I molar ratio = 0.24) and for long equilibration times. The addition of calcium fluoride seeds (approx. 20 mg 1⁻¹) accelerated the precipitation process and the results obtained for the residual fluoride concentrations were close to the theoretically calculated ones regardless of the calcium ion concentration used. Under these conditions fine CaF₂ precipitate with poor settleability was formed. The addition of small amounts of polymeric aluminium hydroxide, P, (F/Al molar ratio = 10) greatly facilitates the settleability of the precipitate. The advantage of using P over alum for the removal of fluoride is that less concentration of the former is required and the reproducibility of the results are good. The effect of sulphate on the precipitation of calcium fluoride has been also studied. Tests with fluoride containing waste water collected from aluminium industry showed that fluoride can be effectively removed.     

混凝/气浮与混凝/沉淀工艺处理微污染原水的对比

采用混凝/气浮工艺代替混凝/沉淀工艺,进行了处理北方地区微污染原水的中试研究。中试装置由不锈钢制成,处理水量为120 m^3/d,通过连续运行对比了两系统对浊度、UV254、CODMn、TOC、藻类、THMFP等指标的去除效果。试验结果表明,与传统的混凝/沉淀工艺相比,混凝/气浮工艺具有运行稳定、除污效果好、药耗低等优点,适合处理北方地区的微污染原水。