Synergistic coagulation of bauxite residue-based polyaluminum ferric chloride for dyeing wastewater treatment

Considering that Fe,Al elements in bauxite residue are active components for water purification,an effective polyaluminum ferric chloride(PAFC)coagulant derived from bauxite residue,with Fe2O3 content>5.1%,Al2O3%>6.5%,basicity>65%,was successfully prepared.The effect of as-prepared PAFC on the zeta potential for printing and dyeing wastewater was investigated.Comparing with polyferric chloride(PFC)and polyferric sulfate(PFS)for printing and dyeing wastewater treatment,prepared bauxite residue-based PAFC exhibited the optimal performance in the aspects of chromaticity and chemical oxygen demand(COD)removal rate.Furthermore,the combination of bauxite residue-based PAFC and PFS for synergy coagulation of such wastewater demonstrated an obvious positive effect.With the proportion between as-prepared PAFC and PFS to be 2.5:1,the COD of treated wastewater could be further reduced to meet the national level A standard of China,providing a promising route to solve the problem of substandard printing and dyeing sewage outfall by a simple coagulation strategy.

Life cycle assessment of high concentration organic wastewater treatment by catalytic wet air oxidation

There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in catalytic wet air oxidation(CWAO).There are no cases of using actual industrialized data onto life cycle assessment.This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO,and comprehensively explains the impact on the environment from three aspects:the construction phase,the operation phase and the demolition phase.In addition,sensitivity analysis and uncertainty analysis were performed.The results showed that the key factors affecting the environment were marine ecotoxicity,mineral resource consumption and global warming,the operation stage had the greatest impact on the environment,which was related to high power consumption during operation and emissions from the treatment process.Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity,and it also proved that global warming is mainly caused by pollutant emissions during operation phase.Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.

Experimental Study on Treatment of High-concentrated Sulfur Wastewater by Process of Depositing Natrojarosite and Its Environmental Significance

High-concentrated sulfur wastewater with sodium and COD （chemical oxygen demand） up to 26000 mg/L from a chemical plant, Jiangsu Province of China has been treated by deposition of natrojarosite in lab. The results indicated that the COD of the wastewater was decreased sharply from 26000 mg/L to 1001 mg/L, with removal rate of COD up to 96% by twice precipitations of natrojarosite and twice oxidation of H202. The treated sulfur wastewater reached the requirement of subsequent biochemical treatment to water quality. The optimal operational parameters should be controlled on pH value between 2.50 and 3.20 and 50 g FeCly6H2O solid added in per liter wastewater. The study provided an experimental basis for pretreatment of high-concentrated sulfur wastewater and proposed a new mineralogical method on treatment of other wastewaters. Depositing process of jarosite and its analogs should be able to be used to treat wastewater from mine and other industries to remove S, Fe and other toxic and harmful elements, such as As, Cr, Hg, Pb, etc. in the water.

Development of an evaporation crystallizer for desalination of alkaline organic wastewater before incineration

A wastewater evaporation-desalination pretreatment method was introduced to remove the Na+ and K+ salts in volatile organic compounds (VOCs) wastewater before it was fed into the incinerator. VOCs in the wastewater were volatilized in the evaporation system and then the vapor was combusted in an incinerator. Simulated phenol wastewater containing sodium chloride was evaporated and concentrated and sodium chloride was crystallized in different parameters. The experimental results showed that the higher initial concentration of sodium chloride increases the ratio of volatilization of VOCs, which was due to the effect of “salting out” (a decrease in the solubility of the nonelectrolyte in the solution, or more rigorously, an increase in its activity coef-ficient, caused by the salt addition (Furter and Cook, 1967)). When evaporation speed was increased from 1.67 ml/min to 2.73 ml/min, the total removal coefficient of sodium chloride was about 99.88%～99.99%. This pretreatment procedure eliminates the slag phenomenon caused by Na+ and K+ salts during wastewater incineration, so the incinerator could operate continuously, and the wastewater evaporation could increase the heat value of wastewater, and the operation cost would be reduced.

Effect of Ferric Chloride on the Properties of Biological Sludge in Co-precipitation Phosphorus Removal Process

This paper studied the effect of ferric chloride on waste sludge digestion,dewatering and sedimentation under the optimized doses in co-precipitation phosphorus removal process.The experimental results showed that the concentration of mixed liquid suspended solid(MLSS) was 2436 mg.L-1 and 2385 mg.L-1 in co-precipitation phosphorus removal process(CPR) and biological phosphorous removal process(BPR),respectively.The sludge reduction ratio for each process was 22.6% and 24.6% in aerobic digestion,and 27.6% and 29.9% in anaerobic digestion,respectively.Due to the addition of chemical to the end of aeration tank,the sludge content of CPR was slightly higher than that of BPR,but the sludge reduction rate for both processes had no distinct difference.The sludge volume index(SVI) and sludge specific resistance of BPR were 126 ml.g-1 and 11.7×1012 m.kg-1,respectively,while those of CPR were only 98 ml.g-1 and 7.1×1012 m.kg-1,indicating that CPR chemical could improve sludge settling and dewatering.

Treatment of sauce wastewater by sequencing biological -chemical reactor (SBCR)

The concept of SBCR was put forward to treat sauce wastewater. Further study showed that adding appropriate amount of calcium chloride to SBR can improve the quality of effluent. The removal rate of COD and color was 84% and 80%, 36%, 96% higher than those of traditional SBR respectively. The results of continuous experiments and biophase observing showed that calcium chloride accumulation increased the sludge production slightly while the sludge dewatering characteristic was improved.

Pretreatment of Wastewater Streams from Petroleum/Petrochemical Industries Using Coagulation

Coagulation-flocculation processes using different types of conventional coagulants, namely, ferric chloride (FeCl3), aluminum sulfate (AL2(SO4)3·18H2O), lime and ferrous sulfate (FeSO4) were investigated using the Jar-test technique. A further aim is to determine the optimum conditions for the treatment of industrial wastewater effluents i.e. coagulant dosage, mixing rate, temperature and pH control. Under optimal condition of process parameters, coagulation/flocculation process was able to lower the turbidity well below the permissible level (1.8 NTU). The results indicate that ferric chloride had superior efficiency compared with other coagulants with efficient dose of 800 mg/l. The optimal initial pH of the effluents that enhanced the turbidity removal was 8.6. The temperature showed no significant effect on the turbidity removal.

赤泥用于酸性含锰废水中锰的净化研究

采用还原焙烧-磁选预处理赤泥,得到非磁性物;非磁性物经煅烧、盐酸溶出后加入饱和偏铝酸钠聚合剂聚合后过滤、熟化制备聚合氯化铝(PAC)基液;使用该PAC基液,在沉降时间5 h、PAC基液与废水体积比1∶120、搅拌转速140 r/min、pH值8、反应温度30℃、聚丙烯酰胺(PAM)投加量20 mg/L条件下处理含锰酸性废水,处理后液中锰质量浓度由325.3 mg/L降至1.5 mg/L,锰去除率达99.5%,净化后液中锰质量浓度达到国家一级排放标准。

絮凝-电化学氧化协同工艺处理兰炭废水

采用絮凝-电化学氧化协同工艺处理兰炭废水,探究了反应过程中絮凝剂投加量、反应时间、初始pH值、外加电压以及NaCl添加量对化学需氧量(COD)和氨氮(NH_(3)-N)去除的影响及絮凝-电化学氧化协同作用机制.结果表明,随着絮凝剂聚合氯化铝铁(PAFC)投加量和外加电压的增加,兰炭废水中COD和NH_(3)-N的去除率逐渐升高.当PAFC投加量为50g/L、电压6V、反应时间4h,初始pH=9,NaCl添加量30g/L时,COD和NH_(3)-N去除率分别为82.37%和100%,更换极板进行二次电解COD去除率可达100%.兰炭废水中有机污染物主要是苯酚类､醇类和酰胺类物质,处理后酚类物质含量大幅减少,酮类、醇类和酸类物质相对占比有所增加.絮凝-电化学氧化过程中,PAFC既是絮凝剂又是Cl^(-)的提供者,其水解产生的Cl^(-)与NaCl引入的Cl^(-)在电场作用下向阳极定向迁移.阳极表面发生氧化反应产生的有效氯(Cl_(2)/ClO^(-))将兰炭废水中有机污染物氧化成中间产物氯酚,与絮凝剂中Al^(3+)的水解产物Al(OH)^(2+)、Al(OH)^(+)_(2)及Al(OH)_(3)通过静电和吸附作用结合形成絮凝体被去除.废水中剩余少量的氯酚及酰胺、环己二醇等有机污染物及NH_(3)-N则在ClO^(-)的间接氧化作用下转化为N_(2)、CO_(2)和H_(2)O得以去除.

枣树枝改性生物炭对水溶液中锌离子的吸附性能研究

通过水热碳化枣树枝生成水热炭,以氯化锌为活化剂对水热炭进行活化,得到枣树枝改性生物炭,所得生物炭表面具有丰富的孔结构及高度芳香化结构。以枣树枝改性生物炭为吸附剂吸附溶液中Zn^(2+),在吸附时间80 min、溶液pH=9、改性生物炭投加量700 mg/L、反应温度55℃、Zn^(2+)初始浓度30 mg/L条件下,Zn^(2+)去除率达到99%以上;吸附过程与Freundlich吸附模型拟合度高,表明改性生物炭对Zn^(2+)的吸附过程为多层分子吸附;改性生物炭经5次循环吸附与解吸后,对Zn^(2+)去除率仍在97%以上。

炼厂污水臭氧处理系统的腐蚀特性与选材研究

针对炼厂污水臭氧处理系统长周期运行过程中,设备及管道存在跑冒滴漏现象,尤其是在管道的焊缝热影响区腐蚀尤为严重的问题,采用电化学试验、模拟浸泡试验和现场腐蚀评价试验,研究臭氧浓度和氯离子浓度对腐蚀速率的影响,明确不同金属材料在臭氧和污水环境中的耐蚀性能,并给出了推荐选材方案。结果表明,在炼厂高氯污水和臭氧环境中,022Cr17Ni12Mo2的点蚀敏感性与臭氧浓度和氯离子浓度呈正相关,且两因素之间存在协同腐蚀作用;Q245R,022Cr19Ni10,022Cr17Ni12Mo2材料在该环境下的耐蚀性能相对较差;022Cr19Ni13Mo3,015Cr21Ni26Mo5Cu2,022Cr23Ni5Mo3N,015Cr20Ni18Mo6CuN等材料则表现出良好的抗点蚀及缝隙腐蚀能力。建议炼厂污水臭氧处理系统主要设备和管道的选材以022Cr19Ni13Mo3为主。

响应面优化超高石灰铝工艺去除高氯废水中的氯离子

以工业生产产生的高氯废水为试验对象,采用超高石灰铝(UHLA)工艺去除高氯废水中的氯离子(Cl^(-)),根据单因素结果,以Cl^(-)去除率为响应值,采用Box-Behnken中心组合试验优化工艺参数。结果表明,钙氯摩尔比对Cl^(-)去除率有极显著的影响,温度对Cl^(-)去除率具有显著影响,而铝氯摩尔比对Cl^(-)去除率无显著影响,影响程度由大到小依次为钙氯摩尔比、温度、铝氯摩尔比;UHLA工艺去除高氯废水中Cl^(-)的最佳工艺参数为n(Ca)∶n(Al)∶n(Cl)=5.4∶2.9∶1.0,反应温度为25.5℃,理论的Cl^(-)去除率可达90.56%;采用模拟废水对最优工艺进行横向验证,模拟废水中Cl^(-)去除率为97.85%,显著高于工业高氯废水;采用ICP-MS分析UHLA工艺处理前后高氯废水中的元素变化,发现UHLA工艺能有效去除阴离子如SO_(4)^(2-)、SO_(3)^(2-)、I^(-)等及重金属离子如Sr^(2+)、Cr^(3+)、Zn^(2+)等。

化学混凝沉淀法处理含氟废水研究

文章采用氯化钙、氯化钙-聚合氯化铝(PAC)处理氟离子浓度为95 mg/L的废水,考察氯化钙投加量、PAC投加量对氟离子去除率的影响,出水浊度随沉淀时间的变化,进水pH对氯化钙-PAC除氟的影响。实验结果表明,氯化钙-PAC处理效果优于氯化钙单独处理效果,进水最佳pH值为7,最佳Ca/F(物质的量比)为0.9,PAC(10%)最佳投加量为每升水样6.0 mL。在此条件下,出水残余氟离子浓度为8.6 mg/L,出水浊度为2 NTU,处理1吨水的药剂费为2.7元。

聚合氯化铝-聚丙烯酰胺处理含氟废水研究

使用聚合氯化铝(PAC)-聚丙烯酰胺(PAM)联合处理含氟废水,考察了PAC投加量、PAM浓度、pH值、反应时间以及搅拌速度对除氟效果的影响。结果表明,在PAC投加量4400 mg/L、PAM浓度1 mg/L、溶液pH值7.0、反应时间20 min、搅拌速度300 r/min时,氟去除率达97.98%,除氟后溶液中氟离子残余浓度为0.81 mg/L。溶液中杂质离子的存在会降低PAC的除氟性能。

响应面法优化焦化废水生化尾水混凝药剂投加量研究

采用聚合氯化铝(PAC)+聚丙烯酰胺(PAM)混凝处理焦化废水生化尾水,通过单因素实验考察了混凝剂PAC、PAM投加量对混凝处理效果的影响。基于单因素实验开展响应面混凝实验,构建PAC、PAM投加量为自变量,出水残留浊度和出水过余电导率组成的加药控制系数为响应量的数学模型并对其参数进行了响应面优化。结果表明,混凝处理最佳药剂投加量PAC为2546.96 mg/L,PAM为10.90 mg/L,此条件下出水平均浊度残留率为4.24%、电导率过余率为2.77%、加药控制系数为7.01,与模型预测值相对误差<5%,进一步证明该响应面模型合理有效,对同时实现处理过程混凝充分反应和盐分有效控制具有指导作用,并可为相关自动化加药模型开发提供思路。

自动监测技术分析聚氯乙烯生产废水的处理方法

聚氯乙烯是工业领域应用最为广泛的树脂材料之一,但其在生产过程中会产生大量含有难降解的高浓度有机物的废水,直接排放到自然界后会对生态环境造成严重污染,因而要充分发挥现代技术优势,对聚氯乙烯生产废水进行无害化处理。废水自动监测技术在聚氯乙烯生产废水处理中的应用,为废水处理工艺的优化和改进提供了有力支持,也提高了废水处理效率和效果。基于废水自动监测技术,利用聚氯乙烯废水的混凝成沉淀法、生化处理和膜处理方法对聚氯乙烯生产废水进行监测,能够有效提升聚氯乙烯废水处理效果,降低污染物排放量,改善生态环境质量。

聚氯乙烯膜在废水处理中的研究进展

在众多聚合物材料中,聚氯乙烯(PVC)因其较低的成本和优异的性能被用作制备膜材料并广泛应用于废水处理等领域。然而,由于PVC膜具有一定的疏水性,导致废水中的大分子和生物分子(如多聚糖蛋白质)、盐和胶体容易在膜表面和孔隙上吸附或沉积,出现结垢现象,从而影响膜分离性能。因此,改善PVC膜的亲水性和抗污染性能是提高其应用前景的关键。本文重点论述了近几年提升PVC膜亲水性能的有效方法和研究进展。

基于浊度法的贵金属合金电镀废水中氯离子含量的测定

目前,对于贵金属合金电镀废水中氯离子含量的测定,国内、国外还没有专门的标准。研究建立了一种基于浊度法的贵金属合金电镀废水中氯离子含量的测定方法。通过对一系列条件实验的研究,确定了选择无水乙醇作为分散剂,亚硫酸钠加入量为10 mL,加热温度为70℃,加热时间为8 min,并在此条件下进行了准确度和精密度实验。本方法加标回收率为98.67%~102.00%,重复性相对标准偏差为0.23%~2.68%。

脱硫废水热烟气蒸发过程中氯离子的释放机理研究

脱硫废水的气化特征及过程中挥发性组分的迁移转化是实现其零排的关键,但目前对其的认识仅停留在宏观层面,缺少相应的量化研究。此次研究探讨了脱硫废水水滴蒸发过程和蒸发工艺条件、脱硫废水特性、氯离子释放机制和影响因素。研究旨在揭示脱硫废水热烟气蒸发过程中氯离子释放规律,以期为脱硫废水热烟气蒸发技术的推广应用、抑制二次污染提供理论与数据支持。此次研究利用仿真试验,对氯的释放机理进行了探讨;同时,还讨论了温度、酸碱度等因素对氯离子释放性能的影响。研究发现,氯离子的释放呈现出一定的阶段性;当温度升高时,水的电离和氯化物的水解将加速氯的析出;pH值越高,对HCl的产生有抑制作用。

钌铱电极与BDD电极处理以氯化钠为电解质的染料废水的对比研究

本文以钌铱电极和BDD电极为研究对象,以氯化钠为电解质,考察了两种电极对染料废水中难降解有机物的去除差异,研究电流密度、pH值和氯化钠浓度对染料去除的影响,探究染料降解过程中的自由基贡献。结果表明:钌铱电极和BDD电极均能有效去除染料,但BDD电极的效率更高。最适宜的去除条件为电流密度为10mA/cm^(2)、pH值为5和氯化钠浓度为2g/L,此条件下反应速率常数可达2.964min^(-1)。·OH被证实对污染物的去除贡献最大。