强化混凝技术处理南淝河污染水的效果

选用聚合氯化铁(PFC)、聚合硫酸铁(PFS)、聚合氯化铝(PAC)和聚合氯化铝铁(PAFC)作为混凝剂;选用阳离子型聚丙烯酰胺(CPAM)、阴离子型聚丙烯酰胺(APAM)和非离子型聚丙烯酰胺(NPAM)作为助凝剂,通过室内试验对比研究强化混凝技术中多种混凝剂单用及其和助凝剂联用对南淝河污染水的除浊和去污效果,并用于南淝河现场构建的混凝沉淀系统。结果表明,4种混凝剂单用时,PAFC对浊度、TP去除效果最优,对CODMn有良好的去除效果,且不影响原水的p H值,而PFC和PFS单用时可明显降低原水p H值,4种混凝剂单用时对TN均没有明显去除效果;PAFC与CPAM联用时对浊度的去除效果最佳,明显优于PAFC与APAM和NPAM联用和PAFC单用的效果;混凝剂与CPAM联用提高了其除浊和去除TP的能力,但不能明显改善其去除CODMn的效果,对原水p H和TN的影响与单用时相同。选取"PAFC+CPAM"作为南淝河示范工程的混凝剂和助凝剂,现场混凝沉淀出水水质稳定,浊度和TP的去除效果较好,去除率分别达到90%和80%,对CODMn的去除率约为52%,而对TN的去除效果有限,去除率约为22.4%。     

城市小区雨水径流投加细砂强化混凝沉淀优化条件研究

城市小区雨水径流水质的污染主要为有机污染和悬浮固体污染,且污染物的可生化性差,采用投加混凝剂同时加细砂的强化混凝沉淀实验,确定了小区径流混凝沉淀处理最适宜的混凝剂种类、最佳的混凝反应运行条件及最优的药剂和细砂投加量.实验表明:在混凝沉淀过程中投加细砂,不仅能提高混凝沉淀效果,而且能提高沉淀速度.小区径流强化混凝沉淀的浊度去除率达99.7％,COD去除率达92.6％,处理水的浊度1.66 NTU,COD 35mg/L两主要指标均优于杂用水水质标准.因此,投加细料的混凝沉淀是小区雨水径流处理利用及污染控制最简便易行且有效的处理方法.     

The effectiveness of humic acids coagulation with the use of cationic polyacrylamides

The chemical coagulation process is a popular method for eliminating the precursors of disinfection by-products. This study presents the results of a laboratory experiment which investigates the use of cationic polyacrylamide copolymers (CPAMs) as primary coagulants in the purification of solutions containing humic acids (HA). A number of polymers with various molecular weight and charge density were tested. The optimal doses were determined by colloidal titration. The effectiveness of coagulation-flocculation was determined by jar test method. The post-coagulation suspension was separated by filtration through cellulose filter paper. The experiment showed that charge neutralization destabilizes organic colloidal particles. An inversely proportional relationship was observed between the optimal dose and polymer charge density. The effectiveness of UV254 reduction (52-81%) and colour removal (51-88%) was determined by the effectiveness of filtration in removing post-coagulation turbidity, as well as by the type of applied polymer. The results of the study suggest that the use of CPAMs with high charge density and low molecular weight enables effective removal of humic acids from water in the coagulation and filtration process.     

利用溶气气浮工艺强化处理低浊高色富含有机物地表水

低浊高色富含有机物地表水难于混凝,试验采用“混凝-溶气气浮”(“混凝-DAF”)工艺处理此类水,并与常规“混凝-沉淀”工艺进行了比较。结果表明,“混凝-DAF”工艺在较低投药量时能取得更好的处理效果;对于“混凝-DAF”工艺,增大混凝剂投量后出水浊度基本不变,但出水色度及CODMn可进一步降低;“混凝-DAF”工艺去除水中有机物的能力优于“混凝-沉淀”工艺。最后,对“混凝-DAF”工艺去除水中有机污染物的机理进行了探讨。     

Application of chemical precipitation for piggery wastewater treatment.

Several series of experiments were conducted to investigate the treatment of piggery wastewater using chemical precipitation (CP) where various types of coagulants such as aluminium sulfate (Al2(SO4)3), poly aluminium chloride (PAC), ferric chloride (FeCl3), ferric sulfate (Fe2(SO4)3), ferrous sulfate (FeSO4) and ferrous chloride (FeCl2) were used. Throughout the experiments, CP was found to achieve high removal efficiencies for organic compounds and nutrients (nitrogen and phosphorus) from the piggery wastewater. Experimental results showed the optimal doses of FeCl3, Fe2(SO4)3, FeCl2 and FeSO4 was 2.0 g/L, while 0.31 g/L and 2.5 g/L were the optimum dose for PAC and Al2(SO4)3, respectively. The pH range 4-5 resulted in the best performance to all coagulants except FeCl2 and FeSO4, whose optimum pH were more than 6. Percentage removal efficiencies for COD were in the ranges of 70-80%, 90-95% for SS, 80-90% for organic-N and TP. Those removal efficiencies were achieved within 5 min of operation. Three times of repetition in CP resulted in higher removal efficiencies for COD, SS and colour up to 74%, 99% and 94% respectively, in which Al2(SO4)3 was used as the coagulant. Removal efficiencies of various water quality parameters in a continuously operated reactor were similar to those of the batch experiments. Biodegradable ratios (BOD5/COD) increased up to 65% after the application of CP.     

聚合铝盐混凝剂混凝除藻机理与强化除藻措施

针对微污染水处理中藻细胞的去除,研究聚合氯化铝形态分布对混凝除藻效率的影响。结果表明,混凝剂水解产物中,中等聚合物含量影响混凝过程中藻细胞去除率。中等聚合物含量越大,藻细胞去除率越高;在一定条件下,藻细胞去除率与中等聚合物含量线性相关,混凝出水中残铝含量与单体和低聚物含量线性相关。对聚合氯化铝,中等聚合物含量与碱化度线性相关。适量加聚磷酸根、硅酸根可以提高混凝除藻效率,并能显著降低混凝出水中残铝含量,所阐述的混凝除藻机理可以较好地解释实验现象。     

Simultaneous optimization of multiple performance characteristics in coagulation-flocculation process for Indian paper industry wastewater

The goal of this study was to optimize the coagulation-flocculation process in wastewater generated from the paper and pulp industry using a grey relational analysis (GRA)-based Taguchi method. Process parameters included types and doses of natural coagulants and coagulant aid, and pH. To track the efficiency of the treatment process, the following responses were chosen for optimization: chemical oxygen demand (COD), total dissolved solids (TDS) and turbidity of wastewater, alone or in combination or all together. Analysis of variance showed that the type and dose of the coagulant aid were the most significant parameters, followed by pH and the dose of the coagulant; the type of coagulant used was found to be insignificant in the coagulation-flocculation process. Optimization of process parameters to achieve lower turbidity and greater removal of COD and TDS was verified in a separate confirmatory experiment, which showed improvements in COD and TDS removal and a decrease in turbidity of 8.2, 6.35 and 26.17%, respectively, with the application of the Taguchi method and GRA.     

常规混凝沉淀工艺对阴离子表面活性剂的去除研究

随着阴离子表面活性剂(LAS)在民用和工业上的广泛应用,由此带来的水污染问题也日益加剧,对供水安全造成了很大威胁。针对目前大部分水厂仍采用混凝沉淀常规水处理工艺,考察了常规混凝沉淀工艺对LAS的去除效果。以Al2(SO4)3,PAC,FeCl3,PFS为混凝剂,非离子PAM为助凝剂进行了试验,结果表明混凝沉淀对LAS有一定的去除效果,而且有机物和LAS的去除有一定相关关系。但浊度与LAS的去除相关性较差。试验条件下对于LAS去除最佳混凝方案是投加量为40 mg/L的FeCl3。相同水质条件下铁盐混凝剂在除浊、除有机物和除LAS方面优于铝盐混凝剂。pH和水温对LAS的去除有一定影响,较低的pH和较高的水温均有利于LAS的去除。     

高锰酸盐-聚丙烯酰胺联用强化混凝处理太湖支流原水研究

太湖B支流地表水受水土流失、水体富营养化和环境污染等因素影响,水体污染严重,水中有机物浓度和藻密度相对较高。常规的"混凝—沉淀—砂滤—加氯消毒"处理工艺难以有效地去除水中有机物、铁锰、藻类等物质。采用高锰酸盐(PPC)-聚丙烯酰胺(PAM)联用强化混凝工艺对原水进行处理。高锰酸盐投量在0.45 mg/L和聚丙烯酰胺投量在0.07 mg/L条件下联用强化混凝的静态试验结果表明:PPC-PAM联用强化混凝对浊度、色度、铁、锰和耗氧量的平均去除率为90%、73%、92%、99%和38%。PPC在0.3～0.5 mg/L投量和PAM在0.05～0.10 mg/L投量下联用强化混凝生产试验的出厂水浊度、色度、铁、锰等指标,均比历史同期水平要好。     

九龙江流域水厂生产废水回用条件的初步研究

以九龙江原水为研究对象,从改善低浊水混凝条件优化净水工艺角度,对生产废水的回用条件和作用规律进行了研究。研究认为:回用具有适当含固率的生产废水可以改善水处理过程的混凝条件,节省投药量,节药率一般为10%～40%;存在改善混凝条件、节省投药量的最佳含固率和最佳混合水浊度范围,最佳含固率为0.1%～0.7%,最佳混合水浊度为60～400NTU;原水浊度是显著影响最佳含固率的因素。当原水浊度小于60NTU时,最佳含固率随原水浊度的升高而增加,当原水浊度大于60NTU时.最佳含固率随原水浊度的升高而降低,最佳混合水浊度表现出相同的规律;在生产过程中,建议以最佳混合水浊度控制生产废水的回用。     

强化混凝超滤组合工艺对有机污染物去除效能的研究

为了进一步提高水质处理效果,采用强化混凝超滤的组合工艺对湖水进行处理,考察该组合工艺对有机物的去除效能,及影响有机物去除效能的因素。试验结果表明:①强化混凝超滤组合工艺对原水浊度的去除效果较好,对TOC和UV254的去除效果也明显优于传统水处理工艺;②原水中UV254含量的波动,对UV254的去除率和滤后水UV254含量影响并不大。原水中TOC含量的波动,对TOC的去除率有很大的影响,对滤后水TOC含量的影响并不大。TOC的去除率普遍高于UV254的去除率;③根据原水和滤后水SUVA值的变化发现,强化混凝超滤组合工艺对亲水性有机物的去除率大于该工艺对疏水性有机物的去除率。在一定范围内,pH的变化对TOC和UV254去除率变化趋势相反。     

Optimizing the coagulation process in a drinking water treatment plant -- comparison between traditional and statistical experimental design jar tests

In this study of coagulation operation, a comparison was made between the optimum jar test values for pH, coagulant and coagulant aid obtained from traditional methods (an adjusted one-factor-at-a-time (OFAT) method) and with central composite design (the standard design of response surface methodology (RSM)). Alum (coagulant) and polymer (coagulant aid) were used to treat a water source with very low pH and high aluminium concentration at Sri-Gading water treatment plant (WTP) Malaysia. The optimum conditions for these factors were chosen when the final turbidity, pH after coagulation and residual aluminium were within 0-5 NTU, 6.5-7.5 and 0-0.20 mg/l respectively. Traditional and RSM jar tests were conducted to find their respective optimum coagulation conditions. It was observed that the optimum dose for alum obtained through the traditional method was 12 mg/l, while the value for polymer was set constant at 0.020 mg/l. Through RSM optimization, the optimum dose for alum was 7 mg/l and for polymer was 0.004 mg/l. Optimum pH for the coagulation operation obtained through traditional methods and RSM was 7.6. The final turbidity, pH after coagulation and residual aluminium recorded were all within acceptable limits. The RSM method was demonstrated to be an appropriate approach for the optimization and was validated by a further test.     

The use of ozone during advanced primary treatment of wastewater for its reuse in agriculture: an approach to enhance coagulation, disinfection and crop productivities.

The purpose of this work was to evaluate the effect that ozone (O(3)) has on the advanced primary treatment (APT) and disinfection of wastewaters for their reuse in agriculture. The enhancement and optimization of APT was done by applying low O(3) doses during coagulation. By applying an ozone dose of 2 mg/L during APT, the required coagulant dose may be reduced by up to 25% to achieve a similar turbidity removal (and up to 50% for total suspended solids removal), when compared to a conventional APT treatment. When the same coagulant dose was applied (60 mg/L), the volume of settleable solids was reduced from 31.0 to 25.5 mL/L, and the settling velocity increased from 0.111 to 0.139 m/min. Disinfection was also improved by the use of ozone, which leads to better plant germination rates than when using chlorination, because of reduced toxicity of the ozonated effluents. Additionally, helminth eggs content was reduced by applying ozone.     

二次凝聚法去除受污染原水TOC的影响因素研究

基于已有的研究成果通过混凝烧杯试验就二次凝聚法的凝聚剂投加量比例、快速混合强度和pH范围等因素对原水TOC去除效果的影响进行了研究。试验结果表明,将常规凝聚的加药量等分2次投加能取得最好的原水TOC去除效果,高混合强度有利于去除原水TOC,二次凝聚的最佳pH范围与原水pH范围一致。     

Treatment of oilfield wastewater by Fenton's process.

A combination of coagulation and Fenton's process was used for the removal of total oxygen carbon (TOC) from oilfield wastewater. Compared with aluminium sulfate, ferric coagulant had better TOC removal efficiency at the same mass dosage. In Fenton's process, the effect of H2O2 and Fe2+ dose on the removal of TOC was studied. The optimum conditions required for TOC removal were an Fe3+ concentration of 40-50 mg/L, an H2O2 dose of 50 mmol/L and an Fe2+ concentration of 1.0 mmol/L. GC-MS chromatographic analysis indicated that most of the alkyl hydrocarbons of carbon numbers < 21 were removed in the first minute of Fenton's process mainly through adsorption. Alkyl hydrocarbons and phenols were oxidized almost completely following 120 min of treatment. The pathway of newly formed intermediates in Fenton's process was proposed on the basis of the GC/MS chromatogram.     

混凝改善超滤膜过滤性能的研究

研究有机物的特性如亲、疏水性以及相对分子质量的大小对超滤膜通量的影响.着重考察混凝对有机物特性的影响以及改善超滤膜通量的效果.试验表明,超滤膜直接过滤原水时,主要截留疏水性有机物,从而造成膜通量的下降.投加硫酸铝25 mg/L和100 mg/L时,虽然TOC去除率仅为18.4%和48.2%,但明显提高了膜通量,这是由于混凝有效地去除小分子疏水性有机物的缘故.研究表明,膜通量的下降与膜截留疏水性有机物的多少有密切关系.     

采用活性炭强化常规处理原水突发油类污染的研究

中试研究表明,常规处理(混凝—沉淀—过滤)可以将含油约为10mg/L的原水处理达标,并且除油率不受混凝剂投加量的影响。油污染浓度为7.2～18mg/L的原水经混凝沉淀去除的效率基本相同。20mg/L的油污染仅通过常规处理无法达标,需采用投加粉末活性炭(PAC)的强化混凝或颗粒活性炭(GAC)的强化过滤,即投加40mg/L的PAC,或在过滤阶段铺40cmGAC层的炭砂滤柱。KMnO4和Cl2的预氧化对除油效果无影响。     

新型中置式高密度沉淀池优化投药试验研究

通过小试和生产性试验对新型中置式高密度沉淀池的投药系统(包括回流污泥、混凝剂及助凝剂PAM的投加)进行了详细研究.小试研究表明回流污泥和混凝剂投加量的增大降低了上清液浊度,PAM的投加略微降低了上清液出水浊度,但影响不大.生产性试验研究结果表明,实际生产运行中可灵活利用回流污泥来提高絮凝效果,在合理的范围内回流污泥投加量越大,絮凝效果越好;沉淀池随着混凝剂投加量的增大,出水浊度逐渐降低,同时,不同的回流污泥投加量条件下混凝剂投加对沉淀池出水浊度的影响表现出不同特性;增大PAM投加量对直接提高沉淀池的絮凝效果以及降低出水浊度的贡献不明显,PAM投加量的增大间接引起回流污泥投加量变大是导致出水浊度变小的原因.     

Effect of 200 days' sludge retention time on performance of a pilot scale submerged membrane bioreactor for high strength industrial wastewater treatment.

A high strength industrial wastewater was treated using a pilot scale submerged membrane bioreactor (MBR) at a sludge retention time (SRT) of 200 d. The MBR was operated at a high sludge concentration of 20 g/L and a low F/M ratio of 0.11 during 300 d of operation. It was found that the MBR could achieve COD and TOC overall removal efficiencies at more than 99 and 98% TN removal. The turbidity of the permeate was consistently in the range of 0.123 to 0.136 NTU and colour254 absorbance readings varied from 0.0912 to 0.0962 a.u. cm(-1). The sludge concentration was inversely proportional to the hydraulic retention time (HRT), yielded excellent organic removal and extremely low sludge production (0.0016 kgVSS/day).     

The transformation of aluminium species in the processes of coagulation, sedimentation and filtration.

The aluminium toxicity is closely related to aluminium species. In this work aluminium was fractionated into seven forms: Al(T), Al(Sus), Al(C + S), Al(S), Al(C), Al(O) and Al(I). Four Al-based coagulants and simulated raw water were used in the laboratory to investigate the aluminium transformation in coagulation, sedimentation and filtration processes. It is the use of Al-based coagulants that contributes more to the increase of the residual aluminium for the low-turbidity raw water, while the Al-based coagulants, especially the polymeric aluminium coagulants, work to remove the aluminium from the high-turbidity raw water. In the case of traditional coagulants, the increase of the turbidity or the dissolved organic carbon (DOC) concentration in the raw water results in a high concentration of Al(C + S). The removal rate of aluminium species in the filtration process is not only related to its size: RAl(Sus) > RAl(C+S), RAl(C) > RAl(S), but also to the physicochemical properties of aluminium species and filter. For the kaolin-polyaluminium chloride system, a lower removal rate of aluminium species results is due to the complexation of humic acid and aluminium species.