不同混凝剂除磷性能的对比研究

以含磷水样为研究对象,考察了不同混凝剂(聚合氯化铝、三氯化铁及三氯化铝)的除磷效果及其影响因素,同时比较了不同碱化度PAC除磷效果的差异,明确了聚合氯化铝、三氯化铁及三氯化铝的最佳投加量和最佳pH值.搅拌条件对除磷效果的影响结果表明,混合强度的增大对除磷效果有一定的提高,混合时间以60 s为宜.     

Comparing polyaluminum chloride and ferric chloride for antimony removal

Antimony has been one of the contaminants required to be regulated, however, only limited information has been collected to date regarding antimony removal by polyaluminium chloride (PACl) and ferric chloride (FC). Accordingly, the possible use of coagulation by PACl or FC for antimony removal was investigated. Jar tests were used to determine the effects of solution pH, coagulant dosage, and pre-chlorination on the removal of various antimony species. Although high-efficiency antimony removal by aluminum coagulation has been expected because antimony is similar to arsenic in that both antimony and arsenic are a kind of metalloid in group V of the periodic chart, this study indicated: (1) removal density (arsenic or antimony removed per mg coagulant) for antimony by PACl was about one forty-fifth as low as observed for As(V); (2) although the removal of both Sb(III) and Sb(V) by coagulation with FC was much higher than that of PACl, a high coagulant dose of 10.5mg of FeL(-1) at optimal pH of 5.0 was still not sufficient to meet the standard antimony level of 2 microg as SbL(-1) for drinking water when around 6 microg as SbL(-1) were initially present. Consequently, investigation of a more appropriate treatment process is necessary to develop economical Sb reduction; (3) although previous studies concluded that As(V) is more effectively removed than As(III), this study showed that the removal of Sb(III) by coagulation with FC was much more pronounced than that of Sb(V); (4) oxidation of Sb(III) with chlorine decreased the ability of FC to remove antimony. Accordingly, natural water containing Sb(III) under anoxic condition should be coagulated without pre-oxidation.     

混凝沉淀工艺深度处理污水厂二级出水的混凝剂优化

通过烧杯试验，确定了采用混凝、沉淀工艺深度处理城市污水处理厂二级出水时，最佳的混凝剂组合及投量。结果表明，铝盐混凝剂与PAM组合使用时比铁盐混凝剂与PAM组合使用时的处理效果更好，当PAC＋PAM的组合投量为20mg／L＋5mg／L或30mg／L＋1mg／L、硫酸铝＋PAM的组合投量为30mg／L＋5mg／L时，混凝、沉淀出水浊度为2．5～3．5NTU，COD为25-40mg／L，TP为0．06-0．12mg／L。由于混凝后水中所形成的絮体较小，难于沉淀，因此混凝沉淀工艺对SS的去除效果较差，实际工程中可考虑增设过滤单元。     

再生水处理中混凝剂最佳投量与助凝剂选择试验研究

针对天津市某再生水厂原水水质情况,通过烧杯试验确定了混凝剂聚合氯化铝(PAC)的最佳投加量及助凝剂种类.结果表明,PAC的最佳投加量为12～ 16 mg/L;粉煤灰对原水的强化混凝作用不明显;粉末活性炭可以提高色度去除率及泥渣的沉降性能;前加氯可以明显提高氨氮及色度的去除效果,且加氯量宜控制在4 ～6 mg/L.     

化学混凝对两级曝气生物滤池出水的除磷效果研究

为解决两级曝气生物滤池处理城市污水时除磷效果欠佳的问题，采用化学混凝工艺对其出水进行处理，以聚合硫酸铁（PFS）为絮凝剂，通过烧杯试验考察了PFS投量及助凝剂聚丙烯酰胺（PAM）对除磷效果的影响，并通过中试考察了混凝、沉淀、过滤工艺的除磷效果。结果表明，PAM的助凝作用并不明显，单独投加130mg／L的PFS即可使出水TP〈1mg／L。在生物处理单元稳定运行的情况下，中试工艺的PFS投量在90-95mg／L时可使出水TP〈1mg／L，总铁〈0．5mg／L。     

Enhanced coagulation for high alkalinity and micro-polluted water: the third way through coagulant optimization

Conventional coagulation is not an effective treatment option to remove natural organic matter (NOM) in water with high alkalinity/pH. For this type of water, enhanced coagulation is currently proposed as one of the available treatment options and is implemented by acidifying the raw water and applying increased doses of hydrolyzing coagulants. Both of these methods have some disadvantages such as increasing the corrosive tendency of water and increasing cost of treatment. In this paper, an improved version of enhanced coagulation through coagulant optimization to treat this kind of water is demonstrated. A novel coagulant, a composite polyaluminum chloride (HPAC), was developed with both the advantages of polyaluminum chloride (PACl) and the additive coagulant aids: PACl contains significant amounts of highly charged and stable polynuclear aluminum hydrolysis products, which is less affected by the pH of the raw water than traditional coagulants (alum and ferric salts); the additives can enhance both the charge neutralization and bridging abilities of PACl. HPAC exhibited 30% more efficiency than alum and ferric salts in dissolved organic carbon (DOC) removal and was very effective in turbidity removal. This result was confirmed by pilot-scale testing, where particles and organic matter were removed synergistically with HPAC as coagulant by sequential water treatment steps including pre-ozonation, coagulation, flotation and sand filtration.     

Removal of perfluorooctanoate from surface water by polyaluminium chloride coagulation

Perfluorooctanoate (PFOA) has been detected in surface water all over the world, and little is known of its removal by coagulation in water treatment plants. In this study, polyaluminium chloride (PACl) was used to remove PFOA from surface water, and the effects of coagulant dose, solution pH, temperature, and initial turbidity on the removal of both PFOA and suspended solids (SS) from water were investigated. Since the SS had high sorption affinity for PFOA, most PFOA was adsorbed on the particles and removed via the SS removal in the coagulation process. PFOA concentrations in aqueous phase decreased with increasing initial turbidity and PACl dose, while they increased with increasing solution pH and temperature. Other perfluorinated compounds (PFCs) with different C-F chain lengths and functional groups were also compared with PFOA. It was proved that hydrophobic interaction played an important role in the adsorption of PFOA on the SS. The addition of powdered activated carbon (PAC) before the coagulation process significantly enhanced the removal efficiency of PFOA in water, and the residual PFOA concentrations in water were less than 1 μg/L after the addition of 1-16 mg/L PAC and subsequent coagulation when the initial PFOA concentrations were in the range of 0.5-3 mg/L.     

化学生物絮凝工艺处理低浓城市污水研究

考察了化学生物絮凝和化学混凝两工艺对低浓度城市污水的处理效果。试验表明，在PAC加入量为70mg／L、PAM加入量为0．5mg／L、絮凝反应时间为35min时，化学生物絮凝工艺对COD的平均去除率为61％，对TP的平均去除率为70％，对SS的平均去除率为90％，效果明显优于化学混凝工艺；在化学生物絮凝工艺中污泥回流不仅可以提高去除效果，而且对进水水质波动有一定的稳定作用。     

化学沉淀法去除水中汞的试验研究

在实验室条件下,利用混凝搅拌设备模拟水厂净水工艺,研究了化学沉淀法对汞的去除效果.结果表明,调整原水pH>10.5(反应后pH>10.1),采用三氯化铁或聚合硫酸铁作为混凝剂,投加量为5 mg/L,能将水中汞从0.005 mg/L降低至<生活饮用水卫生标准>限值(0.001mg/L)以下,是一种有效去除汞污染物的应急处...     

Insights into function of hydrocyclone separator and modified volcanic rock coagulant on formation of aerobic granular sludge

Hydrocyclone separator and novel coagulants were adopted to separately enhance the granulating process of aerobic granular sludge. For hydrocyclone separator, although there was no obvious large particle, it was feasible to improve the sludge sedimentation capacity, indicated by the sludge volume index. Moreover, the nitrogen removal performance was promoted by the separator with a nitrogen removal rate of 8.2 mg/(L·h), nearly two times of system without a separator. Meanwhile, nitrogen-related microbial communities were stimulated, for example, Thauera and Nitrosomonas. Another method of coagulation by the modified volcanic rock promoted the sludge settling performance. The optimum coagulating conditions were the coagulant size of 100 μm with dosage of 6 g/L. The addition of polyacrylamide played a weak role in granulation. Overall, the role of hydrocyclone separator and modified volcanic rock coagulant belonged to the improvement of the settleability of sludge and the aggregation of sludge, respectively.     

混凝剂中的铝形态对藻类混凝过程的影响

为了考察混凝剂中的铝形态对藻类混凝过程的影响,使用3种具有不同铝形态分布的混凝剂对含藻水进行了混凝试验。结果表明,硫酸铝由于具有较低含量的Alb,电中和能力较差,故需要较大的投量才能去除藻类,形成絮体;含藻水体系中的有机物主要是腐殖酸及富里酸类物质,微生物代谢产物(SMP)在硫酸铝作混凝剂时得到较好的去除,而腐殖酸及富里酸的去除率较低可能是造成硫酸铝混凝效果较差的原因;Alc(Al(30))在混凝中的作用机理主要是吸附架桥作用,可有效去除水体中的有机物,Al₁₃的主要作用机理是电中和作用,可以有效去除水体中的颗粒物;Al₁₃与Al₃₀由于具有形态的稳定性,其混凝过程受pH值的影响较小。絮体强度因子随着pH值的升高先增大后减小,Al₁₃作混凝剂时絮体恢复因子随pH值的升高先增大后减小,而其他两种混凝剂所形成絮体的恢复因子随pH值的升高而增大。     

HA-A/A-MCO工艺的基质转化与除污特性研究

针对现有污泥减量技术对氮、磷去除率低的问题,开发了一个具有同步脱氮除磷和污泥减量功能的HA-A/A-MCO工艺.采用该工艺处理校园生活污水,当进水COD为316～407mg/L时,出水COD≤18 mg/L,对COD的平均去除率为96%;将相当于进水量2%的厌氧释磷污泥回流至水解酸化池与原水-并进行水解处理后,大部分污泥转化为溶解性有机物,且主要是VFA(约275 mg/L),为原水中VFA(58 mg/L)的4.74倍,这为后续A~2/O单元进行脱氮除磷提供了充足的碳源.通过考察各反应池出水的三维荧光特性还发现,HA-A/A-MCO系统的各工段对原水中的溶解性有机质(DOM)具有显著的降解作用.     

混凝法去除水体中邻苯二甲酸二甲酯

研究采用强化混凝法去除水体中特征性有机污染物邻苯二甲酸酯类化合物(PAEs).以邻苯二甲酸二甲酯(DMP)为目标物,阳离子混凝剂聚二甲基二烯丙基氯化铵(PDMDAAC)与聚丙烯酰胺(CPAM)为混凝剂,对含DMP的水体进行强化混凝处理,混凝处理后水体中DMP的残余浓度采用高效液相色谱法(HPLC)测定.研究内容还包括混...     

Color removal from cotton textile industry wastewater in an activated sludge system with various additives

The low biodegradability of many dyes and textile chemicals indicates that biological treatment is not always successful in the treatment of cotton textile wastewater, in terms of color removal. In this study, a specific organic flocculant (Marwichem DEC), powdered activated carbon (PAC), bentonite, activated clay and commercial synthetic inorganic clay (Macrosorb) were directly added into the activated sludge laboratory pilot plant model. Before dosage, the optimum sludge retention time and hydraulic retention time were determined as 30 days and 1.6 days, respectively. The Monod kinetic constants were determined as Y = 0.76 kg MLSS/kg COD, Kd = 0.026 l/day, K(S) = 113.3 mg/L, k = 0.42 l/day and mu(max) = 0.32 kg MLSS/kg COD day. Under these conditions the average COD removal was 94% and color removal was 36%. The addition of these materials did not change COD removal significantly. The most effective materials were found to be DEC and PAC for color removal. While the color removal efficiency for 120 mg/L DEC addition was 78%, it was 65% for 100 mg/L, 77% for 200 mg/L and 86% for 400 mg/L PAC addition. The advantage of DEC compared to PAC was the lower sludge production. Statistical analyses using multiple linear regression indicate that there is no relationship between the effluent color with the influent color and total suspended solids (TSS) for DEC and PAC addition. On the other hand, when only bentonite, activated clay and Macrosorb were added, the effluent color was primarily dependent on the influent color and the TSS concentration had little effect. When the data is examined by using Kruskal-Wallis H and Mann-Whitney U tests and it was found that there was a significant difference between the color data groups.     

HA-A/A-MCO工艺水解酸化单元运行性能研究

针对现有污泥减量技术中存在的氮、磷去除率低的问题,开发了一个新型的具有同步除磷脱氮和污泥减量功能的HA-A/A-MCO工艺,对回流污泥种类及比例对水解酸化池产酸、污泥减量及系统释磷效果进行研究,结果发现：回流污泥种类及比例影响水解酸化出水VFA总量进而影响释磷效果,回流2%厌氧释磷污泥水解产生的VFA总量最大（275 mg/L）,系统释磷量也最大（57 mg/L）。     

二甲醚生产废水的深度处理及回用

采用微氧/好氧/混嵩乏/富氧生物活性炭/UV消毒组合工艺处理二甲醚生产废水.在进水COD为1 095～1 600 mg/L、pH值为5.0～7.0、氨氮为2.1～6.7 mg/L、总磷为1.7～5.4mg/L、SS为100～300 mg/L、色度为40～110倍、LAS为0.31～1.92 mg/L的条件下,混凝沉淀单元的出水水质满足绿化用水要求,富氧生物活性炭处理出水水质满足洗车及景观用水等要求,实现了二甲醚生产废水的零排放,具有良好的经济效益和环境效益.     

复合混凝剂PTA-CPAM的形貌结构与净水性能

以聚合氯化铝(PAC)、四氯化钛(TiCl_4)、阳离子聚丙烯酰胺(CPAM)为原料成功制备无机-有机复合混凝剂聚钛氯化铝-阳离子聚丙烯酰胺(PTA-CPAM),采用红外光谱(IR)、扫描电镜(SEM)、能谱分析(EDS)与差热热重(TG-DTA)对产物的结构、组成及热稳定性进行分析。此外,对PTA-CPAM的混凝性能进行研究。结果表明:当m(CPAM)/m(PTA)=0.4、PTA-CPAM投加量为9.0mg/L、pH为9.0的条件下,混凝剂的净水效果最优,且PTA-CPAM对不同初始浊度的水样都有较优的除浊能力;协同增效作用使PTA-CPAM具备更强的吸附电中和与吸附架桥网捕能力,表现出优异的除浊性能。     

泥渣回流强化混凝沉淀工艺处理污水厂二级出水

通过中试考察了泥渣回流强化混凝沉淀工艺深度处理污水厂二级出水的可行性.试验结果表明,通过泥渣回流来强化混凝沉淀工艺是完全可行的,不仅提高了对污染物的去除效果,而且还达到了降低混凝剂投加量的目的.在确定的试验条件下,泥渣回流强化混凝沉淀工艺对浊度、TP、PO3-、COD、UV254、色度的去除率分别为71.63%、71.21%、52.00%、36.62%、15.55%、47.25%;而且通过泥渣回流还成功地解决了斜板沉淀池的积泥难题,无需安排专人对斜板进行定期清洗,提高了再生水厂的产水率.     

污泥调理废水的特性及其处理工艺

采用离子色谱法及化学分析法分析了污泥调理废水的水质特性,在氨吹脱及混凝试验的基础上开展了氨吹脱—厌氧—SBR工艺处理该废水的研究。结果表明,污泥调理废水是一种高浓度含氮有机废水,其中有机污染物主要以溶解态存在,不宜采用混凝处理。该废水具有较好的生物可降解性能,当HRT为24h、进水COD为8658.7~9650.3mg/L时,厌氧对COD的去除率可达62.1%,厌氧/好氧交替运行的SBR对COD、氨氮的去除率分别为92.1%、88.4%。动态运行结果显示,氨吹脱—厌氧—SBR工艺对该废水水质具有良好的适应性,处理出水水质能稳定地达到GB8978—1996的二级标准。     

Cellular proteins of Microcystis aeruginosa inhibiting coagulation with polyaluminum chloride

Cyanobacterial growth in semi-closed water areas such as reservoirs brings about a coagulation inhibition in a drinking water treatment system, but the inhibitory substances and mechanisms involved have yet to be elucidated. In this study, proteins having a high affinity with polyaluminum chloride (PACl) were isolated from organic substances produced by Microcystis aeruginosa with the affinity chromatography technique. Both extracellular organic matter (EOM) and cellular organic matter (COM) disturbed the flocculation of suspended kaolin with PACl, but it was likely that nonproteinous substances in EOM cause the reduction of coagulation effciency. In contrast, proteins in COM were obtained as possible inhibitory substances for the coagulation with PACl. These proteins could consume PACl in the coagulation process due to the formation of chelate complexes between these inhibitory proteins and the coagulant. The consumption of PACl by cyanobacterial proteins could be one of the important causes of the increase in coagulant demand.