硫酸铁混凝剂处理焦化废水A/O 工艺出水的研究

利用Fe₂(SO₄)₃ 作为混凝剂,对焦化废水生化处理出水进行深度处理,考察pH 值和投加量对混凝过程的影响,从而分析不同条件下有机物的去除机理.结果表明,在pH3~9 的条件下,混凝对生化出水中的有机物均能取得较好去除效果.弱酸性条件有利于有机物的去除,在Fe₂(SO₄)₃投加量为400mg/L、pH5 的条件下,DOC 去除率达到40.1%,出水COD<150mg/L.络合沉降、络合吸附和吸附是混凝过程中有机物的主要去除机理,但在不同pH 值条件下,三者作用程度不同.混凝过程主要去除生化出水中的中等分子量、疏水性有机物,对亲水性有机物几乎没有作用.     

低温污水前置强化混凝

研究低温对强化混凝过程的影响,合成新型复合混凝剂(Synth A),利用膜分离分级、三维荧光光谱(3DEEM)和紫外差异分析等技术研究常温、低温(2~5℃)条件下强化混凝对溶解性有机物、溶解性有机氮等的去除特征及其对后续生物处理的影响.结果表明,常温下氯化铝(AlCl_3)、聚合氯化铝(PACl)和Synth A混凝后浊度去除率和颗粒态COD、N去除率,胶态COD、N去除率高度相关;与相应溶解态指标关系不明确.混凝对溶解性有机物荧光响应值的去除率远高于溶解态COD的去除率.溶解性有机氮(DON)是除颗粒氮(PN)和胶态氮(CN)外,前置混凝分离去除总氮(TN)的主要部分.低温对强化混凝的影响主要体现在,低温抑制上述3种混凝对浊度和COD去除,且抑制程度依次为AlCl_3PAClSynth A;低温对颗粒态、胶态和溶解态COD、N的混凝去除效果产生不同程度的影响,且对颗粒态和胶态COD、N的负面影响较大.低温原水溶解性有机物荧光响应值较常温原水大幅度升高.低温混凝对荧光响应值及紫外差异吸收的影响较常温更为显著.低温条件下,Synth A对TN、DN及DON的去除率较常温略有提高,保持了对PN和CN的去除能力,投量为30 mg·L-1以上时,DON去除率约为28.5%~41.7%,而常温仅为17%~31.4%.采用前置混凝分离去除大量COD和一定量的TN,能大幅减少曝气池停留时间,稳定TN控制效果.因而冬季采用Synth A等低温适应性强的混凝剂强化前置混凝可以在一定程度上弥补生化效率降低,缓解脱氮压力,稳定处理效果.     

混凝-活性炭吸附对化工废水深度处理效果的研究

通过试验对比了活性炭吸附法、混凝-活性炭吸附法深度处理化工废水中有机物的去除效果。在对影响深度处理化工废水中有机物的去除率的各种要素如投加量、配比、吸附时间、pH值等条件进行试验后,得出了去除有机物的最佳试验条件。结果表明,对混凝-活性炭吸附法深度处理化工废水中的有机物而言,混凝可以有效去除浊度,去除率达93.9%以上,活性炭对有机物去除效果明显,其最佳投加量为35mg/L。     

聚硅酸硫酸铁强化混凝去除微污染水源水中天然有机污染物

应用强化混凝技术,降低原水中有机物含量,是控制消毒副产物生成的有效途径之一。通过混凝搅拌试验,评价了聚硅酸硫酸铁混凝剂对原水中有机污染物的去除效果,考察了混凝剂投加量、pH值等对去除效果的影响。结果表明：聚硅酸硫酸铁去除有机物和除浊能力明显优于硫酸铁、聚合硫酸铁,其适宜的投药量范围和pH值范围宽;聚硅酸硫酸铁在混凝过程中形成的矾花较大,沉降速度快,因而可缩短处理水在构筑物中的停留时间,提高系统的处理能力;此外,通过正交实验确定了聚硅酸硫酸铁混凝剂的最佳水力条件。     

强化混凝去除黄浦江水有机物的试验研究

强化混凝去除有机物的效果与水源的分子量分布特性有着密切的关系.由于黄浦江水中低分子量的溶解性有机物占多数,因此,强化混凝处理有机物效果有限.对于＜1k分子量区间的有机物.增加混凝剂投量可有效去除紫外吸光值(UV254),但去除溶解性有机碳(DOC)的效果很差.尽管增加混凝剂投量和降低pH都能有效地去除有机物,但决定强化混凝效果的主要因素是pH,去除黄浦江水有机物的最佳pH范围为6～5.     

不同聚合铝对水中有机物的去除研究

强化混凝是去除水中消毒副产物的最佳方法之一。文章针对强化混凝技术,从去除水中有机物的角度出发,对不同聚合铝的处理效果进行了研究。结果表明,酸性条件、加大投药量有利于水中TOC及UV254的去除,且酸性条件更为有利。在pH=6.3,工业PAC投药量为1.5×10-4mo(l有效铝)时去除效果最佳,水中总有机碳(TOC)及紫外吸光度(UV25)4的去除率分别可达到46%及57%,实验室制备的聚合铝碱化度越高越有利于水中有机物的去除。     

强化混凝去除湘江原水中天然有机物的研究

文章应用强化混凝技术对湘江原水中天然有机物的去除效果进行了研究。通过选择混凝剂、增加混凝剂的用量和降低pH值等措施强化混凝处理湘江水。实验结果表明,选用聚合氯化铝(PAC)作为混凝剂,并控制PAC的投加量为3 10-4 mol.L-1,pH在5 6之间,能有效去除湘江水中的有机物。同时还初步探讨了TOC和UV-254之间的相关性,得出UV-254=0.048 5 TOC-0.073 8。     

超滤及其组合工艺对污水的深度处理试验

超滤及其组合工艺 ,混凝 UF和粉末活性炭 (PAC) UF对污水深度处理的试验结果表明 ,超滤对水中浊度几乎可以完全去除 ,对细菌和大肠杆菌的去除效率大于 99% ,对水中有机物、氨氮、总铁和总锰也均有一定的去除。超滤前加混凝预处理或粉末活性炭吸附后 ,提高了水中有机物的去除率 ,同时减轻了膜污染 ,提高了膜通量和产水量。此外 ,三种工艺在等量冲洗用水的条件下 ,适当缩短过滤周期 ,增加反冲洗频率均提高了单位能耗产水量。     

混凝处理抗生素废水研究

采用混凝法对抗生素废水进行预处理.试验结果表明:混凝沉淀方法去除混合液中的有机物及部分非溶解态的溶媒物质具有较好的效果,CODCr平均去除率达到32.0%,且运行成本合理,具有较高的应用价值.     

强化混凝去除微污染湖泊水浊度及TOC的研究

通过烧杯混凝试验和动态连续混凝试验,就混凝剂种类、投药量、pH值、水温等因素,研究强化混凝对水中浊度和TOC去除效果的影响。试验结果表明:PAC最佳投量为30mg/L,浊度去除率为90.19%,TOC去除率为38.2%,水温高于20℃时,聚合氯化铝对浊度和TOC去除率分别高达84.95%、33.18%以上。虽然pH值是影响有机物去除的主要参数,动态连续混凝试验表明,不改变pH值,强化混凝工艺依然能极大地改善出水水质,滤后水质浊度为0.1NTU,TOC为6.23mg/L。     

Fractionation of residual Al in natural water treatment from reservoir with poly-aluminum-silicate-chloride (PASiC): Effect of OH/Al, Si/Al molar ratios and initial pH

An aluminum fractionation study was conducted for a surface reservoir water treatment to understand the performance of poly-aluminum-silicate-chloride (PASiC) in terms of the residual Al fractions as a function of initial pH. The coagulation performance expressed as turbidity and organic matter removal was established as supporting data. Some extra data were evaluated in terms of the residual Al ratio of the composite PASiC coagulant. The main residual Al sources were the Al fractions derived from the use of PASiC. The turbidity and organic matter removal ability was optimal at initial pH 6.00-7.00, while the concentrations of various residual Al species and the residual Al ratio of PASiC were minimal at an initial pH range of 7.00-8.00. Under the conditions of OH/Al molar ratio = 2.00 and Si/Al molar ratio = 0.05, PASiC had superior coagulation performance and comparatively low residual Al concentrations. The Al fraction in the composite PASiC coagulant seldom remained under such conditions. Experimental data also indicated that the suspended (filterable) Al fraction was the dominant species, and organic-bound or organo-Al complex Al was considered to be the major species of dissolved Al in water treated by PASiC coagulation. Additionally, the dissolved inorganic monomeric Al species dominated the dissolved monomeric Al fraction.     

混凝去除垃圾渗滤液中DOM的实验研究

选取氯化铁(FeCl3.6H2O)为混凝剂,以经0.45μm膜和1nm膜分子切割的垃圾渗滤液为研究对象,通过混凝剂投加量和混凝pH值实验,研究了垃圾渗滤液中DOM的去除情况,并比较了两种不同分子量水平的渗滤液中DOM的混凝去除特点。研究表明,pH值是影响渗滤液DOM去除的主要因素,氯化铁在pH=5、投加量为4g/L的条件下混凝效果最佳。混凝pH值对大分子量渗滤液中DOC去除的影响较大;而两种分子量水平的渗滤液UV254的去除差异不大。     

pH modeling for maximum dissolved organic matter removal by enhanced coagulation

Correlations between raw water characteristics and pH after enhanced coagulation to maximize dissolved organic matter (DOM) removal using four typical coagulants (FeCl₃, Al₂(SO₄)₃, polyaluminum chloride (PACl) and high performance polyaluminum chloride (HPAC)) without pH control were investigated. These correlations were analyzed on the basis of the raw water quality and the chemical and physical fractionations of DOM of thirteen Chinese source waters over three seasons. It was found that the final pH after enhanced coagulation for each of the four coagulants was influenced by the content of removable DOM (i.e. hydrophobic and higher apparent molecular weight (AMW) DOM), the alkalinity and the initial pH of raw water. A set of feed-forward semi-empirical models relating the final pH after enhanced coagulation for each of the four coagulants with the raw water characteristics were developed and optimized based on correlation analysis. The established models were preliminarily validated for prediction purposes, and it was found that the deviation between the predicted data and actual data was low. This result demonstrated the potential for the application of these models in practical operation of drinking water treatment plants.     

无机-有机复合混凝剂处理夏季引黄水库水的对比研究

合成了具有不同Fe(Al)/聚二甲基二烯丙基氯化铵(PDMDAAC)质量比的无机-有机复合混凝剂PFC-PDMDAAC和PAC-PDMDAAC,并对夏季引黄水库水进行混凝处理.考察了复合比例、投药量、pH值和投加方式对浊度、有机物和叶绿素-a的去除效果;并通过混凝过程中形成絮体的Zeta电位的变化分析了2种混凝剂的混凝机理.结果表明,无机-有机复合混凝剂处理夏季引黄水库水的效果好于2种单独成分的复配使用;复合比例对PFC-PDMDAAC和PAC-PDMDAAC处理夏季引黄水库水的效果影响较大,Fe(Al)/PDMDAAC质量比为4:1,投药量为4mg/L时混凝效果最好;与无机混凝剂相比,复合混凝剂的最佳pH值范围较广,可在5.0~8.0的pH值范围内取得良好的混凝效果;2种混凝剂相比,PAC-PDMDAAC对浊度和叶绿素-a的去除效果较好,而PFC-PDMDAAC对有机物的去除效果更佳.     

Study on the effects of organic matter characteristics on the residual aluminum and flocs in coagulation processes

Characteristics of organic matter may affect the residual aluminum after the coagulation process. This study reported the results of a survey for one drinking water treatment plant and measured the concentration of residual aluminum species with different molecular weights. Survey results indicated that humic acid or organic matter whose molecular weight was smaller than 1500 Da had significant effects on residual aluminum. All the treatment processes were ineffective in removing dissolved organic matter whose molecular weight was smaller than 1500 Da. These results also indicated that the addition of sand or polyacrylamide in the coagulation process could greatly decrease the concentration of humic acid, and the concentration of residual aluminum also decreased. These results revealed that for all water samples after filtration, the majority of total residual aluminum existed in the form of total dissolved aluminum, accounting for 70%–90%. The concentration of residual aluminum produced in bovine serum albumin solutions indicated that when the DOC was larger than 4.0 mg/L, there were still significant differences when the solution pH value varied from 4.0 to 9.0.     

电凝聚臭氧化耦合工艺混凝剂水解形态分析 ——基于单/双电极排布

探究了不同初始pH值和不同电极布置条件下电凝聚臭氧化耦合工艺(E-HOC)中混凝剂的水解形态特征,同时进行了效能分析.结果表明,初始pH值为5时,E-HOC工艺具有更高的有机物去除效率,与单极排布的E-HOC工艺相比,双极排布的E-HOC工艺的有机物去除效率提高了12.29％,能耗降低了1.74kWh/g,法拉第效率提...     

Selection of magnetic anion exchange resins for the removal of dissolved organic and inorganic matters

Four magnetic anion exchange resins (MAERs) were used as adsorbents to purify drinking water. The effect of water quality (pH, temperature, ionic strength, etc.) on the performance of MAER for the removal of dissolved organic matter (DOM) was also investigated. Among the four studied MAERs, the strong base resin named NDMP-1 with high water content and enhanced exchange capacity exhibited the highest removal rate of dissolved organic carbon (DOC) (48.9% removal rate) and UV-absorbing substances (82.4% removal rate) with a resin dose of 10 mL/L after 30 min of contact time. The MAERs could also effectively remove inorganic matter such as sulfate, nitrate and fluoride. Because of the higher specific UV absorbance (SUVA) value, the DOM in the raw water was found to be removed more effectively than that in the clarified water by NDMP resin. The temperature showed a weak influence on the removal of DOC from 6 to 26℃, while a relatively strong one at 36℃. The removal of DOM by NDMP was also affected to some extent by the pH value. Moreover, increasing the sulfate concentration in the raw water could decrease the removal rates of DOC and UV-absorbing substances.     

紫外辐射对小球藻混凝效果作用途径探讨

针对藻类在常规水处理过程中难以被有效去除的现状,采用紫外辐射对藻类混凝过程进行强化处理.结果表明,随着紫外照射时间的增加,混凝后对藻细胞和浊度的去除均呈先上升后下降的趋势,并在照射50 min时达到最大值.PAC(聚合氯化铝)投加量为5 mg·L~(-1)时,照射样的除藻率和去浊率达到最大,分别比空白样高20.1%和18%左右.pH值在6~9范围内,紫外辐射强化混凝效果的变化较小.溶液pH=8、紫外照射50 min,混凝后的除藻率和去浊率分别达到了93.5%和90.6%.此时,藻细胞Zeta电位最大,同时释放出藻黏液,有利于混凝沉降.而当紫外照射超过60 min后,出现细胞膜破裂,胞内有机物渗出,使得溶液中的有机物浓度急剧上升,Zeta电位开始下降,不利于后续混凝的进行.