The effect of coupling coagulation and flocculation with membrane filtration in water treatment： A review

Water supply and sanitation demands are foreseen to face enormous challenges over the coming decades to meet the fast growing needs in a global perspective. Significant growth in the industry is predicted and membrane separation technologies have been identified as one of the possible solutions to meet future demands. Application and implementation of membrane technology is expected both in production of potable water as well as in treatment of wastewater. In potable water production membranes are substituting conventional separation technologies due the superior performance, potential for less chemical use and sludge production, as well as the potential to fulfill hygienic barrier requirements. Membrane Bio-Reactor (MBR) technology is probably the membrane process which has had most success and has the best prospects for the future in wastewater treatment. Trends and developments indicate that this technology is becoming accepted and is rapidly becoming the best available technology (BAT) for many wastewater treatment applications. A major drawback of MBR systems is membrane fouling. Studies have shown that fouling mitigation in MBR systems can potentially be done by coupling coagulation and flocculation to the process.     

絮凝学研究的新领域——具有重金属捕集功能的高分子絮凝剂

絮凝是水质净化的重要方法之一.絮凝剂的作用对象主要是水中由不溶性物质形成的憎液溶胶及悬浮颗粒.近年来的研究发现,将重金属离子的某些强配位基团通过化学反应连接到高分子絮凝剂分子上能赋予原有高分子絮凝剂捕集水中溶解性重金属离子的功能,因此制备出具有去除重金属离子功能的高分子絮凝剂.研究表明,这类高分子絮凝剂用于水处理时表现出显著的优点,如去除效率高、沉降速度快,分离效果好,尤其适合于处理重金属离子与浊度共存的体系,显示出很好的研究及应用前景.本项研究拓展了絮凝剂作用对象的种类,开创了水处理絮凝学研究的新领域.     

聚铝及其加载粘土矿物高效絮凝沉降铜绿微囊藻的研究

考察了4种聚铝絮凝剂絮凝沉降铜绿微囊藻的效果，发现编号为HPACS02的聚铝絮凝剂除藻效果最好，并进一步研究得知HPACS02在pH7．5时絮凝除藻的效率最高。在采用HPACS02作为絮凝剂时，如果少量投加滑石、海泡石或高岭土等粘土矿物会对铜绿微囊藻的絮凝沉降产生增效作用，其中滑石的助凝效果最好。     

絮凝-DAF(dissolved air floatation)工艺的化学因素与颗粒特征研究

研究了絮凝－DAF工艺的化学因素和颗粒特征。PAC类絮凝剂的碱化度B值越高，其荷电量和立体结构越显著，絮凝－DAF工艺的除浊效果越好；但除了絮凝剂的电中和能力外，其形成絮体的结构特征也对絮凝－DAF工艺有影响。随着投药量、絮凝搅拌强度和时间的增加，絮体都分别会趋于某一极值尺寸而后逐渐变小，且较大粒度的密实絮体才是与微气泡作用效果最好的絮体。此外，增加絮凝搅拌强度和延长时间都可能有利于水中颗粒的去除，且DAF出水中粒径越大的颗粒含量越少，其中大于15μm的颗粒极少，但2－4μm的颗粒数目时常多于原水。     

混凝过程中铝与聚合铝水解形态的动力学转化及其稳定性

采用Ｆｅｒｒｏｎ逐时络合比色法，并结合电泳测定研究了混凝过程中氯化铝和聚合氯化铝的水解形态动力学转化及稳定性。结果表明，ＡＣ在混凝过程中所形成的水解形态完全不同于ＰＡＣ的预制水解聚合形态，其电荷及分子量均明显低于聚合铝且不稳定，ＡＣ随混凝条件如投加浓度、ＰＨ和混合时间而变，而ＰＡＣ－２５水解聚合形态不随混凝条件变化，始终保持稳定状态，ＡＣ水解沉淀规律与理论计算相符并形成无定形Ａｌ（ＯＨ）３絮体颗粒     

Purification of AS-CMP effluent by combined photosynthetic bacteria and coagulation treatment

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｐｕｌｐａｎｄｐａｐｅｒｉｎｄｕｓｔｒｙｉｓａｍａｊｏｒｃｏｎｔｒｉｂｕｔｏｒｔｏｗａｔｅｒｐｏｌｌｕｔｉｏｎｉｎＣｈｉｎａ.Ｉｎ1995,ｔｈｅｗａｓｔｅｗａｔｅｒｄｉｓｃｈａｒｇｅｄｂｙｐｕｌｐａｎｄｐａｐｅｒｉｎｄｕｓｔ...     

膨润土吸附－絮凝法处理废水中的有机染料

研究了天然膨润土对阳离子、分散、还原、中性、活性和直接等类有机染料的吸附特性，并比较了膨润土吸附－絮凝法与单纯絮凝法处理染料水溶液的脱色效果，前者比后者的脱色率可提高４０％－２００％。使用０．０１％的膨润土加０．００５％的聚合氯化铝，可使以阳离子染料为主的印染废水脱色率达９４％－１００％。     

应用旋流絮凝法处理选矿废水

将Х１８ｍ的浓缩机改为两级串联旋流絮凝沉淀池处理选矿废水，达标率为１００％，净化率为９９．８５％，其它水质指标均低于国家废水排放标准，浓缩机底部排污率由１５％提高到３１．８９％，还可获得１４３．１４万元／年的直接经济效益。     

铝质固体废料制取聚合氯化铝及絮凝脱色性能

采用酸溶一步法利用三种铝质固体废料制取了聚合氯化铝。实验表明 :该法生产聚合氯化铝 ,工艺可行 ,产品主要指标满足国家标准 (GB1 5892 95)的要求 ,所制的PAC对模拟染料废水的絮凝效果与用AlCl3.6H2 O制成的聚合氯化铝的相当。     

Chemical and biological flocculation process to treat municipal sewage and analysis of biological function

The pilot-scale experimental apparatus and the procedure of the chemical and biological flocculation process to verify the feasibility in treating Shanghai municipal sewage were introduced in this paper. In addition, the biological function of the process was discussed. The results of optimal running showed that in the reaction tank, the concentration of mixed liquor suspended solid(MLSS) was 2 g/L, hydraulic retention time(HRT) was 35 min, dosage of liquid polyaluminium chloride(PAC) was 60 mg/L, and the concentration of polyacrylamide(PAM) was 0.5 mg/L. The effluent average concentrations of CODcr, TP, SS and BOD5 were 50 mg/L, 0.62 mg/L, 18 mg/L, and 17 mg/L, respectively. These were better than the designed demand. In addition, the existence of biological degradation in this system was proven by several methods. The removal efficiencies of the chemical and biological flocculation process were 20% higher than that of the chemical flocculation process above at the same coagulant dosage. The treatment process under different situations was evaluated on a pilot-scale experiment, and the results provided magnificent parameters and optimal condition for future operation of the plant.