1、外文资料2009 International Conference on Energy and Environment TechnologyStudy on Coagulation-Microfiltration Combination Process for Treating Luan River Water Liang Wang, Yueqi Zhu Department of Environmental Engineering Tianjin Polytechnic University Tianjin, China e-mail: mashi7822 AbstractStudy on
2、coagulation-microfiltration combination process for treatment of Luan river water was carried out. The experimental results showed that when the dosage of FeCl3 was 35mg/L, the removal of turbidity was above 95%, the organic matter was above 50%, and recovery of membrane flux reached 81% for the com
3、bination process. On the other hand, among the four coagulants (FeCl3, Polymeric Ferric Sulfate, Al2(SO4)3, Polymeric Aluminum Chloride) the iron-based coagulant is superior to Al-based coagulant not only in the removal of turbidity but also the organic matter, and the effect of coagulation was affe
4、cted by pH. The results also suggested that coagulation could mitigate membrane fouling, and the influent water quality of MF membrane process which followed coagulation could be improved. Keywords-Coagulation; Membrane filtration; Membrane fouling I. INTRODUCTIONWith more and more serious pollution
5、 of water resources and implementation of the new Sanitary Standard for Drinking Water (GB 5749-2006) in China, conventional treatment process (e.g. coagulation-sedimentation-sand filtration- disinfection) which most existing water plants adopt could not provide satisfied drinking water1. In recent
6、years, Membrane Technology has been widely applied in water treatment for its prominent advantages, such as higher separation efficiency, more stable and reliable effluent water quality, shorter processes, and small occupation area, etc. Therefore, Membrane Technology has been considered as an impor
7、tant guarantee for the safety of drinking water at present. Nowadays microfiltration (MF) and ultrafiltration (UF) processes are main application techniques in water plants, but their removal ability of dissolved organic matter (DOM) are very poor (only about 5%10%) because the diameter of DOM in wa
8、ter is much smaller than the pore size of micro-filtration membrane or ultra-filtration membrane. So combined processes of enhanced coagulation, granular activated carbon (GAC) adsorption or photochemical oxidation with MF (or UF) were considered to be effective technologies to remove DOM in water 2
9、. Moreover, many studies have demonstrated that removal of DOM could be improved and membrane fouling could be alleviated when coagulation was used as pretreatment of membrane filtration process 3.The objective of this study was to discuss the influence of different coagulants and dosing methods on
10、removal efficiency of DOM and the influence of coagulation on membrane flux for combined process of coagulation-MF in treatment of Luan River water.II. MATERIAL AND METHOD Experimental Methods At first, raw water was pumped into a coagulation reactor where coagulant was dosed and the water was agita
11、ted with blender. Then two types of water samples were taken from the reactor, one was supernatant from coagulation-sedimentation followed by membrane filtration, another was mixed liquor from the coagulation reactor followed by membrane filtration. MF membrane used in the experiment was PVDF hollow
12、 fiber membrane with film holes diameter 0.22m, and fiber inside and outside diameter were 0.6mm and 1.0mm respectively, provided by MOTIANMO Company of Tianjin Polytechnic University. Self-made membrane module in U pattern, with length 40cm, 20 pieces and membrane surface in one set. III. SELECTION
13、 OF COAGULANTSA. The influence of different coagulants on removal effect of pollutants Four coagulants were considered in the experiment: ferric chloride (FeCl3), Polymeric Ferric Sulfate (PFS), aluminum sulfate (Al2(SO4)3) and Polymeric Aluminum Chloride (PAC). The experimental design was as follow
14、s: FeCl3, PFS, Al2(SO4)3, and PAC were used as coagulants in beaker test, dosage of which were 20mg/L, 25mg/L, 30mg/L, 35mg/L,40mg/L and 45 mg/L respectively. Removal of turbidity, TOC and UV254 were used to evaluate coagulation performance. 1) The influence of coagulants under different dosing cond
15、itions on removal of turbidity It was showed that removal of turbidity increased with the increase of coagulants dosage, especially for aluminium coagulants. Among the four coagulants the best removal efficiency of turbidity was when PFS was added and the poorest removal of turbidity was obtained wh
16、en Al2(SO4)3 was added. When the dosage was set at 45 mg/L, removal rate of turbidity for the four coagulants were separately 93.87% (PFS), 91.21% (FeCl3), 86.15% (PAC) and 82.9% (Al2(SO4)3).However, in view of efficiency disparities among them,due to the main aluminium species in aluminium coagulant solutions are monomeric species as well as polymeric species which make up of floc
