| The combined wastewater process of enhanced coagulation and dynamic membrane to treat contaminated river water was put forward, and the idea was based on a great deal of relevant researches both home and abroad and the serious polluted status in quo of river in China. In this paper coagulant and optimized coagulation conditions were selected based on jar tests. Then, appropriate support media attached dynamic membrane was chosen. After that, pollutants removal and dynamic membrane formation ad filtration process were studied under two operation conditions: constant pressure and constant flow. The research provides a new idea to solve the problem of city river pollution, and it also offers technical support for application of the technology. Main research contents and the results are as follows:1. The contaminated river water was treated in Zhulong river in Zibo and Yaotou river in Jinan. Because the contaminated river water of Zhulong river was directly pumped into the southern wastewater treatment plant of Zibo City for enhanced coagulation treatment, the effluent quality, the size and the growth speed of floc, the removal efficiency of turbidity, COD, SCOD, TP and the effect of pH were investigated to select the optimum coagulant. The combination use of inorganic coagulant and organic flocculants and the impact of load were also studied.The results showed that the optimized coagulants were APAM and PDMDAAC, and the optimum dosage were 0.3mg / L and 0.5mg / L, respectively. COD removal efficiency of APAM was 54 %～64 %, and for PDMDAAC, it was 43 %～60 %. APAM and PDMDAAC had lower removal efficiency of TN, about 15 %～20 %, but the TP removal efficiency is higher, for about 70 %～80 %. The removal efficiency of turbidity was above 86 % when the dosage of APAM is above 0.3 mg/L. The pH had little effect on the removal of COD for both APAM and PDMDAAC. At pH 7～10 range good coagulation performance was obtained. When load raised from 0.8m~3/ (m~2·h) to 1.2m~3/ (m~2·h), the influence of the COD and turbidity removal efficiency was insignificant.For the more seriously contaminated river water of YaoTou river in Jinan, the selection of coagulant was based on removal efficiency of turbidity, COD, SCOD, TP, and pH effect. Photometric Dispersion Analyzer was used to study the floc formation process, the content of residual aluminum in effluent was also investigated. The results showed that the optimization of coagulant was PAC, and the optimum dosage was 60 mg / L. The results of PDA online research for floc formation process showed that the optimum coagulation conditions were rapid mixing (200 rpm) 1 min, slow stirring (40 rpm) 1.5 min, static precipitation 3 min. pH changes had little effect on pollutant removal efficiency. The content of residue aluminum in effluent showed that utilization of PAC was best when at pH 7.2. Based on the recently research of dynamic membrane and the common support media filter in market, five different kinds of support media - dacro mesh (140 mesh), dacro mesh (260 mesh), non-woven fabric filter(75 g/m~2), non-woven fabric filter (450 g/m~2) and stainless steel net (140 mesh) were studied, and membrane flux, the effect on filter performance and economic comparison were conducted.The results showed that the dacro mesh (140 mesh) was suitable support media, because of the slower increase in water head drop, the more stable dynamic membrane, and non-shedding during operation. Non-woven fabric and dacro mesh were two types of material. Non-woven fabric (450 g/m~2 ) which was easy in the formation of dynamic membrane and slow in water head drop was also chosen for further inspection. Therefore, dacro mesh (140 mesh) and non-woven fabric (450 g/m~2) were the selected support media for the formation of dynamic membrane. Dynamic membrane reactor can greatly reduce the construction costs because the support media was cheap.3. At constant pressure condition when dacro mesh (140 mesh) and non-woven fabric filter (450 g/m2) as the support media, the removal efficiency of turbidity, organic matter, TP and TN were investigated in treating the contaminated river water of YaoTou river. The reactor was run at 2 cm water head drop (WHD), 4 cm WHD, 6 cm WHD, 8 cm WHD and 10 cm WHD,the aeration intensity was 0.1 m~3/h. The formation of dynamic membrane and filtration mechanism were studied under the condition of constant pressure in accordance with the relation of effluent volume and running time.The results showed that the removal efficiency was higher no matter the non-woven fabric or dacro mesh as support media. When non-woven fabric acted as support media the formation time for coagulation - dynamic membrane was 70 min at 4 cm WHD and 20 min at 8 cm WHD. The formation process of dynamic membrane was complete-standard model.While after the dynamic membrane formation, intermediate-standard model and cake- standard model worked, and intermediate-standard model play a major role. After the dynamic membrane formation, Intermediate-standard model, Cake-intermediate model and Cake-complete model were fit better than typical models, and the cake model plays a major role in the combined models, next is the intermediate model. When dacro mesh acted as support media the formation times for coagulation - dynamic membrane were 100 min at 4 cm WHD and 70 min at 8 cm WHD. The formation process of dynamic membrane was complete-standard model. While after the dynamic membrane formation, intermediate-standard model and cake- standard model worked, and cake-standard model plays a major role.4. At constant flow condition, non-woven fabric and dacro mesh were also used to investigated the characteristics of reactor operation. Removal efficiency of turbidity, organic matter, TP, TN, and flux changes of the water head drop during the operation process were studied. And according with the changes of pressure versus running time the formation and mechanisms of coagulation - dynamic membrane filtration were derived.The results showed that the chosen support media all has higher removal efficiency of turbidity, COD removal efficiency was more than 50 %, and TP removal efficiency was above 85%. For the entire operation process, the intermediate-standard model was better than other models to interpret the filtration process.When non-woven fabric acted as support media, based on pressure changes with time in the whole operation, two phases were divided: the first phase was 0～9.5 h (4.72 pa/h), the second phase was 9.5～20 h (113.9 pa/h). Complete - Standard model can better explain dynamic membrane formation and filtration process of the first phase. And for the second phase, intermediate-Standard model can better explain the formation of dynamic membrane filtration process. When dacro mesh acted as support media, intermediat model can better explain the formation of dynamic membrane filtration process, and after that, cake model plays a major role.5. Two main factors (flux and cross-flow velocity) which affected coagulation -dynamic membrane reactor were studied. At different cross-flow velocity and membrane flux, the removal efficiency of turbidity, COD and TP were investigated.The results showed that the optimum aeration capacity was 0.15 m~3/h, and at this aeration capacity the cross-flow speed was 2.85 cm/s. And at this cross-flow velocity, the effluent turbidity is below 1 NTU after the dynamic membrane was formed, and the removal efficiency of COD, TP were higher. Flux had an impact on particle deposition on the support media surface. Larger flux was conducive to floc deposition at the support media surface and favored the formation of cake layer. The results showed that the favorable flux was 75 L/(m~2·h). Water head drop of the effluent had considerably small effect on removal of COD and TP. On the whole the flux of coagulation - dynamic membrane at different water head drop was the same.
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