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Xiang P.,Chongqing University | Jiang S.-J.,Chongqing University | Zhang Z.,Chongqing University | Lai L.,Southwest Research Institute | Zhang N.,Chongqing Sino French Water Supply Co.
Chongqing Daxue Xuebao/Journal of Chongqing University | Year: 2011

High turbidity raw water of Jialing River in summer is treated by polyaluminum chloride (PAC) and Polydimethyldiallylammonium chloride (PDM) composed with PAC. Jar tests are used to study the removal effect of turbidity and organics by PAC-PDM and single PAC. The results show that the turbidity and organics removal capacities of composed coagulants is better than that of single PAC and the optimum proportion of PAC-PDM is 3:500. The charge neutralization is the dominant mechanism for organics removal. Using this optimum proportion of PAC-PDM to perform the continuous production test, when the effluent quality meets the requirement of Standards for Drinking Water Quality (GB5749-2006), PAC-PDM and PAC average dosage are 15~60 mg/L and 6~40 mg/L respectively, which can save about 40%dosage cost compared with single PAC for the water plant in the treatment of raw water. Source


Jiang S.,Chongqing University | Jiang H.,Chongqing Jiaotong University | Xiang P.,Chongqing University | Zhang N.,Chongqing Sino French Water Supply Co. | And 2 more authors.
Chinese Journal of Environmental Engineering | Year: 2013

Because of the algae outbreak in Jialing River water system, the algae in source water was hard to be removed in pretreatment process, which caused more than 10 water factorties' blockage in filter and shorten the backwashing cycle from normal 24 h to 2 h. It seriously affected normal operation and dramatically decreased the producing ability of waterworks. Due to the algae outbreak (the dominant species was synedra acus belonging to Diatoms), the effect of PAFS, PAC, and PFC coagulants on algae removal and turbidity removal was compared, with PAFS presenting the best effects, which was chosen as the optimal coagulant. In addition, different pro-oxidations and coagulant aids were added to enhance flocculation removal effects of algae, the result showed that PDMDAAC combined with PAFC gave the best effect, and other promoting coagulation effect was PPC>ClO2>PAM>H2O2>HCA-1. Using 0.6 mg/L PDMDAAC+25 mg/L PAFS applied to exising plants, the residual algae decreased to 49×104~55×104 cells/L, the algae removal rate could reach up to 70%~75%, which greatly reduced the operation load of the filter and recoved the normal operating mode of the waterworks. Source


Jiang S.,Chongqing University | Jiang H.,Chongqing University | Xiang P.,Chongqing University | Zhang N.,Chongqing Sino French Water Supply Co. | And 2 more authors.
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2012

According to the algae outbreak (the dominant species was synedra acus belonging to Diatoms) in source water, the effects of PAFS, PAC, and PFC coagulants on algae removal and turbidity removal were compared. PAFS was chosen as the optimal coagulant. In addition, different pro-oxidations and coagulant aids were added to enhance flocculation removal effects of algae. The experimental results show that PDMDAAC combined with PAFC shows the best effect, and the order of other promoting coagulation effect was PPC>ClO2>PAM>H2O2>HCA-1. Based on the box-Behnken Design (BBD) experiment design principle, the effects of pH, stirring rate and stirring time on algae removal using PAFS+PDMDAAC were investigated. The results show that the three factors play significant effect on the removal of synedra acus, and the influence degree is pH>stirring rate>stirring time, while the interactive influence of the three factors is not significant. Moreover, the optimum condition of enhanced coagulation is obtained, in which pH is of 7.5, stirring rate is 75 r/min and stirring time is 15 min, and the alga removal effect is 98.75%. Source


Xiang P.,Chongqing University | Zhang Z.,Chongqing University | Zhang N.,Chongqing Sino French Water Supply Co.
Chongqing Daxue Xuebao/Journal of Chongqing University | Year: 2013

Recent researches on the Yangtze River and the Jialing River water in Chongqing section of the Three Gorges Reservoir indicate that the pH value is relatively high and the CODMnconcentration is more than 4.5 mg/L in most of the time. Especially the proportion of dissolved molecule organic is high, as well as the high turbidity during the summer flood period. And the organic contamination is relatively serious. The fuzzy weighted water quality coefficient and hierarchical cluster analysis methods are applied to evaluate and sort the characteristic qualities of two-river water sources. During the research period, the results show that the Yangtze River water source quality is characterized by high turbidity and polluted of summer stage, middle temperature and micro-polluted of spring-autumn stage and low temperature and micro-polluted of winter stage. The Jialing River water source quality is characterized by low turbidity stage, high alga-polluted of early spring stage and high temperature and polluted of winter stage. Due to the various water qualities of two-river water sources at different periods, it is hard to meet the requirement of Standards for Drinking Water Quality (GB 5749-2006) by using traditional water treatment technologies. So the research on enhanced treatment is necessary. Source


Xiang P.,Chongqing University | Zhang N.,Chongqing Sino French Water Supply Co. | Jiang S.,Chongqing University | Zhang Z.,Chongqing University
Advanced Materials Research | Year: 2011

In this study, micro-polluted raw water in winter western mountainous cities was treated by PAC-PDM. The CCD model of response surface methodology was employed to investigate the removal rate of turbidity. Taken the model as constraint conditions and taken the minimum agent cost as the objective function, optimization model of composite coagulants is established. The results showed that when the turbidity was 1 NTU, the dosage of PAC (based on Al 2O3) is about 26mg/L, and the proportion of optimization model of composite coagulant PAC-PDM is 5% and the dosage of PAC (based on Al2O3) is about 8mg/L. Therefore the dosage of PAC of the optimized composite coagulant could be decreased by about 70%, and agent costs decreased by about 56% compared with those of PAC. © (2011) Trans Tech Publications. Source

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