Cui Fuyi

Study on coagulation property of metal-polysilicate coagulants in low turbidity water treatment

In order to remove the low turbidity present in surface water, a novel metal-polysilicate coagulant was used to treat the raw water taken from Tanjiang River in Guangdong Province. This study on the effects of A1/Fe molar ratio on the performance of a complex compound formed by polysilicic acid, aluminium and ferric salt (PAFS) showed that PAFS with Al/Fe ratio of 10∶3 seemed to have the best coagulation performance in removing turbidity and color. Experimental results showed that under the conditions of polymerization time of 15 d, sedimentation time of 12 min, and pH of 6–8, PAFS with Al/Fe molar ratio of 10∶3 had the best coagulation efficiency and lowest residual Al concentration. The turbidity decreased from 23.8 NTU to 3.23 NTU and the residual Al concentration was only 0.165 mg/L in the product water. It could be speculated that colloidal impurities and particulate Al were removed by adsorption bridging and electrical neutralization of long chain inorganic polymer coagulants.In order to remove the low turbidity present in surface water, a novel metal-polysilicate coagulant was used to treat the raw water taken from Tanjiang River in Guangdong Province. This study on the effects of A1/Fe molar ratio on the performance of a complex compound formed by polysilicic acid, aluminium and ferric salt (PAFS) showed that PAFS with Al/Fe ratio of 10∶3 seemed to have the best coagulation performance in removing turbidity and color. Experimental results showed that under the conditions of polymerization time of 15 d, sedimentation time of 12 min, and pH of 6–8, PAFS with Al/Fe molar ratio of 10∶3 had the best coagulation efficiency and lowest residual Al concentration. The turbidity decreased from 23.8 NTU to 3.23 NTU and the residual Al concentration was only 0.165 mg/L in the product water. It could be speculated that colloidal impurities and particulate Al were removed by adsorption bridging and electrical neutralization of long chain inorganic polymer coagulants.

Drinking water toxicity study of the environmental contaminant--Bromate.

Bromate is a byproduct of water disinfection that is produced when waters contain bromide treated with ozone. To investigate the level of the toxicity of bromate and find the most sensitive indicators in a short time, a series of toxicological assessments were conducted including the acute toxicity, cumulative toxicity, genetic toxicity and subacute toxicity of bromate (using Potassium Bromate to represent bromate). The LD50 of orally administered Potassium Bromate was 215 mg/kg in Wistar rats and 464 mg/kg in ICR mice. The cumulative toxicity of Potassium Bromate was not obvious. The Ames test, mouse bone marrow cell micronucleus test and mouse sperm abnormality test did not indicate mutagenicity. The results of the subacute study did not exhibit significant differences in most of the parameters, except the white blood cell count, which was significantly decreased in male rats. In addition, Potassium Bromate influenced the albumin, creatinine, total cholesterol, triglycerides and glucose levels in male rats to various extents. A thorough analysis of the above tests clearly demonstrates that bromate has toxicity, not obvious cumulative toxicity and the white blood cell count can be used as an indicator to reflect the toxicity of bromate and investigate bromates toxic mechanism.

Effect of Continuous Direct Recycling of Combined Residual Streams on Water Quality at the Pilot Scale in Different Seasons

AbstractThe overall objective of this study is to conduct pilot-scale experiments to examine the effects of the direct continuous recycling of combined residual streams (CRS) of clarifier sludge (C...

The harm and control technology of Limnoperna fortunei

The harm to raw water supply and treatment of Limnoperna fortunei is a new problem. It not only has influence on the ecosystem of water source and the water quality and resistance in the transmittion process, but also does harm to the facilities of water treatment. Through analysis of lots of literatures, the biological characters and damages of Limnoperna fortunei are summarized in this paper. Meanwhile, the author discusses the control technologies at home and abroad and makes suggestions on future study.

Characterrictics of bioaccumulation of DDT by Microcystis aeruginosa in water

Currently synergistic pollution occurs in the presence of cyanobacteria and synthetic organic compound in water body. Consequently, it is of great significance to reveal the partition of persistent organic pollutants in water phase and algae phase for understanding mechanisms of partition and transformation of persistent organic pollutants in natural water environment. In this study bioaccumulation processes of DDT in Microcystis aeruginosa were investigated experimentally, and effect of HA concentrations and pH on the bioaccumulation effectiveness of DDT in Microcystis aeruginosa was also studied. Results showed that if DDT concentration was less than 100^g / L, DDT removal efficiency will be above 70% The presence of humic acid in water will impede bioaccumulation of DDT by Microcystis aeruginosa. When the pH value is between 8.5 and 9.5, the best bioaccumulation effectiveness could be reached. Therefore under suitable conditions removal efficiency of synthetic organic compound could be effectively improved when algae was removed from natural water body.

Study of Bromate Formation and Control by Ozonation-Biological Activated Carbon Process

The formation of bromate by ozonation-biological activated carbon process is a problem of drinking water treatment. By pilot test, the influence of bromide ion concentration, contact time of ozone column, ozone dosage, Ct value, changes of water quality and adsorption time of activated carbon column on bromate formation and control were investigated. The results showed that when [Br-]=100~500μg/L, t=3~15min, the process operating parameters could be adjusted to control the concentration of BrO3- which did not exceed the amount of 10μg/L. The changes of TOC, UV254, temperature, ammonia nitrogen, pH would affect the concentration of BrO3- formation. When the adsorption time of biological activated carbon column reached 20min, the average removal efficiency of BrO3- could achieve 62.24%. When [Br-]≤300μg/L, the Water quality of ozonation-biological activated carbon process could meet the requirements of [BrO3-]¿10μg /L.