Fanzhong Chen

Geochemical characteristics of inorganic sulfur in Shijing River, South China

Different inorganic sulfur species distributed in overlying water, pore water and sediment in a heavily polluted river were determined. The concentrations of S(2-) and SO(4)(2-) in the overlying water were much more than those in the pore water. This result perhaps indicates the S(2-) was mainly from discharged wastewater, not from sediment resuspension. In the sediments, acid-volatile sulfide, chromium(ii)-reducible sulfide, and elemental sulfur were determined by a modified diffusion method. The results indicate that acid-volatile sulfide was the dominant component of the reduced inorganic sulfur, making up about 62% of the total reduced inorganic sulfur.

Water quality remediation in a heavily polluted tidal river in Guangzhou, South China

A field-scale experiment was performed to remediate a heavily polluted river located in the urban area of Guangzhou, China using biological and chemical techniques combined with engineering processes. Before comprehensive remediation was undertaken, several small-scale experiments to test river-water remediation techniques were successfully performed. After comprehensive remediation, the average reduction rates of chemical oxygen demand and biochemical oxygen demand and removal rates of other pollutants were all above 70 percent. Furthermore, the unpleasant odor emanating from the polluted river was also greatly reduced. The field-scale experiment thus indicated the feasibility and validity of the method applied to remediate this heavily polluted river; this method can therefore be applied to remediate other heavily polluted rivers in the Guangzhou urban area and elsewhere.

Factors influencing the purification efficiency of photosynthetic bacteria

One strain of photosynthetic bacteria (PSB) was isolated from substrate sludge of fresh-water fishpond. Influence of the use level of PSB culture solution, illumination condition, temperature, salinity, the use level of copper sulfate and dipterex on the purification efficiency was investigated. The results showed that the optimum use level of PSB culture solution was 10 mg/L, and the purification efficiency at illumination was higher than that at black, and if the temperature was lower than 15 °C., or the use level of sodium chloride, copper sulfate and dipterex were higher than 10 000 mg/L, 0.4 mg/L and 2.0 mg/L, respectively, the purification efficiency dropped distinctly.