Xie Qinglin

Study on New Method of Microorganism Acclimation for Biological Treatment of High-Salinity Oilfield Wastewater

A new method of microorganism acclimation for biological treatment of high-salinity oilfield wastewater was proposed, in which the salinity was increased in logarithmic mode, while in the traditional method the salinity was mainly increased in proportion. A contrast experiments was made between new method and the traditional method. The quality of the influent is as follow: salt content was ranged from 27.4 to31.8 g L¨C1, the value of COD ranged from 350 to 640 mg L¨C1, the petroleum hydrocarbon was 10.5 mg L¨C1. The COD removal rate, bacteria adaptation rate and petroleum hydrocarbon removal rate of the new method was 82.3%,86.1% and 69.2%, respectively. These value of traditional method was 72.4%, 75.6% and 60.8%, respectively. The activated sludge acclimated by the new method is less vulnerable to high salt concentration and the structures of the sludge are more stable than the sludge acclimated by the traditional method.

Effects of ORP, recycling rate, and HRT on simultaneous sulfate reduction and sulfur production in expanded granular sludge bed (EGSB) reactors under micro-aerobic conditions for treating molasses distillery wastewater.

An expanded granular sludge bed (EGSB) reactor was adopted to incubate the sludge biogranule that could simultaneously achieve sulfate reduction and sulfide reoxidization to elemental sulfur for treating molasses distillery wastewater. The EGSB reactor was operated for 175 days at 35 °C with a pH value of 7.0, chemical oxygen demand (COD) loading rate of 4.8 kg COD/(m³ d), and sulfate loading rate of 0.384 kg SO(4)(2-)/(m³ d). The optimal operation parameters, including the oxidation reduction potential (ORP), recycling rate, and hydraulic retention time (HRT), were established to obtain stable and acceptable removal efficiencies of COD, sulfate, and higher elemental sulfur production. With an ORP of -440 mV, a recycling rate of 300%, and HRT of 15 h, the COD and sulfate removal efficiencies were 73.4 and 61.3%, respectively. The elemental sulfur production ratio reached 30.1% when the elemental sulfur concentration in the effluent was 48.1 mg/L. The performance results were also confirmed by the mass balance calculation of sulfate, sulfide, and elemental sulfur over the EGSB reactor.

The Screening of Strains Degradation Oil Wastewater and Studies on its Characteristics

Three oil degrading strains, named JZ3, JZ10 and JZ4 were screened out from an oil wastewater treatment plant. Their oil removal rates were 52.9%, 52.27%and 50.65%, respectively. The effect of temperature, pH, shaking speed, inoculation amount and culture time were studied. It was showed that the optimal temperatures of the JZ3, JZ4 and JZ10 were all 40°C; the optimal pH values were 7, 6, 5.5, respectively, the optimal shaking speeds were 110r/min, 130r/min, 110r/min, respectively, the optimal inoculation amounts were 3%, 3%, 2%, respectively, the optimal culture times were 6h, 21h, 22h, respectively.