Qian Yi

Microbial degradation of quinoline by immobilized cells of Burkholderia pickettii.

A quinoline-biodegrading microorganism was isolated from activated sludge of coke-oven wastewater treatment plant using quinoline as sole carbon and nitrogen source. It is a gram negative, rod-shaped and aerobic strain, which was identified as Burkholderia pickettii. The biodegradation of quinoline was carried out with this isolated strain. Analysis by high performance liquid chromatography and gas chromatography/mass spectrum (GC/MS) revealed that 2-hydroxyquinoline (2-OH-Q) was the first intermediate in the course of quinoline biodegradation. A novel immobilization carrier, that is, polyvinyl alcohol (PVA)-gauze hybrid carrier, was developed. The isolated strain was immobilized by two different immobilizing techniques and used for the quinolinerdegradation. It was found that biodegradation rate of quinoline by the microorganisms immobilized on PVA-gauze hybrid carrier was faster than that by the microorganisms immobilized in PVA gel beads. Kinetics of quinoline biodegradation by cells of Burkholderia pickettii immobilized on PVA-gauze hybrid carrier was investigated. The results demonstrate that quinoline degradation could be described by zero-order reaction rate equation when the initial quinoline concentration was in the range of 50-500 mg l(-1).

Efficacy of pre-treatment methods in the activated sludge removal of refractory compounds in coke-plant wastewater

Abstract In this study, the possibility and mechanism of anaerobic acidification, ultraviolet radiation, and ozonation as pretreatment methods for improving the biotreatability of coke-plant wastewater have been investigated, a new process—A-A/O system—has been proposed and experiments in lab-scale apparatus and pilot plant have been conducted. It has been concluded that the tested A-A/O system is an efficient and cost-effective way for removing refractory organics from coke-plant wastewater.

Biodegradation of 2,4-dichlorophenol in an air-lift honeycomb-like ceramic reactor

Abstract A novel air-lift bioreactor, with a honeycomb-like ceramic column packed in the inner draft tube as the carrier for immobilization of microbial cells, was developed in this laboratory. A microorganism, identified as Achromobacter sp. and capable of degrading 2,4-dichlorophenol (2,4-DCP), was immobilized in the ceramic carrier and used for biodegradation of 2,4-DCP. Semi-continuous biodegradation of 2,4-DCP as a single substrate and in the presence of phenol as co-substrate was investigated. The results showed that when 2,4-DCP occurs alone, its biodegradation rate increased gradually from Run 1 to Run 6 and the degradation process could be described with zero-order kinetics model. When phenol was used as co-substrate, the existence of phenol could inhibit the biodegradation of 2,4-DCP and the biodegradation rate of 2,4-DCP decreased gradually. However, the biodegradation of phenol increased with the increase of run number of the batch experiments. In addition, continuous degradation of 2,4-DCP was also investigated. The results indicated that 2,4-DCP at the concentration ranged from 6.86 to 102.38 mg l −1 could be degraded at a dilution rate of 0.16 h −1 and the removal percentage ranged between 84 and 100%. The effect of interruption of 2,4-DCP supply to the bioreactor on the degradation ability of microbial cells was investigated by replacing 2,4-DCP with sodium acetate as the sole carbon source for 12 days. Intermission of 2,4-DCP supply did not cause the loss of chlorophenol-degrading ability.