Preparation of Bio-beads and Their Atrazine Degradation Characteristics

Screened atrazine-mineralizing bacterium-Pseudomonas W4 was embedded inside an improved PVA- H<,3>BO<,3> embedment matrix to make bio-beads to degrade atrazine. The atrazine degradation characteristics were stu- died. The preparation procedure of bio-beads was as follows: (1) preparing a mixture of 100, 12.5, 10, 1.5 and 1 g/L PVA, bentonite(Ca), activated carbon powder, sodium alginate and centrifuged Pseudomonas W4 bacterium, respec- tively; (2) the mixture was dropped into a gently stirred cross linker solution(pH=6.7) and cured at 10 ℃ for 24 h. The optimal atrazine degradation conditions by bio-beads were as follows: pH=7, the auxiliary carbon source was glucose, and the concentration of glucose was greater than 325 mg/L. The bio-beads demonstrated stronger tolerance ability than the free microorganism to the increase of PCBs, hydrogen ion and hydroxide ion. SEM images show the uniform distribution of the microorganism inside bio-beads and the porous cross-linked structure of bio-beads which provides excellent mass transfer capacity.