Biodegradation Of Chlorobenzene-Ccontaminated Groundwater By Immobilized Microorganism

Groundwater is important for human beings.There are many kinds of Organic contamination in groundwater,which is of low content and huge harm.and is hard to degradate.lt is important to find an efficient remediation technology for Organic contamination in groundwater.Immobilized microorganism technology is a newly developing method for groundwater remediation in recent years.The following three aspects were researched in this text:(1) CB-degrading bacteria was cultured and the degradation characteristic of the microorganisms was discussed.(2) Polyving alcohol(PVA) and sodium alginate(SA) were used to encapsulate microorganism to make immobilized bacteria beads.The optimal conditions of the immobilized beads were obtained by the orthogonal experiment.The CB removal efficiency of the immobilized beads and the free microorganism was compared by the static experiment.The factors influencing the degrading ability of the immobilized microorgnism were studied.(3) By the indoor sand column experiment,the CB removal efficiency of the immobilized beads and the free microorganism were compared,and the effect of the transport of the immobilized beads on the CB removal of groundwater was studied.By the above research,the following results were gained:(1)Bacteria that could degrade CB was cultured. When the pH was about 7-9,the temperature was 10℃,the rotation speed of the shaking table was 120 r/min,the concentration of bacterium fluid was 8%.the concentration of the NaCl was less than 1.5%,the dosage of phosphate buffer solution was 4mL/L.the initial concentration of CB was 80 mg/L,The CB removal efficiency of the bacteria could reach about 60%.(2)The optimal conditions of immobilized beads were:PVA 80 g/L,SA 1.0%,CaCl21.0%,the volume ratio of embedding medium and bacterium fluid was 25:1.It was feasible for the immobilized microorganism to degrade CB in groundwater,and the removal efficiency of the immobilized beads was better than the free microorganism.When the the initial concentration of CB was 80 mg/L,the diameter of the bead was lmm,PH was about 7,the temperature was 10℃,and the rotation speed of the shaking table was 120 r/min,The CB removal efficiency of the bacteria could reach more than 70%.(3)It was better for the immobilized beads to transport when their diameter was smaller,and their CB removal efficiency could be better.The removal efficiency of the immobilized beads was better than the free microorganism by comparing the CB removal efficiency of the immobilized beads and the free microorganism in the sand column experiment.By comparing the CB removal efficiency of the immobilized beads in the sand column with different diameter coarse sand,the result shows that when the diameter of the immobilized beads was the same,the room for the transport of the immobilized beads got larger with the increasing of the diameter of the sand,and it helped the immobilized beads to degrade CB.