The Quality Control of Eutrophic Culture Sediment by Immobilized Cells and Conditions Manipulation

Abstract

The sediment in intensive culture pond is overloaded by substantial unused nutrients and is conventionally discharged into adjacent coastal areas, which is detrimental to environment. This paper produced a preliminary quality control experiment to mitigate pollution of culture sediment by immobilized Bacillus sp. HSW cells on the composite carrier of sodium alginate and artificial zeolite. Glucose and calcium peroxide respectively were used to improve the sediment conditions of C/N ratio and oxygen level. The sediment quality was monitored periodically for 30 days. The results showed that biocontrol by immobilized Bacillus sp. HSW cells alone would be infeasible. However, the immobilized cells would better perform under controlled conditions. The significant decreases for total nitrogen (TN), total ammonia nitrogen (TAN), and organic nitrogen (ON) were observed at 71%, 91% and 64%, respectively. The phosphorus precipitated as phosphate raised approximately 120 mg/kg, and 60% of organic phosphorus was removed in 30 days. Moreover, the total bacteria abundance presented an obvious increase for over an order of magnitude, which was positive relationship (p < 0.01) to the removal rates of ON and OP. Therefore, the immobilized cells accompanied by environmental manipulation are promising for biocontrol of culture sediment.