Microbial Bioremediation of Agricultural Wastewater: Potential for Environmental Sustainability

Abstract

Wastewater from agricultural processing is known to contain high levels of organic matter, nitrogen and phosphorus and is a common source for surface-water pollution if it is discharged without treatment. This study aimed to investigate the ability of specific microbial strains to treat such wastewater and remove the pollutants. Samples from an agricultural processing facility were divided into various treatments, each containing a different culture of the microorganisms, as well as a control without microorganisms. The biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids, nitrate and phosphate were measured before and after the treatment and the microbial growth was monitored along the treatment period, along with the efficiency of removal of pollutants. One-way ANOVA was performed to compare treatments and percentage-removal calculations were used to identify the treatment that was most effective, using microbial approach. The mixed-culture treatment consistently performed better than the single-strain treatments for all parameters measured for BOD, COD, and TSS removals, and for nitrate reduction, with the largest percentage reduction achieved. The treatment with the mixed culture had the greatest percentage removal of TSS and the most complete removal of nitrate and phosphate. A significant positive correlation between the growth of microbial biomass and removal efficiency of pollutants was established with regression analysis. The results justify the use of microbial bioremediation and more specifically of mixed cultures as a practical and inexpensive method of treating agricultural effluents prior to discharge; scale up and further research ideas are presented at the end of the study.