Resumen
The study investigated the impact of effective microorganisms on the microbiological and physicochemical parameters of produced water. Produced water was obtained from Ebocha oil field within Rivers state. The spread plate method was used to determine the total heterotrophic bacterial counts, and pure isolates were subjected to biochemical characterization. Pure bacterial suspension of Lactobacillus plantarum, Aspergillus sp. and Penicillium italicum were obtained and subsequently inoculated into wastewater sample in consortium. Treated (with the consortium) wastewater sample was analyzed at interval for their physicochemical and microbiological parameters during the appropriate period of incubation (14 days) at room temperature. The bacterial load of produced water decreased from 1.3 x 108 cfu/ml to 3.6 x 107 cfu/ml, coliform counts increased from 2.0 x 105 cfu/ml to 1.4 x 106 cfu/ml, Staphylococcal counts decreased from 3.4 x 105 cfu/ml to 0 cfu/ml and Vibrio counts decreased from 8.0 x 105 cfu/ml to 2.0 x 105 cfu/ml. Biochemical characterization of bacterial isolates from the wastewater revealed the presence of Enterobacter sp, Bacillus sp, Klebsiella sp, Proteus sp, Escherichia coli and Staphylococcus sp. The pH and temperature ranges of water sample during the period of treatment varied. The BOD values decreased from 240 mg/L to 21 mg/L while the COD values decreased from 400 mg/L to 160 mg/L. The results of the heavy metal assessment revealed an appreciable reduction in the heavy metal concentrations of the sample. The concentration of zinc in produced water decreased from 0.113 mg/L to an undetectable level (< 0.01 mg/L), iron concentration decreased from 1.071 mg/L to 0.139 mg/L, Nickel decreased from 2.110 mg/L to 1.081 mg/L while copper and cadmium were undetected. The use of effective microorganisms in the treatment of produced water was effective in the reduction of microbial load, biochemical oxygen demand (BOD), chemical oxygen demand (COD) and removal of heavy metals.