Growth rate and Pattern of Sulphate Reducing Bacteria in Produced Water from Niger Delta Oilfield,Nigeria

摘要

In Nigeria,it is estimated that most oilfields average water to oil ratio is about 1:1,roughly one billion barrel of produced water are annually disposed during oil field production operations,as a result,deterioration of the physicochemical and bacteriological property of the disposal site has been observed.Common produced water impurities are;carbon dioxide,hydrogen sulfide,dissolved organic materials,suspended formation materials,and finally,most of time,are oxygen deficient etc.Most routine produced water treatments does not include consideration for the growth of specific bacteria such the Sulphate reducing bacteria(SRB)which are present in most produced water and ground water.In this study,four(4)produced water samples from Niger Delta oilfields,Nigeria were treated before subjecting to SRB growth monitoring test using serial dilution.The test procedure was based on National Association of Corrosion Engineers(NACE)International Test Method.The growth rate(culturing)of bacteria were monitored after 28 days.The results revealed there was an average constant growth rate between 4 to 28 days,inferring an exhaustion of essential nutrients and/or accumulation of toxic products of metabolism that generally limits the period of high growth.Therefore,prior to disposal of produced water into the environment,routine produced water treatment methods should include disinfection to take care of sulphate reducing bacteria.Additionally,the presence of SRB in produced water could equally influence the on-set and propagation of biologically induced corrosion.