The Study On Improving The Quality Of Sewage In Oil Field Sewage Treatment Station

One oilfield has been developed for at least 10 years.In recent years,with the rapid increase in the water content of oil field,the sewage also increases rapidly.The water quality gets large changed,which caused serious corrosion and fouling problems on ground station network and equipment.The treated water quality is poor,which is unable to meet the injection water standard.In view of the above problems,this topic takes the sewage in oil field processing system as the research object.The corrosion and scaling problem were investigated,and through the indoor simulation experiments,the characteristics of swage were comprehensively analysed.The main factors that affect the water quality are determined.In the light of the characteristics of the wastewater quality and field conditions,we develop two different dosing process.Indoor simulation experiments were respectively carried out to evaluate and select the suitable reagent system.Then the other problems in the system such as sterilization,filtration,etc.are studied,and the corresponding solutions are given.The results of the study show that: the oily wastewater is mixed by 5 waterlines.And the mixed water has poor stability,which causes serious corrosion and scaling problem.In sewage,the content of fouling ion is large,and the scaling reaction mainly occurs in 24 h.With the increasing of temperature,CO2 partial pressure,and the amount of salt in water,the scaling problem gets more serious.The corrosion of sewage is strong,which is mainly due to the effects of dissolved oxygen,CO2 and bacteria.The coexistence of dissolved oxygen and CO2 in water aggravated the corrosion of sewage,and the presence of bacteria further deteriorated the water quality.In order to solve the above problems,respectively,we treated the sewage by using the original reagent system and new reagent systems.The results show that the use of the original water purification agent,ion adjustment agent,and flocculating agent are not enough,but also need to add a corrosion and scale inhibitor to get further treatment,and corrosion inhibitor effect is not ideal.When use the new reagent system,it has obvious advantages on the effect evaluation and treatment cost.Therefore the final dosing process are new purification stabilizers(SDJ-E1),conditioner(SDDJ)and purification of coagulant(SDJ-E3),and the dosage is 200 mg/L,200 mg/L and 6 mg/L respectively.In the presence of a large number of bacteria in the sewage,considering the conditions of the site,we use the salt water sterilization technology after analysis.The experimental results show that the effective chlorine dosage is 15-30mg/L,the bactericidal effect is very good.In view of the problem of poor removal efficiency of the existing filter suspended matter,preliminary comparative analysis is also carried out.And it is recommended to use anthracite and quartz sand filter.