Study On Treatment Technology For Heavy Oil Wastewater In Liaohe Oil Field

Liaohe oil field is the largest heavy oil production base in China, every day about65000m~3of heavy oil wastewater is produced, heavy oil wastewater contains oil andwater with very small density difference, serious emulsification, very poorbiodegradability, high salinity and temperature and viscosity, and so on, results that thetreatment of heavy oil wastewater is extremely difficult.The water quality and the original treatment process were investgated, and to solvethe main difficults for the treatment and to reach the discharge standard, the chemicalcomposition of the COD matters in the wastewater was studied, and some specialmicrobes with special degradability to heavy oil were selected and cultivated, and thenew biological treatment process was studied on site.Papers for acidification-contact oxidation process carried out laboratoryresearch. The combination of filler filler for the biofilm, more than16hresidence time, influent COD of200~400mg/L, oil is40~60mg/L, theoutlet COD in30~60mg/L between the oil class less than5mg/L, COD andoil plant, the average removal rates of up to84.2%,83.7%.In laboratory studies, based on the papers of the hydrolysis acidification-contact oxidation process on-site small pilot study. The flotation treated waterto runoff, the design process flow of3.2m~3/d for2months of field testing asmall test to determine the water flow of1.6m~3/d, water temperature20~50℃, the average influent COD value of302mg/L, the effluent COD in the100mg/L or so, an average of94mg/L, COD removal efficiency of68%.Thesis carried out on-site pilot testing process design and test research.Pilot test the use of biofilm hydrolytic acidification-Contact Oxidation Processheavy water. Among them, the biofilm hydrolytic acidification tank design inlettemperature of55~60℃, hydraulic retention time of15h, COD loading ratebetween0.1~0.2kgCOD/(m~3d); contact oxidation tank design watertemperature60℃, hydraulic retention time21h, COD loading rate between0.1~0.15kgCOD/(m~3d). After four months of operation, the hydrolyticacidification-contact oxidation process effluent COD ranged from70~88mg/L varied between an average of77.5mg/L; oil in4~6mg/L between the change in average value of4.9mg/L.Research pilot plant to further improve the biological treatment process,after research in the biological treatment process using activated carbon andozone treatment means to further reduce the COD and oil content, the CODvalue is expected to be reduced after treatment45mg/L or less, to meet thewater of Liaoning Province efflux COD less than50mg/L of the new standardfor subsequent wastewater treatment expansion project provided technicalreserves.