A Technological Design Of A Refinery Wastewater Treatment Project In Dongying

Refinery wastewater is a kind of oily waste-water discharged in the petroleum refining. The massive discharge of refinery wastewater without treatment will cause damage to environment extensively when considering complex composition and high concentration of pollutants in the wastewater. Furthermore, a large amount of toxic substances and nonbiodegradable organics present in the wastewater. Traditional technology of "grease traps-air flotation-biochemical" is used to treat oily wastewater for a long period time. Though the combined process is reliable in the wastewater treatment, it encounters difficult in reaching increasingly stringent discharge standard. Thus, combination of multiple technologies are applied in grease traps, air flotation and biochemical are applied. The multiple technologies exhibit superiority and effectively avoid limits of mono-technology effectively, achieving more and more application in wastewater treatment.The project presented in this paper was a refinery wastewater treatment project in Dongying, Shandong Province. Methods for treatment were selected and designed for each unit were initiated according to analysis of water quality. Factors of natural condition and discharge standard were taken into consideration as well. Integration of "grease traps-cavitation air flotation-air flotation-MBBR-ozone oxidation-aeration biological filter-filter-disinfection" was used for the projectAccording to the design, the final effluent water quality will meet the first emission limit of "Integrated Wastewater Discharge Standard in Haihe River Basin of Shandong Province" (DB37/675-2007) and its modification in 2011. Concentration of CODcr, BOD5, SS, Nh4+-N, oil, phenol, sulfide, total cyanide and chromatisity index in wastewater will be less than 50 mg/L, 100 mg/L,20 mg/L,5 mg/L,3 mg/L,0.2 mg/L,1.0 mg/L,0.5 mg/L and 30, respectively. After treatment, the removal efficiency of CODcr, BOD5, SS, NH4+-N, oil, phenol, sulfide, and total cyanide will be 97.5%,98.3%,97.1%,99.4%,99.4%,99.6% and 96.7%, respectively.Pollutants in refinery wastewater will be effectively removed using the chosen craft.The combined techniques also show strong resistance to organic shock loads and ensure stable water quantity. Application of the combined techniques presents promising potential in refinery wastewater treatment.