摘要
A N 2 flotation tank combined with coagulation was developed as a pretreatment equipment of biological process to remove oil and other pollutants in coal gasification wastewater( CGW). With optimal PAC dosage of 20 mg / L,the sole coagulation process achieves removal efficiencies of 29. 34% and 26. 83% for oil and COD,respectively. For the sole N 2 floatation process,the optimal N 2 flux and HRT are 20 m3/ h and 20 min. Meanwhile,the oil and COD removal efficiencies are 35. 41% and 14. 26%,respectively. For the combined system of coagulation and N 2 floatation,the optimal parameter values are the same as the ones of separate processes. Correspondingly,the removal efficiencies are 46. 28% and 31. 89% for oil and COD, respectively. Besides,BOD 5 / COD of the effluent is improved. In contrast with conventional dissolved air floatation,the inert gas- N 2 prevents the formation of cyclopentenone, pyridine derivatives, and other heterocyclic aromatic hydrocarbons,thus improving the biodegradability of influent for the subsequent biological processes.
A N2 flotation tank combined with coagulation was developed as a pretreatment equipment of biological process to remove oil and other pollutants in coal gasification wastewater (CGW). With optimal PAC dosage of 20 mg/L, the sole coagulation process achieves removal efficiencies of 29. 34% anti 26. 83% for oil and COD, respectively. For the sole N2 floatation process, the optimal N2 flux and HRT are 20 m3/h and 20 min. Meanwhile, the oil and COD removal effieiencies are 35.41% and 14. 26%, respectively. For the combined system of coagulation and N2 floatation, the optimal parameter values are the same as the ones of separate processes. Correspondingly, the removal efficieneies are 46. 28% and 31.89% for oil and COD, respectively. Besides, BODs/COD of the effluent is improved. In contrast with conventional dissolved air floatation, the inert gas - N2 prevents the formation of cyclopentenone, pyridine derivatives, and other heterocyclic aromatic hydrocarbons, thus improving the biodegradability of influent for the subsequent biological processes.
基金
Sponsored by the Sino-Dutch Research Program(Grant No.SDRP-WRZ)
the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(Grant No.2013DX10)