Removal Of Several Toxic Pollutants In Combined Wastewater Of Chemical Industry Park By A Novel Integrated Process

The potential environmental and safety hazard of chemical industrial parks in China impose extreme pressures to the ecological environment of key areas such as coasts, rivers and lakes. Chemical engineering wastewater is difficult to be biodegraded ascribe to the complicated toxic pollutants. It is hard to meet the discharge standard with the single treatment process, so effective integrated process is a particularly important subject on edge.The integrated process of Fenton oxidation-precipitation-hydrolysis acidification-anoxic/oxic process-coagulation sedimentation-resin absorption is used to treat chemical industrial wastewater in the present paper considering the removal efficiency of phenol, aniline, COD, TOC and chromaticity. The results reveal that the integrated process is satisfactory both at technique and economic benefit, so it provide significance guiding information for the takeover standard in chemical industrial park wastewater treatment plant. Thus, this work included five aspects as follows:1. The pretreatment parameters of wastewater by Fenton reagent were studied. With the removal efficiency of phenol and aniline of the wastewater as the index, different factors that influence the oxidation of organic pollutant by Fenton reagent were analyzed through single factor test. Under the condition of the initial pH value between 3 to 5,298K, the H2O2 dosage l0mmol/L, FeSO4-7H2O lmmol/L and the reaction time 45 min, the removal efficiency of phenol and aniline could reach as high as 97%, and aniline is more likely to be oxidation by Fenton's reagent.2. Hydrolysis acidification-anoxic/oxic process is efficiency to remove phenol and aniline in combined wastewater. The effluent could meet the requirements of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002), in which the inflow concentration of phenol and aniline should be below 10mg/L and 3mg/L, and phenol is easier to be biochemical degradation.3. The process of coagulation sedimentation-resin adsorption could decrease the chromaticity and COD of the biochemical tail water. The removal efficiency of TOC and chromaticity is 67.1% and 93.6% and the effluent could meet the requirements of Class 1 Level A of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).4. The integrated process of Fenton oxidation-precipitation-hydrolysis acidification-anoxic/oxic process-coagulation sedimentation-resin absorption perform well on the removal of phenol, aniline, COD, TOC, and chromaticity, with the high removal efficiency of 99.6%,99.5%,93.7%,92.6% and 98.0%. The effluent could meet the requirements of Class 1 Level A of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002) steadily. The integrated process is feasible both at technique and economy and the running cost is 4.60 Yuan per ton.5. The takeover standard by the integrated process is suggested to be 70 mg/L of the volatile phenol and 60 mg/L of aniline. The value should be 10 mg/L of volatile phenol and 3 mg/L of aniline for the wastewater treat plant without pretreatment. Moreover, according to the assimilative capacity of regional total consumer and pollution characteristic, the charge stander is as follows:the fee is in proportion to 5-100 Yuan per ton when the COD is between 500 and 10000 mg/L. If the COD is lower than 500 mg/L, the charge is in accordance with the special pollutant factor. Moreover, when the influent is higher than 10000 mg/L, the case may be taken into account individually. Besides the basic charge indicators of COD, the special pollutant will be charge at the emissions additionally. For phenol, the charge standard is 1-7 Yuan per ton while the concentration is 10 to 70 mg/L and the anilines is charged at 0.3-6 Yuan per ton as the content is between 3 and 60 mg/L.