| In this paper,the wastewater of organophosphorus flame retardant from a chemical plant in Zhejiang Province was studied.This kind of wastewater is difficult to be treated to meet the emission standards due to its characteristics of high organic phosphorus,high COD,poor biodegradable and a certain degree of biological toxicity.According to the requirements of improving the standard in Zhejiang Province,the wastewater was pretreated by the system of struvite precipitation-Fe/C micro electrolysis-Fenton-EGSB.This study provides some experience for the treatment of organic wastewater with high concentration of organic phosphorus.Struvite precipitation was used to remove most of the PO43-and NH4+-N.The influence factors of the reaction were studied and the optimum reaction conditions were as follows:pH=9.5,HRT=20 min,n?Mg?: n?P?=1.1 : 1.Under the optimum conditions,the removal rates of PO43-and NH4+-N reached 98.45% and 78.66%respectively.Six kinds of advanced oxidation processes were used to treat the effluent from struvite precipitation.Through a series of experimental research,the optimal reaction conditions of each process were preliminarily determined.The results show that:?1?The optimum process parameters of Fe/C micro-electrolysis-Fenton oxidation are as follow: pH=3,HRT=90min,the dosage of H2O2 was 10%.?2?The optimum process parameters of Fenton oxidation are as follow: pH = 3.5?2.5 4 in practical application?,HRT = 100 min,the dosage of 30% H2O2 was controlled at 10% when the concentration of Fe2 + was 100mg/L.?3?The optimum process parameters of O3 oxidation are as follow: pH = 10,HRT = 80 min,the dosage of ozone was 80mg/L,the effect of UV lamp had a positive effect.?4?The optimal process parameters of O3/H2O2 oxidation are as follow: pH = 9,HRT = 6min,H2O2: n?O3?was controlled at 0.5 when the dosage of ozone was80mg/L.Considering the removal rate of pollutants,the biological toxicity of water and the improvement of biodegradability,the Fe / C micro-electrolysis-Fenton oxidation was decided to be used as the advanced oxidation unit to treat the effluent from struvite precipitation.The removal rates of COD and TP were 66.48% and 91.11% respectively.Theconcentration of TP and COD decreased to 106.71 mg/L and 7369.21 mg/L respectively.The effluent of Fe/C micro-electrolysis-Fenton oxidation was treated by EGSB anaerobic reactor,and the start-up of the anaerobic reactor was completed in about 33 days.When the influent load was control in the 0.892 4.283 kgCOD /?m3·d?,EGSB anaerobic reactor had a good treatment effect.The optimum operating parameters are as follows: hydraulic retention time was 4 days,pH was controlled between 6.8 and 7.2.Under this condition,the removal rate of COD was 80% 85%,The concentration of effluent COD was about 1000mg/L. |
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