Study And Application Of The Treatment Of Dye Wastewater By The Physical-chemical And Biochemical Combined Processes

A chemical plant has produced disperse dye through chemical synthesis method,the produced wastewater has the features of high COD,high ammonia nitrogen,poor biochemical degradation and so on,the original treated wastewater quality can not reach the discharge standard.Based on the problems existing in the original process,the combination processes of ferric-carbon/fenton+ABR+UASB+two-stage A/O are adopted to the disperse dye wastewater.Actual operation results indicate that the effluent indexes can meet the specified requirements in the local chemical industry park emission standards.This paper studied the optimal operating parameters of Fe-C/Fenton pretreatment,the start-up and commissioning of ABR and UASB two-phase anaerobic and two-stage A/O biochemical processes,and the study of stable operation conditions.The following results are obtained:1)The small-scale experiments showed that the optimal reaction conditions of Fe-C micro-electrolysis in the Fe-C/Fenton pretreatment process:reaction time 120min,pH=3,iron-carbon dosage 350 g/L,COD removal rate under optimal conditions19%,chromaticity removal rate was 48.6%.The optimal experimental conditions of Fenton oxidation:dosage of H₂O₂ 7.5mL/L,pH=3,dosage of FeSO₄·7H₂O was 1g/L,reaction time 120min,COD removal rate was 25%under this condition,chroma removal rate was 65.1%.Under the condition of Fe-C/Fenton combination,the removal rate of COD was about 36%and the color removal rate was 82%.2)The ABR and UASB anaerobic reactors are started with a low load and the initial volume load was controlled less than 0.4 kg/?m3·d?,and the influent load was gradually increased until reaching the design load.The influent COD concentration was 8000¹0000 mg/L.After 100 days start-up and commissioning,the effluent COD concentration was stable at about 3000 mg/L,the COD removal rate was 66%,and the effluent ammonia nitrogen concentration increased,with an average of 280 mg/L.3)After A/O stable running,the influent COD concentration was2900³100mg/L,the effluent COD was stable at about 870mg/L,the removal rate was up to 71%,the influent ammonia concentration was about 280mg/L,and the effluent concentration was stable at 35mg/L,the removal rate was 87%,and the color of the water was about 100 times.