| Dye wastewater has the characteristics of high COD concentration,high chroma,large salt content,and poor biodegradability.It is difficult to achieve a good treatment effect by simple physical and chemical or biochemical treatment.This study takes the actual production wastewater of a dye production enterprise as the research object.Through the analysis of the research status of similar wastewater at home and abroad,it is planned to use the Fe-C microelectrolysis/Fenton-evaporation-anaerobic-A/O combination process to treat the production wastewater.The optimum operation parameters of each unit were determined by experiments,which provided a reference for engineering design.The practical operation of the project proved the feasibility of the combined process for wastewater treatment,and also provided a reference for similar wastewater treatment.Fe-C microelectrolysis/Fenton can effectively reduce the COD and chroma of the wastewater and improve the biochemical properties of wastewater.Orthogonal test and single-factor test showed that the sequence of the influence of each factor on the removal of COD was p H>reaction time>Fe-C addition>H2O2 addition.When p H=3,reaction time is 2.5 h,Fe-C addition is 200g/L and 30%H2O2 dosage is 4m L/L,the best pretreatment effect was achieved.The COD removal rate is 35%,the chroma removal rate is 42%.The Fe-C microelectrolysis/Fenton synergistic oxidation water was used for evaporative desalting,COD was dropped from 6000 mg/L to 3000 mg/L,and the COD removal rate reached 50%.The chroma dropped from 6800 times to 160 times,and the decolorization rate reached 97.6%.The salt content dropped from 180000mg/L to 1000 mg/L,and the desalination rate reached 99.4%.The anaerobic shaking bottle test shows that the pretreatment wastewater has good anaerobic biochemical properties.The ABR reactor started with a volumetric load of 0.5 kg COD/(m3·d),and gradually increased the volumetric load with a gradient of 0.5 kg COD/(m3·d)by increasing the influent flow rate,The internal volume load of the reactor is 4.0 kg COD/(m3·d),the COD removal rate was 64.39%,the effluent COD concentration was stable at about 1000 mg/L,and the concentration of total volatile fatty acids in the effluent is always less than 3.0mmol/L;The starting volumetric load of the A/O reactor is 0.1 kg COD/(m3·d).The volumetric load in the reactor is increased by increasing the water intake.The internal volume load of the reactor is 0.8 kg COD/(m3·d).At this time,the average concentration of COD in the effluent is about 88.9 mg/L,and the average removal rate of COD is 90.8%;the average concentration of NH3-N in effluent is 9.8 mg/L,the average removal of NH3-N is 70.2%;the average concentration of TN in effluent is 15.8 mg/L,the average removal of TN is 73.4%.Combining experimental research and engineering experience,"catalytic oxidation+MVR evaporation+ABR+A/O"is adopted as the main process of the sewage station,and the treatment scale is 220 m3/d.After physicochemical and biochemical treatment,the average concentration of COD in the effluent is 153.3mg/L;the average concentration of NH3-N in the effluent is 12.3 mg/L;the average concentration of TN in the effluent is 20.1 mg/L.All indicators have meet the requirements of the indirect emission standards specified in the"Water Pollutant Discharge Standard for Textile Dyeing and Finishing Industry"(GB4827-2012).The comprehensive treatment cost of this combined process is 57.3 yuan/t. |
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