Study On The Treatment Of Electroplating Organic Wastewater By F-C Electrolysis And A~2O Combined Process

Nowadays,electroplating process is widely used in various fields.Electroplating industry has become an indispensable industry in today’s industrial system and people’s life.But the electroplating industry produced a huge amount of waste water,and a wide variety of waste water pollutants,biodegradability is poor,with biological toxicity,so the electroplating industry is listed as one of the three pollution industries.Electroplating organic wastewater discharged into the river without standard treatment will also cause great harm to the water environment.Therefore,it is very important to find a suitable electroplating organic wastewater treatment technology for environmental protection.Because the electroplating organic wastewater has many kinds of organic matter and its poor biodegradability,the single treatment technology can not make its effluent meet the requirements.The iron-carbon micro-electrolysis process has the advantages of low cost,high adaptability and can improve the biodegradability of wastewater,so it is suitable for the pretreatment of electroplating organic wastewater,at the same time,considering that A~2O process can meet the needs of wastewater denitrification and phosphorus removal.Therefore,this paper takes the actual electroplating organic wastewater from an electroplating plant of an industrial park in Pingshan,Shenzhen City as the experimental target,and studies on the treatment of electroplating organic wastewater by F-C electrolysis and A~2O combined process.In this paper,the optimal conditions for the pretreatment of electroplating organic wastewater by Fe-C micro-electrolysis were investigated by beaker experiment.The initial p H value is 3,the iron and carbon dosage is 240 g,the aeration amount is 200 min/L,the reaction time is 90 min,and when the initial concentration is 400～1000 mg/L,the final degradation rate of COD has little difference,which is about 72.0%.After Fe-C micro-electrolysis pretreatment,the B/C increased from 0.19 to 0.39,and the biological toxicity decreased significantly,which provided an important guarantee for the subsequent biological treatment of A~2O.Secondly,an A~2O bioreactor was built to cultivate activated sludge,and then pretreatment water was added to the raw water in proportion to acclimate the microorganisms in the reactor to adapt to the composition of electroplating wastewater.Finally,the addition proportion was determined to be 40%.In the commissioning stage,the best operating conditions were determined through single-factor experiments.When the dissolved oxygen was set to 2～3 mg/L,the HRT was 12 hours,and the nitrification liquid reflux ratio was 200%,the effluent effect was the best,and the effluent COD,TN,The concentrations of NH4+-N and TP are 61.7 mg/L,4.47 mg/L,4.21 mg/L and 0.85 mg/L,respectively,which meet the emission standards.At last,the sludge samples from anaerobic,anoxic and aerobic tanks in different stages of A~2O process were extracted to analyze the information of microbial diversity and population structure.With the increase of the proportion of pretreatment effluent,the abundance and diversity of microorganisms in the system decreased gradually.Proteobacteria and Bacteroidetes are the dominant bacteria in the treatment of electroplating organic wastewater pretreatment effluent by A~2O process.The dominant bacteria classes were Gammaproteobacteria,Bacteroidia and Deltaproteobacteria,and the dominant bacteria genus was Aeromonas.