Study On Advanced Treatment And Process Optimization Of High Salt Chemical Wastewater By Small-scale Dual-Mode Reactor

The high salt wastewater has wide sources,many kinds and complex composition.It has the characteristics of difficult biochemistry and easy salting out,which increases the difficulty of sewage treatment.The common treatment is to use membrane technology to intercept sewage ions and organic matter,but long-term use will cause membrane pollution,blockage,membrane cleaning and replacement also caused a high operating cost.In this project,the dual-mode reactor in the engineering example was optimized and upgraded,and a small dual-mode reactor(SDMR)was designed and manufactured according to the scale reduction,and the pilot test was carried out by combining Eger’s salt-tolerant bacteria and Eger’s biochemical bed.To explore the optimal control conditions of "SDMR+biochemical bed" combined process coupled with A-O-A process and A-O process for the degradation of CODcr,ammonia nitrogen and TN in high-salt chemical wastewater.It provides a choice for process optimization in the advanced treatment stage of high salt wastewater.A large number of pilot experimental data: Under the condition of high salt chemical wastewater with salinity of 20000 ± 2000mg/L,PH 6-9 and temperature of 25-30 ℃,the influent CODcr concentration is 150mg/L,C/N is 6 and HRT is set to 6h.When the concentration of DO is 4mg/L,the CODcr removal rate of the combined process of "SDMR+biochemical bed" coupled with A-O-A process is 65.7%,the ammonia nitrogen removal rate is 97.1%,and the TN removal rate is 80.9%.The effluent conforms to the secondary standard of Shanghai Municipal Comprehensive Sewage Discharge Standard(DB31/199-2018)and Class 1A standard of Pollutant Discharge Standard of Municipal Sewage Treatment Plant(GB18918-2002).This paper shows the concentration change trend and principle of the system when the combined process of "SDMR+ biochemical bed" is coupled with A-O-A process to degrade CODcr,ammonia nitrogen and TN in high-salt chemical wastewater,and compares the characteristics of the two coupled processes,drawing conclusions: The nitrogen removal efficiency of coupled A-O-A process is better,with the ammonia nitrogen removal rate up to97.1% and TN removal rate up to 80.9%,which is significantly better than that of coupled A-O process.The coupled A-O process has A better CODcr degradation effect in high salt chemical wastewater,with a removal rate of 70.6%.The suitable process can be selected according to the characteristics of water quality.SDMR adopts combined filter media to avoid the disadvantages of easy clogging and high backwashing frequency.Compared with 2-4mm filter material layer,the experiment was carried out.The experimental results show that the combined filter material backwashing frequency is lower and the treatment effect is better.In this paper,artificial neural network(ANN)is introduced to solve the problem of strong nonlinearity and complex data.Through the control of four independent variables of influent CODcr concentration,C/N,HRT and DO concentration,accurate prediction of effluent data has very important guiding significance for rapid adjustment of process under different water quality conditions.