Study On Three-dimensional Electrode Technology In The Field Of Water Reuse

In order to explore new water-recovery technology and promote the development of undertakings of sewage reuse, fundamentally relieve the shortage of water resource in China, based on the resource of urban sewage, the treatment effect of secondary effluent from urban wastewater treatment plant by three-dimensional electrode was studied and the effect of the three dimensional electrode assembly method and the reactor operation parameters on the removal effect of secondary effluent COD_Mn, NH₃-N, TN, NO₂-N mainly discussed in the paper.The influence of electrode voltages, electrolysis time, the initial concentration, the proportion of coating activated cardon and aeration on secondary effluent removal efficiency were analysised by the experiment. The results were as following: In certain scope, extending the electrolysis time and increasing the voltage were good for removal efficiency. When the response time was 40min, the removal rates of COD_Mn, NH₃-N, NO₂-N and TN were respectively up to 66%, 75%, 95% and 49%. After 40min, the electrolysis of indexes were stable with the extension of time. The influence trends between voltage and the time to COD_Mn and nitrogen removal rates were similar and the removal rates of COD_Mn, NH₃-N, NO₂-N and TN were respectively up to 66%, 75%, 95% and 49% at the voltage of 15V. With further increases of the voltage, the COD_Mn and NO₂-N were in stable condition, but the removal rates of NH₃-N and TN were discreased.The concentration of water didn't influent the removal efficiency much. Aeration was helpful to improve the pollutant removal efficiency, the removal rates of COD_Mn, TN, NH₃-N were respectively increased by 20% at the condition of aeratin. Orthogonal experiments showed that the influence degree on COD_Mn removal efficiency was as follows: the electrolysis time > aeration > voltage > the percents of coating activated cardon. And the influence degree on TN and NH₃-N removal efficiency was as follows: Aeration > the percents of coating activated cardon > the electrolysis time > voltage. The optimum experimental conditions were that the content of coating carbon was 20%, the voltage was 15V, the plate interval was 9cm, the electrolytic time was 40min and the air was 1L/min.The relationship of redox potential potentials (ORP) and COD_Mn removal rate was studied, the results showed that the relationship of COD_Mn and ORP was related to some extent, the value of ORP reflects the COD_Mn removal efficiency so that the reaction can be judged through ORP declines.Three-dimensional electrode technique which has higher application value in water-reuse field can effectively remove COD_Mn, NH₃-N, NO₂-N and TN. The effluent can meet the water reuse criteria, economic benefit and environmental benefit is remarkable.