Experimental Research On Combined Ozone/Ultraviolet/Composite Adsorption Filter Process For Treatment Of Huaihe Water

Since the quality and quantity of the Huaihe River water changed with seasons, owing to the fluctuation of water temperature and precipitation, it was characterized as seasonal micro-polluted water and the main water pollutants were NH3-N and organics. Water treatment plants around Huaihe River mostly adopted conventional drinking water treatment process, of which the processing capacity was limited, which was a serious threat to the drinking water safety of residents in this region. How to upgrade the process, improve the ability of coping with different water qualities and guarantee the drinking water saftety were problems requiring to be solved immediately at present.This issue’s research object was the Huaihe River water in Huainan City. The combined ozone/ultraviolet/composite adsorption filter process’s removal efficiencies of pollutants, such as turbidity, NH3-N and organics were discussed through a pilot test. We also summarized the removal performance of pollutants and researched the main factors of the test, thus the optimum operation conditions were determined. Based on the pilot test, we conducted a demonstration project which was upgraded from the original water plant, and analyzed the treatment effects of the demonstration project’s start-up phase and stable phase.Raw water of the pilot test was the Huaihe River water in Huainan City after the treatment of coagulation, precipitation and flotation, and its turbidity changed in the range of0.97～3.01NTU, CODMn was2.61-4.80mg/L, UV254was0.054～0.074cm-1, NH3-N was0.15～2.0mg/L. The pilot test results showed that the combined ozone/ultraviolet/composite adsorption filter process ran stably, the average effluent turbidity, CODMn, UV254, NH3-N, and N02--N were0.13NTU,2.20mg/L,0.036cm-1,0.07mg/L and0.001mg/L, respectively, and the average removal rates were92%,35%,44%,77%and98%, respectively; Ozone/ultraviolet oxidation had an obvious removal of CODMn, UV254, NO2--N and UV410. After the oxidation of ozone/ultraviolet, the average of each index were2.70mg/L,0.014mg/L and0.006cm"1, respectively, and the average removal rates were19%,35%,80%and26%, respectively; Ozone/ultraviolet oxidation could’t remove turbidity, NH3-N and NO3--N; The optimal ozone dosage determined by the pilot test was about2.0-2.5mg/L, the best filter type was zeolite/activated carbon composite filter, and the operation speed of the filter was about9.4m/h; In addition, temperature had a certain effect on the removal efficiency of the combined process. When the temperature was16～25℃, the contaminant removal rate by the combined process was better than the temperature under15℃; The pilot system had a certain impact load capacity to NH3-N, and CODMn, and it need a short time when the system was rebooted to restore stability.The demonstration project, which adopted the combined ozone/ultraviolet/composite adsorption filter process and the treatment capacity of which was approximately20000m3/d, was conducted on the basis of the pilot test. When the demonstration project ran stability, the average turbidity, CODmMn, NH3-N and NO2--N of the effluent water were0.25NTU,1.92mg/L,0.12mg/L and0.004mg/L, respectively, and the average removal rates were86%,28%,86%and97%, respectively. The effluent water quality of the pilot test and the demonstration projects could satisfy the standard of drinking water (GB5749-2006).