Study On The Application Of GAC-sand Filter In Advanced Treatment Of Drinking Water

With the development of society, the improvement of people’s living standard and the increasingly strict of the standard of drinking water, the traditional sand filter could hardly meet the requirement of new standard of various water quality parameters. The experiment studied the removal of turbidity, ammonia nitrogen, nitrite nitrogen, CODMn, UV254and improved process-the aeration GAC-sand filter that aimed at solving the southern seasonal water pollution, The main contents and conclusions are as.follows:1. When the turbidity of the water was between1and2NTU, the effluent turbidity of GAC-sand filter and sand filter was about0.1NTU, the effluent turbidity of GAC-sand filter can absolutely meet the national standard.2. The removal rate of CODMn and UV254of the GAC-sand filter was about30%, Lower concentration of ammonia nitrogen (less than0.5 mg·L-1and nitrite nitrogen (less than0.1mg·L-1) can almost be processed completely by the GAC-sand filter, the pollutants removal concentrated in the top0.5m of the filter.3. Under certain conditions, the dissolved oxygen is the limiting factor of ammonia removal, the linear relationship between ammonia nitrogen removal load and influent dissolved oxygen concentration was: dissolved oxygen consumption (mg·L-1)=ammonia removal (mg·L-1)×4.5235+0.0001.4. In one depth’s aeration, The results showed the increased at first and then the same trend with the increasing of gas-water ratios and aeration depths, and the maximum ammonia removal of GAC-sand dual media filter was2.8-3.0mg·L-1,when the gas-water ratio was less than0.1, the ammonia removal of0-0.5of the filter increased with the increasing of the gas-water ratios, and when the gas-water ratio was between0.1and0.25,increasing the gas-water ratio, the ammonia removal of0.5-0.9m of the filter increased.5. Under the conditions of adequate dissolved oxygen, when the aeration depth was less than0.4m, the ammonia removal of0-0.5m of the filter increased, and when the aeration depth was between0.4-0.8m, the ammonia removal of0.5-0.9m of the filter increased; there was almost no ammonia removal below0.9m of the filter. According to determining the SOUR of filter media, we found that the SOUR above the0.5m of the filter was larger and0.5-0.9m depth was relatively small.6. Take the aeration depth was0.6m, the gas-water ratio was0.25for example, in the beginning of the0.5h of the aeration, the surface of the GAC-sand filter decreased rapidly, and then the rate of decline reduced, The interception capacity of the aeration GAC-sand filter got stronger, aeration GAC-sand filter and GAC-sand filter had little difference in the turbidity and the numbers of particles of the initial filtrated water.7. The aeration GAC-sand filter can reduce ammonia of high concentrations, so we can reduce the consumption of disinfectant in the disinfection process.