Comparative study on purification efficiency of typical fillers

The Biofilter is an ecological treatment technology for effective sewage treatment, but the water purification efficiency of this technology depends largely on the performance and economy of the filler. In this paper, ten kinds of typical fillers for gravel, cobblestone, ceramsite, coke, bituminous coal, red volcanic stone, green zeolite, maifan stone, coral sand, and slag are used to study the purification efficiency of black and odorous water body through static water test. Research shows that in the later stage of the still water test, the average pH value of each group of fillers is about 8.5, the dissolved oxygen is at a high level, and the transparency is clear; the COD removal rate is above 75%, the ammonia nitrogen removal rate is above 99%, and the total nitrogen removal rate is above 80%. The removal rate of phosphorus is above 95% on average. The regression analysis method was used to analyze the physical properties of the filler and the water purification efficiency of the filler. It was found that the porosity of the filler had the greatest impact on the water purification efficiency of the filler. The comprehensive evaluation of fillers using analytic hierarchy process shows that the comprehensive evaluation of slag, bituminous coal and volcanic stone is high and can be used in engineering practice.