Biological Zeolite Filler Removal Of Municipal Wastewater Treatment Plant Secondary Effluent Ammonia Pilot Study

Secondary effluent after biochemical treatment in the wastewater treatment plant had become the renewable water resources in the development and utilization of urban sewage,for the lower concentration of the ammonia and organic material in it. In order to remove ammonia and other pollutants from wastewater more sufficiently, it had become an important and urgent issue to develop the advanced treatment technology on the secondary effluent from municipal-wastewater-treatment plant.The natural zeolite had a good adsorption capacity on ammonia ions in wastewater through the way of ion exchange,and the suspended ball was light and had large specific surface area.In the research,a composite filler was formatted using the two units whose surface was easily attached with biofilm,and the self-designed reactor with biofilm was used to start the research about the advanced treatment technology on the secondary effluent from municipal-wastewater- treatment plant,the main influencing factors of removal efficiency of the reactor on NH₄⁺-N and COD_Cr was explored and determined in order to develop the removal technology of nitrogen in low-concentration wastewater which was suitable for the national conditions.The results showed that the bio-zeolite filler reactor undergo a period of adaptation before the retrieval of good removal efficiency on ammonia when water was changed from sewage to secondary effluent,due to the lower substrate concentration of the nutritional requirements of the micro-organisms.The ability of bio-zeolite filler reactor to remove ammonia and COD_Cr in wastewater was influenced by the hydraulic loading,in fluent flow,gas-water ratio,packing height and other factors,and hydraulic loading and air-water ratio are main facts.Gas-water ratio being constant,the removal rate of ammonia nitrogen dropped to 85.16%from 93.5%, and the removal rate of COD_Cr from 68.58%to 65.32%as the water flow was changed from 4L / h to 6L / h.Water flow being 4L/h,the removal rate of ammonia nitrogen increased to 93.2%from 73.5%,and the removal rate of COD_Cr from 64.6%to 69.82%as the ratio of air to water was up from 3:1 to 12:1.When the height of the filler was 0.9m,the optimal hydraulic loading and air-water ratio were 0.23m³/(m².h) and 12:1 respectively,at the same time the average nitrogen removal rate was more than 90%and the average COD_Cr removal rate around 70%.At the same time,the effluent water can meet the country standard of pollutants for municipal miscellaneous water and landsape water.