Pilot Study On Removal Of Three Nitrogen Compounds From Drinking Water With Different Filter Media

In recent years, with the growth of population and rapid development of economy and industrialization,domestic sewage and industrial wastewater increased year by year, which makes the surface water and groundwater pollution more and more serious. The pollution of nitrogen compounds has become a hot issue. In the face of widespread contamination of surface water and increasingly stringent drinking water quality requirements, the conventional water treatment process ushered in an unprecedented challenge and pressure. Filter material is the core of the filter, which plays a key role in improving the quality of drinking water. Different types of filter materials have different characteristics. It is necessary to grasp the characteristics of filter materials and select the most suitable filter material to meet the condition of specific water quality, economical efficiency and management convenience in order to improve the effect of water treatment. So it has a widely potential application.In this study three filter materials anthracite, zeolite and porcelain sand were used to form single layer homogeneous filter column, mixed filter column and layered filter column. It compared the filtration performance of different filter columns and explored the variation of the filtration performance along the layer under the conditions of 10m/h normal filter speed. At last, it chose four filter columns to study the effect of filtration speed on filtration performance. Anthracite, zeolite and porcelain sand were characterized by X-ray energy spectrum analysis, FT-IR analysis and FE-SEM.The main conclusions of this experiment are drawn:(1) The appearance of anthracite and zeolite filter is similar. They are irregular particles with the rough and uneven surface, which has many small openings. But the surface of porcelain sand filter is smooth with less developed pore. They are regular and well-distributed circular particles. The chemical composition of zeolite and porcelain sand is similar, in which O is the most, but the content of SiO2 and Al2O3 in porcelain sand are higher than those in zeolite. So the mechanical strength of porcelain sand is higher than that of the zeolite. Anthracite is mainly composed of organic functional groups, so C is the largest element.(2) With the high mechanical strength, strong scour resistance ability and large interlayer porosity, the initial water loss of porcelain sand filter is small, the filtration period is long and the turbidity removal effect is the best. When combined with other filter media, porcelain sand can help to extend the filter cycle. Such as layered filter, whose filter cycle is 50.5h under the 10m/h normal filter speed, then up to 76 h under the low filter speed of 5m/h.(3) Ammonia nitrogen can be removed most under the normal filter speed, but the removal efficiency of nitrite nitrogen and nitrate nitrogen is weak. The removal efficiency of three nitrogen is improved after the filtration rate is decreased. After the filtration rate is reduced, the contact time between the water flow and the filter layer is increased, and the decrease of the water flow scouring force is helpful to the filter layer to play the role of adsorption fully.(4) The UV254 in filter column is mainly removed by adsorption. Only mixed filter column and layered filter column play roles on the removal of UV254 under the filter speed 10m/h. The removal efficiency of UV254 is affected by the filtration rate and the influentUV254. In another word, it increased with the decrease of filtration rate and the increase of influentUV254.