Experimental Research On Combined Packing System Of Ecological Porous Weir

With the progress of human civilization,the disturbance of human activities to river ecosystem has been gradually expended and deepened.River ecological problems such as eutrophication of water system,urban anaerobic rivers and barrier of longitudinal connectivity are becoming more and more prominent.At the same time,the demand for aquatic ecological environment is ever growing.Therefore,the river ecological restoration technology which takes account of water environment treatment and aquatic ecology restoration,is an important technical force for water harnessing in the new period.As an eco-friendly hydraulic structure,the traditional porous weir and dam make an impact in the river ecological restoration.But their effect on the migration and transformation of nitrogen,phosphorus and other pollutants is limited.In view of the research of traditional porous weir and dam at home and abroad,this paper designed an ecological porous weir by laying a combination of filler areas with adsorption capacity in its interior based on the principle of river ecological restoration.And its design and function are systematically introduced in this paper.Aiming at the current situation of insufficient removal effect of nitrogen,phosphorus and other nutrients by porous weir and dam technology,the combined packing system with the best adsorption effect of nitrogen and phosphorus nutrient salt was optimized by selecting the four parameters of filler in the combination packing area of ecological porous weir,including the type,mass ratio,reactor configuration and laying form of the filler.While improving the geomorphological morphology of rivers,ecological porous weir has better ability of water quality improvement and comprehensively improves its application effect in water environment management and water ecological restoration.Firstly,through the static adsorption experiment of single filler and combined filler,the type and quality ratio of filler with good adsorption on nitrogen and phosphorus are determined,and secondly,through dynamic experiment,the removal effect of different reactor structure and laying type packing system under different water inlet concentration and hydraulic residence time is discussed.Then by means of multivariate variance analysis,use the removal rate of nitrogen and phosphorus as dependent variable,the structure of the reactor and the type of filler laying as factors,to find the significant influencing factors of nitrogen and phosphorus removal rate and their optimum conditions.The conclusions of this paper are as follows.? The filler system of ecological porous weir can effectively remove pollutants from water body,and it is an effective technical measure of aquatic ecological restoration.? The adsorption ability of natural zeolite and volcanic rock to ammonia nitrogen is good,its saturation adsorption amount is 2.57 mg/g and 2.42 mg/g respectively.The adsorption ability of ceramics to phosphorus is optimal,its saturation adsorption amount is 1.57 mg/g.?The combination of pottery,volcanic rock,natural zeolite with mass ratio of 1:1:2:1 has the best adsorption capacity of ammonia nitrogen and phosphorus,the removal rate of which was 86.2%and 98.7%respectively after 48h oscillating adsorption.? At different water inlet concentrations and hydraulic residence times,6 test group including two reactor structures(push-flow,wave-flow)and three types of laying(horizontal laying,full mixing,vertical laying)had certain reduction effect on ammonia nitrogen,total nitrogen,and total phosphorus.The test group with push-flow structure and filler vertical laying had better removal effect of ammonia nitrogen and total nitrogen,the average removal rate were 64.3%and 66.9%.The removal effect of total phosphorus in each group was similar,the average removal rate was in the 35.5%-41.8%range.The average removal rate of the test group with vertical laying filler was slightly superior to other test groups.? Through multivariate variance analysis of dynamic test data,the effect of laying type on ammonia nitrogen removal is significant,the vertical stratification is optimal.The reactor structure affects the removal of total nitrogen,but the effect is small.The removal effect of the push-flow structure on the total nitrogen is slightly better than that of the wave-flow structure.The reactor structure and laying type hardly affect the removal effect of total phosphorus.The significant levels of both are much greater than 0.05.Therefore,in the process of removal of nutrient pollutants based on interception and adsorption,the structure of wave-flow reactor can not improve the removal effect of filler on nutrient pollutants.In summary,the push-flow reactor structure with vertical laying filler is the optimal combined packing system for the removal of nitrogen and phosphorus.Compared with the removal rate of nitrogen and phosphorus in traditional porous weir,the removal rate of ammonia nitrogen,total nitrogen and total phosphorus was obviously improved in ecological porous weir.