Urban Rapid Rainwater Filtration/Adsorption And Receiving Water Bodies Plant Purification Research

The initial rainwater contains a lot of pollutants.Once discharged into rivers and lakes,it will have a great negative impact on the water quality of the lakes and rivers.Therefore,initial rainwater collection and treatment is of great significance for the prevention and control of rainwater pollution.However,how to realize the deep purification of water quality and the maintenance of water quality after the purified rainwater enters the river is a major environmental problem of currently facing.The deep purification technology of plants is one of the environmentally friendly water quality enhancement technologies.In this article,the rapid removal of pollutants from the initial rainwater is achieved through the preparation of composite filter material,and the use of plant purification technology to study the water quality of receiving water bodies.The composite filter material composed with fly ash and zeolite as aggregates,bentonite and bio-carbon as additives,sodium silicate solution as the binder,through acid-base modification of aggregates and iron loading of biological carbon to prepare a new type of filter material.The results of aggregate modification showed that the adsorption capacity of the fly ash and zeolite on pollutants increased by 25 to 45%and 18 to40.5%respectively.The results of aggregate characterization showed that the surface roughness and specific surface area of the modified aggregates are significantly increased.The characterization results of iron-bearing biochar showed that the surface of biochar was loaded with zero-valent nano-iron,and the surface roughness and specific surface area were significantly increased by scanning electron microscopy.The optimized formula for the initial rainwater purification effect is:fly ash:zeolite:bentonite:iron-bearing biochar was 54:36:2:8,and the amount of binder added was 25 mL/100 g.The experimental results of dynamic filtration of preliminary rainwater show that the removal effect of pollutants decreases with the increase of filtration rate,and the removal rate of turbidity,COD,TN,ammonia nitrogen and TP was 91%,52.1%,62.5%,65.8%,81.2%respectively,at a filtration rate of 10m/h;the results of comparative experiments of the two kinds of filter materials showed that the removal rates of turbidity,COD,TN,ammonia nitrogen and TP by compositefilter materials were increased by 21.0%,8.6%,28.0%,22.8%and 16.0%than that of quartz sand-activated carbon filter materials.The filtration performance analysis results of 22 consecutive days showed that its purifying effect on pollutants has a tendency to decrease.The backwash cycle Was 28h,the optimal backwash parameter was 8L/(m2·s),and the washing time was 4min.The results of deep purification of aquatic plants showed that the purification effect of emergent plants that Scirpus Tabernaemontani on pollutants is better than that of reed,and the removal rates of COD,TN,ammonia nitrogen and TP by Scirpus Tabemaemontani were 10.2%,6.9%,11.5%and 16.0%higher than that of reed.The optimization results of floating plant and submerged macrophyte are crassipes and myriophyllum sp.respectively.However,at the later stage of plant growth,there is a problem of pollutant re-release.Therefore,in terms of the depth of water purification,it is necessary to harvest with the plant purification technology.