The Constructed-wetland’s Restoration And Simulation Of The Surface Water Body For Garden System

In recent years, the phenomenon of Eutrophication has become quite prominent in our country and our government has made great efforts in its restoration and treatment. This article is based on the experimental station in Nanjing Research Institute of hydraulic science. In addition to monitoring the water quality, they analyzed the trophic status and nutrient enrichment. They were able to restore the eutrophic water body by constructing wetland cells, as well as estimation of pollution and artificial wetland restoration simulation, with small-sized weather monitoring (SWMM) device reporting temperature and humidity.(1) Under the normal water monitoring condition, this paper used single-factor method to assess the degree of surface water pollution and TSI comprehensive evaluation method to measure the degree of trophic status. The results showed that: ① It met the water use of landscape, but not up to standard Ⅳ. The water quality of TIEXINQIAO experimental base was at the mild trophic state. ②XIANGMUHU and YUDAIHE rivers were of good connection and showed a correlation in trophic status. XIAANGMUHU is better than YUDAIHE in water quality and superficial water body is of high eutrophication than swallow water body.③The concentration of pollution indicators can be sorted as TN> CODMn> TP, the TSI indicators can be sorted as TSI (TN)> TSI(TP)>TSI(SD)> TSI (CODMn)> TSI (Ch1 a),which TSI (TN) and TSI (TP) were strongly influenced by weather and rainfall.(2) Two types of artificial wetland system were established and the results showed that:①Constructed wetland have the ability to cut down pollutants, The TN,TP and CODMn removal rate attained 10%-70%,15%-25%,5%-20% in turn.② Vertical flow pattern has better restoration effect than horizontal pattern. The gap between them were more than 10 times in repair efficiency.③considering the types and combination of wetland plants and matrix, Ⅱ-1 type of constructed wetland were found to be the best in garden system, Ⅱ-1 type of constructed wetland to be least effective.(3) Related information were collected to build the SWMM model in TIEXINQIAO experimental base, which can reflect the pollutant mass under different rainfall recurrence.The results showed that:①The amount of pollutants into the lake had a positive correlation with the designed rainfall reappearing periods. Pollutants mass can be roughly sorted as TN> CODMn> TP. The rainfall during one year return period can generate 10kg of CODMn,3kg of TN,2kg of TP. Point source pollution accounted for a small proportion, less than 10%. ②Contaminants discharged with sewage from the drainage network in most cases, or stuck in the garden water body. ③Constructed wetland have a good effect of pollution control. The maximum mass of removing pollutants by constructed wetland can reach 10% of the total storage pollutants. Thus Ⅱ-1 type of constructed wetland is recommended to repair the water body for the experimental zone, with the aids from adopting approaches such as increasing the constructed wetland water flow velocity, minimizing the water retaining time.