Research On Artificial Recharge Of Groundwater Based On Constructed Wetlands System In Deyang City

Using the fill water from the constructed wetland for artificial recharge of groundwater is a new way for the utilization and development of water resources;which is benefit for the construction of Ecological river- Constructed wetland- Groundwater artificial recharge system.Not only the system can improve the urban water environment,but also can provide an important water supply source for urban water supply by treating and improving the polluted river water into the sourse of groundwater artificial recharge with ecological value.The Research on artificial recharge of groundwater based on constructed wetlands system in Deyang City contribute to enrich domestic research and provide some suggestions for urban water supply safety in Deyang City while promoting the construction and implementation of similar projects in China.Systematic tests were conducted on the Ecological river- Constructed wetlandGroundwater artificial recharge system including current background river water and ground water quality test of the study area, the pre-treatment of the river water – the flocculation and sedimentation laboratory experiment and field test,the substrate and plant selecting tests of constructed wetland; the infiltration test.This paper estimate the effect of water treatment, selects plants and substrates of constructed wetlands through integrated analysis and evaluation of the system's water treatment process based on Chinese standards GB3838-2002, GB5749-2006 and the water quality standard for groundwater recharge in Beijing City together with some examples of measurement under these standards. Numerical simulation of groundwater flow is an effective approach in groundwater resource evaluation,the paper estimate the dynamic of groundwater environmental quality after the groundwater recharge variety through constructing the conceptual model and mathematical model of the study area. Through the research all above, the paper summarizes all works and draw the following conclusions:(1)The most suitable flocculant dosage amount is 60ml/m3~80 ml/m3 41% FeCl3 to the current river water, Constructed wetland- Groundwater artificial recharge System water-source, quality test.(2)The turbidity, Total Phosphorus of the source water is mainly removed in the Pre-treatment period of flocculation and sedimentation while the COD,Total Nitrogen mainly removed during the Constructed wetland system.(3)The removal rate of turbidity in the Pre-treatment period of flocculation is 67%~89.7%, while the Total Phosphorus removal rate is 58.67%~88.52%.The removal rate of COD is 30%~50% and the Total Nitrogen removal rate is 20%~30% during the Constructed wetland system.When the A/O technology added to the system,the Total Nitrogen removal rate increased to about 70%.(4)Some water quality index(Cr6+?Zn?As?Hg ? Cd ? Se)of the system's water source has reached the recharge water standard before treatment.Most of the water quality index achieve the water quality standards after the flocculation and sedimentation Pre-treatment, Constructed wetland treatment and the filtering effect of the aquifer.(5)The hydrogeological model simulation results show that it takes more than 60 days the infiltration pool water pointing migration to the water supply wells? 63.25% of the water supply pumuping out comes from the infiltration recharge pool and 36.73% comes from the Mianyuan river reacharging.Infiltration recharge and disrecharge form a local small groundwater flow system, which will not have a large impact on the occurrence and dynamics of the surrounding groundwater.