Simulation Experiment Study Of Groundwater Recharge Gas Clogging Based On ASR Technology

As the regional economic and social development, the over-exploited groundwater occurs in many areas,this raises regional groundwater level decline,surface subsidence,seawater intrusion, atrophy of wetland and vegetation destruction and a series of environmental and geological problems.In order to solve the above problems,in addition to series restrictions of limiting groundwater exploitation,more positive and active way is implementation of groundwater artificial recharge.So Far the clogging during the recharge process of injection well seriously affect the efficiency of groundwater recharge,even caused the recharge well scrapped. According to incomplete statistics,about 10% of the clogging of recharge well is caused by gas,the reason why gas clogging has certain concealment greatly increases the difficulty of the study.ASR equipment can adjust the the opening of the drainage holes of 3R Valve to keep pressure of recharge pipe constant,reducing the formation of bubbles and gas clogging.This study carries out the indoor sandbox experiment to explore the rule of gas clogging, the specific study contents and the main results are as follows:Firstly, we use de-aerated water after treated by Liqui-cel to recharge 18 hours in succession,the result shows that the amount of recharge increases with the time,the permeability coefficient and time are highly positive correlation,not happening the gas clogging.Then,we use water with micro bubble to recharge for 162 hours continuous,the result shows that the amount of recharge and permeability coefficient reduce with time,and reduce to the minimum in 96 hours.There has been a obvious gas clogging.Further analysis about relative permeability coefficient(K/K0) of adjacent infiltration area shows that the adjacent K/K0 are highly negative correlation.In other words,the permeability coefficient of behind permeability area increases while the permeability coefficient of front area reduces and the clogging degree intensifies,indicating that the gas clogging caused by micro bubble has some mobility.We discover that the mass concentration of the main ion has some changes by checking water quality,indicating that mineral facies of aquiferous medium has certain dissolution-deposition and cation exchange adsorption. Therefore,water-rock interaction during the process of recharge and the realignment of aquifer grain caused by dissolution-deposition of mineral facies of aquiferous medium also can reduce the permeability of the aquifer.We use de-aerated water to recharge again after returning pump water,the amount of recharge is about 0.63 L/min has increased that of gas clogging(0.55L/min) more than 10 percent,indicating that returning pump water can effectively improve the gas phase plug.Experiments show that Liqui-cel can completely remove the micro bubble from recharge water and lower dissolved oxygen to the equivalent of groundwater.We can completely prevent gas clogging in the case that de-aerated water after treated by Liqui-cel does’ t come into being of empty space.The author designs a type of groundwater recharge device to prevent gas clogging combined with ASR equipment.