A method for in-situ electrochemical circulation well repair of chlorinated hydrocarbon polluted groundwater

Abstract

The invention provides a method for repairing in-situ electrochemical circulation wells polluted by chlorinated hydrocarbons. The steps are as follows: dig wells in groundwater polluted areas, and install well pipes in the wells, wherein every two wells form a group, and in each group of wells, One well is used as a water injection well, and the other well is used as a water pumping well. The top end of the well pipe is open and the bottom end is closed. Several small holes are opened on the lower end of the well pipe; the anode plate is suspended into the water injection well and the cathode plate, the anode plate and the cathode plate are respectively connected to the positive pole and the negative pole of the power supply arranged outside the well through wires; the power supply is started to energize the anode plate and the cathode plate, and at the same time, the groundwater in the pumping well is continuously pumped by a water pump and injected into the water injection well In order to strengthen the groundwater flow circulation, the hydrogen and oxygen produced in the water injection wells diffuse to the aquifer under the action of the groundwater flow circulation to promote the chemical / microbial degradation of chlorinated hydrocarbons in the groundwater. The restoration method provided by the invention has stable effects and is environmentally friendly.

Description

technical field [0001] The invention relates to the field of groundwater treatment, in particular to an in-situ electrochemical circulation well repair method for chlorinated hydrocarbon polluted groundwater. Background technique [0002] In recent years, chlorinated hydrocarbons such as carbon tetrachloride, chloroform, dichloroethane, trichloroethylene (TCE), and tetrachloroethylene have been used in large quantities as organic solvents, cleaning agents, and chemical raw materials, causing serious pollution to soil and groundwater environments. . Taking TCE as an example, statistics show that as of 2012, the total production capacity of trichlorethylene in my country was close to 570,000 tons / year, and the production capacity has exceeded one million tons / year in recent years. Chlorinated hydrocarbons are extremely harmful to the human body and have strong carcinogenic, teratogenic, and mutagenic properties. They are currently key pollutants controlled by various countrie...

AI Technical Summary

Problems solved by technology

In-situ aeration mainly includes the direct injection of air or pure oxygen. Air injection has low oxygen supply efficiency and is easy to supply inert gas components and impurities in the air to the aquifer, while pure oxygen injection is costly. In addition, for deeper Area aeration needs to overcome extreme pressure

There are two main ways to inject aerobic water. One is to use the in-situ groundwater pumped out by double well circulation to inject back into the aquifer after enriching the surface with oxygen. However, there is a limit to the amount of well water pumped out. There is a risk of pollutants leaking during the oxygen-enriched period on the surface, and the failure of groundwater to recharge in time will greatly affect the groundwater flow field in the aquifer and accelerate the diffusion of chlorinated hydrocarbons

The other is to use additional surface water and other aerobic water bodies to directly inject into the aquifer, but the injection of surface water will introduce a large amount of impurities, which may cause physical blockage of well pipes or other pollution, and make the groundwater table rise

In addition, the injection of a small amount of aerobic water can only affect the shallow groundwater, while the injection of a large amount of aerobic water will greatly affect the in-situ flow field

There is no relevant report on the input of hydrogen in the underground environment by the circulating well process, because hydrogen is highly dangerous and difficult to store and transport in large quantities

[0005] Therefore, it is difficult to provide oxygen and hydrogen in situ to the underground aquifer to promote microbial degradation by traditional circulating well technology.

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