In-situ circulation well repair system and method for perfluorinated and polyfluoroalkyl compounds in underground water

Abstract

According to the in-situ circulation well repairing system and method, a well pipe is composed of a solid pipe, an upper-section screen pipe and a lower-section screen pipe, the upper-section screen pipe is located at the underground water level, and the lower-section screen pipe is located at the lower edge of the underground water pollution range; the aeration system comprises an aeration pipe, the air outlet end of the aeration pipe is provided with an aeration head, and the aeration head is arranged in the lower-section screen pipe area; the collecting and extracting system comprises an extracting pipe, a foam collecting head is installed at the collecting end of the extracting pipe, and the foam collecting head is arranged above the water surface of underground water in the well; the separation treatment system comprises a gas-liquid separator, a gas treatment device and a liquid phase collection tank, an inlet of the gas-liquid separator is connected with the discharge end of the extraction pipe, an exhaust port is connected with the gas treatment device, and a liquid discharge port is connected with the liquid phase collection tank. The PFAS recovery rate is increased through aeration stripping in combination with the underground water circulating well, the PFAS polluted underground water remediation cost is reduced, and the remediation period is shortened.

Description

technical field [0001] The invention relates to the field of groundwater in-situ technology, in particular to an in-situ circulation well repair system and method for perfluorinated and polyfluoroalkyl compounds in groundwater. Background technique [0002] Per- and polyfluoroalkyl substances (PFAS) are a general term for a series of synthetic organic fluorides. It was originally used to extinguish large oil fires. Due to its extremely stable chemical structure and oleophobic and hydrophobic properties, it is often used in the manufacture of daily necessities and fire-fighting products that require waterproof, anti-fouling, anti-grease, etc. PFAS contains high-energy carbon-fluorine bonds, which are refractory, extremely high persistence, and mobility. They are ubiquitous in water, sediment, soil, atmosphere, and organisms, and have potential environmental and health risks. [0003] Due to the special properties of PFAS, such as high electronegativity and strong carbon-fluo...

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Problems solved by technology

[0003]Due to the special properties of PFAS, such as high electronegativity and strong carbon-fluorine bonds, commonly used in-situ groundwater remediation technologies (such as bioremediation, chemical oxidation, etc.) The effect of groundwater treatment is not good; although in-situ thermal desorption technology is effective, it requires extremely high heating temperature to destroy the stable structure of pollutants, and the repair cost and energy consumption are extremely high; extraction treatment technology is to pump a large amount of polluted groundwater to the surface, Water treatment is then carried out to remove PFAS in the pumped water, but the system has a long operating cycle and requires continuous energy supply and regular monitoring and maintenance, which is costly and poses a high risk of secondary pollution

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