Positive and negative pressure enhanced drainage shaft structure for precipitation of landfill site and construction method

Abstract

The invention discloses a positive and negative pressure enhanced drainage shaft structure for precipitation of a landfill site and construction method. The shaft pipe structure comprises a negative pressure suction seal section with the upper section not provided with holes, a percolating liquid inlet section with the middle section provided with holes and a sand settling section with the lower section not provided with holes. The material of the shaft pipe is galvanized steel pipe, and has good corrosion resistance and deformation resistance. The construction of the shaft is completed by digging a hole, laying down a shaft pipe and a steel reinforcing cage, filling and sealing and filtering a material, installing a pumping pipe and pumping / injection gas pipeline, sealing a head of theshaft, washing the shaft and the like. When the shaft is pumped by a submersible pump, the negative pressure pumping is carried out simultaneously. The percolation gradient of the percolation fluid isincreased by the high negative pressure in the shaft. At the same time, the block effect of the landfill gas on the percolation of the percolation fluid is weakened so as to improve the working performance of the shaft. Silt is produced after a period of operation, and the shaft can dredge the sieve hole by injecting positive pressure gas into the shaft to recover the drainage performance.

Description

technical field [0001] The invention relates to the field of leachate water level control in landfill sites, in particular to a positive and negative pressure enhanced pumping and drainage shaft structure and construction method for dewatering in a landfill site. Background technique [0002] During the operation of the landfill, a large amount of leachate will be produced due to the infiltration of rainfall and the degradation of the landfill itself. Compared with low food waste in developed countries such as Europe and the United States, my country's high food waste has a high leachate yield (51%) due to high initial moisture content (40-60%) and high food waste content (61.6%). On the basis of the large daily landfill volume (5000-10000 tons / day), landfilling waste will produce a large amount of leachate (2500-5000 tons / day). Due to the low permeability coefficient of the waste at the bottom and the blockage of the drainage layer, a large amount of leachate produced cann...

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Problems solved by technology

[0004] In order to overcome the poor drainage effect of traditional leachate drainage shafts, the present invention provides an enhanced drainage shaft that utilizes the high negative pressure in the well to increase the seepage gradient of leachate and at the same time weaken the blocking effect of landfill gas on leachate seepage Structure and Construction Method

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