Method for dredging underwater polluted sediment

Abstract

The invention discloses a method for dredging underwater polluted sediment and relates to a dredging method. The invention provides a pollution dispersion-free dredging method. A dredging device which consists of a reaming system, a vertical flushing system, a horizontal rotary flushing system, a sand-suction system, a water charging system and a cylindrical sleeve is adopted by the invention. The dredging device is characterized in that a guide rail of the dredging device is glidingly matched with a guiding device on a pile frame; when the dredging device is lowered to approach the surface layer of the sediment, a mooring rope is loosened, and the dredging device passes through a polluted sediment layer and a pollution-free layer to reach a pollution-free sand layer along with the rotary cutting of a reamer head of the reaming system, the flushing of the vertical flushing system and the dead weight of equipment; the dredging device screws in the pollution-free layer, and meanwhile, the sand source of the pollution-free sand layer is pumped by a sand-suction pump of the sand-suction system to cause the pollution-free layer and the polluted sediment layer at the upper part of the pollution-free sand layer to subside; and pollution-free sand pumped by the sand-suction pump is discharged through the sand-suction pump and is backfilled to the polluted sediment to cover the polluted sediment layer.

Description

technical field [0001] The present invention relates to a method of dredging. Background technique [0002] A large amount of industrial wastewater contains high concentrations of toxic and harmful and high nitrogen and phosphorus pollutants, such as heavy metals Cr, Hg, Zn, etc., and toxic and harmful organic substances such as petroleum, chlorobenzene, aniline, etc. Although industrial wastewater is treated by sewage treatment plants, according to the current process of sewage treatment plants, its ability to treat toxic and harmful pollution is extremely limited. Most of the pollutants are discharged into rivers and lakes with water, and accumulate in the sediment, which deteriorates water quality. And destroyed the original ecological cycle of aquatic organisms. Existing dredging and reclamation projects use excavators to loosen the soil, suck it in by a mud pump, and transport it to the shore through pipelines. The sediment will be violently disturbed during dredging ...

AI Technical Summary

Problems solved by technology

The sediment will be violently disturbed during dredging by machinery and equipment. Even if the equipment with environmental protection function is used, it will inevitably cause secondary pollution to the water around the dredging site. After dredging, the water content of the polluted sediment is high, and the subsequent dehydration and drying treatment is difficult, and the workload is heavy. The cost is high, and there are strict requirements on the discharge of residual water. More importantly, in the current situation of scarcity of land resources, it has become very difficult to find a suitable treatment site

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