Method and system for treating high-salinity and poor-biodegradability percolate

Abstract

The invention discloses a method and a system for treating high-salinity and poor-biodegradability percolate. The method comprises the following steps: removing a large amount of suspended matters anda part of macromolecular organic matters in the percolate by adopting coagulating sedimentation; enabling supernatant after carrying out coagulating sedimentation pretreatment to enter a two-stage DTRO (Disk Tubular Reverse Osmosis) system, thus obtaining two-stage DTRO produced water and two-stage DTRO concentrated water; separating salt from the two-stage DTRO concentrated water by adopting DTNF (Disk Tubular Nanofiltration), thus obtaining DTNF produced water and DTNF concentrated water; concentrating the DTNF produced water by adopting DTRO-L, thus obtaining DTRO-L produced water and DTRO-L concentrated water; enabling the DTRO-L produced water to flow back to a water inlet end of the two-stage DTRO system; treating the DTNF concentrated water by adopting advanced oxidation, removinghigh-concentration organic matters, and then recharging a landfill; treating the DTRO-L concentrated water by adopting an MVR (Mechanical Vapor Recompression) evaporation crystallizer, thus obtainingcrystallized salt and MVR condensed water; mixing the condensed water with the two-stage DTRO produced water, carrying out standardized discharging, and discharging the crystallized salt. According tothe method and the system, disclosed by the invention, the percolate which is high in salinity and difficult in biochemical treatment can be treated by adopting multiple combination technologies, theyield of the produced water is effectively increased while standardized discharging of the produced water is ensured, and the operating pressure of a membrane system is reduced.

Description

technical field [0001] The invention relates to the technical field of landfill leachate treatment, in particular to a method and system for treating leachate with high salinity and poor biodegradability. Background technique [0002] Landfill leachate belongs to high-concentration and refractory organic wastewater, which has the characteristics of complex components, high pollutant concentration, unbalanced biological nutrient ratio, high chroma, strong odor, and poor biodegradability. Therefore, the treatment of landfill leachate has always been a Difficult to treat high-concentration wastewater. Both landfill and incineration will inevitably produce landfill leachate. With the strict implementation of the "Pollution Control Standards for Domestic Waste Landfills" (GB16889-2008), the treatment of landfill leachate has gradually formed a "biochemical + MBR +NF+RO" and "two-stage DTRO" mainstream processes. [0003] For some special landfills, such as landfills with landfi...

AI Technical Summary

Problems solved by technology

Some leachate is directly treated by the two-stage DTRO system. Due to the high salt content of the influent, the two-stage DTRO system operates under high pressure, and the yield of product water is often low, and a large amount of high-salt and high-COD concentrated water (approximately 35~45%) needs to be recharged, and the recharge of a large amount of concentrated water will easily lead to the accumulation of salt and COD, which will easily form a vicious circle and cause the system to fail to operate continuously and stably

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