Multi-grade biological tank+MBR (Membrane Bioreactor) treatment system for strengthened denitrification of landfill leachate

Abstract

The invention provides a multi-grade biological tank+MBR (Membrane Bioreactor) treatment system for strengthened denitrification of landfill leachate. The multi-grade biological tank+MBR treatment system comprises a multi-grade biological tank and an external type ultra-filtration membrane assembly, wherein the multi-grade biological tank is formed by connecting multi-grade denitrification-nitrification tanks in sequence; a final output of the multi-grade biological tank is connected with the external type ultra-filtration membrane assembly through a centrifugal pump and a pipeline; the landfill leachate is conveyed into each grade of a denitrification tank through a pipeline; and an outlet of the external type ultra-filtration membrane assembly is communicated with a primary-grade denitrification tank and the next working section respectively. Compared with a traditional two-grade A/O+MBR biological treatment system, the treatment system has the advantages of no reflowing of a mixed solution and reduction of an adding amount of an external carbon source, so that the energy consumption of the system is reduced, the operation cost is saved and the denitrification efficiency can be improved.

Description

Technical field [0001] The invention belongs to the technical field of sewage treatment, and relates to a biochemical treatment process for landfill leachate, and in particular to a multi-stage biological pond + MBR treatment system for the enhanced denitrification of landfill leachate. Background technique [0002] Landfill leachate is a kind of high-concentration organic wastewater. Its water quality and quantity are affected by many factors such as garbage type, local environment and precipitation, landfill volume, landfill time and other factors, which vary greatly, especially with the landfill time. Extension, CODcr and BOD 5 Gradually decrease, the ammonia nitrogen concentration gradually rises, the C / N ratio is gradually out of adjustment, and biological nitrogen removal is very difficult. However, as the country pays more and more attention to environmental protection, the discharge standards for leachate treatment effluent are becoming stricter. In addition to the leach...

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Problems solved by technology

Although the biochemical treatment system has a good denitrification effect, it also has the following problems: 1) Due to the high content of ammonia nitrogen in the leachate, the biological denitrification system must be equipped with a high mixed liquid reflux ratio, which is as high as 20 to 30 times. Even higher, resulting in high energy consumption of the leachate treatment system and increased operating costs; 2) Due to the high reflux ratio of the mixed solution, the mixed solution carrying a large amount of dissolved oxygen flows back to the primary denitrification tank, resulting in Dissolved oxygen is high, which affects the denitrification effect and reduces the efficiency of biochemical treatment; 3) In order to further remove residual nitrate nitrogen in the secondary denitrification tank, a large amount of external carbon source must be added, which increases the operating cost

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