Landfill leachate high-performance denitrification system and denitrification process thereof

Abstract

The invention relates to a landfill leachate high-performance denitrification system and denitrification process thereof. A movable bed membrane bio-reactor is combined with a denitrification pool ofthe active sludge membrane bio-reactor. For the landfill leachate with sufficient carbon source on the front end, the landfill leachate high-performance denitrification system comprises a core structure of the denitrification pool combined with the movable bed membrane bio-reactor, the denitrification pool and a hyperfiltration membrane; for the landfill leachate with insufficient carbon source onthe front end, the landfill leachate high-performance denitrification system comprises a primary denitrification pool, the denitrification pool combined with the movable bed membrane bio-reactor, a secondary dentrification pool and a hyperfiltration membrane; and for the landfill leachate with high denitrification requirement, the landfill leachate high-performance denitrification system comprises a core structure of a front-mounted denitrification pool, a primary denitrification pool, a rear-mounted denitrification pool combined with the movable bed membrane bio-reactor, a secondary denitrification pool and a hyperfiltration membrane. By sufficiently utilizing the existing carbon source, the ammonium nitrogen and total nitrogen can be significantly removed, the operation expense can be reduced, an effect of continuity, stability, high performance and low operation cost can be achieved, and the landfill leachate high-performance denitrification system and denitrification process thereof are suitable for treating high-ammonium-nitrogen waste water of the landfill leachate.

Description

technical field [0001] The invention relates to the technical field of environmental engineering, in particular to a denitrification system suitable for treating high-ammonia-nitrogen wastewater such as household garbage leachate. Background technique [0002] With the improvement of environmental quality requirements, the country's discharge requirements for total nitrogen in external sewage are gradually increasing. The "Standards for Pollutant Control of Domestic Waste Landfill Sites" (GB16889-2008) promulgated in 2008 has clear requirements for total nitrogen for the first time. According to the Beijing local standard "Comprehensive Discharge Standard of Water Pollutants" (DB11 / 307-2013), units that discharge sewage directly to surface water shall implement the standards in Table 1 for the discharge of water pollutants, in which the ammonia nitrogen requirement is 1mg / L, and the total nitrogen The requirement is 10mg / L, and the existing leachate biochemical treatment te...

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Problems solved by technology

[0005] Even if the leachate has undergone single-stage or two-stage activated sludge series biochemical treatment, the MBR effluent still contains about 10-30 mg / L of ammonia nitrogen and 100-600 mg / L of total nitrogen under normal operating conditions, causing the entire leachate treatment It is difficult for the effluent of the system to meet the discharge standard

The main reason is: nitrifying bacteria and denitrifying bacteria are continuously circulating in the aerobic and anoxic reactors with the sludge in the reactor, and the living environment of the microorganisms is constantly changing. It is difficult for the two types of bacteria to form an absolute Dominant flora, affecting nitrification and denitrification effects

Specifically, (1) the carbon source utilization efficiency is not high. In the nitrification and denitrification (A / O) process, the denitrifying bacteria are mainly facultative heterotrophs. The reaction is the main reaction process for removing organic matter, which requires a large amount of carbon source consumption. The appropriate carbon-to-nitrogen ratio is 5-7:1, and this part of the carbon source is mainly provided by easily degradable organic matter, refractory organic matter and external carbon source in the leachate; (2) Competing with the substrate, in order to have To achieve the ideal treatment goal within the limited residence time, the sludge residence time (SRT) must be maintained at an appropriate level, so as to ensure that microorganisms can grow mixedly; (3) In order to ensure a higher sludge concentration, a larger sludge concentration is required. Return flow, resulting in the loss of anoxic conditions for secondary denitrification, and more carbon sources need to be added to consume excess dissolved oxygen, which in turn increases the operating costs of the operating system

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