The integrative reactor and key technology of high efficiency autotrophic nitrogen removal by air-lift self-reflux

Applicating Company

Suzhou University of Science and Technology

Technology Name

The integrative reactor and key technology of high efficiency autotrophic nitrogen removal by air-lift self-reflux

Technical principle

The air-lift reflux integrated reactor contains aerobic zone, anaerobic zone, precipitation zone and self-reflux system. In the aerobic zone, MBBR was used as the carrier to enrich nitrifying biofilms. In the anaerobic zone, upflow sludge bed was used to enrich anammox granular sludge. Solid and liquid separation is realized in the precipitation area. At the same time, the aeration tail gas of the aerobic zone is collected as the power and the water from the precipitation zone is returned to the aerobic zone. The reflux ratio can reach more than 10 times without additional power consumption. The self-reflux system not only achieves the dilution of high ammonia toxicity in raw water, but also creates good upflow hydraulic conditions in the anaerobic zone to promote the sludge granulation in the anaerobic zone. The device greatly reduces the investment, maintenance and energy consumption of machinery and equipment such as sludge reflux pump and nitration liquid reflux pump.

Scope of application

The equipment and technology are mainly applicable to the ammonia nitrogen efficient autotrophic denitrification pretreatment unit of low C/N ratio and high ammonia nitrogen wastewater, such as: photovoltaic industry wastewater, aquaculture industry wastewater, landfill leachate wastewater, food industry wastewater, etc. As an efficient denitrification unit for high ammonia wastewater, the effluent needs to be connected with conventional nitrification and denitrification depth denitrification to ensure the effluent quality reaches the standard.

Process flow and description

Firstly, the low carbon and high ammonia wastewater was put into the aerobic zone of the air-lift reflux integrated reactor, and the dissolved oxygen in the aerobic zone was controlled to be about 0.5-1mg/L, and part of ammonia nitrogen was converted into nitrite under the action of nitrosation membrane in the aerobic zone. Then, the effluent from the aerobic zone enters the anaerobic zone, and under the action of anammox granular sludge, the ammonia nitrogen and nitrite in the wastewater are converted to nitrogen. The mixture of mud and water separates solid and liquid in the precipitation area. Then part of the effluent is returned to the aerobic zone through the air-lift reflux system to dilute the high ammonia concentration of the inffluent water. Another part of the effluent flows out of the reactor and into the deep denitrification system.

Promotion prospects

This project aimed at high ammonia wastewater, low carbon, using conventional denitrification technology need to adding the large amounts of organic carbon and handling the problem of high cost, by means of anammox for the core coupled autotrophic denitrification equipment innovation, do not rely on organic carbon efficient denitrification, and original gas lift the reflux technology realize coupling system denitrification efficiency enhancement and energy saving, greatly reduce the energy consumption of wastewater denitrification and material consumptions, Enhance the market competitiveness of the enterprise's main products. At the same time, significantly reduce greenhouse gas emissions, reduce the residual sludge and other solid waste emissions, to create a good social and ecological environment has significant benefits, can lead many research directions of wastewater denitrification.