Denitrification Deep Bed Filter Tank
Denitrifying deep bed filter process
The denitrification deep bed filter process is a treatment unit that combines both biological nitrogen removal and filtration functions. It is a treatment process that simultaneously addresses both denitrification and filtration. Most filter beds are prone to clogging or hardening on the surface, quickly losing head pressure. However, the uniform quartz sand in the denitrification deep bed filter allows solid impurities to pass through the surface of the filter bed, deep into the filter media of the pool, meeting the requirement of retaining solid particles throughout the entire depth of the filter pool.
Denitrification deep bed filter tank, utilizing narrow and elongated channels for even water inflow; filter brick structure ensures excellent backwashing effect; nitrogen gas produced during denitrification can cause air resistance in filtration, which is mitigated by expelling the nitrogen to ensure optimal filter tank operation.
In operation with an external carbon source, it is a deep bed denitrification filter with denitrification function, capable of removing TN, SS, and TP. Without the external carbon source, it is a deep bed filter that can simultaneously remove SS and TP.
The denitrification deep bed filter is essentially a fixed film reactor in a packed form. It is a biological membrane process for wastewater treatment combined with water filtration, categorized under biological filtration technology. Bacteria and other microorganisms grow as a film on a solid medium, and when the fluid flows over the solid filter material, it removes pollutants through the dual actions of the filter material's interception and the biological degradation of the biofilm on the filter material.
Filter Pond Structure
System Composition
Filter Media: Natural sea sand, silicon content ≥95%, particle size: 1.7-3.35mm, filter media thickness ≥1.83m, K60<1.4, specific gravity ≥2.6 tons/m³, Mohs hardness >6.
The gravel base layer is composed of natural cobblestone, with particle sizes ranging from 3-38mm, thickness of 380-420mm, and is layered in 5-6 layers to support the filter material.
Filter Bricks: Constructed with a concrete core and an outer HDPE (high-density polyethylene) shell, "T" type air-water distribution filter bricks, offering backwashing air-water distribution performance.
Anti-siphon pipe: Material SS304, the anti-siphon intake pipe provides uniform distribution of backflush gas.
Inlet weir plate: Material SS304, thickness ≥4mm, providing conditions for uniform distribution of incoming and backflush water.
Control System: PLC programmable controller, capable of system controlling all operating equipment inside the filter pond.
Valves: Manual and automatic valves control the inflow and outflow of water and gas.
Carbon Source Storage and Supply System: Generally using sodium acetate, controlled by the amount of nitrate nitrogen entering the filter pond.
Backwashing Pump: Provides backwashing water for filter bed backwashing and nitrogen release system.
Reverse Osmosis Blower: The blower, based on the set air volume, supplies backwash air through the entire filter tank base.
Other Equipment: Field instruments, valves, pipelines, and denitrogenation systems, etc.
Process Features
1. Integrated system technology for air-water co-injection backflushing units, gas distribution systems, and operational processes, which address issues such as direct filtration and biological filter media clogging due to biofilm detachment in biological filters.
2. The denitrification deep bed filter continues to operate, removing NO3-N while producing nitrogen to form a "gas blockage." As it continues to run, the filter resistance loss keeps increasing, potentially leading to short-circuiting in the filtration process and deteriorating the effluent water quality.
3. Comprehensive, integrated automation equipment and technology, online monitoring instruments, and computer program control ensure the continuous, stable, and reliable operation of the entire process, including operations such as air and water backflushing and nitrogen purge, addressing the control issues in process operations that cannot be achieved manually.
4. The effluent water quality meets the aquatic standards.
Current Standard Process: T-Shape Filter Brick Air-Water Distribution System
