Tertiary treatment with sand filters, phosphorus precipitaion, denitrification reactor and UV disinfection
Sand Filters- Continuous-Backwash, Upflow, Deep-Bed, Granular Media Filter
The Dynasand Filter is a continuous-backwash, upflow, deep-bed, granular media filter. Filter media is continuously cleaned by recycling the sand internally through an airlift pipe and sand washer. The cleansed sand is redistributed on top of the sand bed, allowing for an uninterrupted flow of filtrate and reject (backwash) water.
Feed is introduced at the bottom of the filter and flows upward through the sand bed bottom. Solids are trapped in the sand bed and the filtrates exit over an effluent weir. The sand bed, along with the accumulated solids, is drawn downward into an airlift pipe. Compressed air, introduced at the bottom of the airlift, draws the sand into the airlift and scours it.
Applications include: denitrification, phosphorus removal, algae filtration and turbidity reduction.
Features
- Continuously cleaned sand
- No underdrains or screens
- Sand washed with filtrate
- Internal, vertical airlift
- Low power requirements
Benefits
- No shutdown for backwash cycles during filter operation
- Elimination of ancillary equipment
- No flow control valves, splitter/boxes, or backwash controls
- No short-circuiting or clogging
- Optimum sand-washing efficiency
- Superior filtrate quality
- Reduces plugging: Significantly reduces wear & maintenance
- Easily maintained without filter shutdown
Phosphorus Precipitaion- Wallaxtm Phosphorus Precipitation System
Phosphorus reduction is achieved with the addition of coagulants such as metal salts, typically iron chloride, iron sulfate, alum or poly-aluminum chloride. These precipitates are acceptable in the wastewater industry and to regulatory authorities. The metal salts react with phosphates in the wastewater to form insoluble precipitates that settle to the bottom of the treatment chamber. This type of phosphorus reduction can effectively achieve 80-95 percent total phosphorus removal and effluent concentrations of <1 mg/l total P.
In conventional settings, Aquapoint`s Bioclere and Lotus technologies can be designed with chemical addition systems to dose the wastewater with coagulant and effectively reduce phosphorus in the waste stream. For special applications such as remote camps and lodges where intermittent flows and lack of power make treatment problematic, Aquapoint WallaxTM phosphorus removal systems are ideal.
Wallaxtm- Phosphorus Precipitation System
Wallax is a modular phosphorus precipitation system designed to achieve <1mg/l total phosphorus. Treatment is accomplished with the addition of metal salts as discussed above.
Flow is equalized inside the Wallax unit and chemical coagulant is dosed to the waste stream. The chemical is rapidly mixed with the wastewater in a vortex mixer ensuring stable floc formation, coagulation and settling. Final effluent flows over a notched weir for disposal.
Features
- Designed to achieve <1mg/l total-P
- Corrosion and acid resistant components
- Modular units for increased flow capacity
- Sealed and insulated for seasonal applications
- Internal flow equalization moderates flow surge and intermittent flows
- Minimal energy requirements
- Gravity flow system
- Low capital investment
- Low installation, operation and maintenance costs
Denitrification Reactor- ANOX Biological Reactor
The Aquapoint ANOX biological reactor provides a suitable environment to initiate and complete tertiary biological denitrification. Biological denitrification is the reduction of nitrate to nitrogen gas by facultative heterotrophic bacteria in the presence of a soluble carbon source.
Nitrified effluent is pumped or flows by gravity to the ANOX reactor. An electrical signal from the pump or flow meter will energize a chemical feed pump that transfers organic carbon to the inlet of the chamber.
Submerged in the ANOX reactor are PVC media blocks on which the bacteria adhere and reduce the nitrate in the waste stream. Submersible pumps operating on a duty cycle of approximately 50% will circulate water through the media blocks, ensuring contact of the carbon source, nitrate and bacteria. Sloughed solids are re-circulated to the primary tank via a sludge return pump. Operation of the two circulation pumps, the sludge return pump and the chemical feed pump is automatic and fully adjustable by the system operator. Audio visual alarms are installed to detect pump failure.
Features and Benefits
- Designed to achieve tertiary/denitrification using an external carbon source
- Will achieve <10 mg/l total nitrogen
- Low capital investment
- Energy efficient
- Minimal O&M requirements
- Modular units for adjusting flow capacity
- Sealed for quiet odor free processing
- Top of tanks set at grade
- ANOX components by Aquapoint.
- Tanks and aluminum access hatch supplied by contractor
UV Disinfection- Ultraviolet Intensity Monitoring
UV Disinfection units are designed to destroy 99% of all organisms left in the waste stream after secondary or tertiary treatment. Electromagnetic energy is transmitted into the waste stream and penetrates the outer membranes of organisms. This process impairs DNA functionality, effectively killing the micro-biology in the wastewater.
UV has several advantages over chlorine disinfection. It eliminates the need to transport dangerous chemicals, perform complex operations and dechlorinate the waste stream.
Units can treat up to 500,000 gpd and can be installed in parallel to accommodate larger flows.
Standard Features
- Stainless steel channel construction
- Built-in level control weir with removable drain plug
- Stainless steel weatherproof modules
- Remote modified NEMA enclosures with window kits displaying lamp status and elapsed run time
- Low pressure high output (HO) or amalgam lamp technology with 8,500 hour lamp life
- Small footprint
- Minimal operation requirements
Optional Features
- Ultraviolet (UV) intensity monitoring
- 4-20 mA output or dry contact alarming
- Transitions for flanged, piped or threaded connections on the inlet and outlet of the UV system
- Cleaning racks or tanks
- Complete standby spare modules
- Redundant banks
