FLOSAND CONTINUOUS BACKWASH UPFLOW SAND FILTERS
Description
Continuous backwash upflow sand filters are water treatment systems designed to provide efficient and continuous filtration without the need for shutdowns during cleaning. In this process, water enters the filter from below, flowing upward through a bed of sand, which traps suspended particles and impurities. Simultaneously, the sand is continuously cleaned by an internal airlift mechanism that removes dirty sand from the bottom, washes it, and returns the clean sand to the top of the filter bed. This allows for uninterrupted operation, making the system suitable for large-scale water and wastewater treatment applications.
The key innovation of these filters lies in their continuous backwashing mechanism, which allows for uninterrupted filtration. While water is being filtered, the sand bed is simultaneously cleaned by a built-in airlift pump that transports used sand to the top of the filter, where it is scrubbed and then returned to the sand bed.
How it's work
Continuous Backwash Upflow Sand Filters are designed for efficient, uninterrupted filtration of water. Their operation relies on an upflow filtration method combined with a continuous self-cleaning mechanism.
Influent Water Entry:
- Contaminated water, containing suspended solids, enters the filter at the bottom through the inlet chamber.
Upflow Filtration:
- The water flows upward through a sand bed inside the filter tank. The sand acts as a filtration medium, capturing and trapping the suspended particles from the water as it passes through.
Clean Water Exit:
- As the water flows upwards, clean filtered water exits from the top of the filter through a collection system, leaving behind the suspended solids in the sand bed.
Continuous Backwash (Sand Cleaning):
- While filtration occurs, the sand in the bed becomes gradually saturated with trapped particles. To prevent clogging and maintain efficiency, a built-in airlift pump continuously pulls dirty sand from the bottom of the sand bed to the top of the filter.
- The dirty sand is transported to a washing chamber where it is scrubbed clean using a combination of water and gravity. The cleaned sand then returns to the top of the sand bed.
Discharge of Waste Solids:
- The solids that are removed from the sand during the washing process are collected and discharged separately as sludge or waste, preventing recontamination of the water.
Ongoing Filtration:
- This continuous cycle of filtering, sand cleaning, and solid waste removal allows the filter to operate without interruption, eliminating the need for downtime or manual cleaning.
The Flosand continuous backwash filter can be applied in both municipal wastewater and industrial water treatment processes.
Whether you need reuse quality water, nutrient removal, industrial water treatment, or raw water treatment, FLOWTEC’s Flosand delivers unmatched effluent quality, meeting the highest of environmental standards.
Municipal
- Suspended solids reduction
- Water reuse (Title 22 Certified)
- Denitrification and nitrification
- Chemical phosphorus removal
- Pretreatment to other processes
Industrial
- Metal finishing
- Backwash recovery
- Process water
- Cooling tower blowdown
- Steel mill scale
- Chemical processing
- Ideal for pretreament in lieu of gravity filters
- Automatically backwashes while filtering for continuous operation
- High filtrate rates in a small footprint
- Controls consist of a level transmitter, modulating effluent valve, air control panel and a filtrate weir
- Low space requirements and ease of installation
- No moving parts and simple, effective operation
- Effectively filters otherwise hard-to-filter solids
- Saves energy and maintenance costs
- Produces an uninterrupted treated water stream, with a minimal resultant waste stream for disposal or further treatment
Flosand Concrete Basin
The filter cells (each consisting of multiple filter modules) share a common sand bed. A plant can be designed for a virtually unlimited filter area, enabling the Flosand to be applied to small and large treatment plants with capacities ranging from 0.05 MGD to flow rates in excess of 100 MGD.
The stainless steel internal equipment can be supplied for existing concrete cells.
Flosand Freestanding Units
Freestanding units can be designed with different tank material:
- Standard painted carbon steel
- Stainless steel
- Aluminum
- FRP