Polymer Floating Filtering Media
Polymer Floating Filtering Media (PFFM)
Comparative technical characteristics
of heavy and floating filtering media and associated equipment
Methods of technical modelling by Dr.Mintz.
Example:
Co = 170 ppm (initial concentration of contaminants)
Reagent dose: 16 ppm
C/Co = 0.01 (C - concentration of contaminants in filtrate, mg/l)
| Position | Sand | PFFM |
|---|---|---|
| Particle shape factor | 1,14 | 1,11 |
| Depth of filtering bed, m | 1,0 | 1,0 |
| Rate of filtration, m/h | 10, 0 | 10, 0 |
| Rate of head loss in the media during filtration, m/h | 0,209 | 0,161 |
| Rate of contaminants advancement into the depth of the media bed, m/h | 0,0558 | 0,0545 |
| Factor of media free space saturation with contaminants | 0,645 | 0,660 |
| Factor of contaminants adherence to the media | 17,3 | 16,0 |
| Safe filtration time, min | 372 | 456 |
| Duration of backwash to restore the initial resistance of the media, min | 16,0 | 2,0 |
The Floating Filtering Media (PFFM) is an effective alternative to traditional heavy filtering materials such as sand, clay, anthracite, etc.
The PFFM is applied in the removal of iron, manganese, hardness, heavy metals, nitrites, nitrates, ammonia, oil products, suspended solids and many other substances.
The PFFM is a chemically stable material withstanding acid, alkali and oil products and impervious to the bacteriological activity.
The PFFM is suitable for operating in liquids with a temperature of up to +45 deg. The PFFM withstands pressure of up to 0.6 Bar (85 PSI).
The PFFM has an unlimited life span (practical experience, more 15 years of service). The PFFM does not require replacement and its operational properties remain unchanged.
The PFFM is extremely easy to handle and does nor represent any health hazard to personnel. It is clean and dust-free. Loading of the PFFM is a fast process and in many cases can be done by hand. Unloading is also a fast and convenient process - as you raise the level of water, the PFFM is efficiently collected from the water surface.
The PFFM can be easily manufactured and in many cases the manufacturers will have PFFM material already certified for contact with drinking water.
The floating capacity of PFFM make it possible to develop water treatment facilities with far more superior technical, economic and operational characteristics in comparison with traditional heavy filtering media installations.
Application of PFFM brings remarkable benefits to the overall configuration of water treatment facilities. For example, the backwash of the PFFM is conducted by the reverse gravity flow of water and is 100% hydro-automatic. No electronics, no pumps, no compressors or any other additional equipment are involved in the backwash process. The backwash process is based entirely on gravity force and difference of water levels.
During the backwash, the PFFM bed is expanded by 20-40%, and the combination of a downward reverse flow of water and upward movement of floating media produce a vigorous agitation/scrubbing effect resulting in the fast (up to 3 minutes) regeneration of the PFFM.
The loss of water for backwash purposes normally does not exceed 0.8% for of one backwashing . Obvious advantages are: simplicity and reliability, reduced foot print (by 2-3 times), reduced capital, operational and maintenance costs.
Akvastroiservis has recently developed a new process for zero backwash discharge filtration (patent of US, etc) to meet demanding water saving requirements and to reduce technological chain in waste water treatment.
During the commissioning, the PFFM facility is tuned to the optimum operating parameters, which are independently (without control devices or operator's intervention) supported by the facility throughout all the years of operation.
Water treatment facilities, based on the PFFM, operate with a prolonged filtration cycle. The combination of different grades of PFFM in the filtering bed provides an increased contaminant-arresting capacity of the filter, such that the initial concentration of suspended solids before the PFFM filter can be up to 500 mg/l.
PFFM is an ideal filtering material for the so-called "contact" filtration when reagents are introduced in the feed liquid immediately in front of the filter.
Water treatment facilities based on PFFM are very easy to fabricate even in the basic conditions of an ordinary metal workshop. Required fabrication materials comprise readily available items such as steel/plastic sheets, pipes of various diameters, mesh and PFFM.
Facilities based on PFFM can operate both in pressure and pressure-free mode. Quite often, the developers adopt the pressure-free mode. In such a case, the electricity is required only for the feed pump (for example, well pump) and the filtrate forwarding pump. The facility itself does not contain any pumps.
Continuously operating PFFM facilities do not require sheltering and can work at ambient air temperature of -40 deg. In such cases, ice serves as a heat insulator.
The water treatment facilities based on PFFM can be positioned underground, on the ground or at the top of water towers.
The water treatment facilities based on PFFM are distinguished for their compactness; modular design; high reliability due to the absence of electrical, moving or rotating parts; ease of fabrication and maintenance and very low operational costs.
The water treatment facilities based on PFFM can be designed for a wide range of flow rates: from 12 m3/day to 500 m3/day for of one filter (the transport size: up to ID2400 mm.) and more
