Filtration is the process of removing turbidity from water, both coarse as well as colloidal, adsorbing undesired odours, taste and colours and organic pollutant (antiparasitics, solvents, cyanotoxins), eliminating Iron, Manganese, Arsenic and other heavy metals (such as Chromium, Aluminium, Nichel, etc.) or neutralising the water acidity. All these results can be achieved with a proper filtration treatment that in many cases is preceded by a pre-oxidation and chemical conditioning equipment. Filtration makes possible to remove Ammonia by means of nitrification.
Simple in appearance, filtration is in reality a sophisticated water treatment process available. It does not always correlated to precise chemical reactions but, in many instances, it is connected to mechanical and biological reactions, not always easily explainable.
Our industrial filters are entirely manufactured in our Culligan plants. They are made of steel and are protected by anti-corrosion coatings, a heavy layer of food-grade epoxy resin on the inside, and synthetic paint on the outside. The smaller Hi-Flo 22 Filters are manufactured in FRP fiberglass, with internal protection achieved with a non-toxic polyethylene liner. On the industrial filters, the automatic cycles of service and backwash are regulated by a group of diaphragm hydraulic valves driven by an hydraulic pilot that, in turn, is controlled by an electronic logic programmer.
Hi-Flo 22 Filters are controlled by a hydraulic piston valve. Starting time, duration and frequency of backwashes can be programmed on the logic programmer. The flow rate control of all the service and backwash phases is performed by automatic flow rate controllers, which prevent leakage of the minerals during the backwash and optimise filter efficiency during service. - Models: Hi-Flo 22, Hi-Flo 6 and Hi-Flo 9. The filters of the Hi-Flo 6 and Hi-Flo 9 series can be combined in modules achieving filtration systems of greater capacity (see later "Twin System" or " Four-leaf Clover System"); they can also be combined as double filtration in series, making Culligan's exclusive "Omnifiltration" system.
A complete range of filtering minerals can be selected for all types of Culligan filter, achieving the best solution for each problem. The more common versions are:
FILTR-CLEER, a multi-layer filter whose typical. application is the elimination of turbidity, suspended solids and of small quantities of heavy metals (particularly Iron and Manganese). The minerals utilised in the filter bed are Cullcite, a granular anthracite with a low density that makes the upper layer, and Cullsan, an ultra-pure silica sand with no carbonates, chemically inert and with a unlimited life.
CULLAR typical. applications are removal. of undesired odours and tastes and excess Chlorine and its derivatives. Cullar is a granular form of activated carbon with high degree of porosity, giving it an extraordinary adsorbing capacity.
CULLNEU typical. applications are remineralisation of water with low mineral. content and neutralisation of acid water, inhibiting water aggressiveness toward metal. piping. Cullneu is a granular Calcium Carbonate mineral. that dissolves in proportion to the amount of neutralised acidity and must therefore be refilled periodically.
SUPER IRON, a multi-layer filter using a selective mineral. for Iron and Manganese removal.. Super Iron can be activated with many oxidising agents.
G.A.C., granular activated carbon, a specific adsorbent for organohalogenated compounds, antiparasitics, heavy metals and other substances harmful. to health.
BIOFILTER, a special. filter for removing Ammonia, where the main function of the quartz filter media is to support the nitrification biomass, consisting in two strains of aerobic bacteria. Nitrosomonas converts ammoniacal Nitrogen to nitrous Nitrogen, while the nitrobacter completes the oxidation to nitric, transforming Ammonia ultimately into Nitrate. The biofilter is also able to oxidise and remove appreciable concentrations of Iron and Manganese when present in the water.
Filtration made with the traditional. "single layer" filters has three limitations: only the upper part of the mineral. layer "works" trapping the turbidity, while the lower layers remain idle; the resistance opposed to the water flow (pressure loss) increases very rapidly, making frequent backwashes necessary. Flow rates have to be decreased in order to maintain quality.
The most recent "multi-layer" filters allow selective turbidity removal. within the filtering layers. Layers have different thicknesses and are made of minerals with different mesh and specific weight.
This technology allows a higher filtration speed (if necessary) and very low usage of coagulants. Multi-layer filtration was developed and perfected by Culligan and its most common application is in "Filtr-Cleer" filters and in "Omnifiltration" system.
OMNIFILTRATION® SYSTEM AND OFSY FILTERING GROUPS
While "multi-layer filtration" performed by Filtr-Cleer captures very large quantity of turbidity with limited pressure losses, it does not prevent the leakage of small turbidity particles that escape from the granules before maximum adsorbing capacity of filtering beds is reached. In order to solve this problem, Culligan has developed the "Omnifiltration" system, made of two filtering sections of "Filtr-Cleer" placed in series: the first works until. complete saturation of the mineral. is achieved and the second buffers any turbidity leakage, guaranteeing output of constantly crystal-clear water, even if the quality of the inlet water changes.
Some of the most appreciated features of the OMNIFILTRATION system (OFSY) are:low installation and operation costs, smaller size, high versatility, simple and quick start-up procedure, as well as excellent quality of water produced.The OFSY system is by far superior to any other conventional. filtration method. OFSY is in operation in hundreds of waterworks around the world.
Fully automatic filters, controlled by a hydraulic piston valve which directs water during service and backwash phases. They are
manufactured in FRP fiberglass, with internal protection achieved with a non-toxic polyethylene liner. 4 Available in different versions: see models in the Technical Specifications.
Filters suitable for industrial applications. Differing from the Hi-Flo 9 in that they have lower filtering bed thickness (and therefore total. height). They are recommended for treatment of water without specific characteristics.4 Available in different versions
Industrial filters suitable for commercial and industrial applications. Available models from 20" to 120" (20" to 48" range features Noryl valves and non toxic piping).
The tank is protected by a layer of food-grade epoxy resin inside and by synthetic paint outside.4 Available in different versionsA special filter, recommended for Ammonia removal. 4 Available in BF version, models from 48" to 120".
The picture shows two Hi-Flo 9 filters in TWIN configuration characterised by a single group of valves that controls both filters. The advantage of this configuration is that the flow rates for service as well for backwash are the same. Backwash occurs in sequence one filter after the other, thus saving on plumbing and pumping costs.
OMNIFILTRATION SYSTEM (OFSY)
The versatility and adaptability of the Omnifiltration (OFSY) is certified by hundreds of systems installed in waterworks plants around the world, with a wide range of flow rates.The Omnifiltration System has acquired a well deserved reputation thanks to its excellent performance, both from an economical and quality point of view.
"FOUR-LEAF CLOVER" CONFIGURATION
This system is made of four filters assembled in a "clover" configuration, controlled by a single centralised group of valves. The compactness of the system is dear. The modular design of the system makes it possible to be very flexible whenever capacity increases are necessary, or when stand-by equipment is mandatory