Filtri a Tela a Fibra Libera

Pile Cloth Filters

for tertiary wastewater treatment

Very high solids removal yields and minimal product life-cycle cost: these are the advantages of free-fiber cloth filters for tertiary filtration. These are filtration systems suitable for industrial wastewater, civil wastewater and, in some cases, first rainwater.

Very high filtration rates.

Very high filtration rates. Due to the depth filtration of the free-fiber cloth. TSS concentrations below 10 mg/l expected at discharge, depending on application.

Reduced energy use.

Reduced energy use. Gravity filtration, power consumption only in backwash phase.

Operational continuity.

Operational continuity. Filtration is continuous during counter-current cloth washing.

Flexibility with different loads.

Flexibility with different loads. Excellent tolerance to hydraulic variations and fluctuations in input loads.

Simple Maintenance.

Simple Maintenance. Simplicity and reduced frequency of intervention.

Minimum life-cycle cost.

Minimum life-cycle cost. Low investment costs (CAPEX), maintenance and resource utilization costs (OPEX) result in optimal return on investment.

Pile Cloth Filters: description

Wastewater treatment plant operators have requirements such as improving the final quality of the effluent, adapting plants to new operating conditions, and recovering water for industrial or agricultural use. Precisely for the solution of these problems, MITA Water Technologies offers an effective and simple cloth filtration system: pile cloth filters, or free-fiber cloth filters, or else pile cloth media filters, for tertiary wastewater treatment.

Pile cloth filters combine the surface filtration typical of microgrid systems with the depth filtration of sand filters (similar in operation and performance in terms of suspended solids removal). All with extremely low investment, operation and maintenance costs.

The construction concept of cloth filters allows backwashing during operation, without stopping the machine, and thus filtration, and allows for minimal pressure drop (max 0.5 m w.g.), reduced energy use, and minimal footprint. Cloth filters consist of a support structure (drum or disc), covered with a special filtering cloth: these are synthetic fibers. The filters are equipped with a device for backwashing the cloths controlled by level sensors.

Several models are available with capacities up to 1,500 m3/h for a single filter unit.

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    Application Field:

    Standard Components on all MITA Pile Cloth Filters

    Tela Filtrante per Filtrazione Terziaria

    Free-Fiber Cloths

    Cloth pile types: classic 10, micro 5 and others in development. They provide extraordinary filtration yields (even < 5 mg/l SST). The type of treatment achieved combines surface and depth filtration.

    Controlavaggio dei Filtri a Tela Pile

    Cloth Backwashing

    As the solids deposit on the cloth increases, the hydraulic resistance increases: having reached a difference of 15 ÷ 20 cm between the water inlet and outlet levels, the process of cleaning the cloth is automatically activated by the countercurrent passage, through the cloth, of the already filtered water sucked by the pumps. Minimal energy costs.

    Filtri a Disco o a Tamburo per Filtrazione Acque

    Disc or Drum Filters

    The cloth filter consists of either a drum or filter discs (2 to 32), mounted on a hollow central shaft: discs and drum work completely submerged in the water to be treated. Filtration takes place by gravity, from outside to inside, with the machine stopped.

    Pile cloth filters: available versions

    Filtri a tela Standard

    Basic Version

    Backwash works with only one pump at a time-an additional energy saver.

    Filtri a Tela HD

    HD version

    Backwash works with one or two pumps at a time: great versatility of operation.

    Filtri a Tela FHD

    FHD Version

    Backwash works with only two pumps at a time: fast and efficient tele-washing.

    Some Projects with Pile Cloth Filters

    Cloth Filters and Cooling Towers for Plastic Industry

    Cooling and wastewater treatment together: that's the card that proved successful in supporting a plastics equipment company in northern Italy, which was already working with Group company MITA Cooling Technologies. The possibility of water reuse, through comprehensive management of this resource, is a card that industries can exploit to derive value from blue gold.

    Read more

    Tertiary treatment of municipal water

    Pile cloth filters are used with great success for tertiary filtration of suspended solids, with an expected downstream concentration of up to < 5 mg/l: they are installed downstream of secondary settlers, in biological wastewater treatment plants for civil and industrial wastewater. Their application stems from the need to have increasingly high water quality at the point of discharge into the receiving water body. They often represent an important barrier to the escape of light sludge, which would otherwise cause the limit on the concentration of suspended solids at the discharge to be exceeded. Crucial are simplicity of construction and operation and minimal maintenance.

    Trattamenti Terziari di Acque Municipali
    Rimozione Fosforo nel Trattamento Acque

    Phosphorus reduction

    Pile cloth or microfiber filters, inserted as the final stage of filtration, separate phosphorus-containing sludge as a result of the high removal of suspended solids: this is both downstream of sludge oxidation tanks and “post-precipitation” and secondary settling tanks.

    Pre-filtration upstream of UV disinfection

    Disinfection of wastewater pre-spill into water bodies is increasingly carried out with UV systems: pile cloth filters (or “free-fiber cloth filters”) reduce suspended solids to the UV-required suspended solids concentration of less than 10 mg/l, preventing fouling of the lamp surface and increasing lamp efficiency. The energy efficiency of ultraviolet systems is also preserved by installing an upstream cloth solution.

    Pre-Filtrazione a monte di UV con Filtri a Tela Pile
    Filtrazione e Trattamenti Chimici-Fisici di Acque Reflue

    Filtration downstream of physical-chemical treatments

    Some production processes in the industrial field lead to the production of polluted water: for example, by metals, in soluble ionic form. These can be separated in the form of sludge flocs by the dosing of appropriate chemical compounds and the use of cloth filtration: free fiber is indeed suitable for the type of chemical sludge.

    Secondary sedimentation downstream of biomass-added processes

    The cloth filter is used as a substitute for secondary settling only in cases where biological treatment is carried out with biomass-adhesive type technologies: e.g., rotating biological contactors (biodiscs) and percolating beds. In these cases, the effluent from the biological stage has a sludge concentration such that it can be treated directly with a cloth filter (without a secondary settling stage): this guarantees a suspended solids content at discharge that is certainly less than 35 mg/l. It is noteworthy that MITA Water Technologies has developed a compact plant (biocombi) that combines Biorulli® biodiscs and secondary sedimentation through a cloth filter.

    Filtrazione a valle di Processi a Biomassa Adesa
    Pre-Filtrazione e Processi a Membrane

    Pre-filtration upstream of membrane processes

    In the case of very stringent treatment of civil or industrial wastewater, technologies with membranes of the ultrafiltration and reverse osmosis type are used: the aim is the reuse of the same water in the industrial field and sometimes also in the civil field. Reverse osmosis in particular requires effluent with very low suspended solids content in the feed to safeguard the membranes from fouling, limit flushing, and maintain system performance. Again, the cloth filter is an optimal filtration system to be inserted upstream of the reverse osmosis membranes.

    Pre-filtration of surface water

    Surface water, often used for drinking water supply, undergoes pre-filtration as its first treatment: the purpose is the separation of solid particles present in the form of silt, microalgae and the like. The pile cloth filter is a very useful filtration system.

    Pre-Filtrazione di Acque Superficiali
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