Belt Filter (BF)
When treating process and wastewater, mechanical filtration represents an efficient, economical and environmentally friendly method of solids removal. The MP-BF Belt Filter has high applicability with some examples given below:
Municipal wastewater treatment plants
Filtering requirements for wastewater are dependant on the actual stage of the treatment process. The Belt Filters are available with various sizes of belt openings:
- Inlet screening (1000 – 5000μm)
- Primary treatment (100 – 500μm)
- Polishing (40 – 60μm)
Removal of solids at wastewater treatment plants to enhance further treatment. Solids usually suitable for biogas.
Removal of solids within the process line:
- fruits & vegetable processing
Pre-treatment of surface water to prevent unintended discharge to sewer. Filtration of recirculated liquids for removal of solids.
- Waste treatment stations
- Zoo and nature parks
Onshore & offshore fish farms and recirculated aquaculture systems use belt filters for:
- pre-treatment or primary filtration
- sludge thickening/dewatering
- concentration of backwash from drum filters
In some cases, using a MP-BF Belt Filter with combined chemical and mechanical filtration is required to achieve the discharge consent.
The MP-BF Belt Filters are available in several standard models dependant on application, flow and available space. Multiple belt filters are installed for larger flows.
All models are based on the same design concept, this makes all models equal in terms of efficiency, reliability and applicability.
An internal drum motor ensures a compact design, long operational lifetime and low power consumption, available with two fixed speeds. Optionally, a frequency controlled belt filter with automatic start/stop gives better and more efficient solid filtration
The smallest model is designated l.3C and the largest model 3.6M. The maximum flow per belt filter depends on application and choice of filter mesh openings. The length -of the belt filter affects both flow capacity and dewatering efficiency.
The capacity also depends on the concentration of suspended solids. A preliminary estimation for MP-BF-3.GM with 150 μm filtration is maximum 80 m3/h and with 5000 μm filtration maximum 800 m3/h.
Belt filter mesh is chosen based on filtering requirements. MP-BF Belt Filter mesh is available in range from 40 μm to 5000 μm. The high quality polyester fibres are used to produce filter belt mesh. The belts are woven with different patterns and openings which determines the filtering efficiency and flow capacity. The design gives important properties such as dimensional stability, anti-corrosion and a long service life.
MP-BF Belt Filters are equipped with a static scraper or optional rotary scraper to ensure proper discharge of sludge and solids. Choice of scraper depends on belt filter application and belt filter
mesh openings. The rotary scraper is designed with a drum motor to sustain the compact belt filter design.
Belt Spray Cleaning
Belt filter cleaning is crucial for continuous efficient filtering. Spray cleaning with filtered water and/or clean water are the most common. Nozzles are installed with quick-release functionality for
easier maintenance. The belt filters are delivered with one spraying bar and is prepared for one extra optional spraying bar.
Separate outlet for spray water is the most common setup to avoid reduction in sludge dry matter.
Belt cleaning using water is economical due to low cost of electricity, compared to cleaning with air knifes for example. The spray water also contains the particles which provides a healthier working environment compared to using compressed air cleaning.
Cloth Media Filters
The effluent from municipal and industrial wastewater treatment plants that employ biological secondary treatment can contain high levels of total suspended solids (TSS), that could impact downstream treatment processes and the environment into which it is discharged. Filtration is typically used to remove the TSS and improve the effluent quality. Traditionally conventional sand or media filters have been used for tertiary filtration of secondary treated effluent. However, sand filters typically require a large footprint, require standby filtration capacity with ancillary equipment (including filtered water storage and compressed air systems for air scouring), to allow for backwashing of duty filters, and can be difficult to operate with high concentrations of TSS and where variable influent TSS levels a highly variable.
MITA Water Technologies offers a simple and effective cloth media filtration system for tertiary filtration applications that overcomes the problems typically experienced with sand media filters. Cloth media filtration achieves similar performance in terms of effluent quality (with typical effluent TSS < 5 mg/L) when compared to sand filtration. In addition, cloth media filters provide forward filtration while backwashing occur; this means there is no need for standby filters to take a filter offline for backwashing. Cloth media filters require low headloss (max 500 mm), have reduced energy consumption, and have minimal space requirements.
The cloth media filters are made of a support structure (drum or disc), coated with a special polstoff filtration fabric consisting of synthetic fibers that offers a filtration depth of 4 – 5 mm.
The cloth media filters are equipped with an onboard cloth backwashing system. Numerous cloth filter models are available with a working capacity ranging from 10 m3/h up to over 800 m3/h for a single filtration unit.
The technology and the application experience of MITA Water Technologies offer highly reliability equipment that is simple to use, with very low investment, operation and maintenance costs.
The cloth filter is made up of a drum or alternatively of filter discs mounted on a central hollow shaft. The filtration is done by gravity. During filtration operation the discs (or the drum) are stationary, and only rotate when backwashing (or cleaning of cloth media) is required. The level difference between the inlet and outlet of the filter activates a backwash sequence. The discs (or the drum) are completely immersed in the water to be treated.
During the filtration phase, the solids are held back or removed by the special polstoff cloth. The minimum water level in the tank containing the filter is controlled by a weir placed on the filtered water outlet. As deposition of solids on the cloth increases, the hydraulic resistance increases in passing liquid through the cloth, which results in a water level differential.
When a differential of about 200 mm is reached, it automatically activates the cleaning process of the cloth to restore its filtering capacity, called a backwash sequence.
During the backwash process, the discs (or drum) are rotated slowly. Solids are removed by passing filtered water as backwash through the cloth. A backwash pump, connected to special suction nozzles that contact the cloth media, provides suction that causes the free fibers of the cloth filter to straighten to release the solids particles retained therein.
As the discs (or drum) rotate, the contact of the suction nozzles with the cloth filter generates the recompression of the free fibers and the consequent formation of an even filtration panel.
The cloth media of the drum or disc filters is made of polstoff free fibers (fiber length from 10 to 12 mm and a diameter of 13 to 27 µm) that are fastened to a large weave fabric that serves as support. The type of filtration obtained is comparable to the deep bed filtration of sand filters and not the surface filtration of the monofilament cloth or screen-type filters.
Cloth filters: advantages and application
- Available as packaged filters in steel tanks, or fitted into concrete tanks
- Gravity filtration with low headloss
- Continuous filtration without the need for standby units for backwashing
- Cloth media manufactured in polstoff free fibre, with high mechanical strength
- Operational flexibility, tolerating high variability in hydraulic and solids loading, and self-regulating with regard to the input parameters
- Cloth media backwash requiring very low energy consumption
- High filtration rate
- No aerosols and noise pollution
- Small footprint
- Low electrical installed power draw
- Low backwash water volumes
- Simple operation, fully automated
- Very low maintenance
- Direct access to all utilities
Clean water flowing over effluent wier
- TERTIARY TREATMENT: Cloth media filters are used with great success for tertiary filtration downstream of secondary settling tanks in biological wastewater treatment plants, both municipal and industrial. Through reduction of total suspended solids and associated BOD, cloth media filters greatly enhance effluent quality to the receiving water body. MITA Water Technologies cloth media filters often perform an important barrier function to prevent discharging sludge into the effluent when poor sludge settling occurs in the upstream treatment processes, that would otherwise exceed the limit of suspended solids concentration in the discharge. The design and construction of these machines are robust, operation is simple, and routine and supplementary maintenance requirements are very low.
- PHOSPHORUS REDUCTION: In purification plants, the chemical reduction of phosphorus concentration from the effluent, can be achieved in several ways: simultaneous phosphorus precipitation in an activated sludge process, further phosphorus precipitation prior to the secondary settling, and flocculation & coagulation upstream of the filtration process. In all cases cloth media filters provide the last filtration to separate solids containing chemically bound phosphorous. Given the very high rate of solids removal( TSS < 5 mg/L), very low effluent phosphorous concentrations are obtained.
- UPSTREAM PRE-FILTRATION DISINFECTION WITH UV: Disinfection of treated effluent prior to reuse or discharge to receiving water bodies is increasingly done with UV systems. Removal of TSS from the effluent is required for efficient UV disinfection, to reduce energy consumption and limit fouling of UV lamp sleeves; typically TSS concentration of less than 10 mg/L is required. The cloth media filter can be incorporated readily upstream of UV systems, to ensure effective UV disinfection.
- DOWNSTREAM FILTRATION OF CHEMICAL-PHYSICAL TREATMENTS: Treated effluent from some industrial processes that contain metals (for example) can lead to environmental pollution. Through chemical addition such metals can be converted into insoluble form, that can be separated from the liquid. Cloth media filters can be used to separate such chemical solids from the effluent prior to environmental discharge.
- SECONDARY SEDIMENTATION DOWNSTREAM OF attached growth BIOMASS PROCESSES: The cloth media filter can be used to replace secondary settling only in cases in which the biological treatment is carried out with attached growth technologies such as immobilized biomass, Rotating Biological Contactors (RBC) and percolating filters. In these cases, the wastewater from the biological stage has such a high solids concentration that it can be treated directly with a cloth filter (without a secondary sedimentation stage), to ensure the filtered effluent has a TSS content of less than 35 mg/L and almost always less than 10 mg/L. MITA Water Technologies has developed a compact Biocombi package plant which combines biorulli (RBC) for biological treatment and providing secondary sedimentation with the cloth filter.
- PRE-FILTRATION for membrane PROCESSES: In municipal and industrial applications where high level of treatment is required for the purpose of reusing the water, ultrafiltration (UF) and reverse osmosis (RO) technologies are used with the membranes. The use of UF and RO requires a water supply with a very low content of suspended solids in order to protect the membranes from fouling, thus limiting the frequency of cleaning washes to maintain the performance of the system. Even in this case the cloth filter is an optimum filtration system for an upstream treatment with UF and RO membranes.
- PRE-FILTRATION OF surface WATER: Surface water, often used for the supply of drinking water often requires pre-filtration for the removal of solid particles in the form of silt, micro-algae and others. The cloth filter is a useful pre-filtration system for this purpose, with or without an upstream flocculation treatment.
MAK Water’s Multimedia Filtration (MMF) plants are designed to treat ground water, surface water, tertiary treated effluent, storm water or wastewater with <30 mg/L of total suspended solids. Standard filtration media includes sand media for suspended solids removal, granular activated carbon (GAC) for removal of organics, colour, odour or chlorine and DMI-65 greensand for dissolved iron and manganese. Additional filtration media, such as calcite for hardness correction and various ion exchange resins, are available on request.
Additional pre-filtration and post-filtration treatment steps may be added as required to suit feed water conditions and/or treated water quality requirements. The MAK Water MMF plants are available as skid mounted or containerised systems.
If you have specific requirements, contact us about our custom water filtration systems.
MAK Water’s Ultrafiltration (UF) plants are designed to treat ground water, surface water, tertiary treated effluent, storm water or wastewater with turbidity <300 NTU. The standard treatment process includes pre-screening (bag filter or self-cleaning screen filter), outside-to-inside capillary ultrafiltration modules, automated air scouring and maintenance cleaning (MC) system, as well as a CIP system for periodic recovery cleaning (RC). The UF system can be configured as either: dead-end for lower turbidity applications, or cross-flow for higher turbidity applications.
Additional pre-filtration and post-filtration treatment steps may be added as required to suit feed water conditions and/or treated water quality requirements. The MAK Water UF plants are available as skid mounted or containerised systems.
Ultrafiltration – Basic
The Ultrafiltration (UF-B) plants are designed to treat surface water, tertiary treated effluent, storm water and waste water to achieve potable/process water or may be used as pre-treatment to reverse osmosis. They treat a wide range of highly variable waters with <50 NTU of turbidity and <100 mg/L of suspended solids.
The standard treatment process includes optional pre filtration (500 micron screen filter), Ultrafiltration process and automatic backwashing for membrane cleaning. Additional pre or post UF treatment steps may be added to suit feed or filtered water requirements such as iron removal, pH correction or sterilisation. The MAK UF plants are available as skid mounted units or containerised systems.
If you have specific requirements, contact us about our custom water filtration systems.
Water Softening with Ion Exchange
MAK’s Water Softening plants (WSP) are designed to reduce hardness from water sources that may have negative downstream implications such as scaling of pipework and equipment. The WSP contains resin beads charged with sodium ions. When the hardness ions come in contact with the resin beads the hardness ions are collected and the sodium ions are released, thereby softening the water via ion exchange. The WSP automatically completes a regeneration cycle whereby the filter is backwashed and the resin recharged with sodium ions via the brine regeneration tank.
Water Softening can be used in a range of applications such as potable water, boiler feed water and domestic appliance feed water (washing machines, dishwashers etc). Additional pre or post WSP treatment steps may be added to suit feed or softened water requirements such as iron removal, odour removal, colour removal, hydrocarbon removal, pH correction or sterilisation. The MAK WSP’s are available as skid mounted units or containerised systems.
Demineralisation/Deionisation with Ion Absorption
Activated carbon can be added as a pre-treatment option to remove free chlorine from the feed water, there by extending the life of the resin. MAKPAKs are supplied as individual components and can be installed on site by MAK Water or a registered plumber.
If you have specific requirements, contact us about our custom water filtration systems.
Our MAK Water Screen Filters are designed to filter liquids with suspended solids. The Screen Filter’s innovative suction pad design:
- Enables the filter to be cleaned without stopping the filtration process.
- Automatically cleans the filter depending on differential pressure or time.
- Is manufactured from high grade stainless steel.
- Minimises water used for backwash.
The screen filters can be supplied in three different configurations (O, L and Y), depending on the position of in/out connections. The filter element can be supplied either as a polyester mesh inserted between two 316 net tubes, or as a three layer 316 stainless steel element, with the filtration degree ranging from 25 μm to 810 μm. All filters are supplied with valves, pressure gauges, a differential pressure sensor, cleaning system, and an electronic controller.
Raw water flows into the filter under pressure across the filtering element, trapping the suspended solids inside the housing prior to the filtered water exiting the filter housing. The cleaning of the filtration element can be performed by preset time or when the progressive build-up of suspended solid causes an excessive differential pressure between inlet and outlet (0.8 bar). During the cleaning cycle, the opening of the drain valve and the engine rotation actuate the suction scanning system. The adherence of scanners to the internal surface of the element removes the particles trapped by the filter element. Wastewater and solids are purged through the drain.
If you have specific Screen Filter requirements for your project, then contact us about our custom water filtration systems today.
Here at MAK Water, we have a range of industrial water filtration systems available for purchase or hire throughout Australia. Filtration is important, as it plays a large part in removing suspended solids from water. Various types of industrial water filtration systems are available, with selection depending on the raw water make up (particle size and distribution) and quality requirements of the product water.
Filtration is frequently used as ‘pre-treatment’ of raw water, in order to remove suspended solids prior to desalination via Reverse Osmosis (RO). Typical RO pre-treatment systems include Micro Filtration (MF), Ultra Filtration (UF) and Multi-Media and Cartridge Filtration.
Other forms of industrial water filter systems are used to remove excess ‘hardness’ (generally calcium & magnesium), which have the potential to cause scaling of plumbing and other undesired effects. Typically, softening processes involve Ion Exchange, whereby calcium and magnesium ions are replaced with sodium ions, or Nano Filtration (NF).