Backwash disk filter

Types of backwash disc filters

General disc filters for backwash come in three main types:

• Manifold filters

  Manifold disc filters connect multiple filter bowls through a common manifold or header. The manifold serves as a central hub for the input and output piping, while filter bowls contain stacked discs for filtration. Typically, the manifold provides a single inlet for the feedwater that distributes filtrate to each filter bowl. Each bowl then removes contaminants from the water via the disc stack. Filtered water is returned through the same manifold outlet. Manifold backwash disc filter systems enable greater filtration volumes and are easily serviceable. When backwashing is needed, the entire manifold assembly can be flushed rather than individual units.

• End manifold filters

  End manifold disc filters have the manifold located at one end of the filter. This design makes the filters shorter and more compact than models using a center manifold. The reduced length enables easier placement in tight spaces. While the end manifold configuration limits flow rates compared to center manifold models, it still allows high filtration to occur within individual filter bowls. End manifold filters work well for distributing flow in systems with lower demands. Backwashing is still straightforward, but manifolds at one end allow quicker servicing from a single access point.

• Single-disc filters

  Single disc backwash filters have a bowl that contains a stack of filtered discs. Compared to manifold models, single-disc filters take up less space and have a simpler design. The straightforward construction means lower filter costs. Service and backwashing are also uncomplicated since there is only one filter to look after. Single disc backwash filters work well for small to medium-sized systems needing basic filtration. They provide a cost-effective way to remove contaminants from water without complicated filter arrangements.

Specifications and maintenance of backwash disk filters

Specifications

• Flow range: Backwash disk filters typically have flow ranges of up to 1,000 m3/h or more. The exact flow range depends on the diameter of the filter and the number of filter disks.
• Filtration efficiency: Backwash disk filters can remove suspended solids of different particle sizes. Some models can filter particles larger than 50 microns; others can filter particles larger than 10 microns. The filtration efficiency depends on the filter media and the operating parameters of the filter.
• Backwash methods: Some backwash disk filters use the backwash method of centralized flushing, while others use the backwash method of simultaneous flushing.
• Power requirement: The power requirements for backwash disk filters range from 0.5 kW to 5 kW, depending on the size of the filter, the number of filtrations, and the backwashing method.
• Operating temperature and pressure: Generally speaking, the operating temperature and pressure of backwash disk filters should be within the range of -5 °C to 50 °C and the pressure should be up to 1 MPa. The specific operating temperature and pressure depend on the materials and design of the filter.

Maintenance

• Regular inspection: Check the appearance and sealing status of the filter. If any damage or leakage is found, deal with it promptly to avoid pollution and water quality safety risks.
• Cleaning: Based on the application and use environment, take the appropriate cleaning method and cleaning agent to clean the filter. Meanwhile, attention should be paid to the cleaning carefully and avoid the residue and damage of the filter.
• Replace the filter elements: Backwash disk filters' service life depends on factors such as use frequency, water quality, etc. When backwash disk filters' filtration efficiency decreases or the pressure difference between the intake and outlet sides increases, replace the filter elements timely.
• Maintain the sealing parts: Sealing parts such as sealing rings should be maintained and cleaned regularly to ensure the sealing performance and prevent leakage.
• Pay attention to operating parameters: Monitoring and maintaining operating parameters such as pressure, flow, temperature, etc. adjusting the backwash frequency and duration according to the prescribed operating parameters and the actual filtration condition, to ensure the stable and efficient operation of the filter.

Scenarios of backwash disk filters

Backwash disc filters are used in many existing industries and applications:

• Agricultural lift: In the agricultural industry, disc filters are typically irrigated and pressurized filtration systems. The irrigation backwash disc filter can remove contaminants, suspended solids, and sediments from water used for irrigation, ensuring clean water for crops and sustainable growth. As a result, water efficiency and crop quality will be improved.
• Aquaculture industry: In the aquaculture industry, disc filters can be used to rear fish or shrimp. The backwash can clean the filters, reducing water consumption and filtration efficiency improving the water system's recirculation. The disc-backwash filters provide clean and healthy habitats for aquatic organisms.
• Food industry: In the food industry, disc filters can be found in the production process of beer, juice, and dairy. They help remove suspended solids, yeast, and food particles from the final products, ensuring product clarity, stability, and safety. A disc filter can be used to wash a machine that needs to be clean. The disc's filter can remove dirt, residues, and contaminants from the flushing liquid, preventing cross-contamination between products.
• Power plant: In a power plant, disc filters can be found in cooling water systems, boiler feed water systems, and spray water systems. They help remove suspended solids, algae, and particulate matter to protect equipment, maintain efficient operation, and ensure the quality of boiler feed water.
• Mining industry: In the mining industry, disc filters can be used in mineral processing, wastewater treatment, and tailings management. They help remove suspended solids, minerals, and particles from the water, allowing recycling and reducing environmental impact.
• The chemical industry: In the chemical industry, disc filters can be used in the production processes of chemicals, plastics, and fibers. They help remove suspended solids, fibers, and particles from the process streams, ensuring product quality and process continuity.
• The pharmaceutical industry: In the pharmaceutical industry, disc filters can be used in the production of drugs, vaccines, and sterile liquids. They help remove microorganisms, bacteria, and particulate matter, ensuring product purity and compliance with regulatory standards.
• In addition, the disc filters can also be used in municipal water plants, swimming pools, car washes, and textile and oil refineries. Backwash disc filters have broad applications within various industries; they play significant roles by maintaining equipment's sustainability while improving quality standards concerning products manufactured or created through these systems.

How to Choose Backwash Disk Filters

Several factors of the backwash disk filter should be considered before purchasing.

• Filtration needs analysis: Before choosing a backwash disc filter, it is essential to analyze the filtration needs. The factors to consider are the filtration precision required, flow rate, water quality, etc. When the needs are established, it is easier to select a backwash disc filter that meets the requirements.
• Construction materials: The materials used in constructing the disc filters determine their durability and performance. Selecting a backwash disc filter made from sturdy and corrosion-resistant material prolongs its lifespan and make it more effective.
• Operating pressure: Consider the operating pressure of the backwash disc filter. The pressure should be compatible with the system's parameters to avoid any form of damage during operation.
• Auto backwashing filters: Some filters have automatic backwashing mechanisms that enable them to clean themselves periodically. They have higher levels of convenience than the manually backwashed filters.
• Manually backwashed filters: Manually backwashed disc filters require manual input to clean the filter element. It usually goes through the same steps as auto backwash filters, but in this case, the steps are done manually.

Backwash disk filter Q&A

Q1: What makes a backwash disc filter different from a traditional filter?

A1: Unlike traditional filters that accumulate dirt and require manual cleaning, a backwash disc filter automatically cleans itself by reversing the flow of water.

Q2: What is the lifespan of a backwash disc filter?

A2: With proper maintenance and depending on the quality of materials used, backwash disc filters can last 10-15 years.

Q3: How much energy does a backwash disc filter consume?

A3: The energy consumption depends on the power used to pump water through the filter. In general, self-cleaning filters are more energy-efficient than those requiring manual cleaning.

Q4: Can a backwash disc filter handle high flow rates?

A4: Yes, there are models designed to handle high flow rates suitable for commercial and industrial applications.

Q5: Does a backwash disc filter remove bacteria?

A5: Some backwash disc filters are designed to remove bacteria while others are not. To remove bacteria use a backwash disc filter with an ultraviolet (UV) component or replace the discs with those that include an antibacterial element.