Rotary Drum Fine Screen with Long Service Life, Low Backwash-Water Consumption,

The rotary drum fine screen is a precision mechanical filtration unit that uses gravity or differential pressure to pass a suspension through a porous filter medium. Solid particles are retained by the filter medium, thereby achieving effective solid-liquid separation.

The filter medium is a porous solid material that allows liquid to pass through while retaining suspended solids during the filtration process.

According to the filtration requirements and operating environment, industrial filter media should have the following properties:

• Suitable porosity: The pore size should allow the liquid to pass through with low hydraulic resistance while effectively retaining the target solid particles.
• Chemical stability: The material should provide good corrosion and heat resistance.
• Mechanical strength: The filter medium should have sufficient strength to withstand pressure, impact, and continuous operation.

• Tertiary treatment and effluent-standard upgrading of municipal wastewater treatment plants
• Pretreatment of municipal wastewater
• Water recovery, reclamation, and recycling
• Pretreatment of industrial wastewater
• Pretreatment of raw water for drinking-water treatment plants

Wastewater flows into the hollow rotary drum. Under gravity, the water passes from the inside of the drum to the outside through the filter screen, while suspended solids are retained on the inner surface of the stainless-steel screen.

The drum rotates slowly during operation. A backwash pump draws filtered effluent and delivers it to spray nozzles positioned above the drum. The nozzles spray water from the outside of the screen toward the inside, removing the accumulated solids.

The washed-off particles are collected in the backwash collection trough and discharged from the equipment through the waste discharge pipe.

• Long screen service life: The filter screen can have a service life of up to two years under suitable operating conditions.
• Easy screen replacement: The screen consists of independent panels. Each panel can be removed and replaced separately without affecting the other screen panels.
• Strong resistance to shock loads: The equipment can operate normally when the influent suspended solids concentration does not exceed 40 mg/L.
• Continuous filtration: Backwashing and filtration can be carried out simultaneously without interrupting each other.
• Low head loss: The operating head loss is less than 300 mm.
• High filtration efficiency: When the influent suspended solids concentration is below 20 mg/L, the effluent suspended solids concentration can be reduced to below 10 mg/L.
• Fully automatic operation: The complete filtration and backwashing processes can be controlled automatically.
• Compact footprint: At the same treatment capacity, the rotary drum filter occupies considerably less space than many other filtration systems.
• Low backwash-water consumption: Solids do not easily accumulate on the screen surface and can be effectively removed by high-pressure backwashing. The backwash water is taken from the filtered effluent and normally accounts for approximately 0.3% of the treated water volume, which is significantly lower than the 3%-5% commonly required by similar filtration equipment. This also reduces the subsequent treatment load of the backwash wastewater.
• Low foundation requirements and reduced investment: The equipment imposes relatively low load requirements on the foundation and requires limited civil construction investment. It is particularly suitable for upgrading existing wastewater treatment plants and can assist in improving effluent quality from China's Class 1B standard to Class 1A standard.