The mechanical bar screen is the first line of defense in any wastewater treatment plant. Selecting the wrong screen type leads to downstream equipment damage, increased maintenance costs, and treatment efficiency loss. This guide covers everything you need to know to make the right selection.

Screen Classification by Opening Size

Category	Opening Size	Typical Application
Coarse Screen	20-50 mm	Pump protection, headworks
Medium Screen	6-20 mm	Primary protection
Fine Screen	1-6 mm	MBR protection, advanced pretreatment
Micro Screen	0.5-1 mm	Tertiary treatment, reuse

Multi-Rake Bar Screen (Coarse to Medium)

The multi-rake bar screen is the workhorse of wastewater pretreatment. Multiple rakes travel along a vertical or inclined bar rack, continuously removing captured debris.

Key Technical Parameters

Parameter	Specification
Bar Spacing	15 – 50 mm
Channel Width	500 – 3000 mm
Channel Depth	500 – 12000 mm
Flow Capacity	Up to 50,000 m3/h
Rake Speed	2-6 m/min
Motor Power	0.75 – 5.5 kW
Material	SUS304 / SUS316L
Installation Angle	75-80 degrees

Rotary Drum Fine Screen

Drum screens provide fine screening in a compact footprint. Wastewater flows through the rotating drum from outside to inside, with debris captured on the screen surface and removed by a cleaning brush or spray system.

Key Technical Parameters

Parameter	Specification
Screen Opening	1 – 6 mm (perforated plate or wedge wire)
Drum Diameter	500 – 2000 mm
Flow Capacity	Up to 5,000 m3/h
Capture Rate	>95% at rated flow
Motor Power	0.37 – 2.2 kW
Material	SUS304 / SUS316L

Inward-Flow Perforated Plate Screen

Center-flow screens are specifically designed for MBR plant protection. The inward flow pattern prevents debris bypass, and the 1-3mm perforated plate captures hair and fibers that would damage membrane modules.

Critical for MBR Systems

MBR membrane manufacturers require fine screening (1-2mm) upstream. Without proper screening, hair and fibers wrap around membrane fibers, causing irreversible fouling and requiring costly membrane replacement.

Selection Decision Tree

1. Is MBR downstream? Yes = Inward-flow perforated plate screen (1-2mm)
2. Flow rate > 10,000 m3/h? Yes = Multi-rake bar screen (coarse protection)
3. Space constrained? Yes = Step screen or drum screen
4. High debris load? Yes = Heavy-duty trash rake + multi-rake
5. Standard municipal plant? Multi-rake (15mm) + drum fine screen (6mm) combination

Feiran EP Screening Solutions

Feiran EP manufactures the complete range of mechanical screening equipment to German DIN standards. All units feature SUS304/316L construction, integrated controls, and factory acceptance testing.

Request technical specifications: sales@yixingenviroequipment.com | WeChat: 008613771308660