Biological Filter Media: A Comprehensive Guide for Wastewater Treatment

Biological fillers are the most common items in effluent treatment. They can be used as carriers for microbial attachment, increase the sludge concentration of the biochemical system, and reduce the sludge load. Biological fillers are divided into combined fillers, three-dimensional elastic fillers, porous suspended ball fillers, active biological fillers, etc.

Types of Biological Filter Media

Soft Fiber Media:

Composition: PE center rope + acetaldehyde-treated vinylon filament bundles

Applications: Widely used in large-scale wastewater treatment plants due to its high surface area, effective sludge reduction, and overall cost-effectiveness. However, it requires regular cleaning to prevent fouling.

Semi-Soft Media:

Composition: PE center rope + PE rings

Applications: Suitable for both aerobic and anaerobic conditions, including aeration tanks. Its unique structure and hydraulic properties minimize clogging and fouling, making it a good choice for smaller wastewater treatment facilities.

Composite Fiber Media:

Composition: PE center rope + PE rings + acetaldehyde-treated vinylon filament bundles

Applications: Similar to soft fiber media, it is effective in sludge reduction and overall performance. Its combination of materials provides a balance between surface area and ease of maintenance, making it suitable for large-scale wastewater treatment plants.

Elastic Stereo Media:

Composition: PE center rope + PP elastic filaments

Applications: Applicable in both aerobic and anaerobic conditions, with limited use in aeration tanks. It exhibits efficient sludge reduction and overall performance, but its lower cost comes at the expense of durability and ease of maintenance, making it suitable for medium-sized wastewater treatment plants.

Suspended Media:

Composition: PE spheres + acetaldehyde-treated vinylon filament bundles or PP wide flat ribbons

Applications: Versatile for both aerobic and anaerobic conditions, including aeration tanks. It offers good oxygen transfer but requires specialized equipment and may not be compatible with all treatment systems. Its effectiveness in sludge reduction is moderate, and the overall performance is average. The cost is relatively high, making it suitable for retrofitting or small-scale wastewater treatment plants and fluidized beds.

Inclined Suspended Porous Media (MBBR):

Composition: HDPE, PP

Applications: Highly effective for both raw and treated water purification, as well as anaerobic, aeration, and biological fluidized bed stages in wastewater treatment plants. Its high cost is justified by its exceptional performance and versatility.

Plum Blossom Ring Media:

Composition: PP

Applications: Ideal for space-constrained tower-type small-scale biofilm treatment systems. Its compact design and efficient biofilm growth make it a suitable choice for limited-area applications.

Biodiscs:

Composition: Fiberglass or plastic

Applications: Primarily used in membrane bioreactors (MBRs) for medium-sized wastewater treatment plants. Their rotating structure provides a large surface area for biofilm growth, but their complexity and maintenance requirements may limit their suitability.

Fiber Ball Media:

Composition: Polyester fibers

Applications: Effective in high-rate filters and biological fluidized beds. Its spherical shape and porous structure enhance surface area and promote biofilm growth, making it suitable for filtration and fluidization applications.

Honeycomb Inclined (Straight) Tube Media:

Composition: PP or PVC

Applications: Straight tubes are used in small-scale biofilm wastewater treatment plants, while inclined tubes are suitable for settling tanks. Their honeycomb structure provides a large surface area for biofilm growth and efficient solids separation.