Braided belt media (biological rope) — structure, features, parameters and applications, with biological rope, biological curtain and floating-hanging media.
← Back to Biological Rope MediaBraided belt media is a new-generation eco-friendly bio-active carrier. It is made from lightweight, high-strength and corrosion-resistant chemical-fibre net yarn through a special process. Its structure is designed as a spiral tube with a certain elasticity, and its surface carries millions of loops, giving it a large specific surface area, fast biofilm formation and easy biofilm shedding. Through changes in specification and structure, braided belt media suit different environments (aerobic, anaerobic and anoxic), and are generally made in belt form for easy installation.
Braided belt water-treatment media has the following features:
| Item | Value |
|---|---|
| Loop length | 8 – 30 mm |
| Belt width | 0.5 – 3.5 cm (main specifications: 60 mm / 80 mm) |
| Specific surface area | 1000 – 18000 m²/m³ |
| Porosity | 90% – 99% |
| Tensile strength | 100 N per strap |
| Water temperature | 20 – 35 ℃ (optimum 25 ℃) |
| Retention time | 2 – 4 h |
| Dissolved oxygen | 2 mg/L |
The media mainly suit municipal sewage, domestic sewage and industrial wastewater treatment (wool, printing & dyeing, leather, papermaking, pharmaceutical, food industries) and the purification of polluted water in rivers and lakes.
Braided belt biofilm carrier media fall into two categories: one is used in biological-film process tanks (or biological contact oxidation tanks) of municipal and industrial wastewater treatment plants, where the media are usually fixed and suspended at both the top and bottom ends, forming rows of curtains; during flow through the tank, the pollutants come into full contact with the biofilm grown on the curtains through the mixing action of the aeration system, and are biodegraded and purified. The other category is water-grass-like braided curtain media specifically for polluted rivers, ponds and lakes — the lower end is fixed to the river bed, pond bottom or lake bed, and the upper end is free-floating; when the water becomes clear the media appear green due to attached algae and drift left and right like water grass, hence the name water-grass-like braided curtain media.
Two kinds of biological rope are introduced: biological rope made from imported vinylon aldehyde-acetal fibre blended and modified with polypropylene; and biological rope modified on the basis of braided belt weaving.
Common biological curtain media are made of polymer material, with a relatively large specific surface area, able to hold a high microbial density and improve water treatment efficiency.
Floating-hanging media, also called free-swinging media, have a float at the top of the media and hanging media in the middle; the tank bottom is fixed by embedded hooks or expansion bolts, so the media can swing freely with the push of water flow and aeration. They suit large wastewater treatment projects — especially projects that would like to use suspended media but fear accumulation — and are even more suitable for large water bodies such as rivers and lakes where steel-frame suspension is unsuitable and suspended loose media is also unsuitable.
Biological rope / braided belt media are widely used in biological contact oxidation, integrated treatment units, river and lake in-situ remediation, and aquaculture water treatment. Because the belt is fixed at both ends (or one end in water bodies) and hangs like a curtain, installation requires only a simple upper and lower fixing frame — no complex support structure.
Compiled per Water Treatment Packing & Filter Media (3rd Edition) §2.7.5.2–2.8 (text kept as in the source), with supplementary reference notes. Actual parameters to be confirmed against the specific product.