The composite filler is a biocarrier with a hybrid structure designed and manufactured by our company for biological membrane wastewater treatment. This product integrates the structural characteristics of soft and semi-soft fillers, aiming to provide microbial communities with an attachment and growth environment that combines high specific surface area and favorable hydraulic conditions through its unique "plastic ring sheet + fiber bundle" combination structure. This enhances the stability and treatment capacity of the biological treatment system.
- Structure and Working Principle
- Core structural composition
The filler is a unitized, suspended three-dimensional structure, which is mainly composed of three parts:
- The central rope, serving as the load-bearing and suspension framework, is typically made of corrosion-resistant synthetic fibers (e.g., polyester or polypropylene) or plastic ropes.
- Plastic ring: As a support framework, it consists of a double-ring large plastic ring molded from polypropylene (PP) or polyethylene (PE), evenly sleeved over the central rope to maintain spacing, support the wire bundle, and enhance overall rigidity.
- Fiber bundle: The core functional component, composed of multiple polyolefin-based (e.g., PP) aldehyde-oxidized or modified fibers, uniformly distributed in a radial pattern around each plastic ring segment, allowing full expansion in water.
- Working Principle
- Biofilm formation and growth: Microorganisms initially adhere to fibrous filaments with a large surface area to form biofilms. The presence of plastic ring sheets provides stable spatial distribution for the filaments, preventing entanglement in water and ensuring their effective specific surface area.
- Mass transfer and renewal: Under the action of water and air flow, the flexible fiber bundles can freely float, enhancing the contact and mass transfer efficiency among the gas, liquid, and membrane phases. Simultaneously, the moderate oscillation of the fiber bundles facilitates the detachment of aged biofilm, promotes biofilm renewal, and maintains high biological activity.
- Preventing blockage and distributing water/gas: The plastic ring creates regular gaps that allow smooth flow of water and air, reducing the risk of overall clogging in the packing area.
- Core technical features
- Structural complexity with complementary advantages: It combines the characteristics of soft fillers with large specific surface area and semi-soft fillers with structural stability. The fiber bundles provide abundant attachment surfaces, while the plastic ring sheets offer support and form regular flow channels. This structure may facilitate the balance between high biomass retention and favorable mass transfer conditions.
- Rapid biofilm formation and stable operation: The fiber bundles provide an ample and easily accessible surface for microbial attachment, enabling relatively rapid initial biofilm initiation. The formed biofilm is distributed within the space between the fiber bundles and the annular plates, allowing for relatively stable system operation.
- Variable porosity with excellent anti-clogging performance: The fiber bundles remain in a floating state within the fluid, allowing their void fraction to fluctuate, thereby reducing the likelihood of complete blockage by biofilms. The larger space formed by the plastic ring supports further decreases the overall probability of clogging.
- Easy installation and good durability: The modular design requires only the fixation of both ends of the filler during installation. The main materials (PP/PE) exhibit stable chemical properties and corrosion resistance, with a long theoretical service life and minimal long-term operation and maintenance workload.
- The cost-performance ratio is relatively balanced: As a mature and improved biological carrier, it combines high processing efficiency with good operational stability, demonstrating broad applicability in various biofilm processes.
- Main technical parameters
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Parameter item
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Description / Reference range example
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diameter
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Common specifications: ɸ150×80mm, ɸ150×100mm
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annular spacing
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Common specifications: 80mm, 100mm, affecting packing density and specific surface area
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unit packing length
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It can be customized according to the pool depth, with common lengths including 1.0m,1.5m,2.0m, and 3.0m.
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specific theoretical surface area
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Depending on the length and density of the filament bundle, the common range is 650 – 1200 m²/m³.
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void volume
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Generally high, common range> 96%
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Silk fabric material
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Modified polypropylene (PP) aldehyde-oxidized fibers are primarily used to enhance hydrophilicity and biofilm adhesion.
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Materials of the ring and central cord
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Polypropylene (PP), polyethylene (PE), polyester rope, etc.
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- Typical Application Fields
This filler is mainly used in various wastewater biochemical treatment processes requiring the cultivation of high-concentration attached biofilms:
- Municipal wastewater treatment: the biological contact oxidation tank in domestic sewage treatment plants, the supplementary filler in oxidation ditches, and the pretreatment or advanced treatment unit of the aerated biological filter (BAF).
- Industrial wastewater treatment: Biological treatment units for organic wastewater in industries such as food, brewing, dyeing, chemical, and pharmaceutical, particularly suitable for wastewater with good biodegradability.
- Micro-polluted water purification: Ecological restoration projects for rivers, lakes, and other landscape water bodies serve as substrates for biofilm attachment.
- Reclaimed water treatment: Used as a biological carrier in the biological treatment stage.
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