Products
Efficient biological filtration and gas removal system, ideal for recirculating aquaculture setups.
A highly efficient biofiltration module that utilizes suspended plastic bio-media to support bacterial colonies for the removal of ammonia and nitrites. Ideal for recirculating aquaculture systems (RAS) and water treatment plants.
Bio Filter
In a Recirculating Aquaculture System (RAS), the biological filter (biofilter) is essential for converting toxic ammonia (from fish waste) into less harmful nitrate through the nitrogen cycle.
1. Role of a Biofilter in RAS
The biofilter hosts beneficial bacteria that perform nitrification:
Ammonia (NH₃/NH₄⁺) → Nitrosomonas bacteria → Nitrite (NO₂⁻)
Nitrite (NO₂⁻) → Nitrobacter bacteria → Nitrate (NO₃⁻)
(Nitrate is removed via water exchange or denitrification.)
Without a biofilter, ammonia/nitrite buildup can kill fish rapidly.
2. Types of Biofilters for RAS
Biofilters are categorized by their media type and flow design:
A. Submerged (Fixed-Bed) Biofilters
Media: Plastic beads, ceramic rings, or porous gravel.
How it works: Water flows through a submerged media bed where bacteria colonize.
Best for: Small to medium RAS, low energy use.
Pros: Simple, low cost. Fox example, Moving Bed Biofilm Reactor (MBBR) (plastic media in suspension) and Fluidized Sand Filter (fine sand media, high efficiency).
B. Trickling (Drip) Filters
Media: Plastic bio-balls, lava rock, or structured PVC sheets.
How it works: Water trickles over media exposed to air (high oxygen transfer).
Best for: High-load systems (e.g., trout, salmon RAS).
Pros: Excellent aeration, low clogging.
C. Fluidized Bed Biofilters
Media: Fine sand or plastic microbeads.
How it works: Water flows upward, fluidizing media for max bacteria contact.
Best for: High-density systems (shrimp, tilapia).
Pros: Extremely efficient, compact.
D. Bead Filters (Combined Mechanical & Biofiltration)
Media: Floating plastic beads.
How it works: Traps solids while providing surface area for bacteria.
Best for: Small RAS, backyard systems.
Pros: Dual function (mechanical + bio).