Aquaculture Water Treatment
Fine solids are the hidden drag on fish health and growth. DAF systems engineered for RAS farms and hatcheries, sized from your system — not a catalog.
What Fouls Aquaculture Water
In a recirculating aquaculture system (RAS), every gram of feed becomes either fish, dissolved waste or solids. Drum filters and settling tanks catch the large particles. The fine particles — uneaten feed fines, fecal fines and bacterial floc under about 30 microns — keep circulating, feeding heterotrophic bacteria, consuming oxygen and irritating gills.
Dissolved air flotation captures those fines. Micro-bubbles attach to particles too small for screens, float them out in minutes and add oxygen to the water in the process. That is why DAF is increasingly used in RAS loops, hatchery discharge and farm effluent treatment.
Why Fine Solids Cost You Fish
Fine solids raise biochemical oxygen demand, load your biofilter, cloud the water and stress fish. The results show up as slower growth, poorer feed conversion and higher disease risk — directly in the production numbers.
Farm discharge carries its own costs. Permits for hatcheries and RAS facilities increasingly limit TSS and phosphorus, and sludge volume drives hauling cost. Capturing solids in a concentrated float addresses both.
Aquaculture Treatment With Micro-Bubble DAF
Our micro-bubble generator produces a dense, fine bubble cloud that captures sub-30-micron solids drum filters pass. Systems run on a side stream of the recirculation loop or on farm effluent, and can operate with little or no chemistry depending on the target.
- TSS removal of 90–98%, including fines screens miss
- Significant reduction in bacteria and pathogens carried on particles
- Reduced load on biofilters and UV or ozone systems
- Concentrated sludge for lower hauling volume or nutrient reuse
We are straightforward about scope: DAF removes particulate solids and the phosphorus and BOD bound to them. It does not replace your biofilter for ammonia and nitrite, or degassing for CO₂. It makes those processes work better by taking the solids load off them.
Salmon, Trout, Shrimp and More
We design aquaculture systems for salmon, trout, tilapia, catfish, shrimp and other species, plus algae cultivation facilities that harvest biomass with DAF. Hydraulic loading is set for your species, stocking density and feed rate — and materials are selected for freshwater or saltwater service.
Typical Aquaculture Water Characteristics
| Parameter | Why it matters | Typical range |
|---|---|---|
| Suspended solids (RAS loop) | Fines that pass drum filters. | 5–50 mg/L |
| Suspended solids (backwash / effluent) | Concentrated filter backwash. | 200–2,000 mg/L |
| Particle size | Fines under 30 microns are DAF's target. | Under 30 µm |
| Total phosphorus | Bound largely to solids; permit driver. | 0.5–20 mg/L |
| BOD | Feeds bacteria that compete for oxygen. | 5–500 mg/L |
| Salinity | Drives material selection. | Fresh to full seawater |
Ranges from published industry data and our project experience. Your lab analysis sets the real design numbers.
How We Size an Aquaculture DAF System
RAS DAF systems are usually sized on a side stream of the recirculation flow. In this illustrative example, a land-based salmon farm treats a 500 GPM side stream of its main loop.
An FC 180 carries the side stream with margin and cuts loop TSS from about 30 to about 3 mg/L in the treated fraction. Your feed rate, loop flow and water quality targets set the final design.
FC Maximizer models run from the FC 40 at 22 GPM to the FC 700 at 8,850 GPM with 25% recycle — see the full FC Maximizer sizing table.
| Treated side stream | 500 GPM |
|---|---|
| Selected clarifier | FC 180 — 600 GPM with 25% recycle |
| Influent TSS | 30 mg/L |
| Effluent TSS (90% removal) | About 3 mg/L |
| Solids removed per day | About 160 lb |
| Water service | Fresh or saltwater materials |
Clean Water for Healthier Fish
DAF Corp designs aquaculture systems for RAS farms, hatcheries and algae cultivation, built in Kaukauna, Wisconsin and shipped worldwide. The pattern is consistent: fine solids holding back water quality, and a DAF system sized from the farm's real loop and feed data — not an average.
Start With a Free Lab Analysis
Send us your loop flow, feed rate and a water sample. We analyze it, and typically within 5–10 business days return a system specification and budgetary proposal — including what DAF will and won't do for your farm. Micro Bubbles. Massive Results.
Request a Lab Analysis
Get Your Free Consultation
DAF Corporation works with food processors, municipalities, dairy operations, and industrial facilities to solve complex wastewater challenges. Our process begins with your water — not a catalog.
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