Pisciculture & Aqua Farming

• AQUACULTURE SYSTEMS

Better Water.
Better Aquaculture.

Aquaculture depends on consistent water quality. DeLoach designs and builds treatment systems for salt, brackish, and freshwater operations to help keep aquatic life healthy and harvested products safe.

 
Established in 1959

"The oldest and most respected pisciculture, water, and wastewater manufacturer in the USA"

aquafarming
• THE MARKET

Aquaculture Is Growing Fast

86%
of US seafood is imported, about half of it wild-caught
28%
average annual growth of aquaculture farming
3x
faster growth than land-based agriculture
Top 3
producers: China, India, and Vietnam

Demand for seafood and high-quality protein continues to drive aquaculture growth worldwide. The U.S. imports an estimated 86% of its seafood, while China, India, and Vietnam remain major producers.

• KEY TERMS

Aquafarming, Mariculture & Pisciculture

Aquafarming
Growing and harvesting aquatic species for commercial or subsistence use.
Mariculture
Aquafarming in marine environments, often using nets and pens along shorelines.
Pisciculture
Raising fish in tanks or managed ponds.
• INDUSTRY EVOLUTION

Aquafarming Has Deep Roots

Aquafarming has supported food production for thousands of years. What has changed is the scale: modern operations now raise species such as salmon, catfish, and tilapia using more advanced production and treatment systems.

In the U.S., commercial farms must meet strict standards for contaminants, disease, and harmful bacteria. That makes water quality and disease control central to protecting the harvest.

MODERN AQUAFARMING
Forced Draft Degasifier for blog1
• WHAT WE DO

Water Quality First

DeLoach designs custom water treatment systems for salt, brackish, and freshwater pisciculture. Systems can include degasification and decarbonation air stripping towers, pressure filtration, UV disinfection at 254 nm, and complete membrane or reverse-osmosis packages.

We Remove

Hydrogen sulfide (H2S)
Carbon dioxide (CO2)
Ferrous iron (Fe+)
Calcium carbonate (CaCO3)
Manganese (Mg)
 
We Control
pH
Total suspended solids
Total dissolved solids

 

When membrane filtration or reverse osmosis is required, systems can be designed for flows scaling into millions of gallons per day.

• THE PROCESS

How the Water is Treated

Seawater and brackish wells may range from 20,000–25,000 TDS and reach 35,000 TDS near the coast. Treatment typically follows four steps.
1
Adjust pH
Sulfuric acid may be used to lower pH to about 5–5.5, reducing alkalinity and converting sulfides into hydrogen sulfide gas.
2
Degasify
Air stripping removes H2S and CO2. As CO2 is stripped, pH typically rises by about 1–1.5.
3
Filter
If iron must also be removed, pH is adjusted to 7 to oxidize it. Pressure filtration removes oxidized iron to 15 microns, with polishing down to 0.5 microns when needed.
4
Disinfect
UV treatment at 254 nm helps control bacteria in incoming and recirculating water without adding chemicals.

Carbon filtration can be useful for freshwater applications, but media replacement or regeneration adds cost. It is best reserved for final polishing after bulk contaminants have been removed through degasification and filtration.

• THE CHEMISTRY

Why pH Matters

Degasification removes H2S and CO2, which can raise pH by about 1–1.5. When iron is also present, adjusting the pH to 7 promotes oxidation so the iron can be removed through pressure filtration.

Common Acids by Strength
 
No. Acid Ka pKa
1 Hydroiodic acid (HI) 3.16×109 -9.5
2 Hydrobromic acid (HBr) 1.0×109 -9
3 Hydrochloric acid (HCl) 1.0×106 -6
4
Sulfuric acid (H2SO4)
Used to Adjust pH
 1.0×103 -3
5 Hydronium ion (H3O+) 55 -1.74
6 Nitric acid (HNO3) 28.2 -1.45
7 Trifluoroacetic acid (CF3COOH) 5.62×10-1 0.25
8 Oxalic acid (HOOC–COOH) 5.37×10-2 1.27
9 Acetic acid (CH3COOH) 1.75×10-5 4.76
 
Listed from strongest to weakest. A higher Ka (and lower pKa) means a stronger acid.
• GROWING CONDITIONS

Keep Water at the Right Temperature

Different species require different water temperatures. Cold-water operations may use chillers, while warm-water systems can use heat pumps, solar thermal, and heat exchangers. Cooling or degasification towers can remove excess heat.

Cool it down

Cold-water species are cooled with chillers, which is standard practice in Florida.
Warm it up
Warm-water species use heat pumps, or solar thermal paired with heat exchangers.
Shed excess heat
Cooling towers or degasification towers pull excess heat back out of the water.

 

Many operations also fine-tune temperature and lighting around feeding behavior to support natural growth.

• SAFETY

Prevent Disease Before It Spreads

Bacteria and disease can move quickly through an aquaculture operation. Closed systems, UV treatment, and single-pass flow provide greater control and make it easier to isolate a tank if a problem appears.

△ Higher Risk
Open, unlined ponds
×
Waste products build up in the water
×
Birds and wildlife can contaminate tanks
×
Disease spreads quickly, tank to tank
◇ Better Control
Closed, single-pass systems
✓
Isolate a single tank quickly if disease appears
✓
UV treats incoming and recirculating water
✓
Single-pass flow limits how disease spreads
• REFERENCE

Top Farmed Species

A snapshot of the 15 most-cultured fish species by weight, based on FAO 2013 data.

Grass carp
Highest volume, 5.23M tons
Atlantic salmon
Highest value, $10.1B
Species Environment Tonnage (M) Value (US$B)
Grass carp Freshwater 5.23 6.69
Silver carp Freshwater 4.59 6.13
Common carp Freshwater 3.76 5.19
Nile tilapia Freshwater 3.26 5.39
Bighead carp Freshwater 2.90 3.72
Catla (Indian carp) Freshwater 2.76 5.49
Crucian carp Freshwater 2.45 2.67
Atlantic salmon Marine 2.07 10.10
Roho labeo Freshwater 1.57 2.54
Milkfish Freshwater 0.94 1.71
Rainbow trout Fresh, brackish, marine 0.88 3.80
Wuchang bream Freshwater 0.71 1.16
Black carp Freshwater 0.50 1.15
Northern snakehead Freshwater 0.48 0.59
Amur catfish Freshwater 0.41 0.55
Source: FAO statistics, 2013.

Planning an Aquaculture Treatment System?

Talk with DeLoach about your water source, purification needs, and the treatment process best suited to your operation.