RAS – Recirculating Aquaculture Systems
Land-based recirculating systems for salmon, trout, shrimp and other high-value species.
Overview
A Recirculating Aquaculture System reuses 90–99% of its water by mechanically filtering solids, biologically converting ammonia, degassing CO₂, adding oxygen and disinfecting flow before it returns to the culture tanks.
Where it is used
- Cold-water salmon and trout smolt / post-smolt / grow-out
- Warm-water shrimp indoor farms
- Marine finfish (sea bass, sea bream, kingfish, yellowtail)
- Freshwater high-value species (perch, sturgeon, tilapia premium)
Typical applications
- Urban indoor farming close to markets
- Regions with limited water or strict discharge rules
- Biosecure smolt & post-smolt production
- R&D and broodstock isolation facilities
Benefits
- Minimal water use (down to 100–300 L/kg produced)
- Full climate & disease control
- Predictable growth and FCR
- Effluent that can meet zero-discharge standards
- Location flexibility — build near demand
Limitations
- High CAPEX per kg of installed capacity
- High electrical load and O₂ demand
- Complex to operate — requires trained staff
- Single-point failures can be catastrophic without redundancy
Typical project sizes: Typical builds range from 50 t/y R&D pilots to 20,000 t/y mega-farms; most commercial projects fall in the 500–5,000 t/y band.
RAS vs Flow-Through vs Semi-Closed
| Parameter | RAS (Closed) | Flow-Through | Semi-Closed / Hybrid |
|---|---|---|---|
| Water reuse | 90–99% | 0% | 50–90% |
| CAPEX (relative) | High | Low | Medium |
| OPEX (energy) | High | Low | Medium |
| Biosecurity | Excellent | Weak | Good |
| Climate independence | Full | None | Partial |
| Effluent control | Excellent | Poor | Moderate |
| Best for | Premium species, urban sites | Abundant clean water sites | Coastal farms upgrading legacy sites |
Buying guide
How to evaluate suppliers
- Prefer engineering houses with 5+ commissioned facilities in your species and climate band
- Ask for measured (not designed) energy, FCR and mortality data from reference sites
- Verify redundancy on oxygen, power and circulation — not just filtration
- Confirm the supplier is willing to guarantee performance in writing (KPIs, penalties)
Common purchasing mistakes
- Buying a system sized by tonnage without validating peak biomass density
- Underestimating oxygen and CO₂ stripping demand
- Ignoring make-up water quality and pre-treatment cost
- Skipping SCADA + alarm design — most catastrophic losses start with a silent failure
Technical questions to ask
- What is the guaranteed maximum TAN, NO₂ and CO₂ at design biomass?
- How many hours of full oxygen backup are provided at peak biomass?
- What is the water and energy use per kg of fish produced?
- What is the mean time between drum-filter cleanings?
- What redundancy is provided for pumps, blowers and O₂ supply?
Warranty considerations
- Minimum 12 months on all mechanical equipment
- 24 months on pumps, blowers, PLC
- Documented spare-parts availability for 10 years
Maintenance
- Weekly biofilter and drum-filter inspection
- Monthly UV lamp check
- Annual pump seal and blower service
- Quarterly SCADA firmware updates
Expansion capability
- Modular tank + biofilter blocks
- Pre-sized headers for +30% flow
- PLC I/O reserve of 20%
Energy efficiency
- Target 3–6 kWh per kg fish for grow-out RAS
- Variable-frequency drives on pumps & blowers
- Heat recovery from oxygen cones and blowers
Lifecycle
- Design life 20–25 years for tanks & piping, 10–12 years for rotating equipment
- Plan a mid-life PLC refresh at year 8–10
Technical specification checklist
Line-by-line items you should include in a vendor-neutral technical specification. Download as CSV to hand to your engineer or drop straight into the RFQ Builder.
Budget guide
| Project size | Indicative CAPEX | Indicative OPEX |
|---|---|---|
| R&D / broodstock (< 100 t/y) | USD 2–5M | USD 4–8/kg |
| Commercial smolt / post-smolt (500–1,500 t/y) | USD 15–40M | USD 2.5–4/kg |
| Grow-out (2,000–5,000 t/y) | USD 40–120M | USD 3–5/kg |
| Mega-farm (10,000–20,000 t/y) | USD 150–400M | USD 2.5–4/kg |
Indicative ranges only. Real budgets depend on site, regulations, redundancy and scope. Use for internal planning — always validate with an engineering study.
Major cost drivers
- Tank material (concrete vs FRP vs HDPE)
- Oxygen supply choice
- Building envelope and climate control
- Redundancy level
- Local labour and utility cost
Optional equipment
- Denitrification reactor for zero-discharge
- Ozone with foam fractionation
- Automatic feed distribution & AI monitoring
- Fish grading & harvest line
Installation notes
- Civil works often 20–30% of CAPEX
- Piping installation labour 8–12% of CAPEX
- Commissioning window 6–12 weeks
Operating cost notes
- Energy typically 25–40% of OPEX
- Feed 40–55% of OPEX
- Labour 10–15%
- Health, oxygen, chemicals 8–12%
Maintenance reserve
- Budget 3–5% of CAPEX annually for maintenance
- Plan a full mid-life refurbishment reserve
Procurement checklist
- 1Define target species, biomass curve and harvest plan
- 2Confirm water source, quality and legal abstraction volume
- 3Confirm grid capacity, tariff and backup fuel supply
- 4Complete land, EIA and effluent permitting
- 5Prepare civil layout and geotechnical study
- 6Select redundancy strategy (N+1 on critical loads)
- 7Draft technical specification with performance KPIs
- 8Issue confidential RFQ to project-matched engineering houses
- 9Score bids on a weighted matrix (see below)
- 10Line up equipment financing / lease before contract award
Supplier evaluation matrix
Score each supplier from 0 to 10 on each factor. Weights are pre-set with defensible defaults — override if your context differs.
| Factor | Weight | |||
|---|---|---|---|---|
Reference projects in species & climate Minimum 3 verifiable references | 20 | |||
Guaranteed KPIs (energy, mortality, growth) Written performance guarantee | 15 | |||
Redundancy on O₂, power, pumps N+1 on all critical systems | 15 | |||
SCADA & alarm quality Independent alarm channel required | 10 | |||
Total lifecycle cost (10-year) CAPEX + energy + parts + downtime | 15 | |||
Lead time & installation timeline Confirmed by penalty clause | 10 | |||
Warranty & spare-parts programme 10-year parts availability | 10 | |||
Training & operator support On-site + remote support | 5 | |||
| Weighted total | 100 | 0.0 | 0.0 | 0.0 |
Decision wizard
Frequently asked questions
Planning a project?
Now that you have the technical picture, get confidential quotations from project-matched international suppliers — or line up equipment financing first.
Continue exploring
Aeration & Oxygenation Systems
Diffused, surface and pure-oxygen systems for ponds, tanks and RAS.
Filtration Systems
Mechanical and biological filtration for hatcheries, nurseries and grow-out.
Water Treatment & Disinfection
Intake, process and effluent treatment: UV, ozone, denitrification, degassers.
Feeding Systems
Automatic, blower, and AI-driven feeders for tanks, ponds and cages.
Short answer
How do you source RAS Systems for a commercial aquaculture project?
Start from the process requirement — biomass, flow, water quality target and site constraints — not from a product catalogue. FishMatch Group converts that requirement into a specification for RAS Systems, sources it from vetted manufacturers and integrators across Europe, Asia and the Americas, and returns like-for-like quotations with lead times, energy consumption and lifetime running cost stated in the same format.
- What we compare:
- Scope, capacity, energy use, lead time and total cost of ownership
- Typical turnaround:
- Depends on scope and site data; no turnaround is guaranteed
- Delivery terms:
- Quotations normalised to EXW / FOB / CIF so prices are like-for-like
- Cost to buyers:
- No fee charged to the buyer
Before you request quotes
Equipment scope
What equipment does a commercial aquaculture project actually need?
A grow-out project typically needs holding infrastructure (tanks, ponds or cages), water movement (pumps, piping, valves), aeration or oxygenation, water treatment appropriate to the system, feeding equipment, grading and handling gear, monitoring and alarms, and backup power. RAS adds mechanical filtration, biofiltration, degassing, disinfection and tighter process control. Hatchery and processing scopes are specified separately.
Which equipment should be specified before requesting quotes?
Specify the items whose sizing changes everything downstream: design biomass and stocking density, water exchange or recirculation rate, oxygen demand at peak temperature, and installed pumping head. With those four fixed, suppliers can quote aeration, filtration, pumps and power on the same basis. FishMatch calculators produce these figures and attach them to the RFQ.
Can equipment be sourced in stages?
Yes, and phased procurement is common. The usual sequence is water supply and holding infrastructure, then aeration and treatment, then automation and monitoring, then processing and cold chain. Staging works when interfaces and capacity headroom are defined at the start; otherwise later phases force replacement rather than addition.