RAS design

RAS system design: the scope every quote must cover

A recirculating aquaculture system is a chain of linked packages — filtration, biofiltration, CO₂ removal, oxygen, disinfection, pumping, controls, backup power and effluent — all sized from one design basis: species, biomass and peak feed load. Fix that basis and the scope of each package before asking suppliers to quote, so you compare like with like.

Planning guidance only. Final sizing must be done and signed off by a qualified RAS engineer.

RAS cost calculator How the procurement platform works

1. Design basis: species, biomass and feed load

Every package below is sized from the same basis: species, annual output, harvest weight, maximum standing biomass and peak daily feed. Agree it in writing before any supplier sizes equipment, or quotes cannot be compared.

Ask every supplier to state

Peak feed per day (kg) and feed protein %
Maximum stocking density per tank group
Water temperature and salinity range

RAS sizing calculator

2. Water source, intake and make-up water

Source type (well, municipal, surface, sea), chemistry, temperature and daily make-up volume. Pre-treatment needs depend on the source analysis, not on the supplier's standard design.

Ask every supplier to state

Lab water analysis attached
Make-up water % of system volume per day
Pre-treatment included or excluded

3. Mechanical filtration and solids removal

Drum or disc filters, screen mesh size, backwash water use and fine-solids handling. Solids load follows feed load.

Ask every supplier to state

Screen micron size
Backwash water and power use
Sludge flow to effluent treatment

4. Biofiltration (nitrification)

Media type (MBBR, fixed bed, trickling), media volume and specific surface area, sized from the daily ammonia load produced by feed.

Ask every supplier to state

Design ammonia load (g TAN/day) and how it was derived
Media volume and specific surface area
Assumed nitrification rate at design temperature

Biofilter sizing calculator

5. Degassing and CO₂ stripping

CO₂ builds up with feed and oxygen use. Strippers, aeration columns and air-to-water ratios must be stated with the target CO₂ level.

Ask every supplier to state

Target dissolved CO₂ (mg/L)
Stripper type and air-to-water ratio
Fan power

6. Oxygenation

Oxygen demand from biomass and feed, supply method (LOX, on-site generator, cones, low-head oxygenators) and the backup oxygen source.

Ask every supplier to state

Design oxygen demand (kg O₂/day)
Primary and emergency oxygen supply
Dissolved-oxygen setpoint per tank

Oxygen requirement calculator

7. Disinfection: UV and/or ozone

UV dose and the flow it treats, ozone dosing and residual control. State whether intake water, recirculating water or both are treated.

Ask every supplier to state

UV dose at end of lamp life
Treated flow (side-stream or full flow)
Ozone residual monitoring

8. Pumping and hydraulics

Recirculation flow, tank exchange rate, total head and pump efficiency drive the largest continuous power use in most RAS.

Ask every supplier to state

Design flow and total dynamic head
Pump efficiency and installed kW
Duty/standby pump arrangement

Energy cost calculator

9. Tanks and production layout

Tank volume, number, material and grouping into independent loops for biosecurity and staged production.

Ask every supplier to state

Tank count, volume and material
Number of independent loops
Purge/depuration tanks included?

10. Monitoring, controls and alarms

Sensors (O₂, temperature, pH, CO₂, flow, level), PLC/SCADA scope and remote alarms. Specify what is monitored per tank versus per loop.

Ask every supplier to state

Sensor list per tank and per loop
Alarm escalation and remote access
Software licences and support term

11. Backup power and redundancy

Generator capacity, automatic transfer time and which loads it carries. Single points of failure (one blower, one oxygen line) should be named and priced out.

Ask every supplier to state

Generator kVA and transfer time
Loads carried in a power failure
List of single points of failure

12. Effluent, sludge and discharge permit

Sludge thickening, treatment and disposal route, matched to the local discharge permit. Often excluded from equipment quotes and added later.

Ask every supplier to state

Effluent treatment scope included or excluded
Sludge volume and disposal route
Permit limits the design meets

13. Building, civil works and installation

Building, floor loading, insulation, HVAC, civil works, installation, commissioning and training — the lines most often left out of an equipment-only price.

Ask every supplier to state

Which of these are in scope (FAT/SAT, installation, commissioning)
Performance guarantees and their test conditions
Warranty and spare parts

From design scope to comparable quotes

Estimate the budget with the RAS cost calculator, then use the FishMatch procurement platform to send one scope to several suppliers. Every request is reviewed by a person; FishMatch is supplier-neutral and handles projects from USD 250,000.

How to compare RAS quotations →RAS design guide →RAS planning hub →

Sources: RAS design coefficients (Timmons & Ebeling)

The water-treatment figures used in our RAS and farm-cost tools come from these published references. They are design starting points — your system engineer and equipment suppliers confirm final values.

What it measures	Coefficient	Source	Original wording (source)
Ammonia (TAN) produced	TAN (kg/day) = feed (kg/day) × protein fraction × 0.092	Timmons & Ebeling et al., NRAC Publication 01-002 (2002)	“PTAN = F * PC * 0.092 … The constant in the ammonia generation equation assumes that protein is 16% nitrogen, 80% nitrogen is assimilated by the organism, 80% assimilated nitrogen is excreted, and 90% of nitrogen excreted as TAN + 10% as urea.” — Ebeling, Timmons & Bisogni, citing Timmons et al. (2002)
Oxygen used by the fish	About 0.25 kg O₂ per kg feed (design value; adjust by species and temperature)	Timmons & Ebeling et al., NRAC Publication 01-002 (2002)	“POxygen = − 0.25 kg per kg feed consumed by fish (a negative production term) − 0.12 kg per kg feed consumed by nitrifying bacteria − 0.13 heterotrophic bacteria (estimate, can be as high as 0.5) = − 0.50 kg … per kg feed for system.” — Timmons, Mass Balances, Loading Rates and Fish Growth (Cornell / ISTA 7 RAS workshop, 2006)
Carbon dioxide produced	About 1.375 kg CO₂ per kg O₂ consumed (44 ÷ 32 molar ratio)	Timmons & Ebeling et al., NRAC Publication 01-002 (2002)	“PCO2 = 1.375 grams produced for each gram O2 consumed (both fish and bacteria).” — Timmons, Mass Balances, Loading Rates and Fish Growth (Cornell / ISTA 7 RAS workshop, 2006)
Nitrification: oxygen use	About 4.18 g O₂ per g ammonia-nitrogen converted	Ebeling, Timmons & Bisogni, Aquaculture 257 (2006) 346–358	“For every g of ammonia-nitrogen converted to nitrate-nitrogen, 4.18 g of dissolved oxygen, and 7.05 g of alkalinity (1.69 g inorganic carbon) is consumed and 0.20 g of microbial biomass (0.105 g organic carbon) and 5.85 gm of CO2 … is produced.” — Ebeling, Timmons & Bisogni (2006)
Nitrification: alkalinity use	About 7.05 g alkalinity (as CaCO₃) per g ammonia-nitrogen converted	Ebeling, Timmons & Bisogni, Aquaculture 257 (2006) 346–358	“It should be noted that both the consumption of oxygen and alkalinity is less than that which normally reported, 4.57 g of O2 and 7.14 g of alkalinity for every g of ammonia-nitrogen converted (Timmons et al., 2002), because in this equation some of the ammonia-nitrogen is converted to biomass.” — Ebeling, Timmons & Bisogni (2006)

Timmons, M.B., Ebeling, J.M., Wheaton, F.W., Summerfelt, S.T. & Vinci, B.J. (2002). Recirculating Aquaculture Systems, 2nd ed. NRAC Publication No. 01-002. Cayuga Aqua Ventures, Ithaca, NY.
Ebeling, J.M., Timmons, M.B. & Bisogni, J.J. (2006). Engineering analysis of the stoichiometry of photoautotrophic, autotrophic, and heterotrophic removal of ammonia–nitrogen in aquaculture systems. Aquaculture 257, 346–358. doi:10.1016/j.aquaculture.2006.03.019 · Author paper text: Aquacultural Engineering Society (PDF)
Timmons, M.B. (2006). Mass Balances, Loading Rates, and Fish Growth — course notes, RAS short course, Cornell University / 7th International Symposium on Tilapia in Aquaculture. University of Arizona (PDF)

Short answer

What is the fastest way to get quotes for RAS System Design?

Submit one structured request for RAS System Design. FishMatch Group translates it into a technical RFQ, runs a confidential sourcing round with project-matched international suppliers, and returns comparable quotations. No fee is charged to the buyer, and your identity and project details stay private until you choose to proceed.

How it works:: One structured request, human-reviewed before any supplier outreach
Typical turnaround:: Depends on scope and site data; no turnaround is guaranteed
Confidentiality:: Supplier names are never exposed during evaluation
Cost to buyers:: No fee charged to the buyer

What is the fastest way to get quotes for RAS System Design?

How does FishMatch Group source suppliers for this requirement?

You submit one structured request. We translate it into a technical RFQ, run it against qualified manufacturers and integrators in the relevant categories, and return normalised quotations you can compare side by side on scope, lead time and total cost of ownership.

Do buyers see supplier names during the sourcing process?

No. Supplier identities stay confidential during discovery and evaluation. You receive anonymised, comparable technical and commercial packages, and introductions happen only after both sides are qualified and agree to proceed.

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.

Start a structured RFQ