RAS design for marine on-growing fish the seabass team… RAS design for marine on-growing fish

the team… and the coach… and the coach… and the coach…

What we know… 350 g average final weight 100 kg/m3 maximum stocking density 1000 m3 tank volume Make up water contains: 2mg/l TAN 3 mg/l O2 10 mg/l CO2 23 C temperature feed 1.5% of biomass per day

What we are looking for… A flow through system (FTS) An open recirculating system (O-RAS), 5 m3/kg feed A close recirculating system (C-RAS), 0.5 m3/kg feed

Calculations for the beginning… Total biomass = 100 tn Feed per day = 1500 kg/day O2 consumption in the tank, using the formula: 2.85*(0.35^-0.247)*(23^1.25*10^-3) = 446,4 kg O2/day so 18.6 mg/l of O2 consumption per hour the CO2 production = x1.4 O2 cons. = 36 mg CO2 /lt h

1st scenario… max 18 mg/ lt CO2 at the outlet of the tank….we have to change the water 2 times every hour So the flow rate = 2000 m3 per hour We add 12mg/lt/ hour O2 into the system to maintain Shaft 15 m deep in order to take 200% saturated seawater *Assumption for SS: (33*Ci-20)*feed/100 = 393 kg SS/day Where Ci is 1.3 So per hour will be 16.4 kg SS/h or 8.2 g SS/m3 then we have to remove 3.2 g/m3 Drum filtration

Assumption TAN = 3% Feed TN = 4.2 % Feed So… TAN = 45 kg/day TN = 63 kg/day

O - RAS with makeup water 5m3/kg feed Make up seawater 7500 m3 / day Or per hour 312m3 /hour The produced TAN will be 1.875 mg/l, so the total will Mass balance for Tank for TAN: Qr*Ci+Qo*Co+Vp*Kp = (Qo+Qr)*Ci Mass balance for biofilter Qr*Ci-(Vb*Kb) = Qr*Ce For Ci = 2mg/lt: After the calculations Vb = 500 m3, Ce = 0.75 mg/lt, Kp = 2.5 gr NH3 /m3 / hour For Ci = 3 mg/lt: After the calculations Vb = 320 m3, Ce = 1.9 mg/lt, Kp = 2.5 gr NH3 /m3 / hour So O2 consumption of Biofilter in case of 3 mg/lt will be 5 mg/l. So Ci will be 7 mg/lt, taking into account that in the outlet of the biofilter the O2 concentration will be 2 mg/lt So we have to have a concentration of 16 mg/lt of O2 in the tank. We have to add 13 mg/lt O2 after the entrance of make up water The CO2 production will be 1.4 * O2 consumption = 12.6 mg/lt So the inlet of the tank will contain 5.4 mg/lt So the biofilter CO2 production will be 7 mg/lt

C - RAS with make up water 0.5 m3/kg feed Ci = 3 mg/lt Make up 31 m3 /hour Packing media 367 m3 Ce = 1.77 mg /lt TAN In case of 2 mg/lt Ci = 2 mg/lt Make up 31 Packing 510 Ce = 0.75 mg/lt TAN

Thank you for not having questions…