Modelling nitrogen transformations in a pilot scale marine integrated aquaculture system Suzanne Boxman, Brian McCarthy, Fei Zhong, Sarina Ergas, Maya Trotz, Andres Tejada-Martinez, Kevan Main Presented by: Suzanne Boxman Doctoral Candidate University of South Florida Objectives • Overall goal • Understand the nitrogen transformations in marine IAS for future IAS development • Objectives 1. Design, calibrate and evaluate a marine IAS model on simulating the fate of nitrogen 2. Compare model output to observed 3. Understand the fate of nitrogen Mote IAS Model development: Software • StellaTM is computer program for dynamic model building Model development: Components • Black Box • Sand Filter • Geotube • Solids Tank • Physical, Chemical and Biological Processes • MBBR • South Plant Raceway • North Plant Raceway • No Transformations • Drum Filter Model development: Plant raceways • Assumptions: • Constructed wetland • Completely mixed flow reactor Symbol Description • 1st order reaction rates Unit Source L/day Experimental Q1 Flow through solids tank Rate of plant uptake of nitrate mg/L*day Experimental rde Rate of denitrification in plant raceway mg/L*day Literature Volume of plant raceway L Experimental Rate of nitrification in plant raceway mg/L*day Literature Flow through solids tank L/day Experimental Nitrate concentration in south plant raceway mg/L Experimental •CEquations broken down for PON, DON, Nitrate concentration in solids tank 1N • Only equations for NO3- will shown rup2 VPB rni Q2 C2N NH4+-N, --N and NO mg/L 3 Experimental Model verification Ammonia 50 10 40 8 NH4+-N concentration (mg/L) NO3--N concentration (mg/L) • ± 1 standard deviation of the mean Nitrate 30 20 10 6 4 2 0 0 -10 -2 W1 W2 W3 Observed W4 Model W5 W6 W7 W1 W2 W3 Observed W4 Model W5 W6 W7 Model results: MBBR effluent Nitrate Ammonia Model results: South plant raceway effluent Nitrate Ammonia Fate of nitrogen Plant and Soil, 0.2% South Plant Raceway Denitritification, 59.0% Sedimentation, 0.1% PON, 3.6% DON, 10.7% NH4+ -N, 1.3% Other, 40.7% NO3- -N, 25.2% Denitritification Plant and Soil Sedimentation DON NH4+ -N NO3- -N PON Conclusions • Solid waste from marine system can be used to grow wetlands plants • Small constructed wetlands can be used remove nitrate from system water by promoting denitrification • More information on flow rates could improve model • Modeling biological processes in geotube, sand filter, and solids tank should be completed Acknowledgements • Funding for this research has been provided by the National Oceanic and Atmospheric Organization, Award # SI-2014- 0006 • Funding for this research has been provided by National Science Foundation (NSF) Research Experience for Teachers, Award # 1200682 and the National Science Foundation (NSF) Research Experience for Undergraduates, Award # 1156905 and the National Science Foundation (NSF) S-STEM NSF S-STEM Grant No: 0965743 • Mote Aquaculture Research Park & Aquatic Plants of Florida Inc. • Dr. Maya Trotz, Dr. Sarina Ergas, and Dr. Kevan Main • Students and Teachers • • • • • • Brian McCarthy Alex Kruglick Fei Zhong Tuliagenda Beckford Stevie Lockhart Deborah Seto Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation Questions? Model development: MBBR • Assumptions: • Nitrification only transformation process • Completely mixed flow reactor Model development: Plant raceways • Nitrification and denitrification equations Fate of nitrogen 14 12 Average kg/day 10 8 PON DON 6 NH4+ -N NO3- -N 4 2 0 Solids Tank South Plant Raceway Sand Filter North Plant Raceway Geotube Sensitivity Analysis • Sum of squared residuals • k de = • k2 = P2 ûde ∗Xde Yde ∗Kde ûde Yde ∗Kde ∗ CCOD KCOD +CCOD k2 (day*L/mg) 0.3 0.2 0.15 0.12 Preference factor of plant uptake for NO3--N 0.25 0.50 0.75 W2 (mg/L NO3--N) 10.51 19.2 33.7 59.4 ∗ 15200 15200+Csalt W3 (mg/L NO3 --N) 3.40 5.94 9.81 16.3 W6 (mg/L NO3 --N) 1.49 1.55 11.7 26.1 ∗ θT−20 W7 (mg/L NO3 --N) 1.57 1.68 11.8 28.2 Average (mg/L NO3--N) 4.24 7.09 16.5 32.49 W2 (mg/L NO3--N) W3 (mg/L NO3--N) W6 (mg/L NO3--N) W7 (mg/L NO3--N) 10.64 10.51 10.46 3.43 3.40 3.39 1.45 1.49 1.50 5.79 5.78 5.78 Average (mg/L NO3-N) 4.27 4.24 4.24 Calibration • 3 types of parameters • Experimental • Boxman (2013) • eg. fraction of TN taken up by plants, soil • Literature • Metcalf and Eddy (2003) • eg. yield coefficients, half saturation constants • Henze et al. (2002) • eg. half saturation constants • Wynn and Liehr (2001) • Maximum specific growth rates • Calibrated • eg. fraction of active biomass for denitrifiers, preference factor of plant uptake Model development: MBBR influent nitrate • Assumptions: • Nitrification only transformation process • Completely mixed flow reactor Symbol Description f10A Q10 C10A rMBni VMB Q7 C7A Unit Fraction drum filter’s ammonia entering MBBR Source Literature Flow through drum filter L/day Experimental Ammonia concentration in solids tank mg/L Experimental Rate of nitrification in MBBR mg/L*day Literature Volume MBBR L Experimental Flow through MBBR L/day Experimental Ammonia concentration in MBBR mg/L*day Experimental
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