Updated: 30 October 2017 Print version Lecture #19 Streeter-Phelps: Nitrogen, Photosynthesis/Respiration (Chapra, L23, L24) 1
Loading & Overflow Model L = P + 116 . 12 . q s From Chapra (pg 538) David A. Reckhow CEE 577 #6 2
#1 ( ) k L − − − = + − k t k t k t d o D D e e e a a r #2 − o Extended k k a r ( ) k L Streeter − − + − k t k t n No e e n a #3 − k k a n Phelps ' S − + + P R B ( ) H #4 − + − k t 1 e a k a ( ) ) ( ) k S k S #5 − − − + − − − k t k t k t d d d d 1 e e e a a r ( − k k k k k r a r a r ( ) ) ( ) k S k S − − − + − − − k t k t k t n Nd n Nd 1 e e e a n a ( #6 − k k k k k n a n a n David Reckhow CEE 577 #18 3
General Model Kinetics Atmosphere (K a ) K 2 K 4 SOD K N 1 K 1 (K s ) K 3 Dissolved Oxygen NBOD CBOD (K d ) 4
Loading & Overflow Model L = P + 116 . 12 . q s From Chapra (pg 538) David A. Reckhow CEE 577 #6 5
Mechanistic Algal Model α ρ σ 4 1 Organic N β 3 α µ σ 3 1 F NH 3 β α ρ 1 σ 5 2 NO 2 Org-P β 2 β 4 σ 2 NO 3 Diss-P α µ − F ( 1 ) α µ α ρ 1 α µ α µ 3 4 2 1 Chlorophyll a (Algae) σ 1 David Reckhow CEE 577 #21 6
Atmosphere General Model (K a ) K 2 Kinetics with algae K 4 α ρ σ 4 SOD 1 Organic N K 1 (K s ) K 3 Dissolved Oxygen β 3 CBOD (K d ) α µ σ 3 1 F NH 3 β α β α ρ 1 σ 5 5 1 2 NO 2 Org-P β 2 β 4 σ 2 α 6 β 2 NO 3 Diss-P α µ − F ( 1 ) α µ α ρ 1 α µ α µ 3 4 2 1 Chlorophyll a (Algae) σ 1 David Reckhow CEE 577 #21 7
General Model Atmosphere Kinetics with N species K 2 K 4 σ 4 SOD Organic N K 1 K 3 Dissolved Oxygen β 3 CBOD σ 3 NH 3 β α β 1 5 1 NO 2 β 2 α β 6 2 NO 3 David Reckhow CEE 577 #18 8
Nitrogen Modeling Org-N Organic Nitrogen (N 4 ) settling rate (d -1 ) dN = α ρ − β − σ 4 A N N 1 3 4 4 4 dt Algal Org-N Algal Fraction of biomass hydrolysis respiration algal biomass rate (d -1 ) (mg/L) rate (d -1 ) which is nitrogen (mg- N/mg-A) 9
Nitrogen Modeling (cont.) Benthos release rate (g-N/m 2 /d) Ammonia Nitrogen (N 1 ) Specific Algal σ dN = β − β + − α µ 1 3 N N F A growth rate z 3 4 1 1 1 1 dt (d -1 ) Org-N Fraction of Fraction of hydrolysis algal biomass algal-N uptake rate (d -1 ) which is from ammonia Rate of nitrogen (mg- biological N/mg-A) oxidation of ammonia (d -1 ) 10
Nitrogen Modeling (cont.) Nitrite (N 2 ) dN = β − β 2 N N 1 1 2 2 dt Rate of Rate of biological biological oxidation of oxidation of nitrite (d -1 ) ammonia (d -1 ) 11
Nitrogen Modeling (cont.) Nitrate (N 3 ) Specific Algal ( ) dN = β − − α µ 3 N 1 F A growth rate 2 2 1 1 dt (d -1 ) Fraction of Rate of Fraction of algal biomass biological algal-N uptake which is oxidation of from ammonia nitrogen (mg- nitrite (d -1 ) N/mg-A) 12
Nitrogen Modeling (cont.) Concentration (mg/L) NO 3 NH 4 Org-N Time (days) NO 2 13
Nitrogen Modeling (cont.) Inhibition of Nitrification at low D.O. − = − e KNITRF D O * . . CORDO 1 EPA Nitrification inhibition Nitrification correction factor coefficient (0.6-0.7 L/mg) − = − k o f 1 e nitr Chapra nitr 14
Impact of nitrification inhibition 1.0 f nitr 0 D.O. (mg/L) 10.0 Without inhibition D.O. With inhibition 0 Travel Time 15
To next lecture 16
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