Page 283 - Soil and water contamination, 2nd edition

270 Soil and Water Contamination

Suspended solids
dSS O
= F F 2 T 20 k SS
dt r s M SS + O 2 s s

F = m U x U crit 1 if U > U crit 1
x
r
z U crit 1
F r = V s U crit2 U x SS if U < U crit 2
x
z U
crit2
Phosphate

dPO 4 = k ( PO EPC) + p F r PO s + 95 O 2 T 20 k SS P
dt p 4 1 p w 4 31 M SS + O 2 s s SS

Ammonium

dNH O p F
4 = 2 T 20 k NH k ( NH EAC) + r NH s +
dt M + O 2 n n 4 f 4 1 p w 4
n
+ 18 O 2 T 20 k SS N
14 M + O s s SS
SS 2
Nitrate

dNO 3 = T 20 k NO + 62 O 2 T 20 k NH
dt d d 3 18 M + O s n 4
n 2

Oxygen

dO 2 = T 20 k ( O sat O ) O 2 T 20 k SS s 64 O 2 T 20 k NH
dt r a 2 2 M + O s s O /2 SS 18 M + O n n 4
SS 2 n 2
O SOD
2 T 20 + F F
M SS + O 2 SOD z p resp

U 5 . 0 U 5 . 0
k a = . 3 94 x if . 3 94 x > K r min
z 5 . 0 z 5 . 0

k = K r min if . 3 94 U x 5 . 0 K
a 5 . 0 r min
z z

O 2 sat = 1 + y 2 T + 3 T 2

Figure 15.2a Differential equations for a water quality model (Van der Perk 1998).

10/1/2013 6:45:21 PM
Soil and Water.indd 282
Soil and Water.indd 282 10/1/2013 6:45:21 PM