Page 221 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

176 Fundamentals of Water Treatment Unit Processes: Physical, Chemical, and Biological

water) ‘‘air airbubble concentration C o water) 0.024 0.024 of entering system be to with at of

air=m 3 C r ¼ Nb pd b 3 =6) the *check: this is only ‘‘required,’’ as at B ¼ 10 (kg air saturated respect elevation basin), i.e.,
C r 0.0048 0.0069 termed, by Edzwald (1995, p. 8) calculated to float the air=m 3 Concentration (assumed to atmosphere C o ¼ H (air) P(atm)
(kg r(air) 0.007—ok was C r released’’ and is ‘-mass 6.9 mg=L floc air of

water) ‘‘air- by C a water) 0.0264 0.0253 of to air in depth at C s ¼ H I.e.,

air=m 3 f b ¼ N b (pd b 3 =6) bubble-volume concentration’’ (kg with pressure bubbles nozzles, depth)
f b 0.0040 0.0057 termed (1995, air=m 3 Saturation concentration respect (air) P(nozzle
(m 3 0.006—ok was f b Edzwald 8) p.

(kg C) as H(O 2 ) H(air) X þ in as

N b (bubbles=m 3 ) 1.2Eþ11 1.7Eþ11 ‘‘bubble- the concentration’’ 20 H(air, air=m 3 water=kPa air) 0.000243 0.000243 calculated H(air) molar weighted for fraction i.e., H(N 2 ), X(O 2 ) H(O 2 ) (N 2 ) H(N 2 )- 8.4 Example

Nb is number N b ¼ N p B 1.6*10 11 -ok þ
(mg 8C) N 2 ) from empirical H(N 2 ) Data H.6 Table
per
based
rise
of
Balance B (bubbles=particle) 10 10 number generated is and 8.10 1995, showing bubble– of agglomerate B of H(N 2 ,T water=atm N 2 =L 19.60 19.60 as Calculated of fit i.e., ¼ A(N 2 ) exp(B(N 2 ) T8C) is reference
Mass the is B bubbles particle Figure on (Edzwald, 14) p. velocity particle function as dp and best data,

by (mg 8C) O 2 ) from empirical H(O 2 ) Data
Conditions (#=m 3 ) 1.2.Eþ10 1.7.Eþ10 number a gave 13) particles=mL on based of 9) H(O 2 ,T water=atm O 2 =L 44.62 44.62 as Calculated of fit best i.e., data, ¼ A(O 2 ) exp(B(O 2 ) T8C) reference H.6 Table

Stated N p (#=mL) 12000 17000 particle p. (1995, 10 3 –10 5 was used calculations p. (1995, is

for the is concentration. Edzwald of range value matching Edzwald depth) (kPa) 108.569 104.127 pressure nozzles, depth) where equal atmosphere
Solids N p The P(nozzle Absolute of depth P(nozzle ¼ P(atm) (1þD=10.33) the is depth one pressure

Float air=bubble) Mass(bubble) ¼ r(air) V(bubble) at i.e., 10.33 water to of
to Mass(bubble) (kg 4.03486E-14 4.03486E-14 i.e., for pressure law
Pressure solids 8C 20 for P(atmosphere) (kPa) 98.987 80.693 Atmospheric a as Z, of P(atmosphere) ¼ 101325 10^ ( 0.00005456 Z) vapor). correction water-vapor Henry’s using

Saturator float to d b (m=bubble) 4.E-05 4.E-05 bubble— of law Henry’s pressure function ‘-P(water Note in

(continued) Required concentration air Diameter assumed for by C a , D(nozzles) (m) 1.00 3.00 of Depth manifold=nozzles water below surface

CD8.3 of of Calculation gas) air from r(molar) MW ¼ (P=RT) MW(gas)= corrected pressure bubbles concentration,

TABLE Calculation (c) r(air) air=m 3 (kg 1.20406 1.20406 of Density calculated PV ¼ nRT r(molar) ¼ n=V ¼ P=RT r(mass) ¼ (gas)=1000 1000-not Water-vapor air in Gas (d) Z(elevation) (m) 0 1585 Elevation above sea level