Page 508 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Adsorption 463

TABLE CDEx15.1
Determination of Headloss in GAC Column Given k

(a) Temperature coefficients
M0 M1 M2 M3 M4 M5

m(water) 0.0017802356694 5.6132434302E-05 1.0031470384E-06 7.5406393887E-09
r(water) 999.84 6.82560E-02 9.14380E-03 1.02950E-04 1.18880E-06 7.15150E-09
2
3
Formula; y ¼ M0 þ M1 T þ M2 T þ M3 T þ M4 T 4
(b) Fixed data
g ¼ 9.80665 m=s 2

(c) Calculation of headloss in GAC column
HLR Dh
T m(water) r(water) L(reactor) k K d 10
3
2
2
(8C) (N s=m ) (kg=m ) GAC (m=h) (m=s) (m) (m ) (m=h) (m) (kPa) (mm) R
20 0.00100 998.204 Filtrasorb 400 12.20 0.00339 10.00 1.00E-09 3.53Eþ01 3.46 33.90 0.65 2.2
10 0.00131 999.700 Filtrasorb 400 12.20 0.00339 10.00 1.00E-09 2.69Eþ01 4.53 44.46 0.65 1.7

4. Calculate Dh(col) for T ¼ 108C, from the second row
15.1.3 ADSORBATES
in the spreadsheet, to give, for L(reactor) ¼ 10.0 m,
Adsorbates include mostly organic compounds. Macroscopic
Dh(col, T ¼ 108C) ¼ 6.69 m (65.6 kPa) particles, e.g., bacteria and viruses, may adsorb, but ‘‘pas-
sively’’ (as opposed to being the intended ‘‘target’’ material
5. Compare Dh(col, T ¼ 208C) to be removed).
From the first row in Table CDEx15.1(c), for
T ¼ 208C, L(reactor) ¼ 10.0 m,
15.1.3.1 Organic Compounds
Dh(col, T ¼ 208C) ¼ 5.10 m (50.0 kPa) Organic compounds are virtually countless in number
with some 4-million synthetic compounds listed by the ACS
6. Check the Reynolds Number, R, for T ¼ 208C,
registry as of 1977. Some 33,000 chemicals were in common
From http:==www.calgoncarbon.com=carbon_ use and some 1260 were found in ambient waters (Dobbs
products=documents=Filtrasorb400.pdf,
and Cohen, 1980, p. 1), with >1000 being regulated. The
latter estimate was based upon a survey of regulated
0.55 d 10 0.75 mm; therefore, let, d 10
0.65 mm, to give, R ¼ rvd 10 =m 2.2
substances; some 4000 were identified (Champlin and
Hendricks, 1993). Among those regulated are the aromatic
Discussion
First, since the Darcy relationship only starts to deviate compounds that include pesticides, herbicides, surfactants,
from linearity at R ¼ 1, the Darcy assumption gives a and phenol (Cookson, 1978, p. 264). Examples of organic
reasonable estimate of headloss, facilitated by Table compounds found in drinking water, i.e., after treatment,
CDEx15.1. The Forcheimer equation, Section E.7, in a survey involving 11 cities, include (Clark and Lykins,
Equation E.3, would give a more accurate estimate. An 1989, p. 4)
on-site pilot plant is always preferred, however, to a
calculation.

Benzene Hexachlorobenzene Chlorobenzene
15.1.2.5 Shipping Data
carbon tetrachloride Lindane Chloromethylether
For one manufacturer, carbons are packaged in 60 lb bags
bis(2-chloroethyl)ether PCB Dibromochloromethane
(net). They are available on trailer-truck pallets, 38 bags per Chloroform Tetrachloroethylene 1,3-Dichlorobenzene
pallet, 16 pallets per standard 40 ft trailer. Rail car pallets are 1,2-dichloroethane Trichloroethylene Dichloromethane
42 bags per pallet, 24 pallets per standard 50 ft car. Bulk Dieldrin Vinyl chloride Methylene chloride
shipment by truck is 30,000 lb. minimum; by rail 50,000 lb DDT, DDE Bromodichloromethane Vinylidene chloride
minimum (Calgon Bulletin 20-1, 1966). Reactor design may Heptachlor
be based, in part, on shipping data.