Encyclopedia of Environmental Science and Engineering, Volume I and II

1198 URBAN RUNOFF

TABLE 22

Summary of costs for DMHRF facilities (ENR 
 5,000)

Construction costs ($)

Construction costs

($/Mgal/d) O&M costs ($/yr)

Capacity

(Mgal/d)

24 gal/

ft^2 /min

16 gal/

ft^2 /min

24 gal/

ft^2 /min

16 gal/

ft^2 /min

24 gal/

ft^2 /min

16 gal/

ft^2 /min

25 3,600,000 4,200,000 144,000 168,000 110,100 113,100

50 5,424,000 6,550,000 108,500 130,900 137,600 142,000

100 9,951,000 12,150,000 99,500 121,500 244,800 254,900

200 16,900,000 20,100,000 84,400 100,200 323,000 334,600

*^ Includes low-lift pumping station, prescreening, and chemical addition facilities; excludes engineering and

administration.

Mgal/d  0.0438 
 m^3 /s.

gal/ft^2 /min  2.445 
 m^3 m^2 /min.

(EPA-600/8-77-014).

For the two full-scale CSO test sites in Racine, capital costs

(including land) were $1,064,000 and $2,132,000 for 54,100-

and 168,000-m^3 /d (14.3- and 44.4-Mgal/d) facilities, respec-

tively (ENR 
 5,000). Construction cost curves (ENR 
 2,000)

for DAF facilities, based on the experienced cost of the demon-

stration facilities, are presented in Figure 14. The operation and

maintenance cost (ENR 
 5,000) of the systems was $0.16/m^3

($0.58/1,000 gal). It was thought that these costs could be reduced

to $0.09/m^3 ($0.30/1,000 gal) by process and procedural modi-

fications as described in EPA-600/2-79-106a. The major reason

for the high O&M cost is the cost of labor for maintenance

of the sites and cleanup of the sites after a system operation.

These costs were $0.10/m^3 ($0.38/1,000 gal), or 65% of the

total. Therefore, maintenance becomes the major cost item in

TABLE 20

Removal of heavy metals by DMHRF

Heavy metal constituent

Cadmium Chromium Copper Mercury Nickel Lead Zinc

Average removal, %* 56 50 39 0 13 65 48

*^ concentration basis.

(EPA-600/2–79–015).

TABLE 21

Design parameters for DMHRF

Filter Media Depth (ft)

No. 3 anthracite 4–5

No. 612 sand 2–3

Effective Size (mm)

Anthracite 2

Sand 2

Flux Rate (gal/ft2/min)

Range 8–40

Design 24

Headloss (ft) 5–30

Backwash

Volume (% of inflow) 4–10

Air

Rate (standard ft^3 /min/ft^2 )10

Time (min) 10

Water

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