Page 494 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Cake Filtration 449

(a) (b)
t
FIGURE 14.15 Stainless steel pilot plant provided by Johns-Manville (now Celite ) c. 1985. (a) Pilot plant pressure vessel and (b) pilot
plant with instrumentation.

14.5.2.2 100 Mile House, British Columbia etc., the annual costs were compared. The pilot plant studies
In 1981, the Village of 100 Mile House, 1984 population of provided a basis for estimating energy and labor costs, and
about 2075, experienced an epidemic of giardiasis; their water generated data on effluent turbidities.
supply from Bridge Creek, an outlet from Horse Lake with
turbidity <2 NTU and not filtered, was implicated since 14.5.2.2.1 Pilot Plant
beaver and muskrat inhabited the watershed. The peak-day Figure 14.16 shows the pilot plant located at 100 Mile House,
demand was estimated as 3.30 mL=day (0.87 mgd) for 1984 British Columbia. Figure 14.16a shows the pilot plant with
and 6.67 mL=day (1.76 mgd) for 2002 with projected popu- pre-coat tank, body-feed tank and pumps, all skid mounted, as
lation 4200. Minimum demands for 1983 were about 0.2–0.3 set up at the field site. Figure 14.16b shows the pressure
of the peak demand with an average day demand of about half vessel=septum assembly. As seen, each septum is a ‘‘leaf’’
of the peak day. In 1983, the Village engaged their consulting with two sides; the interior has a structure to support the
engineer, Dayton & Knight, Vancouver, British Columbia, to septum mesh in order to withstand the pressure with minimum
recommend a course of action. Subsequently, Dayton & deflection.
Knight embarked on a pilot plant study that compared filtra-
tion alternatives, that is, rapid filtration package plants (both 14.5.2.2.2 Results and Discussion
gravity and pressurized), slow sand, and diatomite. Based In the pilot plant study, the consultant for the village
upon estimates of capital costs, cost of labor, cost of energy, examined rapid filtration (a package plant), slow sand, and

(a) (b)
FIGURE 14.16 Diatomite pilot plant at 100 Mile House, British Columbia. Unit is Type 122, Industrial Filter Mfg. Co., Cicero, Illinois,
2
2
with four stainless steel leaves, septum area 0.93 m (10 ft ). (a) Field setup showing appurtenances and (b) pressure vessel and septum
assembly. (Courtesy of Dayton & Knight, Ltd., Pilot water treatment program, Village of 100 Mile House, Report for Client, Dayton &
Knight, Ltd., Consulting Engineers, West Vancouver, British Columbia, December 1983.)