Page 474 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Cake Filtration 429

14.1.4.2 1950s’ Adaptation of DE for Municipal Use
BOX 14.2 RAY MCINDOE
Based upon the success of the U.S. Army in adopting
A person who was a major force for diatomite filtration diatomite for drinking water for field use, a plant was con-
during the 1970s and the 1980s was Ray McIndoe, structed in 1949 as a standby supply for Gasport, New York,
Marketing Manager, Johns-Manville Corp. McIndoe a community with a population of about 800 (Baumann
was associated with a diatomite filtration primer et al., 1965). Then during the period 1950–1960, nine DE
(McIndoe, 1969b) and was the driving force in its 1988 plants were installed along the Saginaw–Midland pipeline in
update. He was always ready to go the ‘‘extra mile’’ in Michigan. The smallest plant had one filter with a septum area
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helping to facilitate the adoption of diatomite, whether of 4.18 m (45 ft ) serving 120 persons and the largest had nine
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at a small plant serving 200 persons or in being called filters with a total area of 141.4 m (1522 ft ) serving 5000
out of retirement, c. 1989, to supervise the operation of persons (Vander Velde and Crumley, 1962, p. 1495). By 1969
a 1.0 mgd pilot plant for New York City. Alan Wirsig, an there were some 130 municipal installations with sizes of 38 <
associate of McIndoe at Johns-Manville, remained in the Q(plant) 38,000 m =day (0.010 < Q(plant) 10 mgd)
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field as a consulting engineer after his 1982 retirement at (McIndoe, 1969a, p. 50). By 1983 some 170 plants had
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Johns-Manville. They are shown while operating a pilot been built, most in the 3,800–38,000 m =day (1–10 mgd)
plant setup at a field site in northern Colorado, c. 1985 category, with the largest being 76,000 m =day (20 mgd)
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(McIndoe and Wirsig, left to right). at San Gabriel, California (McIndoe, 1983, p. 1) and with
47 plants in New York.
14.1.4.2.1 New York City
In 1979, two consulting firms engaged by the City of New
York (i.e., Metcalf & Eddy and Hazen and Sawyer) proposed
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a 610 10 m =day (160 mgd) ozone-DE plant for treatment
of the Croton water supply (Bryant and Brailey, 1980). An
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11,355 m =day (3 mgd) pilot plant was to have been built first
to provide design criteria for the larger plant. As a note, in
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1980, 610 10 m =day (160 mgd) was the average daily use
of water from the Croton watershed, which had a ‘‘safe yield’’
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of 910 10 m =day (240 mgd). The drainage area was
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2400 km (380 mi ) on the eastern side of the Hudson River
in Dutchess, Putnam, and Westchester counties, with a
permanent population in 1980 of 100,000. Turbidity averaged
1–2 NTU with color about 15 units. The site of the proposed
DE plant was at the 35 ha (85 ac) Jerome Park Reservoir, in
the Bronx, near the northern border of New York City, which
than the sand filtration then available. Effective removal of is the terminus for the aqueducts of the Croton system. Bulk
E. hystolytica cysts (15 mm) was a specific objective (Lowe deliveries of DE would be removed from railroad cars, slur-
et al., 1944). In the Pacific and India–Burma–China theaters ried, and pumped to day tanks from a site approximately
of war, for example, E. Hystolytica was endemic in the popu- 900 m (3000 ft) from the plant. Pretreatment would be bar
lations and the strains were particularly virulent (p. 16). Thus, screens and traveling fine screens. The water would then be
there was a strong impetus for an adequate treatment technol- pumped through variable speed pumps to 48, 2 m (80 in.)
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ogy and the need was considered immediate. The other diameter, 140 m (1500 ft ) septum area DE filters arranged in
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objective was portability (Black and Spaulding, 1944; Lowe 12 clusters with HLR(max) 6.12 m=h (2.5 gpm=ft ). The
et al., 1944). relatively small size of the proposed system and the prospect
Relative to the foregoing background, in 1943 (April– of reclaiming filter media were major motivations for the
August) the U.S. Army, in collaboration with the U.S. Public selection of DE (Spenser and Collins, 1995, p. 72).
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Health Service, conducted a series of experiments to test both The planned 11,355 m =day (3 mgd) ozone-DE pilot plant
their U.S. Army Portable Water Purification Unit Model 1940 was constructed and operated during the period c. 1988–1990
(pressurized sand filter with alum and soda-ash feed) and to determine criteria for a full-scale 1100 ML=day (300 mgd)
eight systems that utilized diatomaceous earth. The test units plant. The pilot plant effluent produced a finished water tur-
were seeded with a large numbers of cysts, for example, bidity of <0.1 NTU and color <2 units (Parmelee, 1990,
hundreds of thousands or millions. The outcome of the experi- p. 1). To filter the Croton water supply, the DE process was
ments was that all grades of DE tested, even Celite 545, recommended for several reasons: (1) diatomite filtration
resulted in passage of zero cysts, albeit the latter was less equipment had a relatively small ‘‘footprint,’’ which was
effective in removal of turbidity. In addition, a technology important in the location selected, that is, the densely devel-
was at hand, for example, diatomite manufacturing, septum oped Bronx; (2) the operational flexibility, that is, to use
designs, tank, and operating protocol. the Croton supply only in times of drought or high demand;