Page 443 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

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

best method to clean it was to scrape the surface layer, wash it, intake was under the influence of the floodtide and so was
and replace it at intervals. subject to some degree of sewage transport to the intake. The
intake for Altona’s water supply was also from the Elbe River,
13.1.3.1 James Simpson and the Start of Slow Sand downstream from Hamburg and downstream from the com-
On January 14, 1829, a 1 ac slow sand filter was put in operation bined sewage discharge. Hamburg had no treatment at the
at Chelsea on the north bank of the River Thames (Baker, 1948, time of the outbreak while Altona had slow sand filtration. As
pp. 99–113). The Chelsea slow sand filter was the first success- noted, Altona had installed slow sand filtration in 1860 and
ful technology for municipal filtration. Its design became Hamburg followed in 1893, just after the cholera outbreak.
the basis for developing a practice of slow sand filtration The two cities were a part of a contiguous metropolitan area
that spread to other countries in Europe and then to the and the only difference was that the water supply systems
3
United States. The 1 ac filter produced 8,250–11,300 m =day were separate. The case became a classic in demonstrating the
value of filtration, to wit (Cosgrove, 1909, p. 111):
(2.25–3 mgd), with associated 0.09 HLR 0.12 m=h (2.25
HLR 3 mgad).
James Simpson, engineer for the Chelsea Water Works To use Professor Kochs own words: ‘Chlorera in Hamburg
Company, had worked out the design of the Chelsea filter went right up to the boundary of Altona and then stopped. In
based on knowledge of various filtration attempts and on one street, which for a long way forms the boundary, there
operation of a pilot filter. At the age of 24, James Simpson was cholera on the Hamburg side, whereas on the Altona side
(1799–1869) was appointed engineer for the Chelsea Water was free from it, and yet there was only one detectable
difference, and one only, between the two adjacent areas–
Works Company and at 26 was elected to the Institution of
they had different water surfaces.’
Civil Engineers.
13.1.3.2.3 Worldwide
13.1.3.2 Evolution of Practice
While Europe, including Great Britain, was where slow sand
From its start in London, the slow sand technology spread to
grew to its greatest extent, there was some diffusion to the
continental Europe and, finally, in 1872, came to America.
United States, Canada, South America, and Asia. Table 13.1
The basic technology has remained unchanged from the pilot
summarizes the installed capacity of slow sand filtration,
filters of James Simpson.
worldwide in 1900 as compiled by Allen Hazen in his 1913
13.1.3.2.1 London book, The Filtration of Public Water Supplies. The installed
capacity of continental Europe was about the same as Great
With the experience of the Chelsea filter, the health benefits of
Britain, with not too much in South America and Asia and
filtered water became apparent, and in 1839 the city’s five
only a modest amount in North America.
commercial suppliers began filtering their water. Then, in
The slow sand technology has been disseminated to less
1852, the London city government required filtration prior to
developed countries, that is, in Asia and Africa by the Slow
public sale, and later established the Thames Conservancy
Sand Project of the International Reference Centre for Com-
Board to regulate potable water quality (Hazen, 1913). By
munity Water Supply and Sanitation (IRC). Raman et al.
1894, five successive increases in area had occurred for the
(1981, p. 44) reported that in the Haryana State, India, about
Chelsea filters and the total surface area was 47 ha (116 ac), 100 slow sand plants were in operation for both urban and
3
producing 890,000 m =day (234 mgd). In 1977, the filter area
village supplies. In Thailand, the influence of IRC had
was 72 ha (178 ac), with zero-coagulation rapid filters or
resulted in numerous village scale slow sand plants. Sympo-
microstrainers preceding the slow sand filters (Poynter and
siums on the topic (Graham and Collins, 1988, 1996) have
Slade, 1977, p. 75). The slow sand filters numbered eight in helped to update the body of knowledge and applications
3
1988 treating 2 million m =day (530 mgd) (Rachwal et al.,
among persons active in the field. The U.S. Environmental
1988, p. 331). This ‘‘double filtration,’’ that is, zero-coagula-
Protection Agency started to revive slow sand under the
tion rapid filters followed by slow sand, became prevalent
guidance of Dr. Gary Logsdon, who along with several others,
over much of western Europe.
has continued to infuse the technology into practice (see, for
13.1.3.2.2 Continental Europe example, Logsdon, 2008).
From the example of the Chelsea filters in London, continen-
tal Europe began filtering public water supplies by the 1850s, 13.1.3.2.4 America
with installations and dates as follows: Berlin, 1856; Altona, The first slow sand filter in the United States was at Pough-
1860; Zurich, 1884; Hamburg, 1893; Budapest, 1894 (Hazen, keepsie, New York (1870 population 20,000), and began
1913). The health benefit of slow sand filtration was demon- operation on December 1, 1872 (Baker, 1948, pp. 148–158).
strated dramatically by the 1892 cholera epidemic in port city The engineer identified with the project was James P.
of Hamburg (population 640,000) which caused 8605 deaths Kirkwood (1807–1877), perhaps the most eminent sanitary
(Cosgrove, 1909, p. 112). By contrast, the adjacent City of engineer of the time (and the second president of the Ameri-
Altona (population 143,000) had only 323 deaths. The water can Society of Civil Engineers). The source water for the filter
intake for Hamburg was from the Elbe River upstream from was the Hudson River, deemed by the chief engineer for the
the combined sewage discharge of the two cities, but the city, J. B. G. Rand, as a polluted source; also the Hudson was