Page 378 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Rapid Filtration 333

BOX 12.1 FULLER
George Warren Fuller and Allen Hazen were ‘‘alumni’’
of the Lawrence Experiment Station in Massachusetts.
For the Louisville experiments, Fuller led a team that
included Robert Spurr Weston and George A. Johnson,
who also became prominent in the field. Fuller, a legend
in the field, was president of the American Water Works
Association in 1923 and is known also by an award in
his name. He had a successful consulting practice and
was candid in his assessments of a client’s needs. An
example was his review of his engagement by
New York City to draw up plans for a filtration system.
In a paper (Fuller, 1914), he criticized the decision by
the City not to proceed. Appendix 12.A reviews the
New York case. FIGURE 12.5 George Warren Fuller, c1930. (Courtesy of
In his report, The Purification of the Ohio River American Water Works Association.)
Water at Louisville, Kentucky, D. Van Nostrand, New
York, 1898, Fuller’s remarks demonstrate that even at
necessary to reduce the solids load to the filters, (5) less
the time he understood the complexities of the filtration
surface area was required as compared with slow sand.
process and that every situation is unique.
By 1898, Fuller (1898, p. 10) estimated that 100 rapid rate
While much careful attention has been given to the
filter systems were in place. He pointed out that slow sand
art of water purification for more than 60 years, the
filtration never got a firm start in the United States, first
general solution of the problem on a practical basis for
because water-borne epidemics were not in evidence, as in
large cities is, however, far from satisfactory or com-
Europe, and by the time that filtration may have been con-
plete at its present stage of development. This is due
templated, the rapid filtration technology was being devel-
partly to varying effects of the adopted processes with
oped. Fuller noted also (p. 10) that alum addition (patented in
different natural waters, partly to the lack of a widely
1884) was a distinguishing feature of rapid filtration, as was
practical and scientific understanding of the influence of
the development of a successful backwash operation. Alum
a number of factors of the processes themselves, and
addition to coagulate water had been practiced, he stated, in
partly to the great cost involved in the construction of
various ways for many centuries, with its description in the
adequate filtration works.
scientific literature starting about 1830.
In his report, he reviewed slow sand filtration starting
Fuller was the President of the American Water Works
in 1829 in London. Based on this review, he referred to
Association in 1923. Figure 12.5 is a photograph of George
the slow sand filters as ‘‘English’’ filters which was
Warren Fuller. He was a prominent personality for four dec-
done to distinguish them from the ‘‘American’’ filters
ades and is given credit for launching the modern practice of
which were those that had alum addition and backwash
rapid filtration.
to remove accumulated material, which as Fuller noted,
were the distinguishing features of the latter.
12.2.2 EMERGENCE OF FILTRATION PRACTICE
By about 1900, a generic practice in rapid filtration began
mud suspended in it, and the mud and clay which it did to emerge. First, patents of proprietary systems were expiring,
contain were formed into flakes of sufficient size to allow a which would make less clouded the development of a
very rapid flow of water through the sand layer, with satisfac- generic technology and practice. Second, the private com-
tory results. The claim that this method of water purification panies had expended much of their working capital in litiga-
was more economical for the Ohio River water than those tion and competition (Fuller, 1933, p. 1571). The first generic
practiced in Europe was based on the assertion that compara- plant, designed by Fuller, was the Little Falls plant of the
tively small amounts of sulfate of alumina permitted a very East New Jersey water company, placed in service in Septem-
great reduction in the necessary area of filtering surface. ber 1902.
Several points are important: (1) the alum addition The Little Falls plant did not, however, lead to the sudden
depended on the raw water quality, (2) lime was considered emergence of a generic technology. Evidence of this is seen in
a part of coagulation (alkalinity was recognized later as the Fuller’s description of his filtration system design for
important constituent), (3) the term ‘‘coagulation’’ was used in New York (see Appendix 12.A). He explained to a critic,
the current sense, (4) settling of coagulated water prior to Mr. Alexander Potter, that he recommended slow sand in his
filtration, with ‘‘passive’’ flocculation, was recognized as 1907 report because only two rapid filtration systems had