Page 145 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

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

BOX 6.2 HAZEN AND CAMP
v H v H
Allen Hazen (1869–1930) was one of the early sanitary
engineers who started at the Lawrence Experiment Sta- Inlet zone v H v H Outlet zone
tion in Massachusetts, c. 1890–1892. He was a prolific
contributor to the advancement of the field with well- v H v H
known books, such as The Filtration of Public Water
Supplies (John Wiley, London, U.K., 1913), and
Top view
numerous papers. His 1904 paper marked the beginning
of the modern sedimentation theory with the notion that L
basins should be shallow. In this paper, in Proposition
v
14, he describes what, essentially, was the plate-settler H
concept that came into practice about 1970. Hazen went Inlet zone D Settling zone v H Outlet zone
into consulting in 1895, forming the firm Noyes &
Hazen, which became Hazen & Whipple in 1904, v H
Hazen, Whipple & Fuller in 1915, and Malcolm Pirnie Sludge zone
in 1930; the latter name remains current (from Malcolm
Side view
Pirnie, Inc., c. 1995).
FIGURE 6.6 Ideal rectangular settling basin. (From Camp, T.R.,
Trans. ASCE, III, 895, 1946.)

Figure 6.7 shows that those particles being translated at
velocity, v H , starting at the top of the water surface and falling
at velocity, v s ¼ v o , will reach the bottom at depth, D, within a
basin length, L. Thus, by similar triangles

D
v o
(6:8)
¼
v H L
Allen Hazen. (Courtesy of Malcolm Pirnie, White Plains, NY.)
In 1916 Thomas R. Camp received his BS degree from where
Texas A&M; he served in the U.S. Army 1917–1919, v o is the overflow velocity (m=s)
and in 1925 was awarded an MSCE degree from MIT. In v H is the horizontal velocity (m=s)
1932, he was appointed associate professor of Sanitary D is the depth of settling basin (m)
Engineering at MIT. At MIT, he started research in the L is the length of settling basin (m)
field of sedimentation. At that time, Hazen’s ideas had
Moving v H to the right side and recalling, v H ¼ Q=wD,
been discussed but not assimilated; and so practice had
gives
remained largely empirical. In general, Camp’s papers
were ‘‘classics’’ (ASCE, 1973) characterized by identi-
fying principles and demonstrations on how to apply D
them to practice. In 1947, Camp resigned his professor- v o ¼ L v H (6:9)
ship at MIT to start the firm, Camp Dresser and McKee.
D Q
(6:10)
¼
L wD
Therefore, the overflow velocity, v o ,is

Q
(6:11)
v o
wL
where
w is the width of the basin (m)
3
Q is the flow through basin (m =s)
Thomas Camp. (Courtesy of Camp Dresser and McKee,
Boston, MA.) The term, ‘‘overflow velocity,’’ v o , is also termed, ‘‘surface
overflow rate’’ (SOR). These terms are used interchangeably