Page 771 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

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

BOX 23.1 ERMAN PEARSON
was a lucid exposition of activated-sludge reactor the-
Anaerobic treatment has had fewer adherents than has ory incorporating Michaelis–Menten kinetics with
activated-sludge. While the latter had the proverbial thou- materials-balance, showing derivative parameters such
sand papers by the 1970s the anaerobic field just started to as substrate removal velocity, U, sludge age, u c , net
flower in the late 1950s. The anaerobic process is more growth rate, and nutrient removal. I asked him how he
complex and requires a great deal of persistence; every- got into activated-sludge theory. He remarked that when
thing is more difficult. One of a handful of academics who he was invited to lecture on the topic at Texas and
pursued this field, along with a number of able graduate started preparing he saw that ‘‘everyone had been flying
students, was Professor Erman Pearson (1920–1985). in the wrong direction.’’ His paper was to ‘‘try to set
Iknew him first in 1953 as an undergraduate student in things straight.’’ The statement illustrated both his sense
two of his courses; he was always well prepared and of humor and, most likely, his frank assessment. The
articulate and transmitted volumes of basic and lasting texas paper had outlined the basics of modern theory,
knowledge on water supply and sewerage. As under- and was a culmination of research that started with
graduates we did not know of his other life as a researcher Andrew Gram in 1956, but with most of his doctroal
and as a leader in the field. I became familiar with these students working on anaerobic topics. The transition to
aspects in 1965 after getting my doctorate. The first thing activated sludge theory was not an issue since the prin-
I learned was that with Harvey Ludwig and about 20 ciples of biological growth and reactor theory are com-
professors, he was the instigator and first president of mon to both aerobic and anaerobic treatment.
Association of Environmental Engineering and Science In addition to his research and leadership roles, he was
Professors (AEESP), formed in 1963. As with all of his a noted consultant and advisor to the State of California,
compatriots, he had a presence when in a room, due to his which had advanced programs in pollution control.
size, his wit, and his incisive remarks. About the same Although teaching itself has not too much recognition,
time, 1960, he was helping to form what is now the he was a dedicated to this role, for both undergraduate
International Water Association (IWA). The first biennial and graduate areas. The field of environmental engineer-
conference was in London in 1962, the second in Tokyo in ing has had, perhaps, more than its share of outstanding
1964, the third in Munich in 1966, and the fourth in professionals, many who were and are known for their
Prague in 1968. Professor Pearson followed Professor own unique character traits. Professor Pearson stood out
Eckenfelder as its third president, 1966–1968. as a professional and as a personality.

23.2.2.1 Materials Balance
A materials-balance statement for a reactor is merely a way to
account for all the happenings within its volume (see also
Chapter 4). The general statement is
accumulated net changes
¼ materials inflow materials outflow

þ rate of production or depletion of material
within the reactor: (23:2)

The material being accounted for may be anything of
Professor Erman Pearson, c.1960. (Courtesy of Department of
interest. For the case of activated sludge, the materials of
Civil and Environmental Engineering, University of California,
interest are substrate and cells.
Berkeley, CA.)
Procedure. The basic technique of analysis is to (1) sketch the
The first issue of Water Research, 1(1), January
system being analyzed, (2) draw a circle around the portion of
1967 lists the governing board members, with an edi-
the system of interest, and (3) write a materials-balance equa-
torial by Pearson. Dr. Samuel H. Jenkins was one of the
tion for the portion circumscribed.
founders and the executive editor. Professor Ecken-
felder and a number of academics from countries world- Homogeneous volume. The most important concern in
wide were also founders. applying Equation 23.2 is that the contents of the volume
One of Professor Pearson’s seminal contributions being analyzed must be homogeneous. If the volume being
was a 1967 paper at a University of Texas lecture series, considered is not homogeneous, then it must be broken down
later published in a book (Pearson, 1968). His paper into homogeneous subunits. Or, for the purposes of an analy-
sis, it is assumed to be homogeneous.