Ozonated Treatment of Wastes
Containing ABS
F. L. EVANS, III, Graduate Student
D. W. RYCKMAN, Director
Environmental and Sanitary Engineering Department
Washington University
Saint Louis, Missouri
INTRODUCTION
The problem of syndets is becoming more acute as production continues to
increase (1), and the technology of their removals from water does not keep pace
with expanded usage. The effects of detergents are rapidly compounding due to
the fafiure to remove them and the increasing discharges of detergent-laden
waters, which results in a continuous build-up of concentrations. The resulting
"frothing" in streams, and even in domestic drinking water supplies, is attracting
national attention through the public press.
The major portion of the synthetic detergent production in the United States
consists of the anionic alkylbenzene sulfonate (ABS) class, which is highly resistant to biodegradation under both natural and accelerated waste-treatment plant
conditions.
In 1948 only 16 per cent of the soap and detergent market was accounted for
by synthetic detergents (2). Detergents now command 77.4 per cent of the total
market (3,4), and the marketed products amount to 3.5 billion lbs (1,2) annuaUy.
The predominant surfactants, as shown in Figure 1 and which account for 70
per cent of the market, are those of the anionic group. In 1960, the production
of anionic surfactants was 1.074 billion lbs, nearly two and one-half times as
much as all the other surfactants put together. Their primary application is in
the household synthetic detergent market, which produces 80 per cent of the
surface-active agent market (1,5). In addition, more than half the production of
anionics is accounted for by sulfonated alkylbenzene compounds alone.
It has been reported (6) that the majority of identifiable refractory contaminants of secondary sewage-treatment plants was clearly recognizable as ABS. In
addition, the persistence of these refractories was specificaUy related to the presence of the anionic surface-active alkylbenzene sulfonate. Persistence beyond a
waste-treatment plant has been demonstrated by ABS measurements in natural surface waters (7), which averaged 0.5 mg/1. On occasions ABS in surface waters
has measured as high as 12 mg/1 (8,9). Ground water contamination by ABS has
been experienced in Wisconsin (10), Minnesota (11), and New York (5). Frothing
tap water, as experienced in Suffolk County, New York (12), was attributed to
cesspool contamination of the well supply. The association of poUuted water with
ABS contamination has been strongly made (10,12,13). The Advisory Committee
on Revision of USPHS Drinking Water Standards has recommended for the 1961
Standards a limit of 0.5 mg/1 ABS in drinking water supplies (14).
PROBLEMS ASSOCIATED WITH ABS
The problems of detergents are many faceted. Their effects on water treatment have been assessed by many workers dealing with problems of coagulation
(15,16,17,18,19),   and tastes and odors (9,16,20).   One-tenth mg/1 sodium tri-
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