Treatment of Strong Organic Waste by a New
High Efficiency Activated Sludge Process
ALFRED B. CHERRY, Vice President
FRANCIS A. SANDERS, President
EDWARD L. GILLETTE, Project Engineer
Betz Environmental Engineers, Inc.
Plymouth Meeting, Pennsylvania 19462
INTRODUCTION
For countless ages, Nature has employed biological organisms in a balanced ecological
system to consume the waste organics produced by other forms of life. However, Mankind's
demographic patterns and activities during the last several hundred years have so changed
the quantity and quality of waste discharges that the natural oxidative capacities of many
waterways were often sorely overloaded. Only lately, in the overall scheme of things, have
remedial steps been developed and actions taken to relieve the overloaded conditions which
exist in and around centers of population.
The process of biochemical oxidation has been one of the principal methods for
stabilizing aqueous organic wastes introduced to natural waterways. Considering the fact
that man-made biological treatment processes are less than a century old, great strides have
been made in a relatively short period of time. Recently, a number of techniques have been
conceived to enhance oxidative biological treatment by optimizing the environment in
which the microorganisms do their work. This presentation discusses experiences with one
of these techniques.
PRIOR STUDIES
Based on a theoretical analysis of the operational parameters of the concentric cylinder
air lift fermentor, L.L. Gasner developed and tested an improved method for transferring
gas to liquid using a "thin channel rectangular air lift mass transfer reactor" (1). The
laboratory work indicated that the thin channel reactor demonstrated improved performance characteristics when compared both to conventional mass transfer reactors as well as
to the concentric cylinder fermentor.
The concept has potential utility in situations where intimate contact, and esepcially
large surface area contact, between a liquid and gaseous medium is a necessity.
Representative processes where this patented concept could be employed are scrubbing,
adsorption, fermentation and waste treatment (2).
Stern, Gasner and Sanders reported (3) their experimental work using the prototype
laboratory scale reactor as a biological oxidation unit for the treatment of a highly
concentrated pharmaceutical waste.
1208