24    APPLICATION OF THE BATCH ACTIVATED SLUDGE
PROCESS
Stephen R. Tate, Associate
W. Wesley Eckenfelder, Jr., Technical Director
AWARE Incorporated
Nashville, Tennessee 37228
INTRODUCTION
This paper presents a case study in the application of the batch activated sludge process. This
particular application of this technology is somewhat unique in that it was instituted in place of a
completely new physical/chemical treatment facility which was found to be incapable of meeting the
permit requirements. To complicate the situation, the POTW to which the plant discharges was under
consent order and absolutely could not permit excursions beyond specified limits. Plant shutdown
was threatened. Although not uncommon to the consulting business, the project carried with it an
almost impossible time constraint.
The general scope of the project was to perform wastewater treatability evaluations for development of an upgrade alternative for their existing wastewater treatment system. The major objectives
of the study were the following.
• Develop a short-term solution for the plant upgrade
• Develop the short term solution such that a system retrofit, e.g., use of existing tankage,
pumps, can be readily accomplished
• Develop sufficient data in the laboratory testing, and subsequent short term system
operation, such that a long term solution can be both defined and permanently implemented
• Develop, design, and construct the necessary fix within 60 days
BACKGROUND INFORMATION
The new physical/chemical plant was intended to replace existing aerated lagoons. This is because
the aerated lagoons had developed a history of violating the permit conditions for BOD and TSS
during the winter months due to a dramatic decrease in biological activity. To initiate the study,
historical waste load and treatment records for the aerated lagoons were evaluated. It was evident
from the data that the wastestream was biodegradable, high strength, and low volume. Table I
presents the average flow and waste load considered appropriate for design. Additionally, the existing
treatment system facilities were inspected and evaluated with.regard to tank capacities, piping and
pumping capability, operational flexibility, and ease of retrofit.
Based on these evaluations, it was determined that the batch activated sludge process was appropriate for treatability evaluations. This process has been found to be applicable in installations where the
wastewater is low volume, high strength (in terms biochemical oxygen demand), and readily degrad-
Table I. Design Flow and Waste Load
Parameter Value
Flow (average) 25,000 gpd
BOD5 7,000 mg/L
(1,460 lb/day)
TOC 4,800 mg/L
TSS 150 mg/L
pH 8-10 std units
MBAS 600 mg/L
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