Anaerobic-Aerobic Treatment of Septage
(Septic Tank Pumpings)
J.J. KOLEGA, Associate Professor
B.J. COSENZA, Consulting Microbiologist
F.S. CHUANG, Post-Doctoral Fellow
J. DHODHI, Research Assistant
Department of Agricultural Engineering
the University of Connecticut
Storrs, Connecticut 06268
INTRODUCTION
This paper presents one phase of a three-year interdisciplinary study, financed in part
by the Environmental Protection Agency Water Quality Office under Grant No.
17070DKA, on the subject of septic tank pumpings and which hereafter will be referred to
as septage. The usage of the term septage refers to the mixed liquid and solid contents
pumped from septic tanks and dry wells receiving domestic type sewage.
Initially, the study was involved with the identification of some of the physical,
chemical and biological characteristics of septage followed by the investigations dealing
with the handling, treatment and septage. A rather broad base was taken to problem
solving. It was recognized that the factors such as population and residential density, the
number of homes on septic tank systems, public attitude and local community financial
outlooks, along with the availability of state and federal funds contribute to the community
decision-making process as to the selection of the final treatment systems most siutable for
septage disposal. Therefore, there is no overall solution to the septage disposal problem.
Instead there are perhaps three broad categories:
I. Water pollution control facilities:
If properly designed, and available, this should be given serious consideration as
the number one solution.
II. Land disposal:
This is the extreme of the solution already indicated in Category I. The solutions
range from the undesirable excavations in the ground, pits or trenches to
accommodate the community's urgent need for immediately solving a septage
disposal problem to a more sophisticated approach and outlook whereby the
land serves as a vehicle for nutrient recycling and ultimate mineralization.
III. The specialized treatment process:
With current technology, a specialized treatment process can be developed to
adequately treat septage. Acceptance of this process by a community will be
contingent upon initial cost, operating cost, system maintenance requirements
and the ability of the treatment process to be trouble-free and be capable of
meeting present day water quality discharge standards.
For the Connecticut study, the anaerobic-aerobic process was selected as the
specialized process for the treatment of septage. Factors which were considered in its
selection were: 1) The variability of trucked septage loads; 2) The frequency at which
trucked septage loads are received; 3) The quantities of septage being pumped in different
areas; 4) The process controls required for system operation and maintenance; and 5)
Possible cost considerations relative to other alternatives.
894