Biological Treatment of Vinegar Plant Wastes
S.K. MALHOTRA, Director
Research and Studies
Williams & Works, Inc.,
Grand Rapids, Michigan
M.J. MILLER, Vice President
Speas Company
Kansas City, Missouri
INTRODUCTION
Speas Company has about two dozen plants in the United States that process apples
for making apple juice, which is fermented to make apple cider and vinegar. The apple
vinegar production also involves production of white vinegar from ethyl alcohol. The
wastewater from such plants during apple crushing season is high in BOD and suspended
solids and has a low pH, whereas the wastewater during off-season (no apple pressing) is
relatively low in suspended solids but high in Bod, and is very acidic.
A number of fruit processing plants have successfully used biological treatment,
lagooning or spray irrigation to treat their process wastewaters. Information on the
characteristics and the treatment of waste from an apple vinegar plant is not available to the
extent that a design engineer can proceed with the plant design without some preliminary
investigations to determine the optimum treatment process and its design parameters.
Since most small food processing plants have wastes with substantial variation in
quality and quantity and contemplate inexpensive treatment, one of the most popular
methods of waste treatment for such plants in the past two decades has been lagoons in one
form or another. Lagoons hold the wastes for a designated period of time,during which the
treatment is accomplished due to biological degradation and utilization of organic matter
by the microorganisms. The low pH of the waste due to the presence of vinegar (acetic acid),
the use of aerobic fermentation to convert apple juice to vinegar, and the odor nuisances
associated with anaerobic lagoons all suggested the use of aerobic treatment for laboratory
investigations.
The purpose of this study was: I) to obtain adequate information on the vinegar
production process and process wastes; 2) To determine the characteristics of vinegar plant
wastes; and 3) To study the feasibility of aerobic biological treatment and to determine the
optimum biological treatment process for vinegar wastes.
It was intended that the results of this study would aid similar industry in evaluating
biological processes for the proper disposal of their wastes.
Figure 1 presents the simplified flow diagram of the processes involved in the
production of vinegar.
From mid-September to the end of November, fresh apples are trucked to the plant.
They are washed and crushed. Apple slurry, which consists mainly of peels and cores of
apples, is also brought from apple sauce plants. This supply of apple slurry lasts until the
end of February, which marks he end of the season for the applesauce plants. The Speas
Company plants processed about 50 percent fresh apples and 50 percent peels and cores
during this study.
Apple slurry is mixed with "Silvacell," which is a trade name for rice shells. This
material facilitates the pressing of the slurry for the extraction of apple juice. Belt and
hydraulic presses are used. The oil leakage from the hydraulic presses is the main source of
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