Section Seven
INDUSTRIAL WASTES
B. FOOD WASTES
60    THERMOPHILIC ANAEROBIC DIGESTION
OF COFFEE WASTEWATER
Jelte Lanting, Environmental Engineer
Jill A. Jordan, Environmental Scientist
Michael T. Schone, Biochemical Engineer
BIOTHANE Corporation
Camden, New Jersey 08104
Arthur Kull, Vice President
Walter W. Carey, Director
Brian L. Kitney. Environmental Specialist
Nestle Foods Corporation
Purchase, New York 01577
INTRODUCTION
During the past few years Nestle Foods and BIOTHANE have studied the anaerobic treatability of
wastewater from several of Nestle's production facilities. Nestle Foods is an international corporation
with production plants worldwide, and makes products ranging from chocolate to freeze dried
coffee.
Freehold, New Jersey is the site of one of the largest freeze dried coffee plants in the United States.
This plant generates about 200,000 gallons of wastewater daily. The present wastewater treatment
plant consists of a primary clarifier followed by a 2.5 million gallon aerated lagoon and secondary
clarifier. The effluent of the existing wastewater treatment plant is discharged to a municipal treatment facility for further and final purification. Nestle was interested in anaerobic pretreatment
because of space, energy, and sludge disposal considerations.
The work on coffee wastewater started in 1985 using a skid mounted pilot plant which incorporates
a 6 cubic meter BIOTHANE UASB reactor. After several pilot projects at other Nestle facilities the
work at Freehold resumed early in 1987 using a glass 10 liter pilot reactor, and continued until
December of that year. The treatability of coffee wastewater was studied under both mesophilic
(±35°C) and thermophilic (±55°C) conditions.
We will present operating data from four pilot trials, and offer some hypotheses regarding the
operational behavior of the anaerobic treatment process when treating coffee wastewater.
LITERATURE REVIEW
Calzada et al1 reported on the anaerobic treatment of coffee pulp juice. In a single stage digester
stable performance was achieved at a volumetric load of 1.3 gram volatile solids per liter reactor
volume per day (gVS/L/d). In a two stage digestion process stable performance was possible at a
loading of 2.1 gVS/L/d and a hydraulic retention time of 5 days. It was noted that treatment of
undiluted pulp juice resulted in digester failure.
Rolz et al2 probably refer to the same reactor when they reported that a mesophilic system had been
in operation at the Central American Research Institute for Industry (1CAITI). Typical performance
characteristics were a HRT of 10 days, a biogas production of 0.5 to 1.0 liter per liter reactor volume
43rd Purdue Industrial Waste Conference Proceedings, © 1989 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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