Brewery Wastes As A Carbon Source
For Denitrification At Tampa, Florida
THOMAS E. WILSON, Principal Engineer
DONALD NEWTON, Partner
Greeley and Hansen, Engineers
Chicago, Illinois 60606
INTRODUCTION
The City of Tampa, Florida, has been ordered by the Florida Department of Pollution
Control to remove 90 percent of the suspended solids, BOD5, nitrogen and phosphorus
from its municipal wastewater before discharging it into Hillsborough bay. The process
selected for removal of nitrogen is two-stage oxygen activated sludge nitrification followed
by denitrification on deep bed filters. The process flow sheet for the proposed 60 mgd plant
has been described elsewhere (1,2). The denitrification process requires the presence of an
electron donor (organic carbon source). It has been shown (3) that methanol may be the best
organic carbon source commonly available. However, this conclusion was based on the
assumption that the organic carbon source would have to be purchased and that the
fraction of the source used for production of cellular matter is best minimized.
Since the cost of methanol is a major part of the total denitrification cost and since the
consumption of methanol results in depletion of natural resources (4) it was felt that
alternative organic carbon sources should be sought.
Three basic considerations were used to guide in the selection of an alternative
organic carbon source: 1) the material should be a waste product, 2) the material should
have a low nitrogen content, and 3) it should be available in large enough quantities to be of
use. The waste streams from two large breweries, located in Tampa, appeared to meet these
qualifications. These breweries currently discharge their wastes into the municipal sewer
system and constitute a significant portion of the anticipated organic loading on the
proposed wastewater treatment plant. Thus not only was there an opportunity to reduce
chemical (methanol) costs but also there appeared to be a possibility of significantly
reducing the BOD5 loading to the new municipal plant.
In May of 1972, a two-phase investigative program was initiated. The first phase
consisted of laboratory experiments to determine the feasibility of using various waste
streams from within each plant. Other investigations (5,6) had indicated that the strength of
the total waste stream from breweries, while high in BOD5, may be too low to permit
practical use of it as a chemical feed source. These same references indicated that various
individual waste streams, isolated within the plant, did contain sufficiently high BOD5
levels to be considered. Thus the laboratory work centered on identifying which of the
streams would be of value.
The second phase of the program consisted of using a mix of the brewery wastes in a
pilot system which was being used to evaluate the overall process concept. In this phase of
the program, two similar deep bed filters, one using methanol and one using brewery
wastes, were used, in parallel, to treat a nitrified pilot plant effluent.
LABORATORY STUDIES
Six different waste streams from the two breweries, Anheuser-Busch, Inc. and Joseph
Schlitz Brewing Company, were evaluated. These were chosen, in general, as the sources
containing the highest BOD5 and most likely to be amenable to recovery for use as methanol
substitutes. These laboratory studies were performed on both a batch and continuous flow
basis in order to investigate the following:
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