67    ANAEROBIC TREATMENT OF A BEEF PROCESSING
PLANT WASTEWATER:
A CASE HISTORY
Craig R. Kostyshyn, Technical Services Manager
William A. Bonkoski, President
Jan E. Sointio,Technical Manager
AC BIOTECHNICS, INC.
West Woodbury, New York 11797
INTRODUCTION
Anaerobic biological wastewater treatment is a process by which the biodegradable organic pollutants (BOD) in an industrial wastewater may be biochemically converted into methane and carbon
dioxide gases by microorganisms held under conditions excluding free oxygen (anaerobic). Some of
the advantages of this treatment process over conventional aerobic biological methods include dramatically reduced operating energy needs due to the elimination of a continuous oxygen supply
requirement, a far lower excess sludge production and corresponding reduction in nutrient requirements due to lower anaerobic bacterial growth rates, and the potential for a net energy production
realized through the utilization of the high grade biogas fuel produced by the process.1
The ANAMET system, and the associated anaerobic contact process, have been researched and
developed by AC Biotechnics (ACB) -formerly AB Sorigona -for over 15 years2 and ACB is an
acknowledged world leader in the full-scale proprietary application of this technology.3
Packerland Packing Company (PPC) operates a high-volume beef processing/rendering plant in
Green Bay, Wisconsin. At processing levels of 2300 head/day the plant produces approximately 10274
kg BOD5 with 8221 kg suspended solids in 3050 mVd of raw wastewater. By 1984 the high costs for
chemicals required to operate the existing physical/chemical wastewater pretreatment process, combined with steep municipal surcharges, prompted PPC to investigate more efficient and economical
treatment alternatives.
The warm temperatures, high biodegradability, nutrient levels, and organic fraction concentration
of the wastewater produced by the meat packing and rendering processes made these streams attractive candidates for anaerobic treatment.
The potential advantages of the anaerobic contact process, especially the ability to degrade high
levels of organic solids, were recognized and ACB was chosen to conduct an on-site development
program with the aim of developing a full-scale design basis. As part of an investigation into the
feasibility of an integrated anaerobic treatment concept,4 pilot scale mesophilic and thermophilic
anaerobic contact reactors, treating plant wastewater and waste solids respectively, were operated
during an eight month study period.
Following extensive economic evaluations, PPC decided to build a new waste treatment/energy
recovery facility centered around a mesophilic anaerobic wastewater treatment system.
The new anaerobic treatment plant, incorporating a flow equalization tank, an anaerobic contact
reactor and a conventional clarifier with vacuum assisted degasification for biosolids management,
was constructed in 1986 with start-up beginning in March of 1987.
This paper will be limited to a presentation of the mesophilic wastewater treatment component of
the pilot scale development program, full-scale recommendations from that study, an overview of
PPC's new treatment system configuration and a presentation and discussion of data generated
during the current full-scale commissioning.
673