WASTEWATER TREATMENT BY SPRAY IRRIGATION. QUALITY OF
EFFLUENT AND IMPACTS ON SOILS AND GROUNDWATER
Loren C. Trick, Process Chemist
Michael L. Crosser, Process Chemist
Donohue and Associates, Inc.
Sheboygan, Wisconsin 53081
Richard A. Geiser, Director
Research and Quality Control
Krier Foods, Inc.
Belgium, Wisconsin 53004
INTRODUCTION
Krier Foods, Inc., is a food processor located at Belgium, Wisconsin, in northern Ozaukee County.
They own and operate an anaerobic/aerobic lagoon system to treat 0.5 MGD of process wastewater
generated at that facility and are permitted to discharge to the Belgium Drainage Ditch. Prior to July
1, 1984, the discharge limitations to the Belgium Drainage Ditch were based on guidelines for the
food processing industry and were 68,200 lbs/yr total suspended solids and 36,220 lbs/yr BOD. BOD
was further limited to a maximum 100 mg/1. The present effluent limits are 20 mg/1 for both BOD
and total suspended solids and are water quality based. Krier also is permitted to discharge pretreated
wastewater by spray irrigation on 40 acres of land. The permitted irrigation rate is 210,000 gallons
per day. The existing lagoon system produces effluent ranging from 20-100 mg/1 BOD and from 20-
200 mg/1 suspended solids.
Five alternatives were identified to allow Krier Foods to comply with the new permit limitations:
1) Lagoon modifications followed by advanced solids removal; 2) Mechanical plant followed by advanced solids removal; 3) Artificial marsh; 4) Absorption cells; and 5) Expanded spray irrigation.
The first four alternatives were investigated and dropped from further consideration because they
were technically not feasible or too costly. Expanded spray irrigation was determined to merit further
study. Because the types of soils on the Krier property are slowly permeable, the concept of using
agricultural drain tiles to aid in the drainage of irrigated water was proposed. An irrigation test was
conducted during the 1984 pack season to evaluate this concept. The purposes of the test were: 1)
Determine whether the tile effluent would meet surface water discharge limits throughout the spray
season; 2) Determine the required tile spacing for the spray field; 3) Determine the application rate
limitations; 4) Determine the impact of irrigation on soil and groundwater chemistry; and 5) Develop
an operating plan for the full-scale spray irrigation system.
IRRIGATION TEST
Background
Figure 1 shows the Krier property including the lagoon system. The irrigation test parcel crosses
the Krier property from east to west in a strip approximately 310 feet wide by 1,580 feet long. This
parcel lies within the Kewaunee-Manawa soil association and crosses through several soil mapping
units. Poygan silty clay loam lies on the eastern 'A of this parcel and Darroch, Matherton, and Man-
awa series soils lie to the west. The boundary between the Poygan and other soil series is distinct and
marked by a change in slope. The Poygan soil is nearly level while the Darroch, Matherton, and
Manawa soils slope gently up to the west at about a 0.6% slope.
All of these major soil mapping units have been farmed in the past with sweet corn, beets, potatoes, and carrots in rotation. Since 1978, a 40-acre parcel in the western portion of the Krier prop-
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