Food processing industries discharge large volumes of waste water that
are generally characterized by high organic matter content, large amounts of
suspended solids, and various inorganic constituents including nitrogen, phosphorus,
and potassium (3, 4, 5, 6). Until recently, food processing waste
water was discharged into streams or rivers, but governmental regulations now
prohibit this. Food processors must either treat their waste water to meet
established water quality standards before discharging it, or find an alternative
waste water disposal method. Secondary treatment, although expensive,
has been satisfactory in some cases, but tertiary treatment with removal of
nitrogen and phosphorus may be required in the future. Energy requirements
for secondary treatment are high, and plant nutrients usually contained in
the waste water are a valuable resource. Irrigating cropped agricultural
land requires little energy and some of the nutrients can be used by growing
plants. Therefore, irrigating with food processing waste water may be a long-term
solution to the waste water disposal problem.
This report gives the nitrogen, phosphorus, and potassium concentrations
in potato processing waste water and the amounts of water and included nutrients
applied to fields at five potato processing plants in Idaho
