CHARACTERIZATION AND TREATMENT OF DAIRY WASTES
IN THE MUNICIPAL TREATMENT SYSTEM
Howard B. Brown, Director Environmental Control
Richard F. Pico, Environmental Chemist
Kraft, Inc.
Glenview, Illinois 60025
INTRODUCTION
The 1977 Amendments (PL 95-217) significantly altered the thrust of The Clean Water
Act of 1972 (PL 92-500) and shifted emphasis to the control of toxic materials and hazardous substances. The 1977 Congressional act also implies a change from rigid technology-
based standards, and a recognition that water quality, economic impact and energy inputs are
considerations in seeking societal cost/benefit balance with environmental need.
The Act as amended in 1977, among other things:
1. Requires the U.S. Environmental Protection Agency to focus on priority pollutants that
are discharged to Publicly Owned Treatment Works (POTW), and to differentiate between
conventional and nonconventional pollutants;
2. Identifies Biochemical Oxygen Demand (BOD), suspended solids (SS), fecal coliform and
pH as conventional pollutants;
3. Provides EPA authority for identifying additional conventional pollutants;
4. Requires the development of pretreatment standards for toxic or priority pollutants;
5. Encourages local enforcement of standards via the requirements that POTWs develop
comprehensive programs to deal with industrial surcharges by 1983;
6. Provides the EPA authority to set pretreatment standards for classifications other than
toxic and priority pollutants.
Since passage of the 1977 Amendments EPA has proposed (August 25, 1978) that fats,
oils and greases (FOG), phosphorus and chemical oxygen demand (COD) be classified as conventional pollutants.
Thus it is established that parameters which are characteristic of dairy processing wastewaters, BOD, SS, pH and FOG, are effectively removed in a well-operated POTW employing
conventional secondary treatment (or BPT—best practicable control technology).
In light of the Act and proposed and contemplated regulations, it is the purpose of this
paper to demonstrate and reaffirm that dairy plant wastes are compatible with POTWs, can
be treated satisfactorily in typical biological treatment systems, and generally do not require
pretreatment.
The first part of this paper will update characterization of various dairy effluent analytical
parameters, summarizing data from the literature, and data generated from the effluent
analyses of various types of Kraft dairy plants.
The second part of the paper examines the treatability of these parameters in biological
treatment systems. Data included show that the organic load originating from dairy plants is
biodegradable, that BOD, SS, pH and FOG are effectively removed, and that wastes from
dairy processing plants do not interfere in the operation of POTWs.
CHARACTERISTICS OF DAIRY EFFLUENTS
Reports in the technical literature, and Kraft analytical data highlight the fact that dairy
plant wastes are extremely variable in nature.
Statistical analysis has shown that there is no relationship between plant size or degree of
automation and BOD discharged/lb of production. The most important factor in reducing
waste loads is management control [ 1 ]. Dairy processing plant management control can significantly reduce waste loads by suitable in-plant short-of-treatment methods.   This is
obviously the most economical method to reduce wastewater treatment charges.
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