Treatment and Disposal of Milk House
and Milking Parlor Wastes

Copyright ©  2008  Regents of the University of Minnesota. All rights reserved.

Table of Contents

Introduction

This lagoon receives waste from a milkhouse and milking parlor serving 125 cows and located 300 feet away. It has a surface area 120 x 120 feet at a depth of 4 feet. Usable depth is limited by elevation of gravity flow inlet. Pumping is required when liquid level rises to inlet or plugging results. Previously serious problem has been solved by this structure.

The treatment of milkhouse and milking parlor wastes on dairy farms must be solved by proper engineering design to protect the public health and to prevent pollution of ground or surface water. The word "treatment" as used here also includes the disposal of the treated waste in an acceptable manner. The information presented in this publication has been prepared in cooperation with the Minnesota Department of Agriculture. Recommendations may be used as guidelines for the production of Grade A milk. The Minnesota Pollution Control Agency and the Minnesota Department of Health each have reviewed this publication and have contributed to and concur with the recommendations made.

Septic tanks and drainfields have been used for milkhouse and milking parlor wastes, but experience has shown such systems generally are unsuccessful. Failures may be due to inadequate size, the sealing effect of milk solids on soil pores, incorrect installation in tight or high water table soils, or not removing accumulated solids from the septic tank.

The "septic" tank for a milkhouse or milking parlor usually functions simply as a "settling" tank, which separates the floatable and settleable solids from the liquids. The high concentration of sanitizing agents used in the wash water depresses bacterial action in the tank. There is a considerable amount of fibrous material in milking parlor flush water from manure because cows track manure in or defecate while in the parlor. Spilled feed may also be flushed into the treatment system. Where cows enter the milking parlor from an unpaved lot, soil particles on their feet add to the nonbiodegradable material that enters the tank.

The waste water from a milkhouse contains a considerable amount of milk solids washed from the bulk tank, pipeline milker, or other milk-handling equipment. Milk solids do not settle out in a septic tank nor do they decompose by bacterial action. These solids flow through the tank into the drainfield and quickly clog the soil pores. When the tank is nearly full of accumulated solids, additional fine materials flow out with the effluent and increase the rate of soil clogging.

Consequently, attempts at subsurface disposal of milking parlor wastes generally have been unsuccessful. The failures may have been partially due to inadequate system size, improper installation, milk solids, and clogging the soil pores. A major contributing factor is inadequate removal of solids from the settling tank.

For the most trouble-free system, milkhouse and milking parlor wastes should be treated on the ground surface, stored in a lagoon, or emptied into a liquid manure tank. However, human sewage from toilets must be treated separately and will be discussed later.

Produced by Communication and Educational Technology Services, University of Minnesota Extension.

In accordance with the Americans with Disabilities Act, this material is available in alternative formats upon request. Please contact your University of Minnesota Extension office or the Distribution Center at (800) 876-8636.

University of Minnesota Extension is committed to the policy that all persons shall have equal access to its programs, facilities, and employment without regard to race, color, creed, religion, national origin, sex, age, marital status, disability, public assistance status, veteran status, or sexual orientation.