Indiana Farmstead Assessment for Drinking Water Protection

Milking Center Wastewater Management

Introduction Milkhouse wastewater Discharge to soil Discharge area Discharge to manure storage Land Application Authors Contacts & References Sources

Milking Center Wastewater Management Survey


Dairy milking centers require large amounts of water. The wastewater frommilking centers include wastes from the milking parlor (manure, feed solids, hoof dirt), and milkhouse (bulk tank rinse water and cleaning products). The mostcommon pollutants found in milking center wastewater are milk, nitrogen, manure and detergents.

Similar to household wastewater, milking center wastewater has a highconcentration of organic matter. Large amounts of organic matter cause a drop in oxygen which can result in fish kills.

The key to managing milking center wastewater is to pr event wastewaterfrom entering surface water or leaching to groundwater. You can either treat the wastewater before discharge to the environment or choose a discharge methodthat allows for treatment by the soil and vegetation. This fact sheet briefly discusses the most common options used in Indiana.

Milkhouse wastewater

Milkhouse wastewater includes the water, acid and detergent used to washout the bulk tank and milk pipelines, and the floor drain water. There are two common practices for disposal: 1) discharge the wastewater to the soil; or 2)collect the wastewater in a tank and use it to wash down the milking parlor prior to discharge to the liquid storage system.

Disposal of milkhouse wastewater must be done in a manner that complieswith other state and local regulations. Check with your local health department or call the Indiana State Board of Health, Dairy Products Division.

Discharge to soil

Settling tanks

With the first option, milkhouse wastewater is collected in a settling or septictank before discharge to a soil absorption area. Both types of tanks provide a place for bacteria to decompose some of the milk solids and fats that wouldotherwise plug the absorption area. Either system poses little risk to water quality if sited and maintained properly.

A common problem with settling and septic tanks is clogging fromthe solids in the wastewater. A clogged tank may cause the system to backup or develop a leak that could contaminate water resources. If waste-water appears in a nearby ditch or low spot, the system is failing. Pumping the tank regularly prevents clogging. Determine a maintenance schedulebased on the size of the tank and volume of wastewater. A licensed sludge hauler can pump out the tank and apply thesludge to an approved site. IDEM regulates the sludge application process.

Discharge area

A settling tank discharges to a designatedsurface infiltration area. Slow infiltration of wastewater into the soil allows bacteria andvegetation to utilize the remaining waste products. Appropriate soil types for such an areadepend primarily on the soil's infiltration rate and depth to water table. The area should also beslightly sloping (<5%) to prevent ponding. Divert surface runoff away from the area. Waste-water discharged to the infiltration area must not reach surface water.

Vegetation on the infiltration area slowswastewater flow and promotes infiltration. Harvesting the vegetation promotes healthyplant growth and prevents buildup of dead plant matter.

Sites with a course textured (sandy) soil anda shallow depth to water table pose the greatest risk to groundwater. On steep slopes the waste-water may runoff too quickly with only minimal infiltration into the soil, putting nearby surfacewaters at risk.

A septic tank discharges to an undergroundabsorption area through fingerlike tile lines. Similar to the infiltration area, selected soilcharacteristics are necessary for proper siting of an absorption area. A poorly sited absorptionarea is a risk to groundwater. Check with your local health department or county extensionoffice for further information.

Discharge to manure storage

Parlor wastewater

With the second disposal option, milkhousewastewater is either collected in a tank to be used later for washwater or diverted directly to aliquid manure storage system. The wastewater is commonly used to wash down the milking parlorbefore it is combined with the manure. The manure is collected in a storage pit or lagoon.The waste can be land applied using a tank spreader or irrigation system. This system has the advantage of using a single waste management practice to handle two types of waste.

The risk of water contamination from thiswastewater storage systems is low provided the storage facility does not leak or overflow. It maybe impossible to determine if the storage pit or lagoon is leaking, especially if it is a slow leak. Monitoring the liquid level is a simple way to detect a large leak. The best prevention against leaks is to construct the storage facility properly using good quality materials. Lagoons may need plastic liners. Contact your local extension office or Natural Resource Conservation Service(NRCS) for design assistance.

Land application

Milking center wastewater and manurehave fertilizer value, and can be an important addition to your crop nutrient managementprogram. You take advantage of the milking center waste's nutrient value when it is handledwith the liquid manure. Apply the waste at an appropriate rate and track soil nutrient levelsclosely over time so that soil tests will not increase to excessive levels. The waste containsnutrients and bacteria which can contaminate water sources. Follow field application guide-lines to prevent contamination of ground and surface water. Contact your local extension officefor more information.


Sarah Brichford
Cheri Janssen
Joe Yahner
Joe Eigel

Contacts and References

	Indiana State Board of Health
	Dairy Products Division
	Indianapolis, IN 46206

	Indiana Department of Environmental
	Management (IDEM) 
	P.O. Box 6015Indianapolis, IN  46206-6015 

	Purdue University Cooperative
	Extension Service
	888/EXT-INFO or local office

What to read about...

	*Milking Center Wastewater TreatmentImprovements (CD-ROM)
	*MWPS-18 Livestock Waste FacilitiesHandbook


	Center for Technology Transfer
	and Pollution Prevention
	1146 Agricultural and Biological
	Engineering Bldg. West Lafayette, IN  47907-1146

Click below for Survey 10

Milking Center Wastewater Management Survey

Reviewed 5/1/01

It is the policy of the Purdue University Cooperative Extension Service, David C. Petritz, Director, that all persons shall have equal opportunity and access to its programs and facilities without regard to race, color, sex, religion, national origin, marital status, parental status, sexual orientation, or disability. Purdue University is an Affirmative Action employer. This material may be available in alternative formats. 1-888-EXT-INFO.