Milk House Wastewater Treatment System Selection
Choosing a milk house waste treatment system is not always easy. Each of the treatment systems described above have site limitations. Sites with high water table or limited soil depth to bedrock, less than 2 ft, may limit the viability of bark beds, aerobic systems, or recirculating media filter systems that discharge into subsoil infiltration areas. Some farm sites may not have enough available land for an irrigation system or site elevations do not allow for proper drainback of below ground distribution pipes. Some bark beds, irrigation areas, or infiltration areas have been located over 350 feet from the milk house because of site conditions.
In some cases, a combination of systems may be appropriate. Combinations might include a bark bed for winter and cropland irrigation for the summer. This combined system would make some of the wastewater nutrients available for crop production and enhance the bark bedís useful life. Combination systems can be more complex because of the different piping and pumping requirements for the different systems. Combination systems are also likely to be more expensive than a single treatment system.
Locating the septic tanks and infiltration areas of the milk house waste systems may require some investigation of state regulations and local ordinances or building codes. For Minnesota the following guidance should be used:
Septic tanks and infiltration areas must be at least 50 feet from most wells but 100 feet from sensitive water supply wells as defined by the Minnesota Department of Health.
Irrigation systems should follow, at a minimum, Minnesota Feedlot Rules Chapter 7020 and stay 300 feet away from lakes, streams, intermittent streams, unbermed drainage ditches and public waters wetlands.
There must be a minimum of two feet of separation between the bottom of the infiltration area and the periodically saturated water table or limiting condition (this could be bedrock). The infiltration area should not be located on course sand. Most research indicates sufficient BOD5 removal and ammonia transformation within 2 feet of unsaturated soils.
Currently, in Minnesota, these systems will be permitted as part of the feedlot.
In general, the following items should be considered when choosing an appropriate system.
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