Landfarming, Landtreatment, & Land Application Facilities
Land-spreading is a method of treatment and disposal of low-toxicity wastes in which the wastes are spread and mixed into the soils to promote reduction of organic constituents and dilution and attenuation of metals.
There are three types of permitted land-spreading facilities:
- Landfarming facilities can treat and dispose of only freshwater-based drilling fluids and associated cuttings.
- Landtreatment facilities can treat and dispose of oil and gas wastes including oil-based drilling fluids and oil-impacted soils.
- Land application permits are an alternative to discharge of fluid wastes. Gas plant effluent or low-chloride produced water may be applied to a controlled area via sprinkler or other irrigation systems.
Land-spreading utilizes the physical, chemical and biological capabilities of the soil-plant system to control waste migration and to provide a safe means of disposal without impairing the potential of the land for future use. Land-spreading facilities should be located on fine or medium grained soil with a thickness of at least 20 inches and a slope of less than five percent. Stormwater runoff must be controlled by either natural drainage features or by diversion structures. Land-spreading facilities should not be located in any area prone to flooding.
The application of fluid waste should be designed so that direct runoff of waste does not occur and so that the soil-plant system is not subject to prolonged saturation. Overloading can damage vegetation, produce odors, and limit oxygenation of the soil. Land-spreading operations are limited by severe weather conditions. Wastes should not be applied during rainy weather to reduce the possibility of contaminated runoff and the excessive compaction of the soil by machinery.
Waste liquids and slurries can be applied to the land surface or injected beneath the surface. Sprinkler irrigation, flood irrigation, ridge and furrow irrigation, and surface spreading from hauling vehicles are methods of surface application. Subsurface application can be accomplished by injection plowing or by following a surface application with a disc or plow. This method is more effective in minimizing runoff contamination, controlling odors, and degradation of oil and grease or other organic waste.
To ensure appropriate incorporation of the waste into the soil and that no waste will migrate off of the approved disposal site, landfarming and landtreatment permits typically require the waste to be mixed into the receiving soil via tilling, disking, or plowing. If the tilling, disking, or plowing of the waste into the receiving soil cannot be done at a proposed disposal site, that site is unsuitable for land-spreading and an alternative site where the tilling, disking, or plowing of the waste into the soil can be done should be proposed.
Landfarming of the following oil and gas wastes is authorized without a permit by Statewide Rule 8(d)(3), provided the wastes are disposed of on the same oil or gas lease where they are generated, and provided written consent of the surface owner of the tract where the landfarming will occur is obtained:
- water base drilling fluids with a chloride concentration of 3000 mg/l or less;
- drill cuttings,
- sands and silts obtained while using water base drilling fluids with a chloride concentration of 3000 mg/l or less; and
- wash water used for cleaning drill pipe and other equipment at the well site.
Other landfarming operations require a permit. Any facility land-applying oil-based drilling fluids and associated cuttings will require a permit.