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Biosolids Land Application Program
A Partnership Between the City of Lincoln, University of Nebraska-Lincoln Extension in Lancaster County and County Crop Producers
by Barb Ogg, PhD, UNL Extension Educator
Program Overview: In May, 1992, the first truckload of biosolids, (processed and treated wastewater solids) from the Theresa Street Wastewater Treatment Facility was delivered to farmland in Lancaster County. This event was the beginning of a successful program. In the last five years, over 150,000 tons of biosolids have been used as a source of fertilizer and organic matter to cropland in Lancaster County. The value of biosolids, based on the nutrient value alone, is over $100,000 annually to the cooperating farmers in our program.
On weekdays throughout the year, de-watered biosolids are transported to approved crop fields in Lancaster County for land application. Approved land must have a battery of soil tests to determine application rates. There are federal and local restrictions that prevent application of this material near wells, rivers or streams and public water supplies. In the case of wet soil conditions that prevent delivery in the field, biosolids are trucked to the North Bluff landfill for storage on a concrete storage slab.
Advantages. The nitrogen in this organic fertilizer is primarily organic N which is released slowly over time so it is available when the crop needs it. Biosolids also have many other essential elements needed for plant growth. Many area farmers use it for its phosphorus and zinc because these two elements are deficient on many area soils. It is especially beneficial when applied to soils that have been subject to soil erosion or excavated. It has about 65% organic matter which loosens heavy clay soils so common in our county and helps water infiltration which helps minimize soil erosion.
Disadvantages. Cooperators who use biosolids must have the time and proper equipment to apply the material in a reasonably prompt manner. Soil around storage sites may become compacted; these areas may need to be disked later to loosen the soil. Like many other field operations, application is dependent on suitable weather conditions.
For the past five years, the goals of the program remain unchanged--to enhance the productivity of area soils through the environmentally responsible use of this material. However, there have been some changes in the biosolids land application program since it began in 1992. Some changes that we have seen are:
Demand for Biosolids. The demand has grown so some interested farmers may not be able to obtain all the material desired at the time of the year they want it. Crop producers who are willing to accept and store biosolids during the spring and summertime, times when crops are growing in the field, are likely to receive more material. When this program began five years ago, many farmers adopted a wait-and-see attitude toward the use of this material. Because of proven enhanced yields and improved soil structure that this material provides, there is more demand for biosolids than ever before.
Payment for Application. When this program began five years ago, providing a partial reimbursement to cooperators for application was not part of the program. Payment has allowed some interested cooperators to purchase machinery or to hire a custom applicator to apply it. Payment is $0.65 per cubic yard, payable only after the material has been applied properly. The payment also provides an incentive for cooperators to apply it in a timely manner. The program also pays a farmer a small incentive for in-field storage during times of the year when crops are growing. The farmer will apply the material after crops are harvested.
Increased Regulatory Guidance by the EPA. In 1993, federal regulations regarding the land application of sewage sludge were announced that set standards for pathogens, heavy metal concentrations and rules that determine application rates and other facets of land application programs. These regulations were meant to prevent harm to people, wildlife and the environment. The standards for metal regulations, for example, have reduced the concentrations of some metals in the biosolids to very low levels, thanks to voluntary compliance by local industries. In fact, concentration levels for all regulated metals is below the clean sludge limit.
Technological Advances. With support from the city of Lincoln, this project has acquired a Global Positioning System (GPS) receiver to map application areas and storage sites as well as environmental setbacks from wells, ponds and steams. The receiver picks up signals from four or more satellites in orbit above the earth, and an internal computer calculates where the receiver is on the face of the earth. It is accurate to within a few feet. By using this receiver, even terraced and irregular fields can be accurately mapped and their acreage determined. The GPS data is then integrated with Geographical Information System (GIS) maps that have been developed by Lancaster County agencies. David Smith, a GPS technician at the Lancaster County Extension Office is our GPS and GIS mapping expert. This GPS/GPS monitoring system will become very important when tracking multiple applications on fields.
Three-Year Nutrient Management Plan. Most of the nitrogen in biosolids is tied up as organic N and is not available immediately for plant uptake, but becomes available over time. This process is called mineralization. Farmers who are in the Biosolids Land Application Program are given rates which will meet the nitrogen needs of the next crop, but there will be some nitrogen available the second and third years after application. Farmers are given application rates of commercial nitrogen fertilizers for successive crops to prevent over application of nitrogen fertilizers.
Successful Program. Overall, the Biosolids Land Application Program has been very successful and a good example of using a waste material in such a way that it becomes a valuable resource. From time to time there have been odor complaints after application. Odor seems to be worse during rainy, humid weather, but is not very predictable. When application sites are close to residences, we do our best to prevent problems by taking into account prevailing winds and requiring the farmer to incorporate the material. Within a couple weeks, there is usually little odor.
People who do not understand the program have concerns about the use of this material. However, when biosolids meets EPA regulations regarding pathogen and metal standards and when responsible application practices are followed, the benefits of this material far outweigh the likelihood of health problems or environmental contamination.
PHOTO Credit: Vicki Jedlicka
Lincoln's biosolids recycling program is a joint collaboration between the City of Lincoln, Public Works and Utilities Department and University of Nebraska-Lincoln Extension in Lancaster County with assistance from the University of Nebraska Agronomy Department, Lincoln/Lancaster County Health Department and the Natural Resources Conservation Service.
University of Nebraska-Lincoln in Lancaster County
Barb Ogg or David Smith
Web site: lancaster.unl.edu
444 Cherrycreek Road, Suite A, Lincoln, NE 68528 | 402-441-7180
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