MUNICIPAL SLUDGE LAND APPLICATION PROJECT

Barb Ogg, Assistant Extension Agent

On May 6, 1992, the first truckload of organic sludge from Lincoln's wastewater treatment facility was delivered to the Frampton Demonstration Farm. This event culminated a decade of planning by Lincoln's sanitary engineers to dispose of the city's organic wastes in a more environmentally sound manner rather than burial in the solid waste landfill. Recent federal legislation regulating landfill wastes make this land disposal of sludge an even more timely event.

This project is a cooperative effort between Lincoln/Lancaster County Health Department, University of Nebraska Cooperative Extension personnel and county farmers. Extension Agent Warder "Gus" Shires has been working with willing farmers to evaluate potential field sites as to their suitability for sludge application. Sites are rejected if they are too close to wells, waterways and public water supplies. In addition, sludge will not be applied to land where plant foods for human consumption will be grown or near residential districts zoned R-1 to R-8.

On potential sites, deep soil samples are taken before application to determine soil fertility needs as well as metals that may already be present in the soil profile. The amount of sludge applied will not exceed the fertility requirements needed for the next crop.

Treatment-plant processed sludge is rich in fertilizer nitrate, phosphorus, potassium and has moderate levels of zinc, copper and other required plant nutrients. Sludge also contains organic nitrogen that will be naturally converted to fertilizer nitrate and become available to crop plants for several years after application. After the sludge has undergone an anaerobic digestion procedure and heated to 90-95 degrees Fahrenheit, most of the bacteria in the unprocessed sludge have been destroyed. Digested sludge also has a less objectional odor than unprocessed sludge. Before delivery, the sludge has been de-watered to about 78% water content and looks like good quality compost material.

Farmers, who have contracted with the city, have received sludge, delivered free-of-cost, to a temporary storage site on their farms. Farmers, however, must have the equipment to spread the sludge and agree to apply it to the land within a reasonable length of time. We have not had trouble finding farmers to cooperate with us on this project. To date, sludge has been delivered to fields belonging to nine cooperators and several other contracts are in the process of finalization.

This project is a cooperative effort between the city of Lincoln, the County Health Department, the University of Nebraska Cooperative Extension in Lancaster County and county farmers who can fit fertilizing with sludge into their crop management system. Careful monitoring of all aspects of this program will provide an excellent soil fertilizer/conditioner while reducing the concentrated disposal of organic wastes in the municipal landfill. Land application of sludge will also serve to increase the life of the landfill.For any additional questions about this project, or about how to receive sludge on your farmland, contact Warder "Gus" Shires or Barb Ogg at the Lancaster County Extension Office, 441-7180.