A Novel Alkaline Biosolids Product as Alternative Landfill Cover

The City of Toledo has been using an alkaline stabilization process to treat their municipal biosolids for over ten years. The resultant product (N-Viro Soil) is sold as an agricultural soil amendment and topsoil component. In 1998 a demonstration project utilizing N-Viro Soil (NVS) as alternative daily landfill cover material, was carried out. The physical characteristics of the product were acceptable as a daily landfill cover, but ammonia emissions were a problem for the operators. Limiting ammonia emissions would make the product more acceptable from an odorgenerating standpoint when used as an alternative daily landfill cover and have additional advantages by retaining the nutrient benefits of the ammonia in the product when used as a traditional soil amendment.Previous research done for N-Viro International has shown that chipped pine boughs are effective in reducing the ammonia emissions from the alkaline stabilized biosolids products in a number of formats. In view of this, a demonstration project to test the ability of chipped Christmas trees to limit ammonia emissions from the alkaline-treated biosolids and utilize this pine-alkaline product as an alternative landfill cover was initiated. This processing yielded a daily landfill cover product that was very workable from a physical viewpoint without the previous problem of ammonia emissions. The demonstration project was divided into two stages, the first in February of 1999 and the second in April 1999. In both demonstrations, the operators noted no objectionable ammonia odor, and the workability of the product was acceptable. The City of Toledo and N-Viro International were both satisfied with the results of the demonstration and will continue to use the “pine-alkaline” material in the future.