Protocols for Use of Biosolids and Co-Amendments for Mined Land Reclamation

This paper focuses on the use of biosolids as amendments to mined lands, which when used properly, promote soil ecosystem recovery and encourage the development of a self-sustaining plant community. Most of the biosolids products that have been applied to mined lands to date have been dewatered anaerobically digested sludge cake or mixtures of anaerobic cake with composted wood chips. Amendment of mine soils with biosolids has been shown to increase soil organic matter, cation exchange capacity, soil nutrient levels, and to promote soil ecosystem recovery after surface mining. Very high rates of biosolids have been applied to highly acidic coal refuse piles and smelter wastes in an attempt to ameliorate the very low pH, high potential acidity, general infertility, and low water holding capacity of these areas. Pathogen transmittal is presumed not to be a problem if biosolids that have undergone pathogen reduction processes are used and proper application procedures are followed. If USEPA trace metal concentration and loading limits are followed, and if soil pH is maintained, the risk of trace metals entering the food chain or contaminating ground-water is extremely low. Nitrate leaching to ground-water is a potential risk from heavy biosolids loading, but does not appear to be a significant risk from one-time applications. Nitrate leaching from higher than agronomic rate loadings can be limited by adjusting the carbon to nitrogen (C:N) ratio of the applied materials with sawdust or woodchips. Care should be taken when applying biosolids to materials with high potential acidity such as coal refuse piles and pyritic mine soils to insure that adequate lime is applied to buffer the pH above 7.0 for long periods of time. Very positive long-term revegetation success results have been reported i