Mineland Reclamation
Introduction Scientific research and 20 years of field experience has demonstrated that biosolids (treated municipal wastewater solids) application to minespoils can greatly improve establishment of a sustained vegetative cover and virtually eliminate erosion. Anecdotal evidence also suggests reclamation with biosolids may help to alleviate AMD. The application of large amounts of biosolids, however, may lead to another NPS problem more familiar at agricultural sites; namely the loss of nutrients, specifically nitrate and phosphate. The goal of this research project is to assess the effects of biosolids on NPS pollution at an abandoned mine reclamation site. Specific project objectives are: (1) to determine biosolids effects on AMD, (2) to determine biosolids contribution to nitrate and phosphate discharge from the reclamation site, and (3) monitor concentrations of regulated trace elements in minesite water during 24 months following biosolids application and mine reclamation. Background Research in the late 1970s and 1980s, much of which was conducted in Pennsylvania by William Sopper (1993), demonstrated that minespoil amendment with biosolids greatly improved the establishment of sustained vegetative cover. Biosolids promote long-term plant growth by supplying inorganic and slow-release organic nitrogen (N) and phosphorus (P) to low fertility minespoils. Large amounts of organic matter are also added which promotes topsoil development, increases water holding capacity, and stimulates microbial activity and nutrient cycling (Seaker and Sopper, 1988a,b). In addition to the benefits for establishment of vegetative cover, water quality measurements and observations by DEP district mining staff over the past 20 years have provided anecdotal evidence that AMD is also reduced by the use of biosolids. Such an effect of biosolids could be an indirect result of establishing a vigorous vegetative cover and stimulating microbial activity in the soil surface. Consumption of oxygen by root and microbial respiration may reduce the oxygen content of water percolating downward into pyrite-bearing spoils, thus limiting pyrite oxidation and generation of AMD. The efficacy of biosolids applications in reducing AMD has not been quantitatively measured. Biosolids research conducted on Pennsylvania minelands led to the recommendation that total N application in the biosolids should be at least 1,000 lb/acre of total N in order to supply at least 200 lb/acre of available N in the first year following application. DEP established a maximum biosolids application rate of 60 tons/acre (dry weight basis), and in practice this has become the standard biosolids application rate used for mine reclamation. At the time these practices and application rates were developed, 60 dry tons/acre of biosolids typically provided from 1,000 to 2,000 lb/acre of total N, and similar amounts of P2O5 (Sopper and Kerr, 1979; Sopper et al., 1982). The anearobically digested and dewatered biosolids cake that is currently being used on mine reclamation sites in Pennsylvania results in much larger total N applications. At a 60 dry ton/acre application rate approximately 5,000 lb/acre of total N is applied and around 1,200 lb of that N is expected to be plant available in the first year. Thus potential for N loss is greater than with biosolids used 20 years ago. Description of the research project Installation
of Site
Water quality data: Surface Water
|
Well Installation
Weir Installation
Revegetation of Site
Lysimeter Installation
