RECLAMATION OF COPPER MINE TAILINGS USING BIOSOLIDS AND GREEN WASTE

Field experiments were conducted to determine the efficacy of applications of municipal biosolids and green waste (shredded plant material) for copper mine tailings reclamation.The study was established in southern Arizona on an area of fresh tailings with neutral pH.Two levels of green waste addition (0, 220 Mg/ha) and four levels of biosolids addition (0, 67, 134, 200 Mg dry matter/ha) were applied to the tailings.The tailings were seeded with a mixture of annual and perennial grasses and small shrubs.Plant biomass and tailing core samples (O-l.2m) were taken every six months during a two year period to determine plant establishment and growth, tailing N concentrations, microbial activity, total and available metals, and tailing NO,•N concentrations.Biosolids and green waste amendments significantly (p ,; 0.05) enhanced plant growth, canopy cover, soil N concentrations, and soil basal respiration.Biosolids applications did not significantly (p ,; 0.05) increase metal concentrations in soil or plant matter, and did not result in significant NO, movement.