Acid reduction using microbiology: treating AMD effluent emerging from an abandoned mine portal

摘要: Abstract The performance of a microbial treatment system, partially implemented, receiving abandoned mine portal effluent in the gold mining district Nova Lima, Minas Gerais, Brazil is documented. system consists four oxidation–precipitation–settling ponds and three treatments operating series. flow volume averaged 0.6 L s −1 , increasing during rainy season to 1.0 . pH ranged from 1.4 3.4, measured between 1995 2001. particle-settling rates specific were 25–3.9 g m −2 day which decreased oxidation–precipitation A–D. Most pyrite oxidation subsequent iron hydrolysis hydroxide occurred underground workings. resulting weathering products flushed out high flows. For these effluents, function was mainly particle removal. Oxidation–settling necessary prevent or reduce coating limestone organic carbon. From oxidation–settling pond D, flowed into series ponds. These “seeded” with 10 t raw potatoes 4.5 whole sugar cane. designed have floating cattail cover turbulence stabilize anaerobic sediments, will form, provide continuous carbon source sediments. However, at time writing, not yet functional. discharge 7.2 June 1999 as-yet incomplete however, removed on average 37–87% monthly Ni load (0.6–1.7 kg month ), 77–98% Al (19–49 74–82% Zn (1.7–0.6 78–95% Fe (71–236 ).