APPLICATION OF ANAEROBIC BACTERIA AND LOCAL GEOLOGICAL RESOURCES IN PASSIVE TREATMENT OF ACID DRAINAGE IN COAL MINES

Abstract

Introduction:
The extraction of mineral carbon generates the formation of acid mine drainage (AMD), which occurs when sulfur minerals, such as pyrite, oxidize in the presence of oxygen and water, which gives rise to the generation of sulfuric acid. The remediation of the acid effluent using sulfate-reducing bacteria provides the generation of alkalinity which results in a decrease in acidity due to the reduction of sulfate and precipitation of metals in the form of sulphurs.
Objective:
To evaluate the use of anaerobic bacteria and local geological resources in the passive treatment of the acid drainage of the Benga mine, Tete Province, Mozambique.
Materials and Methods:
The physical-chemical characterization of the effluent was carried out, followed by the installation of the anaerobic biorreactor using goat feces and materials of geological origin as inoculum, followed by the period of acclimatization and subsequent treatment of the effluent. The evaluation of the remediation by the biochemical reactor was carried out in relation to different times of hydraulic retention, studying the parameters pH, concentration of sulfates and alkalinity.
Results and Discussion:
Hydraulic retention time of 4 days showed greater efficiency in the removal of 80.90% of sulfates, and high alkalinity with 2860 mg.L-1 of CaCO3 and pH of 7.3. The pH values increased to an average of 6.9 (± 0.29). The average final sulfate removal of 69.21% (± 16), and alkalinity of 2270 mg.L-1 of CaCO3.
Conclusions:
The biochemical reactor generates a sulfate removal rate of 69.21% (± 16).