Investigating efficiency of natural zeolite as a remediation for acid mine drainage :

Abstract

Acid mine drainage (AMD) is the most serious environmental problem faced by the mining industry today. This acid mine drainage is usually high in acidity and heavy metals thus requires several mitigation measures. The conventional remediation methods used particularly active treatment and passive treatment methods have a lot of short comings such as high capital and operating costs, production of high volumes of sludge and require large areas for installation which calls for alternatives. Natural zeolites considered as alternatives attributed to their good structural stability, porous structure and high cation exchange capacity. Untreated Natural Zeolites were characterized and utilized as adsorbents for the remediation of acid mine drainage from Tibet Hima Mining Company Limited. XRF analyses showed that Natural Zeolite samples from Mount Elgon are majorly enriched with Silicon (IV) oxide, Aluminium oxide and Calcium Oxide with 46%, 16% and 13% respectively. Laboratory tests showed that AMD is currently discharged at level 42 with a p.H of 4.97, a copper concentration of 854.7 mg/l and iron concentration of 851.3 was above the recommended NEMA limit of I mg/l and 0.3 mg/l respectively for copper and iron. The laboratory tests revealed that natural zeolite was able to neutralize the p.H of AMD from 4.97 to 7.21 and also able to remove 99.874 % of iron and 99.977% of copper from the AMD solution thus efficient as a remediation option. However, for large scale implementation, pilot testing should be done to establish all parameters for an efficient operation.