Inoculum
The GEOCOAT® process uses mixed cultures of mesophilic, moderate, and thermophilic microorganisms to promote biooxidation. Starting with a small volume of culture from the laboratory, the volume of inoculum required for the GEOCOAT® heap is produced by growing the bacteria in a solution of nutrient salts, with periodic addition of small quantities of sulfide concentrate and elemental sulfur. The suspension is agitated and aerated. As the bacterial density increases, the inoculum is transferred to progressively larger vessels and diluted by adding nutrient medium. This process is repeated until the required volume of inoculum is obtained. The inoculum is added to the on-solution pond, which then is used to irrigate the GEOCOAT® heap.