DENITRIFICATION OF GROUNDWATER USING COTTON AS ENERGY-SOURCE

Microbial removal of nitrate from drinking water was studied in labora tory columns packed with unprocessed short fiber (low quality) cotton (Gossypium hirsutum). Cotton served as the sole chemical and physical substrate for the microbial population. Removal of nitrate was rapidly achieved without the formation of nitrite. Cotton (cellulose)-depende nt denitrification was affected by changes in temperature: denitrifica tion rates at 14 degrees C were approximately half of the rates observ ed at 30 degrees C. The cotton was entirely consumed in the process. I n a fresh reactor, colonization of substrate by bacteria appears to be the rate limiting factor in the removal of nitrate. Copyright (C) 199 6 IAWQ.