Microbial Transformation in Oxidation and Reduction
Nitrates are the number one problem causing the shutdown of water wells. The number one cause for taking wells off-line is the presence of unacceptable nitrate levels. The nitrate, when the conditions become anaerobic (reductive) again, will now reverse back toward the ammonium state (ammonification), or the nitrate may be reduced down to nitrogen gas. The symptom causing "blue babies" is high nitrate concentrations in the water. When people drink nitrate in water, the gut microorganisms of adults and children are able to break the nitrate down to nitrite. Like the nitrate-ammonium cycle, the sulfide-sulfate cycle involves an eight-electron transfer. Sulfates commonly occur in water and sulfides are often present, associated with "rotten" egg odors, black water/slime/deposit-problems and corrosion. Sulfur oxidation can also take place by an organism Beggiatoa, where yellow elemental sulfur globules can occur in large quantities. The transformation between oxidative and reductive environments is actually no different for iron.