Disclosed herein is a method for treating odors in wastewater treatment
bodies. The pH of the body is preferably established above about 6 and
most preferably above about 7, usually by adding a base to the body. The
oxidation reduction potential of the body is established at about -300 mV
or higher and more preferably about -200 mV or higher, usually by adding
an oxidizing agent such as oxygen or nitrates. After these conditions are
established, sulfur oxidizing bacteria are added to the body. These
preferably include Paracoccus denitrificans (formerly called Thiosphaera
pantotropha) ATTC number 35,512. The sulfur oxidizing bacterial
population should be established at levels of at least about
1.times.10.sup.4 cfu/mL and more preferably at levels of 1.times.10.sup.5
to 1.times.10.sup.6 cfu/mL or higher. The increased ORP and pH levels
make sulfate reduction thermodynamically unfavorable. Additionally, the
presence of an alternative electron acceptor such as oxygen or nitrate
allows the sulfur oxidizing bacteria to oxidize organic acids.