THE AFFECT OF TOXIC SUBSTANCES ON ODOR RELEASE FROM ANAEROBIC SYSTEMS

Measurements of sulfur gases in anaerobic system off-gas may have practical applications in anaerobic system monitoring and control, and sulfur compounds may be used as a surrogate indicator of toxicity. In this study, several toxicants are demonstrated to cause a release of methanethiol and dimethylsulfide from anaerobic systems. In the case of sodium toxicity, the magnitude of this release correlates directly with the sodium concentration.

In industrial wastewater treatment systems, large changes in a wastewater's constituents are typical, and the conclusions presented here are relevant to day-to-day operations. In municipal systems, large increases in the influent concentration of toxic compounds may occur from industrial discharges, whether these discharges are accidental, intentional and illegal, or intentional and permitted. Regardless of the source or nature of toxic compounds in the influent to an anaerobic system, measurements of sulfur gases in anaerobic system off-gas, especially real-time or frequent measurement, may have practical applications in anaerobic system monitoring and control.

Changes in system odor, as detected by operations personnel, may be the first sign that a system is receiving a toxic influent or that a system is undergoing process upset. Changes or an increase in odor may serve as a trigger to begin closer monitoring of volatile acids, pH and, if possible, influent constituents. If the concentration of sulfur gases in anaerobic system headspace can be monitored on a continuous or regular basis, it may be possible by rapid intervention to prevent anaerobic system failure, i.e. the cessation of methanogenesis and the concurrent drop in reactor pH and rise in volatile acid concentration (“sour digester”).