ODOR MONITORING AT THE CITY OF MONTREAL WASTE WATER TREATMENT PLANT

The City of Montreal Waste Water Treatment Plant (the Plant) is located in an urban area and has atreatment capacity of 3 million people-equivalents. Since 1998, the Plant has implemented an action plan to reduce odor emissions that were impacting neighboring residents or travellers using the adjacent highway. Odors do not constitute an acute public health hazard. On the other hand, they give rise to complaints and disputes. The sequence of record-breaking hot summers since 1998 contributed to a marked increase in the number of odor complaints linked to the Plant.Over the years, various complementary measures were implemented for ever-tighter odor monitoring designed to identify, quantify and mitigate nuisance odors:A residents' committee was set up to identify the various odors potentially emitted by the Plant, and the Plant set up a mechanism to allow these people to communicate their observations to the Plant;Several chemical tracer monitoring campaigns were carried out by the technical staff of the Plant,in conjunction with the residents' observations, in order to determine the odoremitting sources;A chemical monitoring of the odor treatment units was implemented in order to optimize their operation;Finally, a system of electronic noses was implemented for continuous monitoring of the main nuisance odor sources.These measures brought the plant engineering department to implement solutions to significantly reduce odor emissions as well as the number of observations and complaints received.This article describes the primary means used by the Plant for odor monitoring and electronic nosevalidation results.