THE EVOLUTION OF ODOR CONTROL AT A REGIONAL WASTEWATER TREATMENT FACILITY

Odor control was not a design concern in the late 1970's when the Mattabassett District, a 20 million gallon per day (MGD) regional wastewater treatment facility located in Cromwell, Connecticut, began the design to upgrade its plant to include secondary treatment. The plant was originally designed and constructed in the 1960's as a physical/chemical treatment plant that used both lime andferric chloride in the treatment process. In the late 1980's, the upgrade was completed with a newwaste activated sludge secondary treatment system. As the use of ferric chloride and lime were phased out, typical wastewater treatment system odors were no longer treated and the odors became both a problem and a public issue for The District.In response to citizens' complaints and eventually a Connecticut Department of Environmental Protection (CTDEP) administrative order, The District embarked on a long and arduous program to eliminate, contain, control and treat its wastewater treatment facility odors. The odor control challenges faced by The District are somewhat unique in that it is one of the few plants in Connecticut to operate a 1.55 dry ton per hour biosolids fluidized bed incinerator and also accept outside sludgeand septage to supplement its operations on a 24 hours per day, seven days per week basis.This paper discusses the evolution of The District's odor control programs, its use of emerging technologies for odor control, and the experience it has gained over the past thirteen (13) years with containing, controlling and eliminating odors. Discussion is provided on many of the valuable lessons by The District from the installation and operation of odor containment and control technologies such as biofilters, wet chemical scrubbers with activated carbon polishing, chemical oxidizers, odor counteractants, thermal incineration of odorous air with The District.s fluidized bed incinerator, and New England's first bioscrubbing system.