OPERATIONAL CHANGES TO REDUCE ODOR EMISSIONS AT A CENTRAL NEW YORK WASTEWATER TREATMENT FACILITY

The Baldwinsville-Seneca Knolls Wastewater Treatment Facility uses a pure oxygen activated sludge system to treat wastewater flow wastewater generated by the towns on Lysander, Van Buren and Geddes. The facility is currently operating at approximately 40 percent of its 9 million-gallon per day capacity.Odor emissions from the facility are relatively low when compared to other municipal wastewater treatment facilities. However, the Onondaga County Department of Water Environment Protection (OCDWEP) received a number of odor complaints during 1999 and 2000. Odor control planning was initiated in response to these complaints and to mitigate odor complaints from new residential construction encroaching on the facility.Sear-Brown supported OCDWEP's proactive approach to odor control by recommending a cost-effective design that modified plant processes and incorporated existing structures for new odor control systems.An odor survey had pinpointed several primary sources of odor. Working with the OCDWEP and odor subconsultant Bowker Associates, Sear-Brown prioritized emission sources and evaluated treatment methods.Operations were modified to eliminate or reduce the cost of odor control improvements. For example, a water seal was used to trap odors from being released by the gravity pre-thickeners. The effect of the water seal was tested during the preliminary design phase. On average, odor concentrations were reduced by more than 95 percent. The hydraulic impact of the additional 144,000 gallons-per-day was reviewed for the 9-million-gallon-per-day facility and found to be minimal.To treat the headspace air from the pure oxygen aerobic digester, Sear-Brown worked closely with operations personnel. The operators increased the pressure within the aerobic digester and monitored its performance. Comfortable with system performance, the increased pressure was used to eliminate the need for the fan to transfer the air from the headspace to the aeration basin.Using the aeration basin as a “wet” biofilter also reduced the capital cost when compared to the conventional biofilter originally considered. It also reduced capital and operation costs while improving safety.The project also included improved ventilation within the screening room and treatment using a conventional biofilter, the biofilter was constructed on an abandoned sand drying bed.This paper presents the steps taken to develop the approach to these odor control concepts. It also presents the savings associated with the process modifications.