Maximizing Benefits from Municipal Wastewater Treatment Plant Air Permits

Many municipal wastewater treatment plants are finding themselves subject to increasingly complex air quality regulations. Relatively small reciprocating engines burning digester gas trigger the need for state or federal air construction permits. New digester gas fired boilers larger than 10 million BTU per hour are likely subject to Federal New Source Performance Standards (NSPS). Emissions of volatile hazardous air pollutants from wastewater treatment and solids handling operations may be subject to the Federal National Emission Standards for Hazardous Air Pollutants (NESHAP) for Publicly Owned Treatment Works. Title V operating permits (also known as "Part 70" permits) are increasing the recordkeeping and reporting obligations for wastewater treatment plants. In this paper we present some regulatory alternatives available to wastewater treatment plants to help minimize their air permitting requirements. We show exemption levels for several air permitting and regulatory programs. In addition, we present opportunities available to wastewater treatment plants to receive benefits related to their air emissions. For example, electricity generated from the combustion of digester gas or biosolids may be considered a "renewable resource". Utilities in several states are either required or encouraged to provide a portion of their electrical production from renewable resources which provides treatment plants with a financial benefit opportunity.