A decrease in the nitrogen discharge from wastewater effluent has been mandated by the U.S. Environment Protection Agency (EPA) under the National Pollutant Discharge Elimination System (NPDES) program to minimize the nitrogen loading into the Chesapeake Bay. Meeting this regional objective requires increasing the denitrification treatment capacity at the District of Columbia Water and Sewer Authority's (DC Water) wastewater treatment plant by constructing a new Enhance Nitrogen Removal Facilities (ENRF). This will increase methanol usage during denitrification, requiring regulated air permitting prior to construction and facility operation. It also requires implementation of O&M practices that mitigate methanol emissions, and periodic compliance filing to regulatory agencies. This paper discusses design, construction, and operating considerations including: a) implications on equipment and process design and operation b) integration of permit conditions into design and operation of ENRF system, and c) emissions mitigation and management through monitoring, O&M programs and software tools.

This paper will discuss some of the unique challenges presented by the coordination of programs with multiple projects at various phases and contract delivery methods with preconstruction air permitting requirements in an operating plant. DC Water is implementing one of the nation's most ambitious and innovative biosolids management programs. The new and upgraded biosolids facilities will replace the current primary and biological sludge centrifuge dewatering process followed by lime stabilization with a thermal hydrolysis and mesophilic anaerobic digestion process followed by belt filter press dewatering. The Biosolids Management Program divided the work to be done for the new biosolids facilities into five main contracts: Site Preparation (a design-bid-build contract); Main Process Train (design-build); Combined Heat and Power (design-build-operate); and Final Dewatering Facilities (design-bid-build-bid as two separate contracts. Based on the aggregation rule, the biosolids program emission sources under the various projects are considered together and are included in one air permit application. This paper will expand on the challenges of acquiring an air permit for several projects with different delivery methods for an existing large facility in collaboration with other on-going large projects and existing air permit applications for a large advanced wastewater facility. 4491 WEFTEC 2012