APPLICATION OF UPDATED NATIONAL AMMONIA CRITERIA SAVES CAPITAL AND OPERATING EXPENSES

摘要

For approximately 20 years, EPA has been attempting to develop scientifically defensible ammonia criteria. However, these years of effort have not produced criteria that will withstand rigorous scrutiny. In particular, the 1984 Ammonia Criteria Document (by its own admission) was not intended to be applied to establish stringent ammonia limitations without site-specific justifications, and EPA has cautioned against its use for wasteload allocation purposes. The 1984 Criteria Document contains several specific caveats and recommendations intended to limit its application. Unfortunately, over 30 states have adopted the 1984 criteria without accounting for the specific recommendation on its usage. The application of the “wrong” criteria value has resulted in significant unnecessary costs to municipalities attempting to control ammonia discharges (particularly in winter months) at levels that are unnecessary to protect beneficial uses and misdirect local resources. In 1997, a coalition of municipal entities from Minnesota, Iowa, Kansas, California and Colorado petitioned EPA to update the 1984 Ammonia Criteria Document to reflect current scientific information. On December 22, 1999, EPA Headquarters released the 1999 Ammonia Criteria Update. In response to comments submitted by the municipal coalition, EPA made a number of significant adjustments (e.g., temperature, short term chronic criteria, design flows). The new criteria are substantially less restrictive under low pH/low temperature conditions than the 1984 Criteria Document. This paper reviews the major revisions contained in the 1999 Ammonia Criteria Update and specify how those changes affect effluent limitations for POTWs in a number of contexts.