NEW Water’s Challenge to Achieve Compliance With New Sewage Sludge Incinerator Rules for Existing and New Incinerators

The Green Bay Metropolitan Sewerage District (GBMSD), also known by its brand name, NEW Water, operates a 113,600 cubic meters per day (30 mgd) average daily flow municipal wastewater treatment plant in Green Bay, Wisconsin, and a 30,280 cubic meters per day (8 mgd) average daily flow plant in nearby De Pere, Wisconsin. This presentation will describe how GBMSD has prepared for compliance with challenging new air pollution rules for sewage sludge incinerators.GBMSD uses incineration to manage biosolids and operates under a Title V air pollution control operation permit issued by the Wisconsin Department of Natural Resources (WDNR). Two multiple hearth incinerators have operated since the 1970s and are subject to the Emissions Guidelines (EG) for Existing Sewage Sludge Incineration (SSI) Units issued by the United States Environmental Protection Agency (US EPA) under 40 CFR 60, Subpart MMMM. In addition to new, more stringent, emission limits for nine pollutants, Subpart MMMM established rigorous new requirements for monitoring, recordkeeping, operator training, and reporting. The rules have posed many regulatory challenges for GBMSD, a number of which are described herein.The SSI rules were a primary driver for a project that GBMSD has undertaken to replace the existing solids handling system at its Green Bay facility. (The other two drivers were aging infrastructure and the increased volume of solids that occurred when GBMSD’s Green Bay facility combined with the De Pere facility. After the consolidation of the two facilities, waste activated sludge was transferred from De Pere to Green Bay via pipeline for processing.)As part of the project, a single fluid bed incinerator (FBI) will replace the two existing multiple hearth incinerators (MHIs). The new FBI is expected to be installed and operational in 2018 and will be subject to the New Source Performance Standards (NSPS) for new SSIs under 40 CFR 60, Subpart LLLL. Because both sets of SSI rules have a compliance deadline of March 21, 2016, during the time between the compliance deadline and the de-commissioning of the existing MHIs, the existing incinerators will be subject to the SSI rules.Pollutant emissions from the existing MHIs have been tested on numerous occasions throughout the years. A comparison of historical results to the new emission guidelines found that emissions of several pollutants had been within the new limits, but emissions of nitrogen oxides (NOx) were borderline compliant. Because there are few engineering controls available that can reduce NOx without increasing emissions of other pollutants, GBMSD was unsure that its incinerators could meet the new limits during the time it would be subject to Subpart MMMM.In addition to new emission limits, the SSI rules established training, monitoring, recordkeeping, and reporting requirements. Some of these requirements are in conflict with a separate set of regulations that GBMSD’s MHIs are already subject to, the Standards of Performance forSewage Treatment Plants under 40 CFR 60, Subpart O, resulting in redundant monitoring and recordkeeping practices. Operator training requirements in Subpart MMMM require the development of an extensive, site-specific training course to administer to GBMSD’s team of experienced, skilled operators, to ensure that they meet the EPA’s criteria for qualified operators.This presentation will describe these and other challenges GBMSD faced to bring two 40-year-old incinerators into compliance with new air rules for a very brief time while a new FBI is constructed.