What would you do if your state regulatory agency hit you with a stringent nutrient removal standard three years before your plant was due to be upgraded to biological nutrient removal (BNR)?If you’re the operating staff in Bozeman, Mont., you put on your thinking cap and make process changes to your activated sludge system and cut total nitrogen discharges by 45 percent. “We appealed the new standards, basing our case on the lack of a compliance schedule, and won an extension,” explains Tom Adams, plant superintendent. “But we asked ourselves, ‘What could we do quickly to reduce our nitrogen discharge?’”The
