Nutrient removal can be expensive. To meet new nitrogen limits for the 7.1 mgd wastewater treatment plant in Amherst, Mass., a state study determined that a $61 million upgrade was needed. Instead, the city is getting the job done for $75,000 by making informed process changes.
Instead of pursuing the traditional facility planning, design and construction pathway to permit compliance, the Amherst staff, led by Jim Laford, superintendent, experimented with new ways of operating their 1979 vintage facility.
After a few failed attempts at dialing in ammonia and nitrate removal, the staff found that cycling the plant’s mechanical aerators to alternate highly
