The major objective of this study was to operate a full-scale single-stage nitrification-denitrification plant without methanol addition to determine the feasibility and reliability of the process, the design features needed to be incorporated by engineers, and the operating techniques to be employed to ensure optimum performance. Because nitrification-denitrification can become more difficult to operate under extreme cold wastewater temperatures, a full-scale plant located at Owego, New York, was selected which performs under wastewater temperatures ranging from 8 degrees to 22 degrees C. Alternating aerobic-anoxic conditions were achieved in completely mixed reactors by the on-off cycling of mechanical aerators. The following results and conclusions were determined from these studies: Single-stage nitrification-denitrification is a viable nitrogen removal process; and, nitrogen removals of from 76 to 86 percent were normally accomplished with hydraulic retention times of 13 to 27 hours, depending upon wastewater temperature and strength. BOD and suspended solids reductions were well above 90 percent.

"EPA-600/2-77-088." "August 1977." "Grant no. 803618-01." "Project officer, E. F. Barth, Wastewater Research Division, Municipal Environmental Research Laboratory." Includes bibliographical references (pages 62-63).