Theory to Practice: Oxygen Transfer and the New ASCE Standard

Oxygen transfer is an important part of wastewater treatment and accounts for as much as 60% of the energy consumption for the activated sludge process. Prior to 1984, no standard method for quantifying oxygen transfer existed, which created problems in the design and warranties for treatment plants. The ASCE Standard for the Measurement of Oxygen Transfer in Clean Water and the ASCE Standard Guidelines for In-Process Oxygen Transfer Testing have found widespread application and have reduced the variability in new designs and allowed operators and engineers to access the process operation of existing treatment plants. A new clean water standard is in press as of this writing and the in-process Guidelines are undergoing updating for reissue. This paper illustrates the key concepts of both the Standard and the Guidelines and shows why they are important and reduced the variability of testing. The paper also highlights key new areas of the revised clean water Standard, which includes an optional correction for test water total dissolved solids concentration, and applications to loop (ditch) activated sludge process and the high purity oxygen activated sludge process.