It is estimated that an investment of 18.1 billion dollars will be required for the construction of municipal wastewater treatment facilities in the United States to meet the projected 1976 Federal State Water Quality Standards (1). Approximately one fourth of this amount will be used for upgrading the performance of the existing wastewater treatment facilities. The application of todays technology in upgrading plant performance includes (a) techniques that can be used to maintain the original treatment plant efficiency under increasing organic and/or hydraulic loading, (b) the addition of processes that can be used to increase overall plant removal efficiencies and (c) process additions or modifications for specific contaminant removal. Physically, these upgrading procedures may be applied ahead of the plant; as modifications of the treatment process itself; or as effluent polishing techniques. The report describes these upgrading procedures.