The U.S. Environmental Protection Agency (EPA) has established a program to identify emerging wastewater technologies that may be currently considered high risk but could potentially result in significant cost and energy savings over conventional technologies. As part of this program, EPA has sponsored studies to assess the current status, capabilities, and potential applications of emerging technologies. This paper presents an assessment of phased isolation ditch technologies currently used in Denmark. The technologies studied are the type VR, T and DE ditches. They include process modifications to T and DE ditches for nitrogen ad phosphorus removal.