A multi-year research developed since 2003 between the University of Trento, Italy, and the Politehnica University of Bucharest, Romania, allowed defining a few design criteria useful for the optimization of the energy balance and for the minimization of the environmental impact. The design parameters for the biological process are related to the varying food waste content of the input. Values come from pilot scale runs. The design criteria for the environmental impact management refer to the underestimated role of odor and PCDD/F emissions.