ABSTRACT
This chapter provides a critical reflection on the results obtained in this investigation, their limitations and challenges. The faecal indicators concentrations measured in the treated effluent confirmed that they are not entirely removed from the raw wastewater, regardless of the type of treatment. The addition of particulate material in the reactors promoted the overgrowth of protozoa, contributing to removing solids. It was expected that the high abundance of protozoa would also result in the removal of a considerable number of pathogens. A good chemical performance, mainly based on chemical oxygen demand and phosphorus removal, guaranteed the system stability. Long operational times were required to achieve nitrification/denitrification. Predation by protozoa is more efficient than adsorption for the removal of pathogens from the liquid bulk during the aeration phase, which was confirmed in the aerobic granular sludge (AGS) laboratory-scale reactors.
