In the present study, P, Cu, and Zn profiles in swine wastewater
during an activated sludge treatment process were surveyed on 11
farms. In piggery wastewater, concentrations of these elements
were linearly correlated with the SS concentration, with most of
them occurring in solid fraction. They were removed from the liquid
fraction together with SS removal both by the pretreatment
step and by sludge removal during the activated sludge step. Most
of these elements in activated sludge effluent were in soluble fraction.
Concentrations of Cu and Zn in the effluent were sufficiently
low considering the discharge limit, while P removal may be
insufficient.