Duckweed ponds have been successfully used in swine waste polishing, generating a biomass with high
protein content. Therefore, the present study evaluated the efficiency of two full-scale duckweed ponds
considering nutrient recovery from a piggery farm effluent (produced by 300 animals), as well as the biomass
yield and crude protein (CP) content. A significant improvement in the effluent quality was
observed, with the removal of 98.0% of the TKN (Total Kjeldahl Nitrogen) and 98.8% of the TP (Total Phosphorous),
on average. The observed nitrogen removal rate is one of the highest reported (4.4 g/m2day of
TKN). Additionally, the dissolved oxygen level rose from 0.0 to 3.0 mg/L, on average. The two ponds
together produced over 13 tons of biomass (68 t/hayear of dry biomass), with 35% crude protein content.
Because of the excellent nutrient removal and protein biomass production, the duckweed ponds revealed
a great potential for the polishing and valorisation of swine waste, under the presented conditions