High nutrient removal rate from swine wastes and protein biomass production by full-scale duckweed ponds

• Published in: Bioresource technology Vol. 112; pp. 98 - 104
• Main Authors: Mohedano, Rodrigo A., Costa, Rejane H.R., Tavares, Flávia A., Belli Filho, Paulo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-05-2012
• Subjects: Animals; Araceae - metabolism; Biodegradation, Environmental; Biomass; Biomass production; Duckweed pond; Landoltia punctata; Nitrogen - isolation & purification; Nutrient recovery; Phosphorus - isolation & purification; Plant Proteins - metabolism; Ponds; Seasons; Sus scrofa; Swine waste; Waste Disposal, Fluid; Swine waste; Landoltia punctata; Biomass production; Duckweed pond; Nutrient recovery
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2012.02.083

► Swine waste treatment by full-scale duckweed ponds. ► High nitrogen removal rate, one of the highest reported. ► Nitrogen removal ways presented different proportion, depending on nitrogen concentration. ► High protein biomass production (20times higher than soybean). ► High biomass densities reduce protein production and nutrients recovery rates.
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 (4.4g/m2day of TKN). Additionally, the dissolved oxygen level rose from 0.0 to 3.0mg/L, on average. The two ponds together produced over 13tons of biomass (68t/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.