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

Abstract

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/m(2)day of TKN). Additionally, the dissolved oxygen level rose from 0.0 to 3.0mg/L, on average. The two ponds together produced over 13 tons of biomass (68 t/ha year 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.

Potential of duckweed in the conversion of wastewater nutrients to valuable biomass: A pilot-scale comparison with water hyacinth

“…As a result of the higher NO 3 À AN concentrations (approximately 8 mg/L) in summer and autumn (from agricultural wastewater washed by rain), the influent TN concentrations, conversely, were significantly higher (P < 0.05) in summer and autumn than in winter and spring. Table 2 also shows that the effluent NO 3 À AN concentrations of DWS and WHS were significantly higher (P < 0.05) than the influent in winter and spring, which was most likely because of the nitrification by nitrifying bacteria (Mohedano et al, 2012). The higher mat density of water hyacinth might have resulted in significantly lower (P < 0.05) dissolved oxygen concentrations (DO) and pH in the WHS than in the DWS throughout the year (Table 2).…”

Biological removal of triphenylmethane dyes from aqueous solution by Lemna minor

“…5,6 The free-floating aquatic plant, Lemna minor, is considered to be an ideal test system for water remediation research [7][8][9] because of its physiological properties (small size, big surface) and high multiplication rate. 10,11 Lemna minor is considered one of the fastest growing plants, with a productivity of 10-30 tons of dry mass/ha·year, confirmed by Bich, 12 having a good capacity to adapt to different conditions, like a wide range of pH (4.5-8.3), temperature (6-33 °C), and different kinds of wastewaters. 13,14 Recent studies have reported that Lemna minor has great potentials in the phytoremediation of inorganic pollutants.…”

Treatment of recirculating water of industrial fish farms in phytoreactor with Lemnoideae

“…Lemnoideae is used as feed organisms for animals [4,5], treatment agents for the treatment of domestic and industrial wastewater [6,7], raw materials for biofuel production [8]. Interest in waste water as treatment agents of polluted water in fish farms is justified by the intensity of removal of biogenic elements and the possibility of efficient utilization of the growth of plant biomass as food for fish [9].…”

“…Thus, even when treatment heavily contaminated wastewater in ponds with Lemnoideae processes of extraction of ammonium nitrogen and phosphates proceed several times faster than by nitrification followed by denitrification [5].…”