Year-round phytofiltration lagoon assessment using Pistia stratiotes within a pilot-plant scale biorefinery

Phytofiltration lagoons are phytoremediation technologies suitable for tropical and sub-tropical regions requiring cost-effective and echo-friendly technologies. A biorefinery of fourth generation has been implemented at pilot plant level in Xalapa, Mexico, and the phytofiltration lagoon, being the first module for provision of treated water and plant biomass for biofuel production plays a key role. The aim of this work was to evaluate the performance of such phytofiltration lagoon with a working volume of 13,000 L for the removal of nutrients from an urban river polluted with domestic wastewater and the biomass productivity of the macrophyte Pistia stratiotes, during five different experimental periods, comprising 42 days each one. The maximum absolute growth rates (AGR, gdwday−1) registered for P. stratiotes during the Aug–Oct '15 and the March–Apr '16 and Apr–May '16 period were in the range of 13.51±2.66 to 16.54±2.02gdwday−1. The average biomass productivity was 5.808gdwm−2day−1. Productivities were similar during the periods of Aug–Oct '15, Mar–Apr '16 and Apr–May '16 and significantly higher (p