2005 journal article

Role of internal nutrient storage in duckweed growth for swine wastewater treatment

Transactions of the ASAE, 48(6), 2247–2258.

By: S. Chaiprapat, J. Cheng*, J. Classen* & S. Liehr*

Source: NC State University Libraries
Added: August 6, 2018

The objective of this study was to investigate the relationship of the nutrient content of duckweed biomass toduckweed growth in swine wastewater. Batch tests of Spirodela punctata 7776, the selected strain for highest total proteinproduction, were conducted in an environment-controlled growth chamber at 24C and 16 h of light per day. A prolongedgrowth period was observed after the nutrients in the medium were exhausted, indicating that duckweed could use its storednutrients for growth. Prediction of growth using medium concentration as an independent variable was deemed unsuitableto describe this growth. Throughout the 30-day growing period, nitrogen and phosphorus content in the biomass varied from59.7 to 19.7 mgN/gbiomass and from 14.8 to 6.8 mgP/gbiomass (dry weight basis), respectively. The relationship between biomassnitrogen content and specific growth rate of Spirodela punctata 7776 was found to follow Monod-type kinetics with .max of0.24 gN/gbiomass/day and KN of 28.8 mgP/gbiomass. Reduced growth rate was observed in the duckweed culture with highduckweed density (mass per unit area). Effects of the duckweed density on growth rate and nutrient uptake are modeled anddiscussed.