Presentation Title

Nutrient removal from wastewater effluent using duckweed

Faculty Mentor

Monica Palomo, Natalie Mladenov

Start Date

18-11-2017 12:30 PM

End Date

18-11-2017 1:30 PM

Location

BSC-Ursa Minor 110

Session

Poster 2

Type of Presentation

Poster

Subject Area

engineering_computer_science

Abstract

Ensuring availability and sustainable management of water and sanitation for all is one of the 17 United Nations Sustainable Development Goals. There are concerted efforts to use reclaimed wastewater for agricultural use and minimize eutrophication. Decentralized wastewater treatment systems (DEWATS) worldwide improve sanitation and promotes agricultural water reuse applications. Research using aquatic plants like duckweed, which naturally grows in surface water rich in phosphate and ammonia, has been broadly investigated. The effluent from an anaerobic baffled reactor coupled with anaerobic filters (AF) of the DEWATS located in Durban, South Africa was used in this study. The objective was to determine the kinetics of nutrient removal by duckweed, for potential use in the future as a polishing treatment for DEWATS effluent. Two duckweed species, Lemna minor and Wolffia arrhiza, were grown in batch and continuous systems containing AF effluent over a four day period. Grab samples were collected twice a day from both systems to test concentrations of ammonia, nitrate, nitrite, and orthophosphate.

Results showed minimal effectiveness by both duckweed species in reducing nutrient concentrations. Ammonia removal was variable and generally ranged from 0-26% removal. Nitrate and nitrite concentrations were often below detection limits (0.3 mg/L NO3 and 2 mg/L NO2) or had very low concentrations. Phosphate concentrations were variable with no clear trends observed. The lack of nutrient removal over the shorter duration of these experiments suggests that longer residence times may be needed to determine kinetics for nutrient removal with duckweed.

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Nov 18th, 12:30 PM Nov 18th, 1:30 PM

Nutrient removal from wastewater effluent using duckweed

BSC-Ursa Minor 110

Ensuring availability and sustainable management of water and sanitation for all is one of the 17 United Nations Sustainable Development Goals. There are concerted efforts to use reclaimed wastewater for agricultural use and minimize eutrophication. Decentralized wastewater treatment systems (DEWATS) worldwide improve sanitation and promotes agricultural water reuse applications. Research using aquatic plants like duckweed, which naturally grows in surface water rich in phosphate and ammonia, has been broadly investigated. The effluent from an anaerobic baffled reactor coupled with anaerobic filters (AF) of the DEWATS located in Durban, South Africa was used in this study. The objective was to determine the kinetics of nutrient removal by duckweed, for potential use in the future as a polishing treatment for DEWATS effluent. Two duckweed species, Lemna minor and Wolffia arrhiza, were grown in batch and continuous systems containing AF effluent over a four day period. Grab samples were collected twice a day from both systems to test concentrations of ammonia, nitrate, nitrite, and orthophosphate.

Results showed minimal effectiveness by both duckweed species in reducing nutrient concentrations. Ammonia removal was variable and generally ranged from 0-26% removal. Nitrate and nitrite concentrations were often below detection limits (0.3 mg/L NO3 and 2 mg/L NO2) or had very low concentrations. Phosphate concentrations were variable with no clear trends observed. The lack of nutrient removal over the shorter duration of these experiments suggests that longer residence times may be needed to determine kinetics for nutrient removal with duckweed.