Date of Defense
4-2026 11:00 AM
Location
Microsoft Teams
Document Type
Thesis Defense
Degree Name
Master of Science in Environmental Sciences and Sustainability
College
COS
Department
Biology
First Advisor
Prof. Taoufik Ksiksi
Keywords
Duckweed, Biomass, Lemna minor, Harvest, Nutrient Removal, Photosynthetic Efficiency, Saline Water, Tap Water, Greywater, Shoot-root
Abstract
This thesis is concerned with determining the optimal water treatment and harvesting strategy for Lemna minor duckweed plants. The main objective of this thesis is to examine how duckweed plants grow in terms of biomass, photosynthetic activity, leaf morphology, chlorophyll and carotenoid content, and their efficiency in nutrient removal from different water sources. The methodology of the study included assessing duckweed in three water samples including tap water, saline water, and greywater and three harvesting strategies, including low, medium, and high harvesting intensities to determine their growth and nutrient removal efficiency. The results of the study showed that L.minor grown in tap and greywater had significantly higher wet biomass, photosynthetic efficiency, and leaf growth, compared to duckweed grown in saline water. Additionally, the harvesting intensity and water treatment yielded significantly different biomass and photosynthesis efficiency. Low harvesting intensity in greywater and medium harvesting intensity in tap water provided the most balanced outcomes, combining higher biomass, higher photosynthesis efficiency and greater morphological traits. Tap water and greywater duckweed samples showed higher shoot-root ratio, while saline water samples had no root development. However, across all three water treatments, there was no nutrient uptake by the plants and instead, the nutrient concentrations in the water increased. The significant contribution of this study includes the assessment of duckweed growth across various water treatments and harvesting strategies. The study fills a research gap by assessing the effect of saline, tap and greywater on duckweed, rather than focusing on wastewater, as most of the studies in the literature.
Included in
Optimizing Duckweeds Harvesting Strategies to Maximize Nutrient Recovery and its role as a Phytosensor in Different Water Sources while Maximizing Sustainable Biomass Growth
Microsoft Teams
This thesis is concerned with determining the optimal water treatment and harvesting strategy for Lemna minor duckweed plants. The main objective of this thesis is to examine how duckweed plants grow in terms of biomass, photosynthetic activity, leaf morphology, chlorophyll and carotenoid content, and their efficiency in nutrient removal from different water sources. The methodology of the study included assessing duckweed in three water samples including tap water, saline water, and greywater and three harvesting strategies, including low, medium, and high harvesting intensities to determine their growth and nutrient removal efficiency. The results of the study showed that L.minor grown in tap and greywater had significantly higher wet biomass, photosynthetic efficiency, and leaf growth, compared to duckweed grown in saline water. Additionally, the harvesting intensity and water treatment yielded significantly different biomass and photosynthesis efficiency. Low harvesting intensity in greywater and medium harvesting intensity in tap water provided the most balanced outcomes, combining higher biomass, higher photosynthesis efficiency and greater morphological traits. Tap water and greywater duckweed samples showed higher shoot-root ratio, while saline water samples had no root development. However, across all three water treatments, there was no nutrient uptake by the plants and instead, the nutrient concentrations in the water increased. The significant contribution of this study includes the assessment of duckweed growth across various water treatments and harvesting strategies. The study fills a research gap by assessing the effect of saline, tap and greywater on duckweed, rather than focusing on wastewater, as most of the studies in the literature.