INFLUENCE OF SEAWEED EXTRACT IN ENHANCING PHYTOREMEDIATION OF BIO-DIGESTER EFFLUENT BY DUCKWEED

Abstract

Enriching water bodies with nutrients contaminates water bodies. Whereas, the use of duckweed plants to restore eutrophied water bodies have been going on, treating duckweed with seaweed extract to increase N and P removal have not been adequately studied especially under the warm coastal Kenya. The objectives of this study were to determine; 1) the effect of SWE treatment on duckweed biomass accumulation and root elongation; 2) the amount of P and N extracted by SWE treated duckweed; 3) the optimum concentration level and number of applicati ons of SWE to enhance maximum N and P uptake by duckweed from the bio digester effluent. A randomized complete block design experiment, with factorial arrangements of treatments was used for this study. Duckweed plants were cultured in containerized bio-digester effluent and treated with concentrations of 0, 3, 6, 9 and 12μL SWE/L of effluent. Each concentration was applied at 0, 1, 2, 3 and 4 times. Duckweed biomass accumulation, roots elongation, tissue nitrogen and phosphorous and effluent nitrogen and phosphorous content were monitored at seven days interval for 28 days. The data collected was analyzed using Minitab (17th Edition) Software at α ≤ 0.05. The results revealed that four applications of 9μL SWE/L of effluent caused a significant (P ≤ 0.05) increase in duckweed biomass by 27%; and a reduction in effluent N and P by 24.3% and 13%, respectively. Seaweed extracts increased duckweed root length by 21.7%. Thus, seaweed extract can be used to enhance duckweed waste water management.