Aquaculture waste nutrients removal using microalgae with floating permeable nutrient uptake system (FPNUS)

Area of Science:

• Environmental Engineering
• Aquatic Biotechnology
• Wastewater Treatment Technologies

Background:

• Microalgae applications in wastewater treatment are limited by large area and energy demands.
• Developing efficient nutrient removal systems is crucial for sustainable wastewater management.

Purpose of the Study:

• To evaluate the efficacy of a floating permeable nutrients uptake system (FPNUS) for in-situ nutrient removal.
• To assess the impact of membrane pore size on nutrient transfer rates and microalgal growth.
• To determine the feasibility of FPNUS for wastewater treatment, particularly in aquaculture systems.

Main Methods:

• Tested FPNUS with varying pore sizes (1, 5, 10, 40 µm) using Chlorella sorokiniana and Scenedesmus acuminatus.
• Measured nitrogen (N) transfer rates across membranes for different N forms (NH₄⁺-N, NO₃⁻-N, NO₂⁻-N).
• Calculated nutrient removal rates in shrimp wastewater and developed an area ratio prediction model.

Main Results:

• Nitrogen transfer rates varied with membrane pore size and N-type; 1 µm membrane showed high transfer rates sufficient for microalgal growth.
• Ammonium-N and nitrate-N removal rates in shrimp wastewater were comparable to conventional biological nutrient removal (BNR) processes.
• A FPNUS to pond area ratio of 21% was predicted to balance a nitrogen loading of 0.05 mg L⁻¹d⁻¹.

Conclusions:

• FPNUS offers an effective solution for in-situ nutrient removal from wastewater.
• The system shows potential for reducing the footprint and energy consumption of microalgae-based wastewater treatment.
• FPNUS presents a promising technology for sustainable nutrient management in various wastewater applications.