Advanced Biofloc Technology: A Closed-Loop Automated Feedback System for Energy-Efficient, Water-Conservative, and Sustainable Aquaculture Production

Egypt confronts an urgent convergence of food-security, water- scarcity, and technological-underutilisation crises that collectively impede sustainable agricultural and aquacultural development. Automated, resource-efficient solutions that address these systemic gaps at the nexus of engineering and biology are critically needed. This study presents the design, construction, and experimental validation of a fully automated Biofloc Technology (BFT) aquaculture feedback system for Nile Tilapia (Oreochromis niloticus) production, integrating real-time ammonia sensing, microcontroller- driven pump actuation, and precision molasses dosing within a closed-loop water- management architecture. A prototype consisting of four modular containers, three peristaltic water pumps, an MQ135 ammonia gas sensor, and an Arduino Uno microcontroller was engineered and deployed. Three auxiliary containers managed the water-exchange cycle and molasses reservoir; the primary tank housed the culture system. Sensor-triggered logic governed a 10% volumetric water-exchange rate and dispensed 5–10 mL L−1 of molasses proportionally to detected ammonia concentration. Parameters including Feed Conversion Ratio (FCR), fish survival rate, total biomass, and water-quality indices (nitrate, nitrite, dissolved oxygen, pH, ammonia) were assessed over a 21-day trial at the National Research Center, Dokki. Results. The system achieved a mean FCR of 1.8 — consistent with validated BFT bench- marks for tilapia — and a mean fish survival rate of 88.6%, within the accepted range of 70–90%. Total biomass increased from 150 g at baseline to 202.43 g by Day 21, representing a 34.9% growth increment. Post-molasses water quality showed marked improvement across all nitrogen-cycle metrics. This work demonstrates that low-cost microcontroller automation can ef- fectively replicate the precision of laboratory-grade BFT management, offering a scalable, energy-efficient, and economically accessible pathway for sustainable aquaculture intensifi- cation in resource-constrained regions.