Assessment of Water Quality: A Case Study of Recirculation Aquaculture System

Aquaculture's intensification requires water-saving systems to protect environmental quality. Thisstudy was designed to investigate the efficiency of a recirculating aquaculture system in theDepartment of Fisheries and Aquatic Resources Management in enhancing water quality. Fiveculture tanks were sampled before and a month after recirculation. Nutrient (ammonia, nitrate andphosphate) and physico-chemical parameters (conductivity, total dissolved solids, turbidity, pH)were analysed at the Water Research Institute Laboratory, Tamale. Our findings show thatrecirculation significantly improved water quality in general, with an average decrease of 66–96%in turbidity, total dissolved solids and conductivity. Also, nitrogenous and phosphorus fractionsdecreased markedly across all tanks, with ammonia reducing by >80% in almost all the samples andphosphate by >70%, which reflects excellent filtration capability. The variability in pH afterrecycling mirrored interactions between nitrification, carbon dioxide stripping and buffering,supporting the recommendation of precise pH control to reduce ammonia toxicity. One tank (E)consistently produced high ammonia, possibly owing to poor aeration, suggesting that site-specificoperational optimization is needed. In summary, the recirculating aquaculture system significantlyreduced nutrient loads, mitigated eutrophication risk and maintained water quality within WHOrecommended limits, progressing the sustainable fish production and water re-use. The operationalrecommendations were to reduce overfeeding, feed with precision and increase removal of solidwaste to reduce organic inputs before filtration. These results illustrate the robustness of recirculatingaquaculture system in nutrient removal and the control strategy for stable performance.