Iranian Research Organization for Science and Technology Advances in Environmental Technology 2476-6674 9 2 2023 04 01 A pilot study on the removal of ammonia from aqueous solution using the integration of struvite synthesis and breakpoint chlorination 85 97 1275 10.22104/aet.2023.5912.1623 EN Muyahavho E Mugwili Water Pollution Monitoring and Remediation Initiatives Research Group, School of Chemical and Minerals Engineering, North-West University, South Africa Magalies Water, Scientific Services, Research & Development Division, South Africa Frans Boudewijn Waanders Water Pollution Monitoring and Remediation Initiatives Research Group, School of Chemical and Minerals Engineering, North-West University, South Africa Vhahangwele Masindi Magalies Water, Scientific Services, Research & Development Division, South Africa Department of Environmental Sciences, College of Agriculture and Environmental Sciences, University of South Africa (UNISA), South Africa Council for Scientific and Industrial Research (CSIR), Smart Places, Water Centre, Water and Wastewater Research Group, South Africa Elvis Fosso-Kankeu Institute for Nanotechnology and Water Sustainability (iNanoWS), College of Science Engineering and Technology (CSET), University of South Africa, Florida Science Campus, South Africa Department of Mining Engineering, College of Science Engineering and Technology, University of South Africa, Florida Science Campus, South Africa Journal Article 2022 10 17 Herein, a pilot study on the removal of ammonia from surface water using the integration of struvite precipitation and breakpoint chlorination is reported. A two staged pilot plant with a capacity of 1000 liters (1 m³) per run (LPR) was utilized, of which Stage 1 comprised struvite precipitation and Stage 2 comprised breakpoint chlorination. Optimum conditions (i.e., Stage 1) for struvite precipitation were 110 mg/L of Mg and P dosage (concentration), 150 rpm of mixing speed, 60 minutes of contact time, and lastly, 120 minutes of sedimentation, while optimum condition for the breakpoint chlorination (i.e., Stage 2) were 30 minutes of mixing and an 8:1 Cl₂-NH₄⁺ weight ratio. The synergistic effects of this hybrid system proved to be effective, with Stage 1 increasing the pH from 6.8 to 10.1, reducing Mn (≥97.0%) and Fe (≥99.6%) concentrations steeply, and concomitantly deactivated <em>E coli</em> and TPC to ≥ 99% and ≥91%, respectively, while ammonia was reduced from 5.4 mg/L to 2.7 mg/L-N (51.8 %). In Stage 2, i.e., breakpoint chlorination, ammonia was reduced from 2.7 mg/L to 0.02 mg/L-N whilst fully depleting residual microorganisms. Finally, the OPEX amounted to $ 0.31/m³; however, there is a potential for cost savings (≈53.2%) by replacing Kh₂PO₄ with waste phosphoric acid. Lastly, the results from this techno-economic evaluation study showed great potential compared to similar technologies, making this approach a game-changer towards the prudent management of elevated levels of ammonia amongst other problematic contaminants. https://aet.irost.ir/article_1275_32a8d1cdc17539c298dd16753bb56c95.pdf