•Strong acidity removes the economic hurdle of fluidized struvite crystallization.•A 12 m3/d pilot-scale system is built to evaluate the performance on-site.•P recovery rate is achieved at 99.2% via internal circulation mode.•Using MgO with MgCl2 supplement reduces 42.8% of the reagent cost.•Struvite technology saves up to 31.33 million CYN over 20 years at 500 m3/d scale. Production of wood-based activated carbon (WAC) generates large volume of highly acidic and phosphate-rich wastewater. Currently, the routine treatment (i.e. lime precipitation) creates significant secondary pollution, leading to extra economic and environmental burdens. Here, by exploiting the strong acidity of WAC wastewater, we successfully demonstrate fluidized struvite crystallization as a low-cost treatment alternative. Based on a 12 m3/d on-site pilot-scale system, four different fluidized struvite crystallization scenarios are evaluated from technical, economic, and environmental perspectives. The results show that using MgO with MgCl2 supplement saves 42.8% of the reagent cost when treating phosphate-rich wastewater (i.e. P = 3125.2 mg/L), and also maintains ideal P removal rate and struvite product purity. Meanwhile, the internal circulation mode exhibits higher P recovery (99.2%) than the external mode (55.3%-89.3%), while also demonstrates superior economic and environmental benefit because of less chemical consumption. In addition, the struvite morphology can be turned between pellets with strong crushing strength (external mode) to powder (internal mode). By Life cycle cost (LCC) analysis, we find that, on a treatment scale of 500 m3/d, struvite-based technology saves up to 31.33 million Chinese Yuan (CYN) during a 20-year lifespan, with relative payback period of 2.60 year. The technical, economic, and environmental assessments confirm that the struvite technology is a promising alternative in solving the bottleneck of WAC wastewater treatment. Display omitted