Application of disk tube reverse osmosis in wastewater treatment: A review

Disk tube reverse osmosis (DTRO), a modified module RO, has received growing attention in wastewater treatment. However, there is no comprehensive review of DTRO applications for wastewater treatment. In this study, China was found to be a major contributor to DTRO investigations. Specifically, 46 full- and 17 pilot-scale DTRO applications in China from the literature are summarized. The cumulative reported DTRO application scale in wastewater treatment amounted to ~16,500 m³/d by 2020 in China. Leachate and flue gas desulfurization (FGD) wastewater had the highest reported frequencies. Two-stage DTRO and "biological treatment + DTRO/two-stage DTRO" were the most reported processes in leachate treatment. Chemical oxygen demand (COD) and NH₄⁺-N were removed at 99.00-99.95% and 98.00-99.98%, respectively, in full scales in leachate treatment. DTRO was primarily utilized in the concentration unit in hypersaline wastewater treatment (e.g., FGD wastewater). Total dissolved solids (TDS) were removed at 94.69-96.87% and 85.95-96.5% in the full- and pilot-scales, respectively. The overall operating costs were 17.50-60.61 CNY/m³ and 0.69-8.75 CNY/kgCOD for leachate treatment and 26.94-52.28 CNY/m³ and 0.71-3.61 CNY/kgTDS for FGD wastewater treatment. The major components of operating costs were chemical costs (13.09 CNY/m³, 1.63 CNY/kgCOD) for two-stage DTRO and electricity costs (19.73 CNY/m³, 1.67 CNY/kgCOD) for the "biological treatment + DTRO/two-stage DTRO" process. DTRO has shown promising prospects for wastewater treatment.