Evaluation of optimal reuse system for hydrofluoric acid wastewater

► Coagulation and ion exchange technologies were ineffective in removing fluoride. ► Polyamide RO was more efficacious than cellulose RO due to its high flux and rejection. ► Spiral wound RO system was more preferential to disc tube RO system for reusing raw hydrofluoric acid wastewater. ► Combined coagulation and RO technology can be applied to reuse raw hydrofluoric acid wastewater. The treatment of hydrofluoric acid (HF) wastewater has been an important environmental issue in recent years due to the extensive use of hydrofluoric acid in the chemical and electronics industries, such as semiconductor manufacturers. Coagulation/precipitation and ion exchange technologies have been used to treat HF wastewater, but these conventional methods are ineffective in removing organics, salts, and fluorides, limiting its reuse for water quality and economic feasibility. One promising alternative is reverse osmosis (RO) after lime treatment. Based on pilot-scale experiment using real HF wastewater discharged from semiconductor facility, the spiral wound module equipped with polyamide membranes has shown excellent flux and chemical cleaning cycles. Our results suggest that coagulation/precipitation and spiral wound RO constitute the optimal combination to reuse HF wastewater.