Direct contact membrane distillation for surface water treatment and phenolic compounds retention: From bench to pilot scale

Abstract

Membrane distillation has been applied in water treatment for micropollutant retention, such as phenols. Direct contact membrane distillation (DCMD) is the most studied configuration at the bench scale. Translating lab-scale results to large-scale experiments requires attention. In general, by combining both experiment's results, optimal settings, and process conditions can be better determined. Thus, the DCMD scaling up for water treatment and phenols retention was evaluated. As expected, permeate flux reduced considerably from bench to pilot scale (15.8 ± 0.8–2.9 ± 0.1 kg m−2 h−1) due to the inflow energy limitations, membrane compaction, and temperature polarization. Increasing the permeate recovery (50–70 %) did not affect the permeate flux and the compound's retained in both systems. The pilot system was validated with different surface water matrices (14.2, 92.5, and 162 NTU), proving the DCMD robustness. In all operational conditions, the permeate reached the water quality guideline required for human consumption demonstrating the technology consistency and reliability. A preliminary economic analysis, considering three different scenarios (distributed system for communities, mobile system, and polishing for conventional WTP), showed the DCMD as a relatively competitive technology for the application in drinking water polishing (US$ 0.50–0.19/m3).