Exploring Submerged Forward Osmosis for Water Recovery and Pre-Concentration of Wastewater before Anaerobic Digestion: A Pilot Scale Study

Membranes

Federico Ferrari¹  Maite Pijuan¹  Ignasi Rodriguez-Roda¹  Gaetan Blandin² 

[1] Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, 17003 Girona, Spain;LEQUiA, Laboratory of Chemical and Environmental Engineering, Campus Montilivi, University of Girona, 17071 Girona, Spain;

关键词: forward osmosis;    real municipal wastewater;    pilot scale;    submerged membrane;    anaerobic digestion;    water reuse;    wastewater concentration;   

DOI  :  10.3390/membranes9080097

来源: DOAJ

【 摘 要 】

Applying forward osmosis directly on raw municipal wastewater is of high interest for the simultaneous production of a high quality permeate for water reuse and pre-concentrating wastewater for anaerobic digestion. This pilot scale study investigates, for the first time, the feasibility of concentrating real raw municipal wastewater using a submerged plate and frame forward osmosis module (0.34 m²) to reach 70% water recovery. Membrane performance, fouling behavior, and effective concentration of wastewater compounds were examined. Two different draw solutions (NaCl and MgCl₂), operating either with constant draw concentration or in batch with draw dilution over time, were evaluated. Impact of gas sparging on fouling and external concentration polarization was also assessed. Water fluxes up to 15 L m⁻² h⁻¹ were obtained with clean water and 35 g NaCl/L as feed and draw solution, respectively. When using real wastewater, submerged forward osmosis proved to be resilient to clogging, demonstrating its suitability for application on municipal or other complex wastewater; operating with 11.7 g NaCl/L constant draw solution, water and reverse salt fluxes up to 5.1 ± 1.0 L m⁻² h⁻¹ and 4.8 ± 2.6 g m⁻² h⁻¹ were observed, respectively. Positively, total and soluble chemical oxygen demand concentration factors of 2.47 ± 0.15 and 1.86 ± 0.08, respectively, were achieved, making wastewater more suitable for anaerobic treatment.

【 授权许可】

Unknown