Ferrari Federico, Pijuan Maite, Rodriguez-Roda Ignasi, Blandin Gaetan
Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, 17003 Girona, Spain.
University of Girona, 17003 Girona, Spain.
Membranes (Basel). 2019 Aug 5;9(8):97. doi: 10.3390/membranes9080097.
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 m) to reach 70% water recovery. Membrane performance, fouling behavior, and effective concentration of wastewater compounds were examined. Two different draw solutions (NaCl and MgCl), 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 h 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 h and 4.8 ± 2.6 g m h 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.
将正向渗透直接应用于未经处理的城市污水，对于同时生产用于水回用的高质量渗透液以及对污水进行预浓缩以用于厌氧消化具有很高的吸引力。这项中试规模研究首次探讨了使用浸没式板框正向渗透模块（0.34米）浓缩实际未经处理的城市污水以实现70%的水回收率的可行性。研究了膜性能、污染行为以及污水中化合物的有效浓度。评估了两种不同的汲取液（氯化钠和氯化镁），一种以恒定汲取浓度运行，另一种随着时间推移以汲取液稀释的方式分批运行。还评估了气体鼓泡对污染和外部浓差极化的影响。以清水为进料液、35克氯化钠/升为汲取液时，清水通量高达15升·平方米·小时。使用实际污水时，浸没式正向渗透被证明具有抗堵塞能力，表明其适用于城市污水或其他复杂污水；在使用11.7克氯化钠/升的恒定汲取液运行时，观察到水通量和反向盐通量分别高达5.1±1.0升·平方米·小时和4.8±2.6克·平方米·小时。值得肯定的是，总化学需氧量和可溶性化学需氧量的浓缩系数分别达到了2.47±0.15和1.86±0.08，使得污水更适合厌氧处理。
