Reclamation of high-salinity wastewater using a forward osmosis and nanofiltration (FO-NF) demonstration plant

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1 Reclamation of high-salinity wastewater using a forward osmosis and nanofiltration (FO-NF) demonstration plant Teresa de la Torre, Ana Álvarez, Raquel Escorihuela, Beatriz Corzo, Pedro Simón, Jorge Malfeito IWA REGIONAL CONFERENCE OF WATER REUSE AND SALINITY MANAGEMENT June Murcia (Spain)

2 Index Forward Osmosis (FO) FO challenges and advantages OFREA Project: FO for high-salinity wastewater reuse WATINTECH project: FO for wastewater concentration Joint conclusions Acknowledgement

3 Forward osmosis Advantages No application of pressure Low and reversible fouling Product water customization (e.g. boron removal, fertigation) Challenges Low flux and expensive elements DS recovery is energy intensive. DS replacement costs Main studies are lab-scale, synthetic feed, short term and batch conditions

4 OFREA project LIFE project (website and video OFREA) Beneficiaries: Acciona Agua (coordinator) and ESAMUR Duration: 3 years (ended sept 2016) Objective: Find an alternative for reverse osmosis for high-salinity wastewater reuse in agriculture Demonstrate that forward osmosis is a viable alternative for reuse Feed water: San Pedro del Pinatar (Murcia) WWTP MBR effluent Feed water RD 1620/2007 Conductivity 4-6 ms/cm 3 ms/cm Boron 1.2 ppm 0.5 ppm SAR 10 3 limit 3 ms/cm

5 Design of the demonstration plant FO membranes: Porifera clear winner (flat-sheet) Draw solution: Sodium polyacrylate MgSO4 MgCl2 Separation process NF (less energy than RO)

6 Demonstration plant REFO process Acciona s team patented control system Porifera modules PFO 100. Area: 84 m2 of TFC Commissioning Nov.-Dec Operated from Jan 2014-Sept

7 Demonstration plant operation Demonstration plant performance: Second period Specific flux or permeability FO=Flux/(п DS п feed ) NF=Flux/(NDP) Stable operation of the FO (22% of loss of flux the first days) NF permeability decreased due to fouling with Sodium polyacrylate and MgSO4 change to MgCl2 High DS losses Change to HR modules MgCl2 showed stable operation and no fouling issues 7

8 Permeate quality Conductivity 1 ms/cm B < 0.4 mg/l (>70% removal) SAR 1-2 except for initial DS High and stable quality for agricultural use 8

9 UF+RO vs. FO+NF OPEX IN TERTIARY TREATMENT Iglesias et al UF+RO /m 3 FO+NF /m LARGE SCALE PILOT SCALE DS reposition costs were calculated as small-scale purchase FO membranes are improving quickly but still more expensive than RO ESTIMATION LARGE SCALE: Similar to UF+RO process 9

10 WATINTECH project Wastewater concentration as pretreatment for anaerobic reactor using FO (

11 Permeability (LMH/bar) FO for direct ww filtration First experiences in the demonstration plant indicate severe rapid fouling due to TSS 0,4 0,3 0,2 0,1 0 Flushing Osmotic Backwashing Chemical cleaning Before Cleaning After Cleaning Can FO fouling be controlled by using advanced pretreatment? What are the maximal TSS that can be applied? What is the optimal filtration regime? Promising membranes (Toray) to be evaluated 11

12 Conclusions FO technology Tertiary FO treatment: World s first FO demonstration plant for municipal wastewater reclamation Forward osmosis is a low fouling and robust technology High permeate quality OPEX can be similar to UF+RO but CAPEX is high Wastewater concentration FO: TSS fouling is still an issue Stable operation must be found with intermittent filtration regimes (combination with BW/flushing/relaxation ) Interesting niches for FO are found in: Concentration of streams (food and beverage industry) Fertirrigation Cases where energy is not an issue the priority is the reduction of chemicals (Countries with low energy prices/renewable surplus energy) DS available from waste Take home message: FO technology is a niche technology, yes, but these niches are expanding..

13 Acknowledgement LIFE+ Programme of the European Commission (LIFE12/ENV/ES/ LIFE OFREA) MINECO - EU Joint Programme Iniciative WATERWORKS 2014 La Generalitat de Catalunya (Industrial PhD program) San Pedro del Pinatar WWTP staff Rest of colleagues from Acciona Agua Prof. Carme Sans (UB) Winners of the Best Process Technology Award 2018 WEXGlobal for the OFREA project!! Thank you for your attention