A Novel Hybrid Forward Osmosis Process for Drinking Water AugmentaQon using Impaired Water and Saline Water Sources

Transcription

1 A Novel Hybrid Forward Osmosis Process for Drinking Water AugmentaQon using Impaired Water and Saline Water Sources Tzahi Cath, Carl Lundin, Jörg Drewes Advanced Water Technology Center (AQWATEC) Division of Environmental Science and Engineering Colorado School of Mines Golden, CO 24 th Annual WateReuse Symposium September 14 th, 2009 SeaJle, WA

2 PresentaQon Overview The Water- Energy nexus Emergence of osmo5cally- driven membrane processes Poten5al applica5ons and implementa5ons Desalina5on and the energy- water nexus Osmo5c dilu5on of seawater AwwaRF 4150 Concluding remarks

3 The Water Energy Nexus Water to Energy Energy to Water

4 Energy Recovery in DesalinaQon

5 OsmoQc Pressure as an Energy Guzzler membrane Seawater Δπ 350 psi Conc. Seawater (~50% rec.) Δπ 700 psi

6 OsmoQc Pressure as an Energy Source OsmoQcally- driven Membrane Processes Forward osmosis (wastewater treatment, pretreatment, desalina5on) Pressure retarded osmosis (power genera5on) membrane membrane Brine / Draw Solution Draw Solution Osmosis Forward Osmosis ( engineered osmosis )

7 OsmoQc Pressure as an Energy Source OsmoQcally- driven Membrane Processes Forward osmosis (wastewater treatment, pretreatment, desalina5on) Pressure retarded osmosis (power genera5on)

8 Pressure Retarded Osmosis: OsmoQc Power From: R. J. Aaberg, Osmotic power - A new and powerful renewable energy source, ReFocus, 4 (2003) 48-50

9 Forward Osmosis: Draw SoluQons 1600 NH4HCO3 OsmoQc Pressue, atm NaCl CaCl2 MgCl2 KCl sucrose KNO OsmoQc Pressure, psi ConcentraQon, M

10 Forward Osmosis: Draw SoluQons OsmoQc Pressue, atm NH4HCO3 NaCl CaCl2 MgCl2 KCl sucrose KNO OsmoQc Pressure, psi ConcentraQon, M

11 State of Development of OsmoQcally- driven Membrane Processes

12 ApplicaQon of OsmoQcally- driven Membrane Processes Aaberg (2003)

13 So what are the advantages and limitaqons of osmoqcally- driven membrane processes?

14 FO vs. RO Water flux, LMH LFC- 1 RO Mode CA- 2 RO Mode CA- 2 FO Mode Time, Hours Membrane cleaning Holloway, R.W., Childress, A.E., Dennett, K.E., Cath, T.Y., Forward osmosis for concentration of centrate from anaerobic digester, Water Research, Vol. 41 (17), September 2007,

15 Power ConsumpQon Rela5vely good economy at small scale Economy of scale holds promise for successful implementa5on

16 Effect of Feed Chemistry on FO Process Performance Driving force decreases when recovery increases Good rejec5on of contaminants of concern J w = A (ΔP Δπ) Cath et al., Membrane Contactor Processes for Wastewater Reclamation in Space. Journal of Membrane Science, Vol. 257, (1-2), July 2005, Cartinella, Cath, et al. Removal of Natural Steroid Hormones from Wastewater Using Membrane Contactor Processes, Environmental Science and Technology, 40 (23), (2006)

17 What are the LimitaQons? The Complexity of Mass Transport J w = A (ΔP Δπ) Concentrated BW Brine FO J s = B Δc Draw Solution tank J s,ro BW Brine RO Unlike RO, FO exhibits bi- direc5onal diffusion of ions

18 How can we simultaneously reduce energy demand in SWRO, protect RO membrane, and provide mulq barrier treatment of impaired water?

19 Energy Demand of DesalinaQon High energy demand of SWRO desalina5on due to high osmo5c pressure of the brine Additional flux Solvent (water) Flux, J FO Decreasing Feed Conc. Δπ Decreased Osmotic Pressure RO ΔP Membrane

20 The beginning T.Y. Cath, A.E. Childress, System and Methods for Forward Osmosis Assisted Desalination of Liquids, Patent Application No. 11/295,807, December 2005.

21 Water Research FoundaQon (AwwaRF) 4150 Cath, T.Y., Drewes, J.E., Lundin, C. (2009). A Novel Hybrid Forward Osmosis Process for Drinking Water Augmentation using Impaired Water and Saline Water Sources. Draft Final Report. Awwa Research Foundation (AwwaRF #4150), Denver, Colorado.

22 FO/RO Hybrid for Water AugmentaQon: OsmoQc DiluQon of Seawater Low energy desalina5on / enhanced recovery Dual barrier

23 Bench- scale TesQng in the Lab Bench scale forward osmosis system Closed loop system Doses concentrated salt to maintain DS concentra5on SCADA control of salt dosing, temperature, and data acquisi5on

24 Bench Scale Results: Short term fouling test No flux decline seen in short term secondary effluent experiments Conditions: 19ºC 1.5 LPM ph 7.5

25 Bench Scale Results: OperaQng Envelope Seawater Conditions: 19ºC 1.5 LPM ph 7.5 Feed Cond: SE: 850 µs/cm DI: 80 µs/cm

26 Pilot TesQng Temp. Control Seawater Draw Solution FO Cell Feed (Recycled) water Waste Permeate RO Cell

27 Pilot Test Results Secondary Effluent Feed PC PC CC

28 Pilot Test Results Secondary Effluent Feed Temp. Control Feed (Recycled) water Seawater Draw Solution FO Cell Waste Permeate RO Cell FO Cell Waste Feed (Recycled) water

29 Pilot Test Results Secondary Effluent Feed

30 Pilot Scale Results: TerQary effluent feed Conditions: 2.4 LPM ph g/l Seawater Feed Cond: TE: 850 µs/cm

31 Solute Transport: NH 3, NO 3, UV Ammonia rejection: FO: 75%, RO: 75%, Total: 94% Conditions: 2.4 LPM ph g/l Seawater Feed Cond: SE: 850 µs/cm

32 Solute Transport: NH 3, NO 3, UV Nitrate rejection: FO: 79%, RO: 82%, Total: 97% Conditions: 2.4 LPM ph g/l Seawater Feed Cond: SE: 850 µs/cm

33 Solute Transport: NH 3, NO 3, UV UV rejection: FO: 86%, RO: >99.9%, Total: >99.9% Conditions: 2.4 LPM ph g/l Seawater Feed Cond: SE: 850 µs/cm

34 Solute Transport: Micropollutants Rejec5on of organic micropollutants Accumula5on over 7- day experiment Some compounds were not detected in feed water Clofibric acid, dichlorprop, diclofenac, fenofibrate, gemfibrozil, ibuprofen, ketoprofen, mecoprop, naproxen, salicylic acid Compound Bench FO Pilot FO Pilot RO Pilot Total Diclofenac >99.9% 89% >99.9% >99.9% Gemfibrozil 80% 78% 78% 97% Ibuprofen n/a 87% 64% 93% Mecoprop 95% >99.9% - >99.9% Naproxen 90% 85% 94% 98% Salicylic Acid 72% >99.9% >99.9% >99.9%

35 Economic Feasibility Simple model constructed Helps to determine the level of recovery of impaired water possible Parameter Unit Value Finished water flow rate m 3 /day 100 Impaired water flow rate m 3 /day 200 Seawater TDS concentration g/l 35 Seawater stream Forward Osmosis RO influent stream Reverse Osmosis Impaired water stream Concentrated impaired water stream Permeate (finished water) RO reject stream Impaired water TDS concentration g/l 0.5 RO recovery % 50 Energy cost $/kwh 0.20 Forward osmosis membrane cost Minimum return on investment ratio $/m

36 Economic Feasibility

37 Economic Feasibility

38 Economic Feasibility

39 Concluding Remarks High rejec5on of suspended solids and macromolecules and rela5vely high rejec5on of most dissolved ions and molecules Very low membrane fouling Low energy consump5on and energy benefits to downstream SWRO Mul5 barrier protec5on leading to direct potable reuse Preparing for a large scale demonstra5on project

40 Acknowledgements Funding Agencies Water Research Foundation (formerly AwwaRF) California Department of Water Resources National Aeronautics & Space Administration Russell Plakke and Brian Good, Denver Water Christiane Hoppe, Brandy Laudig, Ryan Holloway, Josh Cartinella, Dean Heil Edward Beaudry, Hydration Technologies Inc.

41 Thank You