Technologies and Methods for Treatment of Wastewater from O&G Exploration and Production: Limitations, Economics, and Reuse Opportunities

Transcription

1 Technologies and Methods for Treatment of Wastewater from O&G Exploration and Production: Limitations, Economics, and Reuse Opportunities Tzahi Y. Cath, Ph.D. Colorado School of Mines Department of Civil and Environmental Engineering Advanced Water Technology Center (AQWATEC) December 7, 2015

2 The Water Water for people Water for agriculture Water for industry Waster from rivers & lakes Water from the ground Water from the ocean (desal) Water 2

3 The Water Energy Nexus Water for Cooling in power plants Water for oil and gas extraction, refining, and production Energy for Water and wastewater treatment Desalination Water conveyance Water Energy 3

4 Energy for Water, Water for Energy 4

5 Energy for Water Treatment of unconventional water supplies will be more energy intensive Energy for Water Today Future 5000 US DOE, 2006 kwh per acre foot of water Public Water Supply Systems Brackish Water Treatment Sea Water Desalination Source: EPRI (2000), Water Desalination Task Force (2003) 5

6 Water for Energy and Food 2000 Water Demand, L/cap/day Direct Use Electric Power Production Source: from Gleick, P., World's Water Food Production 6

7 The New Nexus: Water Energy Food Water for Cooling in power plants Water for oil extraction, refining, and production Energy for Water and wastewater treatment Desalination Water conveyance Energy Transportation of food Biofuels displacing food crops é gas prices = é food prices Water Food Livestock and agriculture production Food processing and sanitation Nutrients and minerals from wastewater 7

8 The Motivation: Enhanced Water Recovery and Reduced Energy Demand Relative Operating Cost of Treatment High High Moderate Emerging BWRO Technologies ZLD & Near-ZLD Moderate - High Moderate Low Relative Brine Disposal Cost 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Recovery (%) 8

9 A general problem Current Water Use & Reuse 383 BGD withdrawn Power = 200 BGD Irrigation = 137 BGD Public = 44 BGD 1 BGD reused Irrigation = 0.6 BGD Public supply = 0.15 BGD GW recharge = 0.13 BGD Industrial = 0.10 BGD Research needs: Overcoming barriers to water reuse 9

10 Treatment of Wastewater from Upstream O&G Operations 10

11 Treatment of Wastewater from Upstream O&G Operations A few important notes Water reuse is important and required! Water quantity used in O&G exploration and production Water quality for internal reuse in the O&G industry There are other industrial waste streams that are much more difficult to treat Like in domestic wastewater treatment, we are making progress in identifying what s in the water, before and after treatment. But more research is needed Do we remove everything? Research needs: Improved and simplified analytical methods/procedures to identify and quantify emerging contaminants 11

12 Basic Requirements for Water Treatment for Reuse Treatment objectives (reuse app) Multi-barrier system Pretreatment Removal of suspended solids (large and small) Removal of organic matter (oil, grease, emulsions, hydrocarbons, carbohydrates, natural organic matter) Removal of sparingly-soluble salts Desalination Removal of simple salts Removal of low molecular weight organics (including ) Water recovery target Post treatment (including brine management and disposal) 12

13 Other Requirements for Water Treatment for Reuse Process resiliency Flexibility (quality and quantity) Tailored water reuse or One Water Centralized/decentralized Robustness (environment) Scalability/modularity High water recovery à minimal brine management Low energy demand (potential energy recovery) Low treatment cost Research needs: Techno-economic models 13

14 Pretreatment Protection of downstream processes or production of water for direct use in the field Physical processes Phase separation (sedimentation, floatation) Stripping of volatiles Filtration (still might need its own pretreatment) Membranes (osmosis) Research needs: The future of ceramic membranes (MF, UF) in the O&G industry Is forward osmosis a viable process for O&G 14

15 Pretreatment Protection of downstream processes or production of water for direct use in the field Chemical processes Coagulation Adsorption Oxidation Disinfection Research needs: Electrocoagulation vs. chemical coagulation Disinfection byproduct 15

16 Pretreatment Chemical addition: Coagulants Chemical addition: Softening Chemical addition: Polymer Chemical addition: PAC Flocculation REUSE Disinfection Filtration Dissolved Air Flotation (DAF) Sedimentation Research needs: Process optimization, LCA, TEA Impact on desalination processes 16

17 Pretreatment Protection of downstream processes or production of water for direct use in the field Biological processes Standalone treatment activated sludge or co-treatment with domestic or other industrial wastewater Membranes bioreactors (MBR) (aerobic and anaerobic) Biologically active filtration (BAF) Research needs: Impacts of salinity, temperature, frac chemicals on microorganisms Impact of loading rates on biological processes and post treatment Changes in characteristics of biosolids 17

18 Desalination Conventional (pressure driven) Novel (osmotically and thermally driven) 18

19 Desalination Technologies Specific Energy, kwh/m Membrane Limited Recovery High Pressure Simple/modular High FO/RO Efficiency RO SWRO Crystallizer Brine Concentrators MBC v1.0 Membrane DisKllaKon MBC v2.0 Thermal High recovery Energy to boil water ExoKc metals Membrane Brine Concentrator (MBC) High Recovery Modular No Boiling/Low Pressure 1% 2% 3% 4% 5% 10% 25% 50% 75% Sources: Oasys Water % Total Dissolved Solids 19

20 A few thoughts on desalination Energy for reverse osmosis (SWRO) desalination close to the thermodynamic limit of separation Reverse osmosis is limited to low salinity water Desalination of seawater (3.5%) is limited to ~60% water recovery The cost of desalinated seawater is ~$1.7/m 3 For the same feed water salinity (and even lower), the cost of produced water treatment is ~$1.7/bbl There are ~6.3 bbl in one m 3 20

21 A few notes on desalination Some hydrocarbons will easily diffuse through RO membranes Little is known about the long-term impact of hydrocarbons on RO membranes Forward osmosis is not a desalination process Is membrane distillation a viable desalination process? Research needs: New generation of RO and NF membranes (ceramic?) Sustainable membranes for MD 21

22 Additional notes on desalination Tailored Water Reuse or One Water? Resource recovery from produced water If produced water is to be used for irrigation, in most cases it must be desalinated What is the fate and transport of un-rejected compounds in crops and the soil? Research needs: Resource (mineral, nutrients) recovery from waste streams Impact of residual contaminants on crops and soil Polishing/post-treatment processes after desalination Low-cost small scale systems 22

23 Thanks you 23