L o g o. Chemical and biological treatment of produced water for sustainable operation of oil shales and similar operations

Transcription

1 Chemical and biological treatment of produced water for sustainable operation of oil shales and similar operations Liang Li, and Ramesh Goel Department of Civil il & Environ. Eng. The University of Utah

2 Introduction to Produced water Water generated along with oil, gas, and coal bed methane production is commonly known as produced water, formation water, or oilfield brine. Generally produced water is composed of dispersed oil, dissolved organic compounds, production chemicals, heavy metals, naturally occurring radioactive minerals and other inorganic compounds. U.S. Department of Energy has forecasted the current volume of 250 million barrels of produced water per day to go up to 312 million barrels per day by Treatment and reuse of produced water provides an alternative way Treatment and reuse of produced water provides an alternative way for the sustainable operation of such operations. None of the existing methods provide complete treatment of produced water for its reuse.

3 Composition of Produced Water THE

4 Sources of produced water The sources or produced water can be divided into different categories based on location or type of operation. Location Type of Operation Onshore Operation Oil Production Offshore Operation Coastal Operation Different locations have different discharge limits. Gas Production Coal Bed Methane Production The composition of produced water could be different due to The composition of produced water could be different due to its location and type of operation.

5 Current treatment processes Treatment method Contaminants Removed Advantages Disadvantages Cost Carbon adsorption Foulinf granule carbon; Hydrocarbon and acid, base Low energy requirement; high produces waste stream; need preand neutral compounds treatment capacity treatment Moderate Air stripping VOCs as wells as BTEX, Very effective for volatile and semivolatile organic compounds; low forming; generate gas waste Risk of iron and calcium scales Low capital and naphthalene phenols, H 2 S operating cost and ammonia energy requirement stream; need pre-treatment No removal of volatile and low Membrane filtration require pretreatment Particles, dispersed and Low energy requirement; high molecular weight compounds; oil emulsified oil treatment capacity or bacteria may foul membrane; Low operating cost Reverse osmosis UV treatment Salinity Both volatile and nonvolatile organic compounds; Effective for salinity removal; high effluent quality Does not generate additional waste stream; can handle high loading condition High energy requirement; Oil and particles may foul the system; Need pretreatment No ammonia, dispersed oil, heavy metal or salinity removal; may be fouled; residue may be toxic; require pre-treatment Moderate Moderate Chemical oxidation H 2 S, hydrocarbons, acid, base and neutral organics, volatiles and non-volatiles Low energy required if hydrogen peroxide is used; easy to operate High energy inputs for ozone system; oil may foul catalyst; may produce sludge and toxic residues; Need pre-treatment Moderate operating cost Biological treatment Biodegradable hydrocarbons and organic compounds, H 2 S, ammonia, some metals Fairly low energy required; handles variables loadings Required for long HRT; build up iron and oil hinders biological activity; produced gas and sludge requiring treatment; need pretreatment Moderate capital but low operating costs

6 Integrated treatment approach To develop an Integrated Treatment Scheme for the produced water Remove Dispersed Oil by Air Flotation Advanced oxidation of organics Biological treatment As a final polishing step Reclaimed Water Well proven technology, this research hdid not consider it These two were investigated in detail

7 Detailed Approach Advanced Oxidation Chemical oxidation Electrolytic oxidation Electrochemical oxidation Biological Enriched microorganisms which can degrade selected organics present in produced water Conducted batch experiments to text the degradability Membrane bioreactor to get treated water of reuse quality

8 Model refractory organics Naphthalene as model PAH compound a crystalline, aromatic, white, solid hydrocarbon with two fused benzene rings BTEX Benzene Toluene Ethyl benzene Xylene

9 Fenton reaction with naphthalene Norm malized Naphthalene e Concentration, C/C Co (a ph=4 Blank 1 Blank mg/l H mg/l H mg/l Fe 2+ Time, hours ph 4 was beneficial for the removal of naphthalene during Fenton reaction. High H 2 concentration was beneficial for the removal of naphthalene during Fenton reaction. 2-3 mg/l H mg/l Fe 2+ (b ph=7 tion, C/Co hthalene Concentrat Normalized Nap Blank 1 Blank mg/l H mg/l H mg/l Fe mg/lho +30mg/lFe Time, hours

10 Electrolytic degradation of naphthalene THE Norma lized Naphthalene Concentration, C/C Co Blank 25 ma 50 ma 100 ma 200 ma Time, hours (b (ph=7 The removal of naphthalene during electrolytic aeration was insensitive to ph. tion, C/Co Normalized Nap phthalene Concentrat 00 The removal of naphthalene during electrolytic aeration was insensitive to currents. Blank 25 ma 50 ma 100 ma 200 ma (a ph=4 Time, hours

11 Fenton reaction with BTEX (ph=7 normalized benzen ne conc. (c/c 0 Benzene Under ph 7, both benzene and toluene were insensitive to Fenton reagent. 02 time (h blank Toluene 3 mg/l H mg/l Fe mg/l Fe 2+ oluene conc. (c/c Increasinf H 2 concentration didn t make big different to the removal of benzene and toluene. normalized t.4.2 time (h blank 3 mg/l H mg/l Fe mg/l Fe 2+

12 n ormalized ethyl be enzene conc. (c/c Fenton reaction with BTEX (ph=7 Ethyl benzene blank 3 mg/l H mg/l Fe mg/l H +30mg/LFe 2+ 2 time (h Increasinf H 2 concentration didn t make big different to the removal of ethyl benzene and xylene. normalized xylene conc. (c/c Unlike benzene and toluene, ethyl benzene and xylene could be significantly removed by Fenton reagent. Xylene blank 3 mg/l H mg/l Fe mg/l Fe 2+ time (h

13 Fenton reaction with BTEX (ph=4 Benzene normalized benze ene conc. (c/c 0 Under ph 4, both benzene and toluene could be oxidized.8 Fenton reagent blank 3 mg/l H mg/l Fe mg/l Fe 2+ time (h Increasinf H 2 concentration could increase the removal of benzene and toluene. normalized to oluene conc. (c/c Toluene blank 3 mg/l H mg/l Fe mg/l Fe 2+ time (h

14 Fenton reaction with BTEX (ph=4 norm malized ethyl benze ene conc. (c/c Ethyl benzene time (h Increasinf H 2 concentration could increase the removal of ethyl benzene and xylene. blank Under ph 4, ethyl benzene and 3 mg/l H mg/l Fe mg/l Fe xylene could be removed 2+ significantly by Fenton reagent. normalized xylene conc. (c/c Xylene time (h blank 3 mg/l H mg/L Fe mg/L Fe 2+

15 Electrolytic degradation of BTEX Normalized Benzen ne Conc. (c/c 0 Benzene Benzene and toluene could be removed through electrolytic process. 02 no current 25 ma 200 ma 500 ma Time (h Unlike naphthalene, the removal of benzene and toluene through electrolytic process were sensitive to currents. 0 Normalized Toluene Conc. (c/c 0 no current 25 ma 200 ma 500 ma Toluene Time (h

16 Electrolytic degradation of BTEX ormalized Ethyl ben nzene Conc. (c/c 0 N Ethyl benzene Ethyl enzene and xylene could be removed through electrolytic process. 02 no current 25 ma 200 ma 500 ma Time (h Ethyl benzene and xylene were easier to be removed through electrolytic process than benzene and toluene. normalized xylene conc. (c/c 0 Xylene time (h no current 25 ma 200 ma 500 ma

17 Logo THE Enrichment of bacteria Feed solution Air Supply Minerals Carbon source BTEX BTEX + Naphthalene Onaphthalene/BTEX l Gl as carbon sourceonly Glucose O l Only useonly Naphthalene + Glucose Gl Use naphthalene/btex plus glucose as co-carbon source Seed sludge from wastewater treatment plant Stir Plate 50 ml live biomass was taken for biodegradation g Flow test, while 50 ml dead biomass (heat 80 oc for 1 h was Meterused for adsorption test. Flow Meter Wasting 5% sludge every week Air Pump Power Supply

18 Solids variation of the reactor for naphthalene degradation 10 8 Naphthalene plus Glucose TSS VSS The biomass in both reactors were working very well. (g/l solids conc. 6 4 Only Naphthalene TSS VSS time (d conc. (g/l 6 Due to the additional carbon source of glucose, the biomass concentration in N+G reactor was higher than the N only reactor. solid time (d

19 Biological degradation of naphthalene Norm malized Naphthalene e Conc. (c/c 0 Naphthalene plus Glucose evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h ( The mechanism for the removal of naphthalene could be evaporation, adsorption and biodegradation. Normalized Naphthalene Conc. (c c/c 0 Naphthalene could be successfully removed through biological method. Only Naphthalene evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h

20 Solids variation of the reactor for BTEX degradation 5 BTEX plus Glucose 4 TSS VSS The biomass in both reactors were working very well. (g/l solids conc Only BTEX 1 0 Due to breakage of air bubbler time (d Due to the additional carbon source of glucose, the biomass concentration in B+G reactor was higher than the B only reactor. so olids conc. (g/l time (d TSS VSS

21 Biological degradation of BTEX enriched by BTEX and glucose ene Conc. (c/c 0 Normalized Benz 06 Benzene evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h The mechanism for the removal of naphthalene could be evaporation, adsorption and biodegradation. (c/c 0 Normaliz zed Toluene Conc. ( Benzene and toluene could be successfully removed through biological method by bacteria enriched by BTEX and glucose. Tl Toluene evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h

22 Biological degradation of BTEX enriched by BTEX and glucose ormalized Ethyl ben nzene Conc. (c/c 0 N Ethyl benzene evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h xylene conc. (c/c 0 Ethyl Benzene and xylene could be successfully removed through biological method by bacteria enriched by BTEX and glucose. Xylene evaporation evaporation+adsorption i evaporation+adsorption+biodegradation The mechanism for the removal of naphthalene could be evaporation, adsorption and biodegradation. normalized time (h

23 Biological degradation of BTEX enriched by BTEX only THE ene Conc. (c/c 0 Normalized Benz 06 Benzene evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h The mechanism for the removal of naphthalene could be evaporation, adsorption and biodegradation. 0 Normalized Toluene Conc. (c/c 0 Benzene and toluene could be successfully removed through biological method by bacteria enriched by BTEX only. Toluene evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h

24 Biological degradation of BTEX enriched by BTEX only THE rmalized Ethyl benze ene Conc. (c/c 0 Nor Ethyl benzene evaporation evaporation+adsorption evaporation+adsorption+biodegradation Time (h The mechanism for the removal of naphthalene could be evaporation, adsorption and biodegradation. Normalized Xylene Conc. (c/c 0 Ethyl Benzene and xylene could be successfully removed through biological method by bacteria enriched by BTEX only. Xylene evaporation evaporation+adsorption i evaporation+adsorption+biodegradation Time (h

25 Membrane Bioreactor to get treated t water of reuse quality Feed solution: synthetic Synthetic produced water Similar to real produced produced water dfrom Conoco Philips Membrane water Module Reactor run Timer mode influent (10 mins - aerated mixing (11 hrs -effluent (20 mins backwash (10 mins effluent (20 mins - influent (10 mins Air pump HRT 12 hrs Influent Pump Effluent Pump Airflow Controller Stir Plate Backwash Pump

26 Conclusion ä Both naphthalene and BTEX could be removed through electrolytic degradation. ä Bacteria were successfully enriched for the biodegradation of naphthalene and BTEX respectively. ä From primary results, it is promising to treat produced water by an chemical-biological integrated method.

27 Future Research and Limitations Test integrated scheme Onsite complete treatment scheme Identification of degradation intermediates and the specific bacteria Limitations Lack of future funding to support research During aerobic treatment, volatilization of organics

28 THANK YOU! QUESTIONS?