DICK TH. MEIJER, VWS MPP Systems / VWS Oil & Gas, Veolia Water Solutions & Technologies, Ede, the Netherlands,

Transcription

1 Toxic dissolved and dispersed hydrocarbons removal and reuse in the oil & gas industry, gas/condensate, shale gas produced water, refinery process water and groundwater with the Macro Porous Polymer Extraction technology DICK TH. MEIJER, VWS MPP Systems / VWS Oil & Gas, Veolia Water Solutions & Technologies, Ede, the Netherlands, KENNETH SEVERING, Whittier Filtration, Veolia Water Solutions & Technologies, Brea, CA, United States This paper was presented at the International Water Conference, San Antonio (TX), USA on November 5, 2012 PAPER NUMBER IWC KEYWORDS MPPE, produced water reuse, wastewater reuse, groundwater reuse, dissolved and dispersed hydrocarbons, Zero Harmful Discharge (ZHD), Environmental Impact Factor (EIF), aromatic hydrocarbons, BTEX, Poly Aromatic Hydrocarbons (PAHs).

2 ABSTRACT Environmental legislation worldwide is aiming at a good balance between the extent of environmental protection and spending capital on water treatment systems with the associated carbon footprint. There is a clear trend to move from integral discharge parameters like BOD, COD, AOX etc. to more risk based approaches, like the Environmental Impact Factor introduced in Norway in the beginning of this decade. In risk based approaches a division is made between harmful and non-harmful constituents present in the water. Technologies specifically removing the harmful part are searched for to aim at an optimal balance between capital costs and environmental protection. A real life experience on the disastrous effect of unknown toxic content on the biotreatment confirming the Environmental Impact model will be presented. Macro Porous Polymer Extraction is such a technology that specifically removes the toxic non polar hydrocarbons from water. More than 35 units have been installed in the past years and applied in the various areas of the oil & gas industry. Examples are given of onshore shale gas produced water, refinery process/wastewater, groundwater and offshore gas/condensate produced water on platforms and future floating LNG plants. Constituents that are removed are among others, dissolved and dispersed oil (aliphatics), BTEX, Poly Aromatic Hydrocarbons (PAHs), MTBE, THT (Tetra Hydro Tiophene, an odorant used in natural gas for leak detection). Recently it has been discovered that > 80% of Mercury is removed from produced water raising the possibility to extend scope the technology. Finally the reduction of the Environmental Impact Factor with MPPE will be illustrated versus other technologies. The Macro Porous Polymer Extraction (MPPE) technology from Veolia Water is able to remove dissolved and dispersed hydrocarbons with % if needed. The MPPE technology is basically a liquid/liquid extraction process where the extraction liquid is immobilized in a macro porous polymer. In addition it allows the practically pure separated hydrocarbons to be completely used as a product. No other waste stream is created. 2

3 INTRODUCTION The Macro Porous Polymer Extraction Technology (MPPE) has been proven in various applications to remove the non-polar generally toxic hydrocarbons from produced, waste and groundwater. This MPPE technology makes it possible to change the discharge regulation policy from generic BOD, COD requirements to one that is more focused on the toxic content of the water to be treated. This will lead to a discharge with constituents basically non harmful to the environment. In addition, where low BOD, COD levels are required, the MPPE technology can be applied to protect the biotreatment against toxic loads. In this paper an introduction to a risk based approach vs. total COD removal is given with subsequent examples validating this alternative approach. Cases are presented in the Oil and Gas industry on Zero Harmful Discharge and on combining the MPPE with biotreatment technologies to fulfill total COD requirements where significant toxic content is present. REASONS FOR COD AND BOD REQUIREMENTS FOR WATER DISCHARGE REGULATIONS Most natural waters contain small quantities of organic compounds. Aquatic microorganisms have evolved to use some of these compounds as food. Microorganisms living in oxygenated waters use dissolved oxygen to convert the organic compounds into energy for growth and reproduction. Populations of these microorganisms tend to increase in proportion to the amount of food available, when nutrient (N, P and some minerals) concentrations are not limiting. This microbial metabolism creates an oxygen demand proportional to the amount of organic compounds useful as food. Under some circumstances, microbial metabolism can consume dissolved oxygen faster than atmospheric oxygen can dissolve into the water. Fish and aquatic insects may die when oxygen is depleted by microbial metabolism. Especially discharge of (municipal) wastewaters into rivers or lakes may lead to depletion of oxygen as the feed of organic compounds and resulting oxygen demand is higher than the natural atmospheric oxygen input (related to the available surface area between water and air) and the dilution with fresh oxygenated water (related to the flow rate of fresh water). As the amount of dilution with fresh water is often not controllable the environmental legislation is aimed at the reduction of BOD and COD discharge to the environment. REASONS FOR THE EMERGENCE OF RISK BASED APPROACHES TO WATER DISCHARGE REGULATIONS Discharge regulations based on BOD and COD for municipal wastewater have been proven effective in practice. For the offshore industry emerging in the seventies in the North Sea these requirements were not feasible and not meaningful. Not feasible as space limitations impede the use of biotreatment systems that are needed to lower BOD or COD levels. Not meaningful as the dilution prevents oxygen depletion. From the very beginning the discharge regulations for the North Sea were only based on dispersed oil. The aim of this regulation was to reduce the formation of oil sheens on the surface water. The discharge limit was set at < 40 ppm dispersed oil. The discharge limit was mainly based on technical/practical limitations like space, weight and economics. Given these limitations no technologies were available to achieve lower limits. By the end of the nineties extensive research was carried out by the Norwegian Oil & Gas industry on the toxic and non-toxic constituents of produced water and their effects on the environment. The investigations were probably driven by the Norwegian government dealing with the interests of the fishing industry. It has led to a change in approach of offshore produced water treatment resulting in a focus on the removal of toxic constituents. THE ENVIRONMENTAL IMPACT FACTOR A PRACTICAL APPLICATION OF A RISK BASED APPROACH The basis of this study consists of a detailed analysis to identify molecules and groups molecules that are toxic and nontoxic. The effect of the toxicity on their natural environment was assessed. This assessment was based on the accessibility of the toxic constituents to the natural organisms in the sea (alga, fish etc.), the biodegradability and the tendency of accumulation in the environment. Mathematical models of the spreading of toxic constituents in the sea were validated by the measurements of the constituents in mussels and other species located at different distances from platforms. For example at distances of 16 km downstream from platforms 3

4 higher poly aromatic hydrocarbon concentrations were measured in mussels. Table 1. Toxic/nontoxic part in offshore produced water. PRACTICAL EXPERIENCE ON HOW TO DEAL WITH THE PRESENCE OF TOXIC CONSTITUENTSS IN WASTEWATER Practical real life experiences of the disturbance of toxic loads in wastewater in two significant different situations are presented in the following paragraphs. Statoil in Kollsnes where offshore gas/condensate produced water is treated onshore, basically dealing with a qualitatively constant composition. Wastewater from a specialty chemical producer with a constant changing composition both qualitatively and quantitatively. EFFECT OF TOXIC LOAD IN THE STATOIL KOLLSNESS WASTEWATER TREATMENT A real life case with Statoil and Gassco in Kollsnes (NO) The environmental impact of each toxic constituent was validated and a multiplication factor was applied to its concentration in the producedd water to reflect the environmental impact of that particular constituent. In this way the Environmental Impact Factor could be determined of each platform in its own environment. The EIF concept is a quantitative management tool developed to both focus the legislation and practical measures on Zero Harmful Discharge of producedd water streams (Buller et al). Graph 1. Generic chemical composition and Environmental Impact Factors of produced water streams. Same TOC (Total Organic Carbon) levels, but bioactivity stopped - In autumn 2004 a new gas/condensate production platform Kvitebjørn was tied-in to the gas treatment plant of Statoil and Gassco in Kollsnes, west of Bergen in Norway. The gas treatment plant at that moment was already treating gas/condensate from Troll A, B and C as well as Visund. Shortly after the tie-in of Kvitebjørn in October 2004, the biotreatment plant at the site ceased to function properly and by January 2005 nearly all bioactivity had stopped. This happened without any increasee in total organic carbon content (TOC). After MPPE unit installation bioactivity restored within 3 months - After installation of a mobile MPPE unit in the beginning of 2005, bioactivity was restored within three months. Afterwards it was discovered that the toxic fraction of the influent increased significantly, while the TOC of the influent did not increase. Kvitebjørn producedd water contains more toxic substances than the water from the Troll and Visund fields. The BTEX was times higher (600 mg/l from Kvitebjørn), PAHs weree 10 times higher and alkyl phenols (C2/C4) were times higher. Large variations in BTEX weree observed especially during startt up. The conclusion was that the biomass was poisoned due to the higher concentrations of BTEX, PAHs and alkyl phenols. BTEX content greater than 12 mg/l could be toxic to an unadapted culture (Bergensenn and Jacobsson, Oslo 2006) ; MPPE removed BTEX and PAHs at design levels (98 99%) (Bergensen et al, Kualaa Lumpur 2006). 4

5 Photo 1. Statoil Kollsnes MPPE unit. French Environmental Legislator) this combination has been approved and applied for a French specialty chemical producer (specialty chemicals, pharmaceutical and other chemical raw materials). The MPPE technology removes the aromatic, chlorinated hydrocarbons and AOX while the biorotor removes the remainder more polar and nontoxic biodegradablee constituentss to meet the target COD for discharge. Both the wastewater and the groundwater are treated by this combination prior to discharge. Table 2. Graph 2. Concentration (mg/l) Graph 3. MPPE performance waste water specialty chemical producers Inlet Outlet MPPE/Inlet biorotor Outlet Biorotor AOX, TEX, chloroforme, dichloromethane Remaining COD TOXIC / NON TOXIC HYDROCARBON REMOVAL OF A SPECIALTY CHEMICAL PRODUCER The ultimate challenge and complexity of industrial wastewater treatment is in specialty chemical production. The typical characteristic of such a producer is the high flexibility it offers to its clients to produce any chemical requested. The challenge in wastewater treatment is to cope with chemical constituents that are unpredictable, highly toxic and change every day in composition and concentration. Generic approaches with biotreatment and chemical oxidation and/or activated carbon adsorption appear to be very costly and often ineffective. A field pilot study with a mobile MPPE unit and mobile biorotor has led to the industrial application of the combination of these two technologies. Under strict control of DRIRE (The Photo 2. Specialty chemical wastewater treated by MPPE and biorotor. 5

6 ZERO HARMFUL DISCHARGE IN THE OIL AND GAS INDUSTRY The presence of toxic constituents in the oil and gas/condensate leads to challenges in water treatment. This is upstream in the oil and gas/condensate produced water, both offshore and onshore and shale gas produced water onshore and downstream in refinery wastewater and refinery/gas locations groundwater. Basically in all locations where oil and gas based products are produced, refined and used. This chapter presents a short survey of experiences in removing toxic constituents in all these areas. THE ENVIRONMENTAL IMPACT FACTOR FOR ZERO HARMFUL DISCHARGE IN OFFSHORE OIL AND GAS/CONDENSATE PRODUCED WATER A comparison between the composition of oil produced water and gas/condensate producedd water shows that the gas produced water is far more toxic than the oil produced water. By aiming the attention to lower the toxic content of gas/condensate produced water a high cost efficiency of the environmental impact reduction can be achieved. The concentrations of the toxic constituents in gas/condensate produced water have proven to be in practice times higher than the generic composition of oil produced water after the applications of standard gravitational technologies. (Chen et al) like The Netherlands (NOGEPA; Dale) Australia (Lowe) and Egypt. MPPE has been tested and proven to very effectively reduce the Environmental Impact Factor with 95 to 99% (Buller et al; Grini et al). MPPE removes toxic constituents with more than 99% at inlet level, varying between a few hundred to a few thousands of ppm dissolved and dispersed BTEX and poly aromatic hydrocarbons and aliphatic constituents. Inhibitors (corrosion, scale, hydrate) ), scavengerss (H 2 S), foamers, defoamers, and other field chemicals are partially removed (20-50%) and do not influence the separation performance. Graph 4. Offshore produced water toxic/nonn toxic content. Table 3. Graph 5. MPPE effect on chemical composition produced water versuss gravitational technologies. The flow rates in gas producedd water that have been met in practice, vary from a few m 3 per hour to levels of 180 m 3 per platform. The Environmental Impact Factor (EIF) management tool was introduced by Norway in the North Sea in the beginning of the century to implement a Zero Harmful Discharge policy. A challenging program was set up to reach Zero Harmful Discharge for all Norwegian platforms in This approach or derivatives of it are followed by other countries 6

7 Graph 6. MPPE effect on Environmental Impact Factor of gas produced water versus gravitational technologies. may be the warm waters around the Philippines (average temperature of 20 C or higher compared to the 7 10 C in the North Sea) thatt cause the alkyl phenols to have a low to insignificant harmful impact on the environment. In thesee conditions the alkyl phenols are sufficiently biodegradable. ONSHORE SHALE GAS PRODUCED WATER - The growing importance of shale gas production has led to a wastewater field trial where a combination of different technologies was applied. Here the MPPE technology has proven to remove the non-polar hydrocarbons, BTEX, PAHs and aliphatics (dispersed oil) consistently with 99%. The field test has been running successfully for approx. 4 months with a consistent removal effectiveness of the total COD to meet discharge requirements. Table 4. MPPE removal effectiveness in gas and oil produced water. Table 5. Water treatment technologies shale gas produced water. SHELL MALAMPAYAA CONFIRMS EIF MODEL- SHOWSS IMPACT SEA WATER ENVIRONMENT - These observations are supported by the results of a study carried out by Shell Philippines Exploration B.V., Rob Phillips Consulting Pty Ltd and Sustain- able Solutions Services at the request of the Philippine Government. They studied the toxic impact of a gas and gas/condensate producedd water stream (Shell Malampaya) on the environment and concluded that the polyaromatic hydrocarbons, especially the naphthalenes, and the BTEX, have the highest impact on the environment. Remarkably they found that the alkyl phenols do not have a significant impact on the water environment around the Shell Malampaya platform. This is different from the results of the Norwegian studies. This confirms the EIF model and shows that the marine environment is one of the determinants affecting the environmental impact of the individual produced water stream. It IWC UNDERGROUND NATURAL GAS STORAGE PRODUCED WATER TREATMENTT - Since 2002 the MPPE technology has been successfully applied in underground gas storage produced water treatment to remove BTEX and THT (Tetra Hydro Thiophene). THTT is the odorant of the gas to identify gas leaks. It is a challenging compound to remove from wastewater as it is non- very water soluble and has a very unpleasant strong odor. All biodegradable, toxic, highly flammable, kind of precautions had to be taken to remove this compound from the produced water. After the MPPE treatment on location the treated water is sent to the local municipal water treatment prior to discharge in the local river. Tabel 6. MPPE Gas Storage produced water treatment. Compounds Aliphatics BTEX Tetra Hydro Thiophene (THT) Inlet mg/l Outlet mg/l < 0.5 < 0.3 < 0.5 7

8 Photo 3. MPPE unit Gaz de France, Germigny sous Coulombs, France. Graph 7. Sum of concentration (ppm) Volatile removal from waste water during MPPE fieldtest 35,00 30,00 25,00 20,00 o xylene 15,00 m.p xylenee 10,00 5,00 ethylbenzene 0,00 toluene benzene Graph 8. Sum of concentration (ppb) VPH 1 removal from wastewater during MPPE fieldtest 25000, ,00 dodecanee 15000,00 decane 10000, ,00 octane 0,00 hexane pentane MTBE REFINERY WASTEWATER FIELD TEST - On request a MPPE (Macro Porous Polymer Extraction) pilot unit was operated at a refinery. The operational period of the pilot was around 3 weeks. The process wastewater (both with and without corrosion inhibitor) was taken directly from the plant and treated in three (3) steps. First an API separator, then a pilot DGF unit (for oil & solids removal), followed by the MPPE pilot unit. Due to fluctuations in the refinery wastewater characteristics, the MPPE pilot study was conducted over a three (3) week period to check the overall performance of the MPPE unit and verify its ability to treat fluctuations in influent water characteristics. During the pilot plant trial, the unit was periodically sampled. Samples of both inlet and outlet were taken. The samples were sent to an independent certified laboratory for the analysis of BTEX, VPH (volatile petroleum hydrocarbons) and EPH (extractablee petroleum hydrocarbons). The obtained analytical results are presented in the following graphs. Sum of concentration (ppb) Graph 9. VPH-2 Aromatics removal from waste water during MPPE fieldtest Graph 10. VPH 3 Aliphatics removal from waste water during MPPE fieldtest 70000, , , , ,00 C8 C , ,00 C6 C8 0,00 C5 C6 8

9 Sum of concentration (ppb) Graph 11. C8 C10 treatment, as they are non-biodegradable, toxic, have a strong odor and are spread easily in the groundwater. In addition they are difficult to remove from groundwater. Successful lab tests and field tests have been carried out with major O&G companies of which the resultss are given below. Table 7. MTBE / ETBE information. Graph 12. Sum of concentration (ppb) EPH 1 Aliphatics removal from waste water during MPPE fieldtest 14000, , , ,00 C21 C ,00 C16 C , ,00 C12 C16 0,00 C10 C12 EPH 2 Aromatics removal from waste water during MPPE fieldtest 14000, , ,00 C21 C , ,00 C16 C , ,00 C12 C16 0,00 C10 C12 C8 C10 Table 8. MPPE performance groundwater refinery / gasoline locations Conclusion of MPPE field pilot test: The MPPE technology is able to remove BTEX, VPH 1,,2,3 (Volatile Petroleum Hydrocarbons, aliphatics and aromatics) and EPH 1,2 (Extractable Petroleum Hydrocarbons; aliphatics and aromatics) to any level required; > 99.9% removal efficiency was measured. The unit was operated 24 hours a day, 7 days a week, fully automated. The unit was successfully observed remotely withoutt the necessity of changing parameters. GROUNDWATER REMEDIATION OF REFINERY/GASOLINE LOCATIONS - The profiles of the groundwater contamination in refinery and gasoline locations are generally very similar. Sometimes also chlorinated hydrocarbons were measured probably due to the use of degreasing solvents. Since the introduction of the lead freee gasoline in the seventies the presence of MTBE (Methyl Tertiary Butyl Ether) and ETBEE (the Ethyl version) are emerging in the groundwater. MTBE and ETBE are synthesized compounds that were introduced in the gasoline as octane boosters to replace lead compounds in the seventies and the eighties. It is a salient detail that these molecules are creating a new challenge in water Concentration (µg/l) Graph 13. MPPE performance groundwater refinery/ /gasoline locations Inlet Outlet PAHs DROs GROs BTEX MTBE 9

10 GROUNDWATER REMEDIATION BROWN COAL AND COAL GASIFICATION LOCATIONS In countries behind the former iron curtain brown coal was an important source for energy and manufacturing of chemicals. In the first half of the last century, in the whole of Europe coal was used for energy, a source for city gas and chemicals. Later coal has been mainly replaced by oil and natural gas. This has led to many former coal locations with major groundwater contamination. Typical constituents in these groundwaters are dissolvedd and dispersed aliphatics (oil), dissolved aromatics, polyaromatics and phenols. Often these concentrations are so high that they become prohibitive for natural attenuation. Remediation of these so called hot spots is minimally required to clean up these locations. The MPPE application and performance is presented in graph 14 below. MPPE PARTICLES - A scanning electron microscopicc (SEM) photograph of macro porous polymer particles is shown in photo 4. The porosity is 60 70%. These polymers were initially developed as controlled release media in medical applications. The application in water treatment started in Initially the macro porous polymer was used for absorbing dispersed oil from water. Initiated by the oil and gas industry, the idea emerged to develop a medium to remove dissolved hydrocarbons from water by immobilising an extraction liquid in the pores of the polymer. As a result this (patented) MPPE technology was developed in the mid 1990s. Photo 4. Internal structure of the macro porous polymer. Table 9. Groundwater remediation Brown coal / Coal gasification locations. Concentration (µg/l) Inlet Graph 14. MPPE performance groundwater brown coal/ coal gasification locations PAHs BTEX Aliphatics Outlet MACRO POROUS POLYMER EXTRACTION (MPPE) TECHNOLOGY As indicated in the previous paragraphs, the MPPE technology is basically a liquid-liquid extraction technology where the extraction liquid is immobilised in the macro porous polymer particles. The MPPE process has been specifically designed for optimal use of these MPPE particles in water treatment. MPPE PROCESS - In the MPPE water treatment process, hydrocarbon-contaminated water is passed throughh a column packed with MPPE particles. The particles are porous polymer beads that contain a specific extraction liquid. The immobilised extraction liquid removes the hydrocarbon components from the process water. The purified water can either be reused or discharged. Periodical in-situ regeneration of the extraction liquid is accomplished by stripping the hydrocarbons using low pressure steam. The stripped hydrocarbons are then condensed and separated from the water phase by gravity. The almost 100% pure hydrocarbon phase is recovered, removed from the system and left ready for recycling or disposal. 10

11 Photo 5. The MPPE process. Photo 6. MPPE unit at LBC Rotterdam, the Netherlands. process and photo 6 is a photo of a full-scale MPPE installation. The MPPE technology can reduce dissolved and dispersed hydrocarbons such as aliphatics, aromatics (BTEX), polyaromatic and halogenated (chlorinated) hydrocarbons with % removal (1,000,000 times reduction), if required. MPPE technology can be used for treatment of offshore produced water, process water, wastewater and groundwater in a wide variety of markets including the offshore gas and oil, chemical, coatings and pharmaceutical industries. The MPPE technology separatess the hydrocarbons in practically pure form for (re)usee and does not create a waste stream. MPPE can withstand complex produced water environments containing salt, methanol, glycols, corrosion inhibitors, scale inhibitors, H 2 S scavengers, demulsifiers, defoamers and dissolved ( heavy) metals. Table 10. The condensed aqueous phase is recycled into the system. The application of two columns allows continuous operation with simultaneous extraction and regeneration. A typical cycle is one hour of extraction and one hour of regeneration. Photo 5 shows a simplified flow-sheet of the MPPE CHEMICAL CONSTITUENTS REDUCTION WITH MPPE - After the MPPE technology was developed, the first application in 1994 was actually on a gas offshore producedd water stream of Elf Aquitaine in Harlingen (which later becamee Total, then Vermilion; photo 7). The MPPE separation performance was above 99% at 3,000 ppm influent levels from the very beginning for the target compounds (BTEX) and the results have been published in a Society of Petroleum Engineers conference (Pars and Meijer, 1998). At that time Elf Aquitaine had developed a specific steam stripper (Kloppenburg and Venema, 1997), but has abandoned that technology for 11

12 producedd water treatment due to costs and operational/maintenance reasons. Photo 7. MPPE unit at Vermilion, Harlingen, the Netherlands. units offshore, on the most critical platforms in the Dutch part of the North Sea (Total F15A, NAM K15A and K15B). Thesee units have been in operation successfully since 2002 with a separation performancee of > 99% of BTEX, PAHs and aliphatics at ppm influent concentrations. Statoil/Shell Ormen Lange was started up in 2007 (Shotun; Salevik; Silverstone) and Woodside Pluto in Recently MPPE units are included in Prelude (Floating LNG), Ichthys (FPSO) offshore Australia and in the West Nile Delta. Due to further developments in OSPAR regarding the issue of dissolved aromatics and PAHs emission, a formal investigation was carried out on request of OSPAR on oil produced water of NAM and Total (Meijer et al, 2004). Later an extensive offshore field test was carried out by Hydro on Troll B (Pollestad, 2005). In these field tests a consistent reduction of > 99% was observed for BTEX and PAHs. For aliphatics below C20 a consistentt reduction at 95 99% removal was measured in all field tests. For the total aliphatics removal the picture was mixed: 91 95% for Total and > 95% for Troll B. REAL LIFE ROBUSTNESS OF MPPE As legislation at that time did not formally require a reduction in dissolved aromatics (BTEX) or polyaromatic hydrocarbons (PAHs), it took a while before the MPPE technology was requested by the offshore industry (Dalen). Neverthelesss both governments (NOGEPA study on 55 technologies (Kaa and Petrusevki, 1988), OSPAR (OSPAR, 2004) and the oil and gas industry (Orkney Water Test center) (ERT/Orkney Water Technology Center, 1997), were addressing the issue of dissolvedd aromatics and PAHs emission in producedd water. The first offshore field test was carried out by NAM ( Shell/Exxon) on L2 in the Netherlands part of the North Sea. It was a 4 month test with excellent results, which were presented at the 2001 Offshore Technology Conference (Meijer and Kuijvenhoven, 2001). Some more offshore field tests were carried out on gas/condensate produced water by Statoil (in Norway) and Shell (in Malaysia). The combination of successful offshore field tests at the end of the 1990s and beginningg of this century and governmental pressure in the Netherlands has led to the installation of the first commercial MPPE An example of the robustness of MPPE is shown in graph 15 where the design values and real life analyses since 1994 are given for an MPPE unit treating gas produced water and a mono ethylene glycol (MEG) regeneration stream. The design was to reduce dissolvedd BTEX from 1,500 ppm to < 1 ppm. In practice influent levels of BTEX (dispersed and dissolved aromatics) from 1,400 7,700 ppm and aliphatics (dispersed and dissolved oil) from 150 1,437 ppm were reducedd as a total to ppm in the outlet. Graph 15. A real life example of design versuss actual MPPE performance. 12

13 MERCURY REMOVAL WITH MPPE In recent benchmark studies it was discovered that MPPE also removes Mercury from gas/condensate produced water. This phenomenon was consistently observed in all cases where Mercury was measured. These findings confirm the first time this was measured in 1999 in the NAM field test (Kuijvenhoven et al). Below in graph 16 the results of such a seriess are given. The observed removal effectiveness varies between 82 and 99% at inlet levels from 5 to 120 ppb. Lead, cadmium and nickel were hardly detectable. Graph 16. Mercury removal with MPPE. CONCLUSIONSS BOD, COD, TOC and other integral discharge parameters are effective in municipal and nontoxic wastewaters. Industrial wastewaters where significant toxic contents are present risk based approaches are emerging. They focus on selective removal of the toxic content to create a Zero Harmful Discharge. Risk based approaches are more cost efficient than discharge policies based on integral parameters like COD. The concept of the Environmental Impact Factor as a form of a risk based approach to offshore produced water goals is gaining recognition worldwide. Extraction technologies like MPPE are effective technologies to implement risk based approaches as has been proven in offshore gas/ /condensate produced water treatment. The removal of toxic hydrocarbons is a specific issue to be addressed when COD equirements are to be met and toxic content threatens the function of the biotreatment. MPPE protects biotreatment against high and changing toxic loads. MPPE has proven a 95 to 99% reduction of the Environmental Impact Factor in offshore produced water. The MPPE technology has consistently shown the removal of toxic contents in produced-, waste- and groundwater with levels around 99%. The % separation performance of an installed MPPE unit is independent of the inlet concentration of the target compounds during operation. MPPE removes Mercury with 81 to 99% based on various gas/condensate Offshore produced water benchmark studies. Further studies are planned to further substantiate this phenomenonn so as to come to a controlled and predictable removal. 13

14 Annexes ACKNOWLEDGEMENTS The basis of this paper is the series of field tests carried out on request of Oil and Gas companies and the data provided by them of running MPPE units since This has resulted in a wealth of information that has been used in this paper together with the publications mentioned in the reference list. This paper would not have been possible without the help and support of Peter Nekeman, making the graphs based on the labtest and pilot test figures and Mrs Marijke Kuntzel for consuming the continuous stream of new drafts and her constructive comments. I would like to thank Jan Bart Kok for his contribution to the COD and BOD paragraphs of this paper. REFERENCES BERGERSEN, L. AND JACOBSSON, J New Offshore Tie-ins and impact on Onshore Facilities, Field Case Kollsnes. Tekna Produced Water Management Conference, Stavanger, Norway. BERGERSEN, L., JACOBSSON, J. AND MEIJER D.TH Solving the Impact of High Toxic Loads in the Produced Water at the Kollsnes Gas Terminal by Applying the MPPE technology. NEL Produced Water Best Management Practices, Kuala Lumpur, Malaysia, November. BULLER, A. T., JOHNSEN, S. AND FROST, K Offshore produced water management knowledge, tools and procedures for assessing environmental risk and selecting remedial measures. Memoir 3. Stavanger, Norway: Statoil Research and Technology Offshore. CHEN, G.Z. AND EBENEZER T.I Produced water treatment technologies. Faculty of Engineering, Department of Chemical and Environmental Engineering, and Energy and Sustainability Research Division, University of Nottingham, Nottingham NG7 2RD, United Kingdom. 4 July. DALEN, A.V Produced Water Regulations in the Netherlands. NEL Oil-in-Water Monitoring Workshop, Aberdeen, United Kingdom, September. ERT/ORKNEY WATER TECHNOLOGY CENTER, 1997 The removal of dissolved and dispersed organic components from produced water. ERT F92/178, requested by Exxon Mobil, Total, Amarada Hess. GRINI, P.G., HJELSVOLD, M. AND JOHNSEN, S Choosing produced water treatment technologies based on environmental impact reduction. HSE Conference, Kuala Lumpur, Malaysia, March, SPE paper ITHNIN, I.B. AND CHRISTOPHER, G The discharge of produced water from oil and gas production: Legislation requirement in Malaysia. NEL Produced Water Best Management Practices, Kuala Lumpur, Malaysia, November. KAA, C.C.R. VAN DER AND PETRUSEVKI, B Inventarisation of removal techniques to reduce the benzene heavy metal emissions from offshore platforms. (In Dutch). NOGEPA (Netherlands Oil and Gas Exploration and Production Association) and Dutch Government, Report KLOPPENBURG, M.F.C. AND VENEMA, W De-oiling condensed glycol regenerator overhead vapours by steam stripping SPE/UKOOA European Environmental Conference, Aberdeen, United Kingdom, April, SPE paper no LOWE, I Shaping a sustainable future challenges for Australia s oil and gas industry. APPEA Environment Conference, Coolum, Australia, November. 14

15 MEIJER D.TH. AND KUIJVENHOVEN COR A.T Field-Proven Removal of Dissolved Hydrocarbons from Offshore Produced Water by the Macro Porous Polymer Extraction Technology. SPE Offshore Technology Conference, Houston, Texas, USA, 30 April 3 May, OTC MEIJER D.TH., KUIJVENHOVEN COR A.T. AND KARUP, H Results from the latest MPPE field trials at NAM and Total Installations. NEL Produced Water Workshop, Aberdeen, United Kingdom, April. MINISTRY OF ECONOMIC AFFAIRS, 1995 Declaration of Intent, Implementation of Environmental Policy for the Oil and Gas Industry. NOGEPA (Dutch Oil & Gas Exploration and Production Association), The Hague, the Netherlands, 2 June. OSPAR DENMARK, 2004 Definition of a data collection strategy for aromatic hydrocarbons by OSPAR Contracting Parties in 2004, OSPAR Background Document concerning Best Available Techniques and Best Environmental Practice for the Management of Produced Water from Offshore Installations. OSPAR meeting of the Offshore Industry Committee (OIC), Dublin, Ireland, March. PARS, H.M. and MEIJER D.TH Removal of dissolved hydrocarbons from production water by Macro Porous Polymer Extraction (MPPE). SPE International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, Caracas, Venezuela, June, SPE paper no PHILLIPS, R., RIOS, A. AND CAYMO, A Assessing the Risk from Discharging Produced Water to the Marine Environment. NEL Produced Water Best Management Practices, Kuala Lumpur, Malaysia, November. POLLESTAD, A The Troll Oil Case Practical Approach towards Zero Discharges, Troll Projects. Tekna Produced Water Management Conference, Stavanger, Norway, 18 January. SALEVIK, P Onshore Water Treatment, Experience from Ormen Lange, Nyhamna. Tekna Produced Water Management Conference, Stavanger, Norway. SILVERSTONE, M. and Vik, E Application of whole effluent assessment (WEA): evaluating the performance of the Ormen Lange produced water treatment plant. Tekna International Produced Water Management Conference, Stavanger, Norway, January. SJØTHUN, S., 2002 The Process of Developing a Total Effluent Water Handling System for Ormen Lange. Tekna Produced Water Management Conference, Stavanger, Norway. 15