COSIA’s Water Performance Goals are focused on reducing fresh water use intensity in the oil sands.
The Water Environmental Priority Area has identified Innovation Opportunities to help mobilize the minds and resources of external stakeholders and global solutions providers in order to achieve its aspiration to ‘be world leaders in water management, producing Canadian energy with no adverse impact on water’.
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Water performance goals have been established to drive achievement of COSIA’s water aspiration. The development of water goals is based on freshwater intensity measures. Water use intensity refers to the amount of water required to produce one barrel of oil equivalent (BOE). Over time, industry’s endeavour has been to significantly reduce the water use intensity for both mining and in situ operations.
Starting in 2012, performance against the goals is reported on an annual basis with COSIA members aiming to achieve water performance goals by 2022. This 10-year time frame has enabled the companies to be ambitious while allowing necessary time to develop the new technologies and processes required for success.
Approximately 85-90 per cent of the water used in in situ operations is recycled. The remaining 10-15 per cent is lost mainly due to reservoir retention and the need to remove water with high concentrations of salts and other dissolved solids to maintain effective operational conditions. This water needs to be replaced to make up for these losses. Over half of this ‘make-up water’ is saline and is normally sourced from deep saline water zones or aquifers; the balance of make-up water is mostly fresh groundwater.
At the start of the goal period, in 2012, operators used 0.36 barrels of fresh water for every barrel of bitumen produced in situ. In 2019, industry used 0.20 barrels of fresh water for every barrel produced, which is a 44 per cent reduction from 2012.
Key factors such as increased use of recycled water, improvements in steam efficiencies and increased use of non-potable saline groundwater have contributed to reduced freshwater use intensity through the years.
It should be noted that, in 2019, decreased production – due to a temporary curtailment of oil production imposed by the Alberta Government – resulted in decreased overall facility efficiency. In turn, this resulted in a slight increase to the 2019 water-use intensity for the in situ sector when compared to 2018 levels.
DID YOU KNOW:
Saline water has greater than 4000mg/L total dissolved solids (TDS) and is not suitable for drinking or agricultural use without treatment. Fresh water has less than 4000mg/L TDS.
There are some operators that do not have ready access to saline water sources and as a result need to use fresh water. In most cases the fresh water is sourced from underground aquifers that would require treatment before being suitable for human or agricultural use.
DID YOU KNOW:
All in situ operators are required by Alberta’s Water Conservation and Allocation Policy for Oilfield Injection (2006) to reduce the use of fresh water sources where possible by using alternatives sources.
How will COSIA members deliver the goal while addressing associated challenges?
COSIA members are developing new technologies and sharing best practices to enable further reduction of the impact of their in situ operations on fresh water resources. This Performance Goal singles out fresh water use, rather than saline water, due to its importance to the environment and to other water users in the region.
Achieving this goal will require COSIA members to further increase water use efficiency and recycle rates within their operations. A consequence of both these activities is an increased concentration of salts in recycled water. This increase has the potential to make steam generation more inefficient and as a result increase the volume of highly saline wastewater that needs to be managed and disposed of. Both of these challenges in turn can increase the land or greenhouse gases (GHGs) footprint of in situ operations. It is vital to COSIA members that improvements in one environmental area (fresh water use intensity) are not offset by worsening performance in other areas, like GHGs.
There are a number of areas COSIA members are focusing on to deliver this 50 per cent reduction:
Improved water treatment processes
COSIA members are continuing to improve the efficiency and effectiveness of their water treatment processes used in bitumen extraction.
For instance, removing more hydrocarbons and dissolved minerals from boiler feed water can reduce the amount of water needed to generate steam - thereby cutting overall water use. Specific projects aimed at improving treatment processes include:
- Water Technology Development Centre (Suncor with Nexen, Shell, Canadian Natural, Devon, Husky)
A $165 million water treatment test facility focusing on in situ water treatment technologies.
- Silica Sorption Produced Water Evaporator Pilot (Canadian Natural)
Testing a silica sorption evaporation technology that could reduce chemical consumption, maintenance downtime and blowdown waste.
- The SAGD Produced Water Treatment project (Suncor, Devon, ConocoPhillips, GE, Alberta Innovates Energy and Environment Solutions)
Exploring ways to treat produced water more efficiently and increase water recycling.
Increasing Boiler/Steam Generation Efficiency
COSIA members are also looking at boiler design and operations that could reduce overall water use owing to more efficient steam generation while also reducing GHG intensity.
- Boiler Rifle Tubes (Suncor and Devon)
Improving Once-Through Steam Generator (OTSG) efficiency through the use of rifle tubes to improve steam quality (up to 90 per cent) thereby reducing water use, energy and blowdown waste.
- Boiler Soft Sensors (Suncor)
Using software and real time analysis of boiler data to increase steam quality with less water and energy.
Improving Boiler Blowdown Waste Management
All boilers produce blowdown waste – a salt and organics rich brine that is intentionally removed from a boiler to avoid the build-up of impurities that could impact efficiency and/or cause damage. Increased concentration of salts resulting from increased levels of water recycling can make the management of blowdown more challenging. More effective water treatment can help reduce the amount of salts within the water added to the boiler. This in turn can lead to greater steam generation efficiency, reducing the need to remove water not successfully converted to steam.
However there will still be a need to manage blowdown waste including a focus on the below areas:
- Improving the recycling of water within the blowdown waste
- Finding ways of solidifying the blowdown waste that is produced while reducing the impact on GHG emissions and land use
- Making the final disposal of the remaining blowdown waste more efficient and environmentally responsible.
Specific projects include:
- Evaporator Waste Solidification (Suncor with Canadian Natural, Nexen, Statoil, ConocoPhillips, Devon)
Mixing blowdown waste with various solidification agents to find the most stable end-product to minimize the environmental impacts of long-term sequestration.
- ‘Regional Water Management Initiative’ Regional Disposal Study (Suncor with all COSIA members plus some non-COSIA members)
Evaluating if a regional network, utilising existing pipeline right-of-ways and a large common disposal field, can decrease the regional impact of disposal.
- Long-term strategies for blowdown waste management (Statoil with all Water EPA members)
Looking at the implications associated with different blowdown waste disposal methods.
Specific Challenges and Opportunities - Greehouse Gases
COSIA members are taking an integrated approach to improving environmental performance in the oil sands.
This means every effort is made to ensure activities aimed at improving performance in one EPA do not have a negative impact on any other EPA. For example, attempting to reduce fresh water use intensity could cause an increase in greenhouse gas (GHG) emissions, depending on which technologies are applied. In this way COSIA members need to develop a balanced, integrated approach to water management to ensure reductions in water use have a neutral or positive impact on GHGs as well as other EPA activities. COSIA’s GHG EPA is currently working on a portfolio of projects that will help reduce GHG emissions across oil sands operations, many of which will focus on water related processes and technologies.
Approximately 80 to 85 per cent of water used for oil sands extraction in mining operations is recycled. Of the remaining 15 to 20 per cent ‘make-up’ water, 80 to 85 per cent is taken from the Athabasca River and its tributaries. At the start of the goal period in 2012, this equated to approximately 2.2 barrels of Athabasca river water being used for every barrel of bitumen produced. The remaining proportion of ‘make-up’ water is made up of precipitation (rainwater/snowmelt) captured on operators’ leases and ground water, including groundwater upstream of the mining face (sometimes known as mine depressurization water). Some of this groundwater may be saline, depending on local geology/hydrology.
In 2019, industry used 1.7 barrels of fresh water for every barrel produced, a 22 per cent reduction from 2012.
Key factors which influenced COSIA members’ water mining performance in 2019 include water conservation efforts, improved mine and tailing operations, use of excess water inventory and use of alternative water sources.
How will COSIA members deliver the goal while addressing associated challenges?
COSIA members are committed collectively to “Reduce the net water use intensity from the Athabasca River and its tributaries by 30 per cent by 2022.”
This 30 per cent reduction will be achieved while adhering to sustainable water management principles of ‘reduce-reuse-return’ for all mine sites, more specifically:
- Optimising water reduction and recycling opportunities while balancing the net environmental impact and associated costs of both.
- Reducing the amount of water retained in tailings.
- Confirming the technical basis for returning treated water to the Athabasca River while meeting all environmental and regulatory requirements.
- Understanding and managing the cumulative effects on the Athabasca River watershed.
- Further improving the knowledge and understanding of pit lakes.
- Specific challenges and opportunities – Salts.
Optimizing water reduction and recycling opportunities.
A key area of focus for COSIA members is optimizing the opportunities to reduce water use and increase recycling opportunities where available.
This includes the treatment of mine water for re-use in the bitumen extraction process, while ensuring such improvements are not offset by worsening performance in other areas, like GHG emissions. This area of focus also includes assessing the feasibility of a regional approach to water management across all oil sands operations so that, among other things, tailings water can be used as process water for in situ operations. Specific projects include:
- Regional Water Management Initiative (RWMI) (Suncor with other COSIA members and non-COSIA members)
Investigates the feasibility of sharing water between mining and in situ sectors and the feasibility of a regional approach to managing in situ water disposal.
- Water recycle projects (Canadian Natural and Suncor)
Looking at ways to treat mine water and re-use it in the bitumen extraction process.
Reducing the amount of water retained in tailings.
COSIA members are also working to reduce net water use intensity by improving how tailings are processed and managed.
Removing water from tailings either prior to it entering the tailings pond or when it becomes trapped between fine solid particles (mature fines tailings) within the tailings pond itself helps make tailings easier and faster to reclaim. The water that is captured is then available for re-use in the recycle circuit or for return to the environment, reducing net water demand from the Athabasca River and its tributaries. Specific projects include:
- Tailings Centrifuge (Syncrude with all Tailings EPA members)
Uses centrifugal force to extract process water from fluid fine tailings.
- Tailings Reduction Technology (Suncor with all Tailings EPA members)
Uses chemical flocculants in mature fine tailings to cause clay particles to stick together and release water. The resulting thickened tailings are deposited in thin layers in shallow slopes specifically constructed for drying and dewatering. Here the water is captured and re-used.
- Non-Segregating Tailings (Canadian Natural with all Tailings EPA members)
Uses thickeners and cyclones to significantly dewater tailings before it is sent to the tailings pond. Also, CO2 is added to non-segregating tailings (NST) which further accelerates the release of water. The dewatering process allows warm process water to be captured and re-used.
Assessing the technical basis for returning treated water to the Athabasca River.
Members are actively advancing knowledge and technology to allow the safe return of treated mine water to the Athabasca River during active mining.
This will reduce the net use intensity even further while allowing industry to reduce the volume of untreated mine water in tailings ponds over a shorter period of time, further enhancing the reclamation process. Specific projects include:
- Salt Management (Teck with all Water EPA members)
Assesses the environmental effects of leaving salt to accumulate in the mine throughout its lifetime then releasing it into the environment via pit lakes compared with releasing salt to the environment through the controlled return of treated mine water during active mining.
- Substance Load Allocation Study (Suncor with all Water EPA members)
This study assesses the assimilative capacity of the Athabasca River for return of naturally occurring substances like salt in typical mine waters.
- Technology and Sector-based Standards (Suncor with all Water EPA members)
Assesses the water treatment standards in related industries (refining, mining and pulp paper) to help ensure that what is proposed for the return of treated mine water in the oil sands sector is similar to standards set in these other industries. Both this project and the substance load allocation study will help develop ‘end of pipe’ limits based on regional watershed management principles.
- NSERC Senior Industrial Research Chair (IRC) Program in Oil Sands Tailings Water Treatment: (Canadian Natural, Suncor, Syncrude and Total plus other non-COSIA members at the University of Alberta)
Develops and assesses innovative water treatment technologies and their applicability to oil sands mine water.
The Canadian oil sands sector is subject to a strong regulatory regime and industry expects continued responsible government regulatory oversight, including emerging regulation related to mine water return.
Understanding and managing the cumulative effects on the Athabasca River watershed.
COSIA members are further enhancing their understanding of the cumulative effects of oil sands operations on the Athabasca watershed.
This work focuses on discerning natural from man-made (anthropogenic) effects and assessing the feasibility of enhanced environmental effects monitoring. Specific projects include:
- Natural and Anthropogenic Inputs to the Athabasca River (Syncrude with Canadian Natural, Suncor, Teck, Total)
Three-year University of Alberta study conducted jointly with Alberta Innovates — Energy and Environment Solutions to assess the relative impact on aquatic ecosystems from recent human developments compared to natural contributions.
Improving the knowledge and understanding of pit lakes.
Members are assessing the most effective means of closing knowledge and technology gaps related to the management of pit lakes.
Pit lakes are reclamation features common to virtually every mine site in the world. In oil sands mines several holes or ‘pits’ are dug one after the other in order to extract the bitumen. In many cases, once the first pit is dug, it is filled using tailings material from the next pit excavated. However at the end of a mine’s life there are no materials available to re-fill the last pit. It is this feature that is flooded to create a pit lake. The additional research and understanding derived from this work will help ensure the oil sands pit lakes currently planned will evolve into healthy aquatic ecosystems. Key projects include:
- Base Mine Lake (Syncrude contributed technology with ongoing support from Suncor, Teck, CNRL, Total and Imperial)
This is the sector’s first full-scale demonstration pit lake.
- Demonstration Pit Lake facility (Canadian Natural, Imperial, Suncor, Syncrude, Total and Teck)
This is a proposed pilot-scale research and demonstration facility that would complement the Base Mine Lake project.
Specific challenges and opportunities - Salts.
The management of salts is critical in mining operations. Naturally occurring salts in the oil sands ore are released upon processing and end up in tailings ponds.
Salts are also present in mine depressurization water and river water, all of which are used in oil sands operations. As operators strive to increase the proportion of water that is recycled on site, salt concentrations will increase. That poses new challenges which might include:
- Making it more difficult to extract bitumen from the ore and meet regulatory requirements for bitumen recovery efficiency.
- Reducing the reliability and efficiency of process equipment through corrosion.
- Increasing the levels of salts in tailings and adjoining areas to levels higher than normally found in boreal forest habitats, making the reclamation process more challenging.
There are several COSIA projects related to effectively managing salts on mine sites. A few are noted below:
- Salt Management Study (Teck with all COSIA Members)
Assesses the environmental effects of allowing salt to accumulate in recycle circuits during mining versus reducing the salt concentration of recycled water during mining operations.
- Treatment of Depressurization Water (Canadian Natural)
Involves pilot tests for treating and reusing depressurization and tailings water in operations. Technologies include reverse osmosis, evaporator, crystalliser, saltmaker and thermionic technologies.