Keystone Pipeline Spill Response deemed a Success

In early December, a section of the Keystone Pipeline leaked 210,000 gallons of oil near the South Dakota City of Amherst.  Representatives of Trans-Canada Pipeline, the owner of the pipeline, deemed the detection of the leak and prompt spill response as an example of its exemplary contingency measures that are in place to detect and respond to such incidents.

An aerial view shows the darkened ground of an oil spill which shut down the Keystone pipeline between Canada and the United States, located in an agricultural area near Amherst, South Dakota.
REUTERS/Dronebase

When fully complete, the Keystone Pipeline will carry bitumen from the Alberta oil fields to refineries in Texas.  At present, the pipeline runs from Alberta, through North Dakota and South Dakota.

As reported in the Prairie Public News, Julie Fedorchak of the North Dakota Public Service Commission (PSC) stated that the company’s quick response to the incident shows that its response plan worked perfectly.

“The system was shut down within three minutes,” Fedorchak said.  “And importantly, the spill was detected.”

Fedorchak said the spill showed up on its detection equipment, and the people overseeing system noticed it, and.

“They knew it was something off,” Fedorchak said.  “And the quick shutdown prevented what could have been a much more difficult spill.”

But Fedorchak said there are still questions about why the spill happened.

“It’s a new line,” Fedorchak said. “New lines like this shouldn’t be having those kinds of issues.”

Fedorchak said it’s important that the company and federal pipeline regulators do the tests needed on that pipeline, to try to figure out what caused it.

“That’ll be a learning opportunity for the entire industry,” Fedorchak said.

The company believes it may have been caused by an abrasion on the pipeline coating, that happened during construction.

“Perhaps there were some things in the ground that could have caused it,” Fedorchak said. “Or it could have been a problem with the pipeline protection itself. They’re looking at a number of things.”

Clean-up work continues at the spill site.

RFPs for Spill Response Equipment by Canadian Coast Guard

The Canadian Coast Guard is soliciting bids for new spill response equipment for use on its marine vessels.  The equipment will be used to contain and remove oil and other contaminants from the water in the case of a spill.

The RFPs can be found at the following web sites:

All interested suppliers may submit a bid which is open to companies from Canada, the United States, and other countries that are part of various trade agreements with Canada.

The competitive procurement strategy will be based on lowest bid meeting the technical specifications.

This will be the first equipment acquired under the Environmental Response Equipment Modernization initiative of the Oceans Protection Plan.  The equipment will include curtain booms, high-speed sweep systems, and small, portable multi-cassette skimmers.

The Environmental Response Equipment Modernization initiative will bring the Coast Guard in line with and beyond current standards regarding environmental spill response and take advantage of innovations and advancements in technology.

Innovations in Pipeline Design: Leak-proof technology

By Dema Mamon, M.Sc.Pl, BES and John Nicholson, M.Sc., P.Eng.

In Canada, getting approval to construct an oil pipeline has become increasingly difficult.  Every oil pipeline incident that involves a leak and subsequent clean-up is widely covered in the media,  providing fuel for pipeline opponents that call an end to the construction of new pipelines.

Abacus Data Inc., an Ottawa-based research firm, has been tracking public opinion on the construction of new pipeline capacity and has found some interesting trends.  Since 2014, polling has shown that the negative view of building new oil pipelines has remained steady at 21 to 22% range.  However, there was a drop in the positive attitude amongst Canadians toward building new pipelines – from 58% in 2014 to 44% in 2017.  Over that three year span, a good proportion of Canadians who once viewed building new pipeline capacity with a positive attitude have shifted to a neutral view.  The neutral view on oil pipelines have grown from 20% in 2014 to 36% in 2017.

There can be many theories to explain the three year shift in public opinion on new oil pipelines.  One plausible theory is that oil spills from pipelines typically make headline news, thus leaving an impression in the minds of Canadians the perhaps pipelines are not as safe as the industry states.  Oil leaks from pipelines damage the environment, are costly to clean-up, and fuel public opinion that pipelines are not safe.

One way to eliminate the perception that building new oil pipelines is bad for the environment and shift public opinion in favour of such projects is to build pipelines that don’t leak.  However, is it even possible to build leak-proof pipelines?

Are Double-Walled Pipelines the Answer?

One logical idea for building leak-proof pipelines is for them to be double-walled.  The outer wall would serve as protection from external damage.  The technology does exist to construct double-walled pipelines and they are used in certain circumstances such as when there is a large temperature difference between the liquid in the pipe and the surrounding environment.

Double-walled pipelines are not considered the cure-all by some in the industry.  Those resistant to the use of double-walled pipelines note that in some instances, it may be more cost effective to protect pipelines from the potential of external damage by burying them or placing slabs over them in higher risk areas.  Furthermore, it can be more difficult to monitor a double-walled pipeline and an outer pipe interferes with the maintenance of the inner pipe.

At the University of Calgary, researchers believe their two-walled pipeline design and monitoring system is the solution to preventing spills.  Although double-walled pipelines have been around since the 1980’s, Thiago Valentin de Oliveira, an electrical and computer-engineering master’s student, and Martin Mintchev, an engineering professor, say that their design is superior.

The U of Calgary researchers designed and constructed their prototype to consist of a typical steel inner layer with either a steel or plastic outer layer.  There is an air gap between inner and outer pipeline contains the oil that leaks from the inner pipeline leak.  The real innovation developed by the U of Calgary is the segmentation of the inter-pipe space and the inclusion of a linear wireless network linking the segments.  With the segmentation, a leak of oil from the inner pipe enters the air gap between the two pipes and is contained in a section of pipe.  Wireless pressure sensors between the two walled layers detect the pressure build up and send an alert to the pipeline control staff.

 

If commercially implemented, the U of Calgary system would allow pipeline operators with the means of quickly shutting down the pipeline when a leak was detected into the outer pipeline and crews could be dispatched to make repairs.  The oil that leaked from the inner pipe would be contained in the air gap between the two pipes and be confined to one section of the pipeline.

The U of Calgary researchers estimate that their design would result in an additional 25% in the capital cost of building pipelines.  They believe this cost could be reduced if the outer pipeline material was composite materials or plastic.

Is Advanced Monitoring the Solution?

Also in Alberta, a Calgary-based firm, HiFi Engineering, recently announced that it has developed an innovative pipeline leak detection system.  Dubbed High-Fidelity Dynamic Sensing (HDS™), the monitoring system can spot the exact location of a leak in a pipeline within seconds of it occurring.  The system continuously monitors temperature, sonic and ultrasonic acoustics, and vibration and strain.  Any anomaly in the measurements results in an alert being sent to the pipeline company control room.

Hifi Engineering’s High Fidelity Dynamic Sensing (HDS) technology is being called the ‘ears of pipeline monitoring.’

The system works utilizing fiber optic cables that run the length of the pipeline.  A laser beam is sent down the length of the optic cable and sends signals back that provide a multitude of information to the pipeline control room.

TransCanada Pipelines Corporation has already installed the HiFi HDS™ monitoring system in sections of the Keystone XL oil pipeline that runs from Canada to the U.S.  Also, Enbridge employs the technology in its new northern Alberta pipeline.

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About the Authors

Dema is a graduate of York University’s Bachelor in Environmental Studies program (2008) and the University of Toronto’s Masters of Science in Planning Programme (2010). She is currently pursuing her Canada Green Building Council’s Leadership in Energy and Environmental Design’s Green Associate certification. Her research interests include environmental conservation, green infrastructure, and sustainability. She can be reached at dema.mamon@gmail.com.

John Nicholson is the editor of Hazmat Management Magazine.  He has over 25 years of experience in the environmental and cleantech sectors.  He is a registered professional engineer in the Province of Ontario and has a M.Sc. in environmental engineering.  His professional experience includes time at a large engineering consulting firm, a major Canadian law firm, and the Ontario Ministry of the Environment and Climate Change.

Groundwater and PFAs: State of Knowledge and Practice

National Ground Water Association (NGWA) Press, Westerville, OH. ISBN: 1-56034-037-1, 114 pp, 2017

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a group of chemicals that are emerging contaminants of concern due to their persistence in the environment, bioaccumulative potential, and toxicity.

Chemical structure of perfluorooctanoic acid

PFASs have previously been used in a range of industrial processes, consumer products (such as 3M’s Scotchgard fabric and upholstery protector), aviation hydraulic fluid and fire-fighting foam. The two main PFASs are perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). The unique properties of PFASs that make them useful in products and industrial processes also mean that they are persistent in the environment and highly mobile. They are therefore challenging to manage and remediate once released into the environment. They are potentially bioaccumulative and potential health effects may include developmental, reproductive and systemic effects and possibly cancer. PFOS has been listed as a persistent organic pollutant (POP) in Annex B of the Stockholm Convention since 2010. The use of PFOS in products has been phased out in Australia since the early 2000’s.

Beginning in October 2016, 37 scientists and engineers voluntarily collaborated through the National Ground Water Association to develop information on per- and polyfluoroalkyl substances (PFASs) for the broader groundwater community. Using a consensus-driven process that included a public comment period, their efforts were completed toward the end of 2017.  NGWA published this PFAS document to assist members and other groundwater professionals who may be tasked with investigating the transport pathways and extent of PFASs in groundwater and surface water, assessing potential risks to receptors, or designing and constructing engineering controls to manage subsurface PFAS contamination.  The main purpose of this document is to summarize the current state of knowledge and practice regarding PFAS fate, transport, remediation, and treatment, recognizing that knowledge in this field continues to advance. This document also summarizes current technologies, methods, and field procedures being used to characterize sites and test remediation and treatment technologies. Temporarily available at http://www.ngwa.org/Professional-Resources/Pages/Groundwater-and-PFAS.aspx

PFAs can be used in fire fighting foams

 

Ontario MOECC Issues Draft Order to Mining Company in Northern Ontario

Ontario MOECC recently issued a draft Director’s Order to Ontario Graphite Ltd. and several Directors of the company that, if finalized, will require the company to perform remedial work related to an interceptor trench, mine tailings dam, polishing pond.

The mining operation, referred to as the Kearney Graphite Mine, is located Township of Butt in the District of Parry Sound, approximately 20 km north east of the community of Kearney.

Ontario Graphite Ltd. Kearney Mine Site (Photo Credit: Sudbury Mining Solutions Journal)

Under these sections of the Environmental Protection Act and Ontario Water Resources Act, the Director may require a person who owns, or owned, or who has or had management or control of an undertaking or property, to take immediate actions and environmental measures to protect the natural environment and to prevent or reduce the discharge of a contaminant into the natural environment from the undertaking or property, or to prevent, decrease or eliminate an adverse effect.

The overall objective of the proposed Director’s Order is to amend an existing Director’s Order issued on January 26, 2016 to have the company implement a work plan for the treatment of mine water discharges as well as submit a written report prepared by a qualified person.

On April 10, 2017, Ontario Graphite Ltd. reported that the open pit was overflowing to the environment as a result of spring melt.  Ontario Ministry of the Environment and Climate Change (MOECC) staff visited the site on April 12, 2017 and observed that the collection trench used by the company to prevent acidic water from entering Graphite Lake (i.e. the interceptor ditch) had also overflowed at some point prior to the site visit.

During the April 12, 2017 MOECC site visit, company staff reported to the ministry that additional erosion had occurred on the downstream dam that separates the tailings management area from the polishing pond. Company staff did not foresee concerns for dam stability; MOECC staff, however, recommended that the company have someone with the necessary expertise undertake evaluation of the structure.

In response to the MOECC recommendation, the company retained a consulting firm to provide recommendations for any needed remedial work on the tailings dam. As detailed in the updated action plan submitted to the ministry on October 30, 2017, the company awaits receipt of the report detailing these recommendations and following receipt, will implement the recommendations noted.

In 2017, Ontario Graphite Limited reported several non-compliance incidents with water quality discharge limits specified in the Environmental Compliance Approval including acute toxicity, iron, total suspended solids and pH.  Although the company attributed some of the exceedances to the dewatering of the open pit, a consultant hired by the company as a result of the Director’s Order noted a number of recommendations that should be implemented to improve operation of the sewage works and to maintain compliance with the final effluent limits.

United States: New Standard Of Care Document On Environmental Due Diligence (“Phase I”)

Article by Jerrold Samford and Andrea L. Rimer

Troutman Sanders LLP

The GeoProfessional Business Association (GBA) – formerly known as ASFE – recently released a new study on the standard of care for conducting Phase I environmental site assessments.  This document is the fourth in a series of studies the organization has produced since the inception of the due diligence process in the early 1990’s.  The study is an evaluation of approximately 200 Phase I reports from across the country, written between 2007 and 2010. The results of the study will be a valuable tool in determining whether a Phase I conducted during that time period meets the standard of care or not.

In completing the study, the GBA compared the Phase I reports to the elements of the ASTM Standard E1527-05, applicable during the time period of the reports, to see whether the reports included the elements of the ASTM standard. Although nearly all of the reports stated they were completed in accordance with the ASTM Standard, the committee reviewing the reports concluded that not a single report actually complied with every component required by the Standard. Consequently, the GBA study finds that strict compliance with the ASTM standard does not constitute the standard of care for conducting Phase I evaluations of commercial real estate.

The committee’s conclusion could become critical in legal actions where the issue at hand is whether appropriate environmental studies were completed prior to completion of the transaction. The GBA study could be used to show a court that because strict compliance with the ASTM Standard is not commensurate with the standard of care, a purchaser could still be in compliance with the All Appropriate Inquiry provisions of CERCLA even if some of the elements of the ASTM Standard had not been completed.

The study is available through the GeoProfessional Business Association at www.geoprofessional.org.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

This article was first published on the Troutman Sanders website.

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About the Authors

Jerrold “Jerry” Samford is an environmental compliance specialist at Troutman Sanders.  He is a certified professional geologist in the State of Virginia, a licensed professional geologist in the States of North Carolina and Kentucky.

Andrea L. Rimer is a partner at Troutman Sanders.  She has a national practice representing clients on transactional and regulatory matters involving brownfields redevelopment, hazardous site investigation and cleanup, hazardous waste management, and state and federal Superfund and voluntary remediation programs.

 

New spill reporting, response and recovery requirements in British Columbia

As reported by Norton Rose Fulbright, the Province of British Columbia recently brought into force a new land-based spills regime and three new regulations requiring transporters of liquid petroleum products to have provincial spill response plans, to test such plans and to report and clean up spills. The new regulations apply to two categories of people:

  • “regulated persons,” which are rail and highway transporters in possession, charge or control of 10,000 litres (62.898 barrels) or more of liquid petroleum products and pipeline operators with any quantity of liquid petroleum products in their pipeline; and
  • “responsible persons,” which are persons in possession, charge or control of a substance when a spill occurs or is imminent.

The three new regulations are the Spill Contingency Planning Regulation, the Spill Preparedness Recovery Regulation and the Spill Reporting Regulation.

Spill contingency planning

Regulated persons are required to develop and maintain spill contingency plans based on a worst-case scenario spill. Investigations, tests and surveys must be undertaken to determine the magnitude of the risks to human health, the environment and infrastructure from a worst-case spill. Pipeline and rail transporters must have their spill contingency plans in place by April 30, 2018, while trucking firms have until October 30, 2018.

Spill response efforts have failed to contain an estimated 110,000 litres of diesel and other petroleum products from the tugboat Nathan E. Stewart, which ran aground Oct. 13 in the Seaforth Channel near Bella Bella. (Photo Credit: Ian McAllister/CBC)

It is important to note that, while the spill planning obligations may resemble transportation of dangerous goods-type plans, they impose new requirements.

Spill reporting

New spill reporting requirements require a responsible person to immediately report any intentional or unintentional spill of a substance into the environment that may cause, is causing or has caused an adverse effect to water, the environment, human health or property if the volume of the substance exceeds the amounts set out in a schedule to the Spill Reporting Regulation or if the substance has or is likely to enter a body of water, regardless of the volume. Natural gas spills greater than 10 kg and releases from breakages of pipelines or fittings operated above 100 psi must also be reported.

The new regulation expands the scope of spills that must be reported, as it removes the previous volume/quantity threshold for spills to water.

It also expands the information that must be reported.

If a spill occurs or is imminent, a verbal report must immediately be made to the BC Provincial Emergency Program’s spill reporting hotline (1-800-663-3456) by the responsible person. New requirements stipulate the initial report must include the name of the owner of the spilled substance and a description of the source of the spill.

Starting on October 30, 2018, a written report must also be made within 30 days of the spill, or as soon as practicable on the minister’s request. An end-of-spill report must also be made within 30 days of the end of a spill’s emergency response activities.

Spill response

A responsible person must ensure persons with the skill, experience, resources and equipment arrive at the spill site within a prescribed period and activate an incident command system. They must also ensure actions are taken to address the threat or hazard caused by the spill, including assessing, monitoring and preventing the threat or hazard; stabilizing, containing and cleaning up the spill; identifying the immediate and long-term risks and impacts of the spill; and taking steps to resolve or mitigate such risks and impacts.

 

Class Action suit filed against CN Rail for derailment

As reported in the Sudbury Star, a Timmins law firm has sent a letter out to Gogama area residents and cottagers advising that a class-action lawsuit has been filed against CN Rail in connection with the derailment of an oil tanker train and subsequent oil spill that occurred on March 7, 2015.

The letter, signed by James Wallbridge of Wallbridge, Wallbridge Trial Lawyers of Timmins, was to advise residents to sign retainer agreements or to indicate whether or not they wish the law firm to proceed on their behalf.

The derailment and oil spill occurred in the area of the Makami River bridge, on the CN mainline near the village of Gogama, a town in Northeastern Ontario located between Timmins and Sudbury.  An eastbound CN Rail train hauling 94 tank cars had a derailment after riding over a broken rail. In all, 39 tank cars left the track.  Some of the cars fell into the river next to be bridge, exploded and burst into flame. Several of the cars were breached releasing many hundreds of thousands of litres of synthetic crude oil into the river and the surrounding environment.

Gogama train derailment

Wallbridge’s letter said the claim against CN Rail was filed back in July and that there are indications that the clean-up of the oil spill in the area is not properly done yet.

“We are advised by Fred Stanley of Walters Forensic Engineering that the cleanup continues notwithstanding CN and the Ministry of the Environment’s view the oil spill cleanup is complete,” said the letter.

Wallbridge went on to suggest that more environmental testing would be needed early next year.

“We are of the view that next spring may be an appropriate time to review the work that has been done and undertake independent testing. We have spoken to the Ministry of Environment’s legal counsel about testing and have indicated that we anticipate their cooperation in reviewing the overall cleanup.”

Wallbridge also advised that his firm has indicated that the timetable for the class action should be “held in abeyance” pending a review of the cleanup in May and June of 2018.

He said his firm elected to proceed by class action to preserve the limitation period of two years from the date of the occurrence. The class action serves to suspend the limitation period during the certification process, the letter said.

The Gogama-Makami River derailment was the second CN oil train derailment in that area in the winter of 2015. Both occurred along the section of the CN mainline known as the Ruel Subdivision. Another train hauling tank cars had derailed three weeks previous, on Feb. 14, 2015, in a remote bush and wetlands area, about 35 kilometres north of Gogama.

Canada’s Transportation Safety Board filed a report in August saying that a broken section of rail was the cause of the derailment at the Makami River bridge.

Harnessing the regulation of Maritime Dangerous Goods

As reported in Hellenic Shipping NewsTT Club (a leading provider of insurance and related risk management services to the international transport and logistics industry ) and the  International Cargo Handling Coordination Association (ICHCA) have drawn attention to the state of packing in the intermodal supply chain and the need for greater rigour by all stakeholders to improve safety.

Shipping containers at the Port Newark-Elizabeth Marine Terminal in New Jersey, USA (Photo Credit: Captain Albert E. Theberge)

At the recent meeting of the International Maritime Organization’s (IMO) Sub-Committee on the Carriage of Cargoes and Containers (CCC), ICHCA and TT Club made a submission concerning the inspection programmes for Cargo Transport Units (CTUs) implemented by national governments.

Analysing the reports submitted to IMO in previous years, TT Club established that the number of member states reporting, in comparison with those in membership of IMO, has always been less than 10% and currently stands at about 2.5%. Further, the number of inspections performed has never exceeded 80,000, and currently represents something less than 4 per 100,000 packed containers moved.

Deficiencies
The submission drew out two key concerns from the deficiencies found in this small sample. First, there is an apparently deteriorating trend for ‘Placarding and Marking’ failures, which is the key visual risk alert for all supply chain stakeholders. Wrongly placarded units can create a major hazard, as exemplified at a terminal facility in Vancouver in 2015 when a container packed with dangerous goods caught fire, as well as fundamentally undermine the handling of the numerous incidents on board ship.

Perhaps more importantly, ‘Stowage and Securing’ deficiencies, which TT Club has repeatedly reported to be causative in many cargo related incidents, average in excess of 20%.

At ICHCA’s seminar in April 2017 on dangerous goods, hosted by TT Club, reports were given of widespread disregard of dangerous goods regulations, with one shipping line revealing that many shippers use alternative terms for dangerous goods (DG) to avoid surcharges and having to comply with additional measures, including any ship or port restrictions, as well as the regulations themselves.

Calculating the actual number of dangerous goods shipments is complex, but some estimates are that declared volumes comprise up to 10% of all container movements. UNCTAD calculates in its Review of Maritime Transport 2016 that there were approximately 180 million TEU movements in 2016. Assuming 60% of 180 million TEU equates to actual CTUs, 50% of those are laden, of which 10% contain declared dangerous goods, then approximately 5.4 million units annually are packed with dangerous goods.

The state for non-DG…?
It might also be assumed that more care and attention is given to consignments of declared dangerous goods; it may be expected that deficiencies would be more prevalent where more detailed regulations are not deemed to apply. Thus, the findings reinforce experience that packing and securing remains an enormous issue in the unit load industry.

“The findings reinforce experience that packing and securing remains an enormous issue in the unit load industry”
Whilst the International Maritime Dangerous Goods (IMDG) Code is mandatory, the CTU Code is not, albeit it is referenced from the IMDG Code and International Convention for the Safety of Life at Sea (SOLAS). The evidence from recent events is that awareness of the CTU Code is very low and therefore compliance with good practice will be poor.

Cargo Integrity Campaign
It is for this reason that TT Club has teamed with Global Shippers Forum , ICHCA and World Shipping Council to promote the importance of the CTU Code. This ‘Cargo Integrity’ campaign started at European Shipping Week earlier this year, which the IMO Secretary General and Senior Deputy Director attended, and continued during the CCC sub-committee meetings and most recently at the ICHCA 65th Anniversary Conference in Las Palmas. In each instance, the key messages are aligned to the stakeholders in the audience – whether governments, shippers, terminals or carriers – identifying key responsibilities that they can discharge to improve safety in the intermodal supply chain.

“The level of national government reporting is insufficient to draw concrete conclusions by which to steer IMO’s work, improve compliance or increase safety”
In response to a number of suggestions made in the submission to CCC, the sub-committee recognised that the level of reporting is insufficient to draw concrete conclusions by which to steer its work, improve compliance or increase safety, albeit that the absence of reporting should not necessarily lead to the conclusion that inspections are not being carried out. At least one Maritime Administration, which had not reported in recent years, committed to make the CTU inspection regime more robust, as well as to submit a report to the next meeting of CCC in September 2018.

Strengthening compliance culture
CCC also noted the analysis provided by TT Club and ICHCA, inviting governments to provide information on the experience and lessons learned from the application of national CTU inspection programmes. Further, concern was expressed about the high rate of deficiencies and the lack of adherence to the provisions of the IMDG Code.

The TT Club/ICHCA submission also suggested that consideration be given to advances in scanning technologies that may permit improved and risk-based inspections to be carried out more effectively. While not specifically debated, there was general encouragement for the industry and governments to develop more specific ideas for consideration.

In the meantime, the IMO Secretariat committed to improve the ease of reporting, utilising its GISIS methodology, together with recognising that Maritime Administrations could link up the findings of industry inspections that are carried out to the same standard. It is to be hoped that inspection programmes will be ramped up in the coming months in order that more credible data can be shared, as well as engendering an improved culture of compliance globally.

“It is to be hoped that inspection programmes will be ramped up in order that more credible data can be shared, as well as engendering an improved culture of compliance globally”

We hope that you have found the above interesting. If you would like further information, or have any comments, please email us, or take this opportunity to forward to any colleagues who you may feel would be interested.
 

Performance Assessment of Pump and Treat Systems

Researchers at the U.S. Department of Energy’s Pacific Northwest National Library recently released a paper on the Performance Assessment of Pump-and-Treat Systems.

The pump-and-treat (P&T) remediation technology is comprised of three main aspects:  groundwater extraction for hydraulic control and contaminant removal, above-ground treatment, and groundwater monitoring to assess performance.

Pump-and-treat (P&T) is a widely applied remedy for groundwater remediation at many types of sites for multiple types of contaminants. Decisions regarding major changes in the remediation approach are an important element of environmental remediation management for a site using P&T. Performance assessment during P&T remedy implementation may be needed because of diminishing returns, the complex nature of the site and contamination, or other factors.

While existing guidance documents for the performance assessment of pump-and-treat systems provide information on design, operation, and optimization for P&T systems, these documents do not provide specific technical guidance to support remedy decisions regarding when to transition to a new remedy or to initiate closure of the P&T remedy.

In the paper, the researchers describe a structured approach for P&T performance assessment that was developed  using analysis of three example P&T systems. These examples highlight key aspects of the performance assessment decision logic and represent assessment outcomes associated with optimizing the P&T system, transitioning from P&T to natural attenuation, and supplementing P&T with another technology to hasten transition to natural attenuation.

Decision elements for the P&T performance assessment include:

  • Contaminant concentrations and trends
  • Contaminant mass discharge from source areas or at selected plume locations
  • The attenuation capacity of the aquifer
  • Estimated future plume behavior and time to reach remedial action objectives for the site
  • P&T system design, operational, and cost information

Categories of decision outcomes for the P&T assessment include:

  • Initiate P&T remedy closure
  • Continue with existing or optimized P&T
  • Transition to Monitored Natural Attenuation
  • Supplement P&T with other treatment technologies
  • Transition to a new remedy approach