Monday, 21 January 2013
ISRR Document Review Section 5.0 – Application Tooling Requirements/Methods
Commentary by Craig Sandefur, VP Technology, REGENESIS
Introduction: This series of blog entries focuses on a key technical report titled: Subsurface Injection of In Situ Remedial Reagents (ISRRs) within the Los Angeles Regional Water Quality Control Board (LARWQCB) Jurisdiction. The report was spearheaded by REGENESIS in cooperation with the LARWQCB and the ISRR working group.
Section 5: This section of the ISRR document focuses on tooling and methods for the successful application of injectable reagents. This section also provides the reader with detailed information on first principles guidance for ISRR installation. This section is somewhat generalized due the highly variable and complex nature of the subsurface. Specifically, this section breaks down reagent delivery methods into three sub-sections that are dedicated to the most common injection methods: DPI, injection wells, and fracturing.
The first section is dedicated to DPI methods and discusses a few simple details that will help the user avoid and/or diagnose application problems. One example in this section describes leaks along the drive rod that are associated with worn drive rods. Additional detailed application issues are discussed in two sub-sections dedicated to bottom up and top down application materials and methods.
The second section is dedicated to fracturing methodology. This section is further sub-divided into two sections on the topic of hydraulic fracturing and pneumatic fracturing injection methods. These discussions are a nice summary of the specific methods and issues associated with each technique and offer some recommendations on when to consider each method.
The last section is dedicated to injection well installation and application details. This section is one of the more informative sections of the ISRR manual. A number of the contributing writers have extensive backgrounds in the installation and application of ISRR via injection wells. This section provides some really usable information and advice on installation details. This includes tidbits on how to test your injection well seal to be sure it’s competent and how to select your well pack and screen size to optimize ISRR application rates. This section also has three sub-sections. Two are dedicated to injection well installation methods (DPI and hollow stem auger), and one is dedicated to injection well development. These are short sections that nicely summarize the key considerations for each installation method.
On a related matter, I would add that when it comes to application, the reagent you are applying and its characterisitics often play a large role in the overall success of the injection program. We (REGENESIS) have recently released a new activated persulfate material called PersulfOx™. This remediation technology offers the user a safe and easy-to-handle ISCO agent that is an all-in-one material with built-in activation. This advancement in the science of persulfate activation eliminates the complexity and risk associated with the traditional two-part activation process. PersulfOx provides remediation practitioners with a highly effective, single component product that is easy to ship, store on-site, handle, and inject. More information is available at www.persulfox.com.
In the next review, I will address the topic of measuring and interpreting aquifer injection response.
Tuesday, 2 October 2012
By Craig Sandefur, Vice President
Being that I am a groundwater remediation professional and that our Company has seen thousands of contaminated groundwater sites over the last 18 years, I have been reading and thinking about the topic of methane abundance in groundwater for the past year or so. More specifically, I’d like to submit that since no one has historically been testing groundwater for methane (no baseline) that it is possible that to some extent methane is naturally present in most groundwater aquifers.
Now we have some early data from the United States Geologic Survey (USGS) on the State of New York. This report indicates that methane is fairly abundant in groundwater in >50% of the State (I am pretty sure that the geographic distribution is predictable based on geology). No big surprise really…. however, if you believe the attorneys and some of the regulators, this methane appeared after hydraulic fracturing (fracking) activities. I contend, given what we know about groundwater chemistry, that much of this methane has always been there. People (regulators, research types and the general public) just haven’t paid attention or bothered to ask the question – was it there in the first place? The natural processes are the natural processes. Microseeps of petrogenic gas are ancient (pick your favorite organic rich geologic period), layer in some biogenic gas and you have a significant distribution of low level methane present. Just because we haven’t been enlightened enough to check for it doesn’t mean it’s not there. I sense that the general public has been poorly informed and in my opinion some in the scientific community (and in particular the regulatory agencies) have been too quick to jump onto the anti-fracking bandwagon…
Next step (good science) is to document whether the origin of the methane that is present is biogenic, petrogenic or both… stay tuned…
Wednesday, 11 July 2012
ISRR Document Review Section 4.0 – Injection Specific Design and Safe Application
Commentary by Craig Sandefur, VP Technical Services, REGENESIS
Introduction: This series of blog entries focuses on a key technical report entitled: Subsurface Injection of In Situ Remedial Reagents (ISRRs) within the Los Angeles Regional Water Quality Control Board (LARWQCB) Jurisdiction. The report was spearheaded by REGENESIS in cooperation with the LARWQCB and the ISRR working group.
Section 4: This section focuses on injection specific design and provides the reader with useable recommendations for the safe application of ISRR. This section provides some insight into using a site specific aquifer characteristic as derived by various methods in the derivation of maximum pressures. It is very important to keep in mind that every application is site specific. Many times the success or failure of an application is a result of the applier’s ability to “artfully blend” scientifically derived aquifer characteristics with instinct and previous experience.
Sub-sections 4.1 and 4.2 provide a discussion as well as equations for calculating maximum application pressures for various injection programs. This section also provides rules of thumbs that should be used with these equations to derive a “not to exceed fracture pressure” for a given targeted aquifer section. This is followed by a set of specific recommendations for injection of substrates and includes a table that provides the user with recommendations on soil type specific targets for application base on:
- Pore filling
- Injection solution percentage
- Rates (volume per minute)
- Pressure (psi)
- ROI
- Point Spacing
In Sub-section 4.3 the reader is provided some details on how pre-application site testing can help to get a better handle on the site specific conditions associated with application of a given ISRR. This section provides some solid advice on how to perform a clear water test in order to identify or rule out hydraulic limitations of high volume ISRR’s.
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Wednesday, 2 May 2012
ISRR Document Review Section 3.0 – Pre-Design Considerations and Application Related Issues (Will the Target Section Accommodate the Anticipated Reagent Volume Applied?)
Commentary by Craig Sandefur, VP Technical Services, REGENESIS
Introduction: This series of blog entries focuses on a key technical report entitled: Subsurface Injection of In Situ Remedial Reagents (ISRRs) within the Los Angeles Regional Water Quality Control Board (LARWQCB) Jurisdiction. The report was spearheaded by REGENESIS in cooperation with the LARWQCB and the ISRR working group.
This section provides a useful discussion of data that can assist in determining if the ISRR target zone will be conducive to application and acceptance of the remedial reagent volumes anticipated. In short, will the target section accommodate the anticipated reagent volume applied?
A brief discussion is provided on each of 9 varying types of data that can be used to gain a more complete picture of the target zones acceptance capacity. These data in total can assist you in judging the target zones’ ability to accept the application volume and possibly even assist in determining a relative rate of application (fast or slow). I think it’s interesting to note that this discussion incorporates some of the low resolution data that may not be a typical consideration by user/appliers. These data range from the low tech blow counts (soil boring logs) to the latest innovations such as Hydraulic Profiling Tools (HPT) and Cone Penetrometer Technology (CPT) data. This discussion also provides some helpful logic as well as context for using these various data in order to gain a richer view of the target zone.
The second part of this section discusses some of the important application related issues that must be factored into the Project Managers (PM’s) thinking when considering injection of high volume ISRR’s. If overlooked, these issues may range from a lot of unneeded stress to a costly mistake. Of critical importance is the location of subsurface utilities, I don’t think that this needs much more comment beyond its mention however it is always a consideration and you must call “Dig Alert” two or more days ahead of the application date. The second consideration is the location of previous boreholes. This often overlooked pre-application consideration becomes clearly evident after the 2nd or 3rd application point is injected and ISSR materials daylight. This can be a particularly difficult problem with more reactive oxidants or excessively high volume reagents like emulsified vegetable oils etc. Day lighting or surfacing of any reagent can require a significant amount of on-site reactive management. Even though the management of such occurrences is not terribly difficult to implement (I will discuss in upcoming posts) it invariably causes a slowdown in application rate and loss in field efficiency. It’s my experience that if a significant set of older generation boreholes are present on a shallow groundwater site that it’s always a good idea to equip the application team with plenty of bentonite and hand tools to allow proper re-sealing of the older set of boreholes. Alternatively, if these are known to be a likely problem, the proper repair and sealing of these boreholes prior to application can end up saving time and money.
To access this entire section of the ISRR document visit here.
Wednesday, 28 March 2012
Author: Craig Sandefur, Vice President of Technical Services – REGENESIS
A recent technical paper entitled “Chloroethene Biotransformation in the Presence of Different Sulfate Concentrations” by Marina Pantazida, et al. and published in the Winter 2012 Edition of Groundwater Monitoring and Remediation makes a number of interesting observations about enhanced reductive dechlorination (ERD) under elevated sulfate conditions. The authors clearly provide a recommended upper limit for sulfate (250-300 mg/L) for complete dechlorination to proceed. Of interest to me is their observation that sulfate reduction and reductive dechlorination (RD) proceed concurrently in most studies. This observation is consistent with those of us that have long thought that removal of all sulfate does not have to happen prior to the onset of RD or in order for RD to proceed to completion. For more information on this paper visit the National Groundwater Associations website at ngwa.org to view their online archive or order to order a copy of Groundwater Monitoring and Remediation.
Friday, 10 February 2012
ISRR Document Review Sections 2.0 and 3.0 – In Situ Remedial Reagent Fluid Injection Mechanics and Pre-Design/Application Related Considerations
Commentary by Craig Sandefur, VP Technical Services, REGENESIS
Introduction: This series of blog entries focuses on a key technical report entitled: Subsurface Injection of In Situ Remedial Reagents (ISRRs) within the Los Angeles Regional Water Quality Control Board (LARWQCB) Jurisdiction. The report was spearheaded by REGENESIS in cooperation with the LARWQCB and the ISRR working group. The primary objective of the ISRR Working Group was to compile general tools and best practices into a reference manual to be used during the planning, design, and field implementation phases of ISRR projects. ISRR projects generally include soil and groundwater remediation via: in situ chemical oxidation, enhanced aerobic bioremediation, enhanced anaerobic bioremediation, in situ chemical reduction, etc. In addition, the Working Group also sought to convey that the safe and successful application of in situ remedial reagents requires a proper understanding of site characteristics, delivery methods, application equipment, and monitoring methodology. Finally, this technical document was also intended to guide practitioners of reagent based in situ remediation in performing cost-effective remediation projects while ensuring minimum impact to the public. Intended users of this technical report include regulators, consultants, and appliers of in situ remedial reagents.
Discussion: This review will begin in Section 2.0 of the ISRR Document with and cover Fluid Injection Mechanics as well as some of section 3.0 which emphasizes Pre-Design and Application Related Considerations. Section 2.0 provides a concise description of how fluid moves when injected in the saturated zone. It provides the reader with a specific discussion as to why fluid mounding occurs upon injection and why its dissipation rate is important in understanding how much remedial reagent the aquifer is likely to “accept”. This section also provides the reader with an introductory review of the mechanism of “day lighting” or “surfacing” of remedial reagents. The discussion in Section 3.0 is devoted to Pre-Design and Application Related Considerations that revolve around assessing the hydraulic characteristics of the target zone. In the pre-design discussion the focus is on relevant data, evaluation and testing that can be used by the reader to gain insight on the target zones relative ability to accept remedial reagents. In many cases evaluation of one or a few of these parameters and/or tests will yield significant insight into the likelihood of application success. The suggested data for collection range from the low-cost, low-resolution (such as review of existing boring log blow counts and/or GW well recharge rates) to dedicated high-resolution in situ logging methods, e.g. Hydraulic Profiling Tool (HPT), Cone Penetrometer (CPT). As personal note, I have had some direct and fairly recent experience with in situ logging technologies and I have found them to be very effective in defining the intervals that should most likely be targeted for remediation. Finally, this section concludes with pre-application recommendations that anyone contemplating ISCO should strongly consider since these lessen the likelihood of damaging subsurface infrastructure and/or “day lighting” remedial substrate. These recommendations are to locate subsurface utilities via a pre-application field inspection and use of Dig Alert and locate and inspect the seal of as many assessment or remediation boreholes as possible. Any borehole found to have inadequately seals should be re-sealed prior to beginning an in situ chemical oxidation field application program. This will potentially save the project manager a substantial number of down time hours. Finally, it is always advisable to obtain any injection permits (as necessary) from your local or state regulatory agency. In the next blog entry of this series I will continue the discussion on Sections 2.0 and 3.0 highlighting some of the more salient points regarding injection methods for the delivery of in situ remedial reagents.
REGENESIS provides advanced technologies for groundwater resources, including specialty soil and groundwater remediation products. If you’re unsure of the condition of your site, you can request a free site evaluation from REGENESIS. For more information, follow us on Twitter, “Like” us on Facebook and subscribe to our YouTube channel. Also, keep up with our blog for all the latest updates.
Wednesday, 4 January 2012
Contributed by Craig Sandefur, V.P. of Technical Services, REGENESIS
This is the first in a series of blog posts on an in situ remediation document that was released a few years ago. This document is full of technical gems; unfortunately it does not get much discussion nor is it referenced very often. The limited awareness of this document may be due in part to its: A) location, this document is buried deep in the LARWCB’s website and B) its title, which is quite lengthy and not very catchy. The Report is entitled “The Technical Report: Subsurface Injection of In Situ Remedial Reagents (ISRRs) Within the Los Angeles Regional Water Quality Control Board (LARWQCB) Jurisdiction. Although this in situ remediation document was written for reagent users and appliers in the LARWQCB area, the documents content has much to offer those beyond the geographical region. This is particularly the case in terms of in situ application set up and injection. In my opinion, this document contains some good advice by some very solid users, appliers and vendors that collectively speaking have “untold” years of experience in the proper handling and injection of remedial reagents. The report can be found here.
There are 15 authors listed on the in situ remediation document, the background of these authors range from consultants to regulators and from contract appliers to product vendors. I think it noteworthy that each of the authors provided significant and important contributions to the piece and that their perspectives and experiences are reflected in the documents practical and hands-on approach to in situ remedial reagent injection. This document is full of information on the set up and injection of reagents as well as remediation monitoring programs. In blog posts to come, my aim is to cover individual sections of the document with some brief insights and commentary.
REGENESIS provides advanced technologies for groundwater resources, including specialty soil and groundwater remediation products. If you’re unsure of the condition of your site, you can request a free site evaluation from REGENESIS. For more information, follow us on Twitter, “Like” us on Facebook and subscribe to our YouTube channel. Also, keep up with our blog for all the latest updates.
Monday, 5 December 2011
Contributed by Craig Sandefur, Vice-President of Technical Services, REGENESIS
In my opinion, the recent passing of C.W. “Bill” Fetter marks a significant loss to the Groundwater Remediation industry. Bill Fetter had a long academic career as a staff member at the Department of Geology at the University of Wisconsin – Oshkosh 1971-1996 where he taught hydrogeology. He also practiced contaminant hydrogeology as an environmental consultant for a number of years. It was in his academic role and through two key publications that Fetter influenced a whole generation of groundwater remediation engineers and scientists. In 1980, he authored the classic groundwater textbook “Applied Hydrogeology.” This text remains in publication (in a 4th edition), and recent reviews of this book on Amazon.com indicate that it still serves as both a textbook for students and a resource for many working professionals… including myself. In 1992, Fetter published “Contaminant Hydrogeology,” which was a natural extension of his previous book. Now, some may argue that the classic “Applied Hydrogeology” has too many errors and typo’s or that “Contaminant Hydrogeology” is too stilted and case study driven, for me it is easy to set aside the “errors” and the style issues to see the brilliance of Fetter. I truly appreciate his ability to provide a vast amount of information (some of it fairly complex) in a clear and concise manner. I also think it was his ability to use a “just right” blend of words, figures and equations in a powerful way that readers of all levels found to be useful and appealing. Finding the right balance of math and language is very hard to do but I think Fetter generally got it right. Subsequent to him, many authors have produced some very good work by emulating his style. However, Fetter was the original and his writings will undoubtedly continue to influence a significant number of groundwater remediation professionals for years to come.
