Accelerated Remediation Catalysis (ARC) – An Emerging Water Treatment Technology for the Treatment of a Wide Range of Dissolved Phase Organic and Inorganic Contaminants
The Accelerated Remediation Catalysis (ARC) system is a process that can be applied to reduction or oxidation. For reduction, hydrogen gas and an inexpensive, proprietary catalyst are used to perform a chemical reduction of appropriate contaminants. The application of shear forces that can be achieved by using certain pumps is also a feature that dramatically accelerates reaction times.
On the reduction side, there is data supporting the degradation of 1,4-dioxane (1,4-D), perfluorocarbons (PFCs), chlorinated hydrocarbons, and oxyanions (nitrate and perchlorate). With respect to metals and metalloids such as selenium, these species are precipitated and collected for disposal. ARC is also applicable to oxidative processes for appropriate organics like petroleum hydrocarbons, as well as metals/metalloids that precipitate under high redox conditions. In this application, the oxygen is provided by dilute hydrogen peroxide or peracetic acid with a different catalyst.
To help reduce start-up costs, the ex-situ process uses common tankage, pumps, valves, and process controls that can be obtained from standard vendors. If the process handles low levels of contaminants, it can be constructed of common thermoplastics such as polyvinyl chloride (PVC), polyethylene, and fiberglass.
ARC can operate in either batch or continuous mode. In batch mode, the reaction tank is filled at start-up and the total reaction time is allowed to reach the predetermined level to assure destruction of the constituents of concern (COCs). After this point has been achieved, the process switches to continuous mode, and the reaction tank functions as a single-stage plug flow reactor. The process can be made to be continuous at start-up by simply filling the reactor tank with clean water. The overall retention time for completion of most reactions has been on the order of 10 to 15 minutes. Using reduction, hydrogen used in the catalyst vessel is generated electrochemically at the site, reducing the need to handle compressed gas. Depending on the COC, the reaction will either cause manageable gas evolution, or precipitate out of the water and be recovered by a variety of methods. The insoluble catalyst can be recovered by filtration and recycled back to the reactor vessel.
Case studies where ARC has been used for chemical reduction include:
- The conversion of 1,4-dioxane to ethanol. Water with 100 μg/l of 1,4-dioxane was reduced to <1 μg/l.
- The complete destruction of perfluorocarbons to non-detectable concentrations with a fluorine residue of low concentration, as the initial concentrations of perfluorocarbons are generally low.
- Chlorinated ethenes are easily reduced to ethene and ethane.
- Trihalomethanes have been reduced from a typical 80 μg/l level to <10 μg/l in 10-15 minutes.
- Perchlorate levels as high as 100 mg/l are reduced to chloride.
- Nitrate is reduced to nitrogen gas.
- Selenium in the form of selenate can be reduced to selenite and removed as a precipitate. Selenate was reduced from 200 mg/l to <1 mg/l.
- Chlorobenzene at ppm levels is reduced to benzene that is then collected on the low-cost catalyst.
The ARC system can be designed for a wide range of process flow rates. Design of the system is only limited by the required retention time for the reaction. In essence, the system was brought into focus because of the emerging contaminants issue, and it is applied to pump-and-treat systems. This is important because the nature of 1,4-dioxane and PFCs makes in-situ treatment challenging. It is expected that there will be both an increase in the use of pump-and-treat systems and a need for more efficient water treatment technologies, especially since conventional methods of treatment (such as those that use carbon) are limited.
Additionally, because of the low concentrations of reactants in the process, there is typically no detectable heat gain in the reaction vessel. Therefore, cooling of the process is generally not required prior to releasing the treated effluent. Then there are other applications in traditional wastewater treatment, such as removal of selenium from scrub water at coal-fired power plants. The ARC system’s inherent simplicity allows it to be easily scaled so that dealing with the large flow rates encountered in industrial settings is feasible. While the endpoint for ARC treated water is generally to be discharged, a supplementary feature called Advanced Regenerative Process (ARP) can be added as a further polishing step so that beneficial reuse, including human consumption, is an option.
ARC targets those applications where more complicated and expensive systems, such as conventional Advanced Oxidation Processes (AOP), are being used. The chemical usage, energy, and safety features of AOP systems, combined with their operational footprint, suggest they will eventually be replaced by better remedial options like ARC. There are other developing technologies that have similar objectives to displace AOP systems, such as resin-based operations, but ARC presents distinct advantages in cost, efficacy, physical layout, and scalability.
For additional information, please contact Chris Hortert at (800) 365-2324 (email@example.com); Steve Koenigsberg at (949) 262-3265 (firstname.lastname@example.org); or Thom Zugates at (602) 644-2163 (email@example.com).
The Pennsylvania Department of Conservation and Natural Resources (DCNR) is preparing to roll out an enhanced Environmental Review Tool. The existing tool is widely used by companies and organizations to screen development projects for potential impacts to threatened, endangered, and special concern species and resources in Pennsylvania. Though an exact roll-out date has yet to be announced by DCNR, the most apparent changes in the new tool will be enhanced mapping capabilities and a $40 online credit-card-only fee to be paid before an Environmental Review Receipt is issued. Pennsylvania Natural Diversity Inventory (PNDI) Environmental Review Receipts are required prior to obtaining permits from the Pennsylvania Department of Environmental Protection and the U.S. Army Corps of Engineers. The tool includes databases from three state agencies (DCNR, the Pennsylvania Game Commission, and the Pennsylvania Fish and Boat Commission) and one federal agency (the U.S. Fish and Wildlife Service).
The new tool, called the Pennsylvania Conservation Explorer, will replace the existing PNDI Environmental Review Tool, which has been free-of-charge since its launch in 2005. The Pennsylvania Conservation Explorer combines a new Conservation Planning Tool designed to help avoid impacts during project planning stages with a more robust Environmental Review Tool for formally requesting an Environmental Review Receipt. The new tool also has the ability to serve as a digital hub for revising project boundaries and communicating with DCNR. (The Pennsylvania Fish and Boat Commission, Pennsylvania Game Commission, and U.S. Fish and Wildlife Service may not fully support this functionality.)
Users of the Pennsylvania Conservation Explorer will notice several new features:
- The ability to screen possible project locations for potential environmental impacts without submitting the project locations for review
- The ability to create, revise, and save projects independent of submitting them for review
- The ability to revise submitted projects without resubmitting
The new Conservation Planning Tool provides greater access to conservation and species habitat information and allows users to view sensitive ecological areas and, in some cases, protected species habitats, which should make it easier to identify and potentially avoid sensitive areas. This feature could potentially save time and money by allowing the user to avoid impacts, thus reducing or eliminating the need for correspondence with regulatory agencies. The Conservation Planning Tool may be used without registering or logging in to the Pennsylvania Conservation Explorer website.
The enhanced Environmental Review Tool is more robust than the existing tool and allows users to upload project shape files in addition to drawing project boundaries on-screen. Project boundaries may also be revised without creating a new project search and incurring an additional fee. Additional drawing tools allow a user to edit, crop, and exclude areas—essentially allowing the inclusion of more than one area for a project, a nice upgrade from the previous version. The tool also displays the project buffer area based on the project type.
Digital hub functionality will be available through the My Project feature of the Pennsylvania Conservation Explorer. All correspondence, data, reporting, and project revisions (up to 10 MB in size) can be sent to DCNR through this feature by uploading most common file formats, including doc, jpg, png, text, pdf, ppt, ods, xls, kmz, and kml; however, this feature will be available only to the creator of the project in the Pennsylvania Conservation Explorer. This feature will not be available if a second or third party will be providing project documentation, as project sharing is not expected to be included in the initial release of the tool. In these cases, project information must be provided to the project creator for submission through the tool, or it may be provided outside the tool, as it is now. Users may also choose to submit information via mail or complete an entirely offline review, which would require separate communication and coordination with individual regulatory agencies.
If you have questions about the new Pennsylvania Conservation Explorer tool, please contact the post author, David Quatchak (firstname.lastname@example.org), or Dan Maltese (email@example.com), co-lead of the PNDI workgroup for the Marcellus Shale Coalition’s Surface Use Committee. Both individuals can also be reached at 800-365-2324.
On January 14th, 2016, the United States Fish and Wildlife Service (USFWS) published a final 4(d) rule for the federally threatened northern long-eared bat (Myotis septentrionalis). The final rule lifts the Endangered Species Act’s (ESA) “prohibition against incidental take.” As a result, all otherwise-legal activities related to tree clearing are exempt from the prohibition outlined in the ESA, except:
- Tree clearing within 0.25 mile of known hibernacula
- Tree clearing within 150 feet of a known maternity roost (i.e., a tree used by reproductive females to raise their young) between June 1 and July 31
If these exceptions cannot be avoided by project impacts, a project proponent will need to coordinate with the local USFWS office. The USFWS’s final 4(d) rule recognizes the fact that declines in northern long-eared bat populations are primarily attributable to White-Nose Syndrome (WNS), a fungal disease decimating bat populations, and not from direct take associated with the clearing of forested habitat. While this provides relief for some, it is important to note that take prohibitions of federally endangered Indiana bats (Myotis sodalis) are more stringent and remain in place. The two species’ geographic ranges greatly overlap. Additionally, state agencies have yet to officially weigh in on the final 4(d) rule and whether they will require additional conservation measures for the species.
The entire final 4(d) rule can be found here: https://www.federalregister.gov/articles/2016/01/14/2016-00617/endangered-and-threatened-wildlife-and-plants-4d-rule-for-the-northern-long-eared-bat.
For perspective, northern long-eared bats were listed as federally threatened with an interim 4(d) rule in April 2015. The interim rule allowed certain activities requiring tree clearing to be exempted from the ESA’s “prohibition against incidental take.” Similar to Indiana bats, northern long-eared bats raise their young each summer in trees within forested habitat. Northern long-eared bats range across 39 U.S. states and portions of Canada, which is the largest range of any federally listed species. Each winter, these bats hibernate in the region’s caves and mines (called ‘hibernacula’). WNS was first discovered near Albany, New York, in 2006 and has quickly spread across the eastern United States and Canada. The disease, which is not harmful to humans, causes bats to quickly burn through their fat reserves during the winter hibernation period. Affected animals emerge from hibernacula, depleted of their stored body fat, to a cold and snowy landscape devoid of insects, their sole food source. Mortality as a result of WNS is estimated to range from 90 to 100% at most hibernacula.
If you have any questions about the final 4(d) rule, please contact Ryan Slack at firstname.lastname@example.org or 317-655-7777.
The United States Fish & Wildlife Service (USFWS) is proposing to list the northern long-eared bat (Myotis septentrionalis) as a federally endangered species throughout its range. Based on the information provided in the Federal Register (Vol. 78, No, 191) dated October 2, 2013, the USFWS is seeking data and comments on the listing by December 2, 2013. Requests for a public hearing must be received by the USFWS in writing on or before November 18, 2013. A final determination as to the listing will be made based on comments received. Pertinent information related to this listing includes:
- The northern long-eared bat has been particularly hard hit by White-Nose Syndrome (WNS), especially in the eastern U.S. Typically, federal protection for a species under the Endangered Species Act is driven by habitat declines. However, in the case of the northern long-eared bat, the proposed federally endangered status is more closely related to disease-control and not habitat loss.
- Unlike other species of bats, such as the Indiana bat, the northern long-eared bat does not have a large amount of historical data that can be used to track its decline. Many of the studies are fairly recent and involve winter hibernacula surveys conducted in Pennsylvania by the Pennsylvania Game Commission (PGC). For example, in 2013 the PGC conducted hibernacula surveys at 34 sites where northern long-eared bats were also observed prior to WNS. Researchers found a 99-percent decline (from 637 to 5 bats) at these locations (Turner 2013, unpublished data). However, in other areas, the northern long-eared bats have been consistently caught during summer mist net surveys and regularly detected during acoustic surveys in eastern populations.
- The October 2, 2013 Federal Register also offers that the proposed listing of the eastern small footed bat (Myotis leibii) is NOT warranted.
CEC will be providing comment to the USFWS on this proposed listing and is assisting many of our clients on this issue. For more information, please contact Ryan Slack in our Indianapolis, Indiana office at (877) 746-0749, or Dan Maltese in our Pittsburgh, Pennsylvania office at (800) 365-2324.
A final rule issued by USEPA on July 31, 2013 addresses the management of solvent-contaminated wipes. In the final rule, USEPA conditionally excludes from the definition of solid waste solvent-contaminated wipes that are cleaned and reused, and conditionally excludes from the definition of hazardous waste solvent-contaminated wipes that are disposed. The rules affect nearly 100,000 generators and handlers of an estimated 2.2 billion rags and wipes per year. EPA estimated in 2003 that 88% of these were reusable.
Proper management of solvent wipes has been debated since the early 1980’s. Petitions filed by Kimberly Clark (1985) and Scott Paper (1987) led to an EPA 1994 memo deferring to the States with authorized RCRA programs. Printing industry efforts toward standardization led to a 2003 proposed rule. Following a 2009 Risk Assessment, minor changes to the 2003 proposal were finalized and published on July 31, 2013. The new rules will take in effect six months from publication, on January 31, 2014.
To maintain the conditional exclusion, certain management practices must be followed:
- Store in non-leaking, closed containers
- Label containers “Excluded Solvent-Contaminated Wipes”
- Document accumulation less than 180 days
- No free liquids per Paint Filter Liquids Test (9095B)
- Document procedure employed to assure no free liquids
- Free liquids managed as solid or hazardous waste
- Document reusables sent to handler (laundry, dry cleaner) with permitted discharge
- Document disposables to permitted handler (combustor, landfill)
During accumulation, a closed container means the cover makes complete contact between the fitted lid and the rim, even if not sealed. Containers with flip-top or spring loaded lids or with a self-closing swinging door may be acceptable during accumulation. Bags may be considered closed when the neck of the bag is sealed preventing emission of solvent vapors. No container may leak free liquid. After accumulation and during transportation, a container must be sealed with rings clamped or bolted to the container.
The conditional exclusion may apply to solvent-contaminated wipes which contain listed solvents or exhibit a hazardous waste characteristic. Free liquid spent solvent is not excluded nor are wipes containing listed waste other than solvent or that exhibit a characteristic from other than solvent. Wipes contaminated with trichloroethylene are not excluded.
You should also check with your state for rules that they may have regarding solvent-contaminated wipes, since many state requirements are more stringent than the federal program. If you have any questions about RCRA Waste Determination requirements, please contact the Chicago office at 630-541-0626.
In 2010, EPA reached a settlement with the Chesapeake Bay Foundation and others to develop additional components of a comprehensive suite of strong regulatory actions that EPA has initiated or pledged to take to restore water quality in the Chesapeake Bay and its tributaries. These actions include a more robust application of stormwater quality requirements to all new development, regardless of thresholds set in the Phase 1 and 2 stormwater requirements.
An initial deadline to propose the new comprehensive stormwater rule was set for April 10, 2012. However, EPA has negotiated several extensions to the deadline (the last deadline was June 10, 2013), and EPA now anticipates a December 2013 date for the draft rule. The rule will apply to all areas – not just large and medium sized municipalities, where Phase 1 and 2 stormwater programs are currently in place.
It is EPA’s goal to incentivize redevelopment in urban built-out areas over new development in undeveloped areas, and this rule is expected to reinforce that goal. Stormwater runoff treatment standards are expected to be more restrictive for greenfield development than redevelopment of urban areas. The treatment standard for greenfield development is most likely to mirror the current Phase 2 stormwater treatment requirement to infiltrate the 80th, 85th or 90th percentile storm event, which is around one inch for many areas, depending on a region’s typical rainfall. Lesser stormwater runoff treatment requirements will be required in redeveloped urban areas to reduce urban sprawl. This new rule has been dubbed “Phase 2 lite”.
EPA has also been considering whether to expand the Stormwater Phase 2 programs to encompass areas likely to develop – not just already developed areas. In keeping with a watershed focus, EPA is also considering applying the rule on a watershed basis. The question is not if the stormwater rule will be promulgated; it is how and where it will be applied.
So, what does all of this mean to you? Our approach to development will have to change. We will be incorporating stormwater infiltration practices into our development plans for new development and redevelopment. The success of infiltration practices relies on subsurface conditions at a site, correct design, correct construction techniques, and long term maintenance. Developers will need to engage designers with expertise in soils, vegetation, hydrology and construction techniques so these practices work properly. An infiltration practice can fail quickly if correct construction techniques are not followed during construction, so it is likely that the design professional will be required to oversee construction. And then the infiltration practice owner (developer or property owner) will be required to maintain these structures perpetually. To reduce the long term burden of monitoring and maintaining structural infiltration practices, our future designs will need to address stormwater as an asset and incorporate its reuse into the overall design for irrigation needs and other non-potable uses.
Additional information on the EPA Stormwater rule is available on EPA’s website. If you have questions regarding the implications of these stormwater rules, please feel free to contact CEC’s Nashville office at (800) 763-2326.
So…you have received a Request for Information from the US Environmental Protection Agency (USEPA) pursuant to Section 308 of the federal Clean Water Act. A Section 308 request is done when the agency has reason to think that your facilities are not in total compliance with their NPDES permit limits. No need to panic – just start compiling the needed information.
Often the first thing that companies do after receiving a Section 308 letter is to call an experienced environmental attorney to get some assistance in working through this process. Odds are you wouldn’t have received this letter if you did not have some exceedances of NPDES permit limits, so the attorney can help you work through usually inevitable enforcement discussions with the USEPA.
Here are the types of information that the USEPA will typically ask for in Section 308 letters. You will need to pull this information together into one location so it can be copied and shipped to the USEPA:
- A list of all of your facilities by name, location, NPDES and mining permit numbers.
- Copies of each NPDES permit and permit applications for each identified facility.
- NPDES data for the past five years (or more), including your Discharge Monitoring Reports (DMR’s) and, often, the lab sheets upon which the DMR’s were based.
- You will need to summarize the information from items #1 through #3 (and any additional requested information) into an Excel spreadsheet(s).
Mining facilities with NPDES permits that have discharge violations of metals, chloride, TDS, TSS, pH, etc. may be faced with hefty fines, as well as corrective measures to address and eliminate non-compliant discharges. These corrective measures typically include additional monitoring and reporting, implementing an electronic environmental database management software, implementing an environmental compliance management system, developing a response plan for eliminating effluent limit violations, and conducting internal and/or third-party environmental audits. Depending on the parameters in question, expensive treatment (or pre-treatment) systems may need to be installed.
Known recent civil penalties have ranged from $4 million to $20 million, which doesn’t include costs for corrective measures. Given the amount of money at stake, it is crucial to go into meetings with USEPA as prepared as possible.
If you have questions about the Section 308 process as it relates to mining companies, please contact Jonathan Pachter in our Pittsburgh office at 1-800-365-2324 or email@example.com. Additional information regarding EPA Section 308 matters can be found at the EPA’s website.