MiProbe Environmental Sensing Technology for the Continuous Real-Time Management of Redox, Microbial Degradation Rates, and Metabolic Gases
CEC has collaborated with Burge Environmental of Tempe, Arizona, in the development and deployment of a sensor system called MiProbe that was supported by a series of grants from the U.S. Department of Energy.
The sensor is part of a full package of environmental sensors and data management tools that incorporates telemetry, the Cloud, and computer-generated graphics to bring the dynamics of contaminated site management to life. The system is unique in many ways, but one feature that makes it truly special is its use of biofilm as the sensor itself. The sensor also has a metabolic gas capture capability that gives it a second level of application in line with the current interest in Natural Source Zone Depletion (NSZD). Taken separately, the system’s features include:
Microbial Sensing Capabilities
The microbes and the associated electrode-support structure comprise a revolutionary redox sensor that is both instantaneous in reporting to the Cloud and robust to the point where, for all practical purposes, it has an operational life of several years.
A brief explanation of how it works: a biofilm/electrode combination with associated circuitry generates a steady-state voltage that is held by the electrode, noting that every redox state has an associated voltage. For example, the voltage is highest in an anaerobic environment, but it drops upon the encroachment of aerobic conditions because electrons are drawn away; this change is then recorded and transmitted. The system can work in reverse with voltages rising as anaerobic conditions develop. The sensor data may allow for better management and cost control associated with use of reagent applications (e.g. for providing oxidizing or reducing conditions in the subsurface).
It is also possible to understand the metabolic turnover rate in the environment. Based on the voltage output for the sensor (turning it on and off via remote control and allowing the voltage to drain and recover), a rate of substrate consumption can be calculated. This then factors into natural attenuation petitions or the progress of remedial intervention with oxidative or reductive processes as noted.
Metabolic Gas Capture Capabilities
The application targets a growing interest in documenting NSZD as a means of more enlightened management of complex sites with non-aqueous phase liquids (NAPLs). At present, the focus is on Light NAPLs (LNAPLs) like petroleum hydrocarbons. Depending on the subsurface conditions, LNAPLs will naturally attenuate through aerobic and anaerobic pathways while generating carbon dioxide and methane as metabolic gas end products. Capturing representative samples of these metabolic gases can be useful in calculating the Time of Remediation (TOR) of palpable contaminant masses in the subsurface. Of course, overlaying intervention activities such as oxidants or temperature inputs on this process can accelerate the TOR, and this will be recorded.
Other Applications and Features
Because MiProbe is sensitive to microbial activity, it can detect an uptick in electron flow as a function of a change in substrate availability. This would manifest when, for example, a dissolved-phase hydrocarbon plume impacts the sensor, which has major applications in managing UST sites or accidental releases. Conversely, a lack of electron flow could indicate a lack of bioavailability of contaminants.
The bioavailability application is important in sediments work in support of Monitored Natural Recovery (MNR) strategies. In effect, if a contaminant is unavailable, a case can be made for limited environmental impacts. Additional sediment and landfill management applications include the use of the redox sensor components to allow for characterization and modeling of the water exchanges between capped sediments or landfills and surrounding sources of water. Applications for ecological monitoring are also of interest and are ripe for further exploration by interested parties.
All of these analytical results have been obtained with extremely high reproducibility. The MiProbe system can be deployed several ways, including direct insertion into the subsurface or into monitoring wells, or as part of a floating deployment configuration. Also, the system is solar powered with real-time data transmitted using either cellular or satellite communications. In locations where communications are difficult, a data logging option is available.
This information on the MiProbe System is also available as a downloadable brochure on the Environmental Site Investigation and Remediation page of CEC’s website: http://www.cecinc.com/enviro_site_redevelopment.html.
The Ohio Environmental Protection Agency (EPA) Division of Materials and Waste Management (DMWM) is in the process of finalizing rules, under OAC 3745-515 (Draft Rules), for the disposal of oil and gas (O&G) production waste, specifically for the receipt, acceptance, processing, handling, management, and disposal of radioactive material, including technologically enhanced naturally occurring radioactive material (TENORM). The official title of the regulation is “Oil and Gas Production Waste Rules,” and a summary of the Draft Rules is as follows:
- Applicable to sanitary landfills and solid waste transfer facilities subject to OAC 3745-27 (municipal solid waste regulations) and 3745-29 (industrial waste regulations).
- Excluded from the Draft Rules are:
- Residual waste landfills;
- O&G production operations (including temporary storage adjacent to point of origination);
- Re-used material from horizontal wells;
- Injection well sites; and
- Material that is not TENORM and has not contacted refined oil-based substances (ROBS).
- If TENORM or ROBS are comingled with other drilling operation material, the mixed material is subject to the Draft Rules.
- The Draft Rules do not limit applicability under Ohio Revised Code (ORC) statutes in Chapters 1509 (O&G), 3734 (solid and hazardous waste), and 3748 (radiation control).
- It should be noted that although Ohio Department of Natural Resources (ODNR) has sole and exclusive authority to regulate the permitting, location, spacing, and related O&G activities in Ohio, Ohio EPA also has regulatory authority for sanitary landfills and solid waste transfer facilities that accept and process O&G production wastes.
- In addition, the Ohio Department of Health (ODH) Bureau of Environmental Health and Radiation Protection (BEHRP) provides guidance for field scanning, sampling, and laboratory testing for Ra-226/228, which Ohio EPA is adopting under the Draft Rules.
- Drilling operation material (DOM) means material that results from drilling operations, including waste substances from exploration, development, stimulation, operations, or plugging, and TENORM associated with an injection well.
- DOM is considered a solid waste.
- Source-separated drill cuttings generated while advancing through the underground source of drinking water are not DOM.
- TENORM is defined by reference to ORC 3748.01 and does not include drill cuttings with de minimus liquids; however, there are additions to the ORC 3748.01 definition, including:
- Used frac sands;
- Tank bottoms;
- Pipe scale;
- Used injection-well filter media; and
- TENORM mixed with other materials.
- For comparison, TENORM defined in ODNR’s Draft O&G Facility Rules also includes seven (7) “add-ons” to the ORC 3748.01 definition that are similar to those proposed by Ohio EPA above.
- Drill cuttings, drilling operation, and horizontal well have the same meaning as the ORC definitions.
- The Draft Rule definitions do not override OAC 3745-500-02 (Ohio EPA General Administration definitions).
INCORPORATED BY REFERENCE
- The “Solid Waste Disposal Facility Radioactive Material Detection Program” (amended June 14, 2016) issued by ODH BEHRP is incorporated by reference.
- Sanitary landfills and solid waste transfer facilities cannot:
- Accept TENORM with Ra-226/228 greater than five (5) pCi/g above background concentration (non-exempt TENORM) without authorization from ODH BEHRP. In Ohio, background concentration is considered to be two (2) pCi/g, making the threshold seven (7) pCi/g.
- Accept DOM that has not been stabilized with material other than Portland cement or quicklime or anther material authorized by ODNR under ORC Chapter 1509.
- Accept DOM that is bulk liquids or sludges without authorization from ODNR under ORC Chapter 1509 and shall not commingle solid waste or any other material not authorized in the Draft Rule during the solidification process.
RESOLUTION OF CONFLICTS AMONG AUTHORITIES
- Compliance with the Draft Rule is required when there is conflict with another authorizing document.
- Compliance with an Order is required when there is conflict with the Draft Rule. Once the Order is terminated or ceased, compliance with the Draft Rule is required.
- The Draft Rule shall not infringe upon ODH BEHRP authority statute, including issuing orders, inspections, and enforcement standards.
PERMIT TO INSTALL (PTI)
- Sanitary landfills and solid waste transfer facilities shall obtain a permit from Ohio EPA to accept and process non-exempt TENORM under the solid waste (OAC 3745-27) and industrial waste (OAC 3745-29) regulations.
- A permit to install (PTI) from Ohio EPA is required prior to construction of sanitary landfills and solid waste transfer facilities to process DOM and/or TENORM.
- Sanitary landfills and solid waste transfer facilities are required to have authorization for DOM transfer or disposal from ODH BEHRP.
- If not accepting DOM upon the effective date of the Draft Rule, a notice of intent to Ohio EPA is required.
- If already accepting DOM, a notice of intent to continue accepting DOM is required within 30 days following the effective date of the Draft Rule.
- Sanitary landfills and solid waste transfer facilities cannot accept non-exempt TENORM until Ohio EPA approves any required modification to the facility PTI.
- Implementation of a written radiation protection and detection program is required.
- Analysis for Ra-226/228 is required for TENORM material.
- A daily log is required documenting the waste type and amount received.
- Leachate will be tested for Ra-226/228 annually.
- Groundwater monitoring wells will be tested for Ra-226/228 semi-annually.
- State disposal fees will be levied on DOM.
PROHIBITED MATERIALS – RADIATION PROTECTION PROGRAM
The radiation protection program shall include:
- Implementation of the written radiation protection plan.
- Monitoring of incoming waste with radiation portal monitors (RPMs).
- Pre-acceptance screening procedures that include:
- Identification of sources;
- Generator profiles;
- Well pad name and location;
- DOM description;
- Processes used to remove fluids and stabilization agents used;
- Procedures for the collection of representative samples;
- Procedures for pre-acceptance screening, acceptance, and record keeping;
- Refusal of material procedures; and
- Detections by RPMs require laboratory testing and must be below non-exempt Ra-226/228 concentrations prior to disposal.
COMMENTS ON THE DRAFT RULES
Ohio EPA is accepting comments from stakeholders regarding the Draft Rules until May 12, 2017. Comments may be submitted to Michelle Mountjoy (firstname.lastname@example.org).
If you have any questions regarding the proposed Draft Rules, please contact Ababu Gelaye at email@example.com or (614) 917-3247, and/or Roy Stanley at firstname.lastname@example.org or (614) 545-1260 in CEC’s Worthington, Ohio, office.
Significant changes are on the way for oil and gas waste management facilities in Ohio with the upcoming Oil and Gas Waste Facilities Rules (Draft Rules, OAC 1501:9-X, revised 12/9/16). Oil and gas waste facilities, as currently defined in the Draft Rules, are operations that store, recycle, treat, or process brine and other waste substances associated with oil and gas exploration and production operations but are not part of well operations that are otherwise permitted by Ohio Department of Natural Resources’ (ODNR’s) Division of Oil and Gas Resources Management (such as a production well or Class II brine disposal well). The purpose of these Draft Rules will be to prevent injury or damage to public health, safety, and the environment and to ensure that brine and other waste substances are properly managed and disposed. The Draft Rules include definitions for oil and gas waste substances, treatment, recycling, storage, repurposing, stabilization, and processing. While the statutory definition of Technologically Enhanced Naturally Occurring Radioactive Material (TENORM) is retained, the Draft Rules appear to expand TENORM materials to include seven (7) specific waste types. The Draft Rules also require that the permit applicant shall be responsible for all utility connections of the facility. ODNR issued the Draft Rules asking that written comments from the industry be submitted by January 20, 2017, and held an industry meeting on January 30, 2017.
Until the Draft Rules are finalized, such facilities have been granted temporary authorization via a Chief’s Order from ODNR. At this point, it is not known as to when these Draft Rules will be final and effective; however, oil and gas waste facilities that currently have a Chief’s Order will be required to re-submit a permit to construct and/or a permit to operate once the Oil and Gas Waste Facilities Rules are promulgated. Constructed/operating facilities will be required to meet the location restrictions and construction specifications in the final rules.
Are the Draft Rules Requirements Similar to the Ohio Horizontal Well Site Construction Rule?
The Draft Rules are very similar to the Ohio Horizontal Well Site Construction Rule with respect to surface location and siting criteria, permit application/form and supporting documents, review procedures, construction activities, permit modifications, and certification. A significant difference is the definition of secondary containment, including tanks, vessels, berms, dikes, pipes, liners, vaults, curbing, drip pans, sumps, etc. The definition of material modification is equivalent to the definition in the Ohio Horizontal Well Site Construction Rule with the exception of substituting the name “Oil and Gas Waste Facility” for “Horizontal Well Site” and “Oil and Gas Waste Facility Boundary” with “Well Site Boundary.” The Draft Rules outline processes for permit modifications, requirements during construction activities, and construction certification, all of which are similar to requirements in the Ohio Horizontal Well Site Construction Rule.
The following exhibits will be required with the applications:
- Design and construction drawings,
- Containment integrity document,
- Emergency release conveyance map,
- Stormwater hydraulic report,
- Sediment and erosion control plan,
- Geotechnical report/plan,
- Oil and gas waste facility boundary GIS files, and
- Dust control plan.
These exhibit requirements are very similar to the requirements stipulated under the Ohio Horizontal Well Site Construction Rule, with the exception of the Containment Integrity requirement in the Draft Rules.
What Does the Oil and Gas Waste Facility Permitting Process Look Like Under the Draft Rules?
The permit application process will require the completion of a Permit to Construct (PTC) and a Permit to Operate (PTO). The Draft Rules state that the permits are not transferable and are issued only for a specific location. Thus, mobile facilities cannot be permitted in the current version of the Draft Rules. Application forms, prescribed by ODNR, will require specific facility and/or owner/industry information. Completeness and pre-construction site review time frames are also outlined, and those may take between fifty (50) and seventy (70) business days under normal circumstances.
One of the most contentious components of the Draft Rules is the public notice requirement once the permit application is deemed complete. Written objections to the permit application, if deemed relevant by ODNR, will require a public hearing. The Draft Rules stipulate that ODNR’s Division of Oil and Gas Resources Management provide public notice of the application by posting the application on the division’s website. The question regarding this public notice requirement has to do with its timing and/or its order with respect to the Technical Review Procedure (i.e., whether it is appropriate for the public notice to happen before Technical Review is completed).
A pre-construction site review will be completed by ODNR within fifteen (15) days of notification of a complete PTC application. ODNR is required to complete its technical review of the PTC application within 60 days following the completion of the public notice process. The PTO application will be reviewed within 60 days following the pre-construction site review.
The permittee shall notify ODNR at least forty-eight (48) hours prior to commencement of construction, following permit issuance. Red-line drawings must be kept on site to document deviations from the approved plans, and inspection and maintenance activities must be performed to demonstrate compliance.
The Draft Rules outline processes for addressing permit modifications, requirements during construction activities, and requirements for certification of the constructed site to be operated, similar to what are included in the Ohio Horizontal Well Site Construction Rule.
No later than two (2) years after the effective date of the PTC, the permittee is required to submit a signed and sealed certification from the Ohio-registered professional engineer to ODNR, certifying that the oil and gas waste facility was constructed in reasonably close conformity with the approved application and documented modifications.
What are the Impacts and Implications?
Obviously, finalization and implementation of the Draft Rules will result in higher costs for permitting, construction, and operation of oil and gas waste facilities in Ohio due to increased regulatory requirements.
Oil and gas waste facility owners/operators will need to plan longer lead-times for site selection, plan development, field investigations, and compliance with the permitting, construction, and operation requirements. Increased costs for oil and gas waste facility permits, construction, and operations will likely trickle down through the Exploration and Production industry.
Clear and timely communication and clarifications to ODNR inquiries, along with well-structured and assembled plan sets and application materials will all be critical to navigating the permitting and review process and in securing permits to construct and operate oil and gas waste facilities.
Implementation of an effective construction quality assurance and quality control (QA/QC) program will be critical for facility construction in accordance with the permit conditions, site design plans, and specifications. The Draft Rules also require that all modifications (material or application) are well documented and communicated with ODNR.
Critical Items Requiring Further Consideration:
- The baseline environmental assessment, containment integrity, dust control plan, and geotechnical investigation requirements are more prescriptive than requirements in West Virginia and Pennsylvania rules for similar facilities.
- There is no distinction in the factors of safety requirements for slope stability between cut slope and fill slope. The Draft Rules require the same factor of safety of 1.5 for both types of slopes and a factor of safety for bearing capacity of not less than 3.0. These restrictive factors of safety and bearing capacity requirements are likely to increase the effort and costs for site selection, limiting the options for site development.
- The application and technical review procedures will extend the time frame for permitting, design, construction, and operation of oil and gas waste facilities. The overall permitting process could range from ten (10) weeks to as many as nineteen (19) weeks, depending on relevant objections during the public notification process.
Promulgation and execution of Oil and Gas Waste Facilities Rules will result in additional procedures and requirements for the Oil and Gas industry. The rules will not address all site-specific design, construction, and operational issues; thus, anticipation of permitting issues and optional solutions must be effectively communicated to the owner for a complete and compliant permit application. The planning and permitting process will require assembling effective and well-coordinated environmental, ecological, civil/geotechnical engineering, and land surveying teams. During the ODNR rule-making process, CEC will continue to be actively involved, representing industry and stakeholder concerns.
If you have any questions or concerns regarding how these Draft Rules may affect your business, please contact Ababu Gelaye at email@example.com or (614) 310-2079, or Roy Stanley at firstname.lastname@example.org or (614) 425-6324.
New regulations are coming for underground storage tank (UST) owners and operators in Ohio. The Bureau of Underground Storage Tank Regulations (BUSTR), a division of the State of Ohio’s Fire Marshal’s office, has issued a second draft of its revised rules in the Ohio Administrative Code (OAC) at 1301:7-9-01 et. seq. The draft rules are currently being prepared for filing with the Joint Committee on Agency Rule Review (JCARR) in March/April 2017 with an anticipated effective date of July 2017, according to BUSTR.
The proposed rule revisions are intended to align with new federal UST regulations issued by the U.S. Environmental Protection Agency, which became effective October 2015, and also to comply with the bureau’s own five-year rule review requirement. The proposed amendments and rule changes include the following:
Compliance with New Federal Rules
- Certain types of UST systems that were previously exempt or deferred from state and federal regulations are now required to comply with certain BUSTR rules. These include airport hydrant fuel distribution systems, UST systems with field constructed tanks, and UST systems that solely store fuel for emergency generators.
- Six new terms were added; five to align with federal changes and one (“sole source aquifer”) to accommodate the rescission of OAC 1301:7-9-09 (“Rule 9,” see below). Eleven existing terms were amended, either for clarification or to align with federal changes.
- Rules were amended to implement new federal requirements for: 1) periodic checks of UST system and release detection components, 2) compatibility of release detection components and UST systems with tank contents, 3) methods of UST release detection, 4) retrofitting of older single-wall UST systems, 5) qualifications of persons performing work on UST systems, 6) records retention for UST system components and release detection records, and 7) requirements for release detection on airport hydrant and field-constructed systems. Numerous standards were updated relating to the construction and operation of UST systems to match corresponding federal standards.
- Rule 9, regarding USTs located above sensitive areas, was rescinded because these areas generally correspond to federally designated sole source aquifers, and more accurate geographical information now exists for owners and operators to use in determining whether an UST site is located above a sole source aquifer.
- The definition of “free product” and “suspected release” were revised in OAC 1301:7-9-13 (“Rule 13”) to match the federal version, and references were changed from “sensitive area” to “sole source aquifer” to accommodate rescission of Rule 9.
Permitting, Registration, and Closure
- The annual registration application deadline is being changed from July 1 to June 30. Registration requirements were added for compartments of a manifolded UST and for previously (but no longer) exempt UST systems. BUSTR also added a requirement to modify a registration within 30 days when there is a change of product.
- Clarified that partially exempt UST systems do not require a permit, a certified UST installer, or a certified UST inspector for tank-related activities.
- Clarified changes to the installer license renewal process.
- Clarified timeframes in OAC 1301:7-9-12 (“Rule 12”) for initiating closure assessments, added closure sampling requirements for piping runs, and revised the closure action levels table to reflect current science.
- Added Class A operators to the Class B retraining requirements, but makes retraining discretionary on the part of the State Fire Marshal instead of mandatory.
- Extended the validity of inspector certifications from two to three years, and simplified and streamlined the license renewal process.
Corrective Action, Chemicals of Concern (COCs), and Petroleum Contaminated Soils (PCS)
- The applicability section of Rule 13 was revised to allow ongoing corrective actions to continue under a previous rule version.
- Added “Biodiesel blended fuels” to the list of middle distillation products; added three new chemicals of concern (1,2,4-trimethylbenzene, 1,2-dibromoethane, and 1,2-dichloroethane); and revised action levels throughout Rule 13 to reflect current science.
- Updated public notice requirements for certain advanced corrective actions; owner/operators are now required to submit proof of notification within 90 days.
- Revised the list of re-use chemicals of concern and the action levels for petroleum contaminated soils (PCS) to incorporate most recent science, and clarified that if PCS above action levels are returned to the excavation, the cavity must be lined.
If you would like to learn more about how the new regulations may impact your operations or would like further information regarding the new BUSTR rules, contact Ron Wells (email@example.com), Tom Maher (firstname.lastname@example.org), or Andy McCorkle (email@example.com), or call (800) 365-2324.
When environmental regulations for coal-fired power plants change, effluent treatment methods currently being used may not be able to meet the new standards. Many power plant operators find that one of the new factors they must face is the EPA’s revised Effluent Limitations Guidelines (ELGs), issued in September 2015.
Recently at a mine-mouth coal-fired plant with a nominal capacity of 1,600 megawatts (MW), designers had done what they thought necessary to comply with regulatory expectations – they designed for zero discharge of process water. For blowdown water from the cooling tower, they made plans to discharge in a way that would meet National Pollutant Discharge Elimination System (NPDES) limits for the permitted outfall.
Process water is recycled internally for other plant processes, including the air quality control system (AQCS), which incorporates the flue gas desulfurization (FGD) system. However, as the wastewater continuously cycles through the two FGD absorber units, a buildup of chlorides and other constituents occurs. The level of total dissolved solids (TDS) in the purge water is controlled by blowdowns triggered by the TDS levels, and makeup water is then added to the system.
The FGD wastewater can contain TDS in excess of 31,000 parts per million (ppm), total hardness of 30,000 ppm, chlorides of 20,000 ppm, and total suspended solids (TSS) of 10,000 ppm. The blowdown wastewater is purged from the system whenever the chloride concentration in the water exceeds 20,000 ppm of chlorides.
The purged high chloride FGD wastewater is then disposed of by mixing it with fly ash and gypsum coal combustion residual (CCR) material in a pug mill. That mixture was originally disposed of at an off-site landfill, located about 20 miles away.
One seemingly small change caused this design to tip off-balance: the decision by the power plant to start its own landfill on site for disposal of the fly ash mixture. This action opened up the plant to the responsibility of managing the landfill leachate – water from precipitation flowing through the landfill, picking up contaminants along the way. The plant’s operators began pumping the leachate from the on-site landfill back to the plant’s recycle basin for re-use as make-up water. However, they found that internal recycling of wastewater is not sustainable at that location, as it results in the cycling up of chlorides and other factors that increase pipeline corrosion.
As a result, from 2014 to 2015, the chloride concentration in the recycle basin increased to three times the previous year’s concentration. The design for chlorides concentration for the recycle basin was set at less than 500 mg/L, but the data show levels approaching 3,000 mg/L within two years. These concentrations seemed likely to go on increasing unless measures were taken to manage the problem.
Problems such as these have been found at many coal-fired power plants. At the root of the problem is the fact that the water-management systems were set up to support the efficient combustion of coal to produce power. However, environmental regulations concerning water use and disposal have become more restrictive. This change has put an increasing operational focus on efficient water management to lessen the discharge of water from the plant and reduce materials of concern in that wastewater.
Thus environmental regulations, such as those intended to support zero liquid discharge (ZLD), now have an increased effect on operations, moving water management up on the priority lists of power plant operators.
One of the most common issues at many coal-fired power plants is the one seen in the story above – that, in many cases, the plant’s operators do not have a comprehensive plan for water use. They lack detailed, accurate data on which parts of the plant use water, how much those parts use, and what constituents the processes add to that water.
Many plants combine their wastewater inputs into a central flow and then treat the water that comes from that single pipe. In such cases, a more focused and cost-effective plan could be developed by segregating flows so that each stream receives only the level of treatment it needs. Segregation of wastewaters can generate substantial opportunities for recycling part of that water flow and limiting the most costly treatment and disposal methods to only the streams that need it.
For example, consider pump seal water. Many plants use clean water around the outside of the seals to reduce the possibility of the pumped fluid escaping. The pump seal water that drips out is gathered and then generally is just placed into the plant’s overall wastewater flow. Since this water is virtually clean, it would make more sense to capture this water separately so it can be treated at low cost, rather than being part of the larger, more complex wastewater flow.
Comprehensive analysis of the many water flows within a plant may be able to point to similar opportunities to segregate wastewater streams so that not all water needs to be treated with expensive methods. Specific data on water use at various points within the plant can help guide the choice of treatment approaches. At the plant described above, an astute review of the wastewater components saved the owner millions of dollars that would have been required for a new treatment plant. Instead, the plant managers were advised to use low-cost techniques for reducing the chlorides in their wastewater flow.
It is important to remember that as the plant’s operations change, the effects on the wastewater stream must be considered. The above-mentioned power plant was impacted by just such a change – the new landfill’s leachate forming a new source of chlorides to be managed.
Each coal-fired plant is different – the type of coal, equipment, and other factors such as local geology – so the following steps may be useful in finding an appropriate solution:
Analyze the current situation: One of the first steps for preparing for the new ELGs is to collect data on the flow and composition of wastewater streams and characterize typical wastewater flows.
Develop plans: Review various limiting strategies, such as reusing wastewater to reduce discharges, and then use mass balance and chemistry modeling tools to evaluate reuse, treatment, and discharge strategies to meet these new limits.
Choose management options: The choice for selecting the appropriate management tool depends on yet another wide range of factors that are better understood after carrying out the first two steps. The toolbox can include:
- Discharge to a Publicly Owned Treatment Works (POTW)
- Evaporation Ponds
- Flue Gas Injection
- Deep Well Injection (depending on factors such as geology – experience has found that the tight rock formations of Pennsylvania, for example, are less useable for this purpose than the more appropriate geologic formations of other locations, such as Florida)
- FGD wastewater treatment system (WWTS) Effluent Reuse/Recycle
- Settling Ponds
- Constructed Wetlands, Phytoremediation, and other Natural Based Systems
- Vapor-Compression Evaporation
- Physical/Chemical Treatment
- Physical/Chemical with Added Biological Treatment
- All the above can be components of a Zero Discharge approach
Other approaches utilities should consider include measures such as using existing evaporation (from cooling towers and FGD absorbers), using blowdown water for conditioning of fly ash, and other water reuse and conservation measures to reduce the amount of wastewater requiring treatment.
Working with a qualified professional with experience in each of these technologies can lead to wiser choices around which systems may be best, given the site-specific factors.
If you have any questions regarding your plant, please contact the post author, Ivan A. Cooper, P.E., BCEE, a principal based in CEC’s Charlotte, N.C., office, at firstname.lastname@example.org; (704) 226-8074.
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).
Update — EPA issues final New Source Performance Standards for Oil and Gas with significant new compliance requirements
On June 3, 2016, U.S. Environmental Protection Agency (EPA) finalized amendments to the Standards of Performance for Crude Oil and Natural Gas Production, Transmission and Distribution (Quad O) and a new subpart at 40 CFR 5360a et seq. (Quad Oa) for post-September 18, 2015, affected facilities. As noted in a previous CEC blog on this topic, U.S. EPA received nearly one million comments following the initial proposal. The new Quad Oa rule establishes emission standards for both methane and volatile organic compounds (VOC) at natural gas and oil well sites, production gathering and boosting stations, natural gas processing plants, and compressor stations. There are several new requirements for oil and natural gas production-related activities in these new federal rules, and it is important to understand how these rules might impact ongoing compliance activities under existing state rules and permit requirements already in effect. In this update, we focus on two of these new requirements due to their history and interrelatedness.
It is clear in reading both the proposed and final rules that U.S. EPA has expanded its understanding of oil and natural gas operations, particularly with respect to upstream E&P. Notably, the requirement for a professional engineer (PE) to evaluate and certify closed vent system design brings a new level of scrutiny borne out of a consent decree with a major oil and gas producer, and placed into practice in both the September 2015 Compliance Alert and the ongoing enforcement initiative targeting “energy extraction activities.” Not only is this new requirement intended to bring industry resources to bear on what the Agency views as a significant issue, but it also attaches professional liability to any subsequent violations attributed to closed vent system design. Further, with additional attention being focused on closed vent system design, the next obvious move on the Agency’s part was either construction practices (which are in many cases guided by industry consensus standards) or the operator’s preventative maintenance program.
From an air pollution control perspective, one focus of an upstream E&P maintenance program is to minimize or eliminate fugitive emissions from production facility equipment. As addressed by the industry during the comment period, there is an economic incentive to minimize losses of otherwise saleable products. Rather than dictate the contents of a preventative maintenance program, the Agency has instead required operators to survey for and repair fugitive emissions at well sites. While not a maintenance program per se, the new rule will require operators to engage in some routine maintenance and communication planning to ensure that fugitive leaks discovered during a survey are repaired and verified within the allotted timeframe.
Many producers operating in the Utica and Marcellus plays already had some form of fugitive emissions survey requirements in effect, as does Colorado. In other states, this will be the first time operators will have to grapple with leak detection and repair programs. This new requirement will have a disparate impact on upstream E&P operators that do not have the resources to employ full-time environmental staff or purchase the equipment needed to perform these required fugitive leak surveys in-house.
A summary of the new requirements discussed above is provided here. In the meantime, if you have questions on any aspects of the NSPS for the oil and natural gas source category, please contact the post authors: Kris Macoskey (firstname.lastname@example.org), or Ben Blasingame (email@example.com).
For those interested in exploring this topic further:
Final NSPS OOOO and OOOOa rule from the Federal Register
U.S. EPA National Enforcement Initiatives
CEC’s previous blog: EPA Receives Nearly One Million Comments on Proposed New Source Performance Standards for Oil and Gas