Groundwater contamination due to migration from a natural gas well along natural fractures resulted in benzene and methane in surface water and groundwater. After several years of operating a sparge system with little progress, Rule was selected to provide remediation for the site. Our evaluation concluded that the existing system was not effective and in fact due to the high groundwater flow rates in the aquifer, natural attenuation processes were adequate to control the plume migration. The case for monitored natural attenuation supported by fate and transport modeling was presented to the COGCC and the proposal to shut off the system and reduce the monitoring program was approved. Rule continues to monitor the groundwater with the data supporting our conclusions for natural attenuation and reduce the ongoing costs for our client.
A containment system was designed under a Consent Order with the WDEQ to prevent off-site migration of contaminated groundwater and LNAPL. An alternative evaluation design was used to select a soil bentonite slurry wall with a series of interceptor. Data from a detailed subsurface investigation was used to design a 1,700-foot long by 25-foot deep slurry wall with 500 feet of interceptor trenches using biodegradable polymer construction techniques with consideration for pipelines and other utilities at an active refinery. The work included preparation of construction plans, construction oversight, performance evaluation, and long-term performance monitoring. A groundwater treatment system was designed and an NPDES permit application was submitted and approved for treated water discharge to a creek. The treatment system consisted of an oil/water separator and an air stripper with pretreatment to reduce maintenance due to fouling.
A groundwater model was developed to address corrective actions under the WDEQ to provide an understanding of remedial alternatives to prevent off-site migration of contaminated groundwater and LNAPL. A three-dimensional finite-difference groundwater model was used to assist with the design and placement of a groundwater interceptor trench. The model utilized detailed subsurface characterization to simulate aquifer layers of various permeability to represent bedrock, sand/gravel and clay zones. The model was also used to simulate existing pumping systems, planned and existing interceptor trenches, wastewater ponds, as well as, creeks. Visual MODFLOW was used to generate the model, which works in conjunction with mapping programs to generate groundwater maps which can be incorporated into technical documents.
Closures were completed on over 70 produced water holding tanks covering a large area in a remote part of northwestern Colorado. The replacement of the existing culvert pit holding tanks was coordinated with the oil and gas operator to install above-ground tanks with minimal downtime. The tanks and impacted soils above state cleanup levels were removed where practical under a group COGCC Form 27. Clearance samples were collected from the excavation and impacted soil placed in a landfarm on each pad. Landfarm soils were amended with nutrients and moisture, and mixed periodically. After remediation, landfarm soils were used to fill the excavation and COGCC Form 4's were submitted for closure that included data collected from each pad.
An air sparge/soil vapor extraction (AS/SVE) remediation system was designed based on pilot test data. A total of 6 AS wells and 5 SVE wells were to remediate gasoline constituents in the groundwater by directly volatilizing the constituents and supplying oxygen for aerobic biodegradation. The work included preparation of construction plans, specifications and bid documents, construction oversight and quality control, preparation of an APEN emissions notification, performance evaluation, and long-term performance monitoring.
A multiphase extraction system was designed to address an extensive LNAPL plume spanning multiple off-site properties to dewater the upper low-permeability zone and allow product recovery and vapor extraction in the sand units where the NAPL was trapped. Based on extensive aquifer testing and site characterization, a system of six dual phase (liquid and vapor) wells were installed and piped to a treatment system with an oil/water separator for LNAPL removal and an air stripper for water treatment. A waste water discharge permit with continuous remote monitoring was approved by the local POTW. The system was effective in removing all mobile NAPL and reducing groundwater concentrations of petroleum hydrocarbons.
Prepared a FMP to comply with the final Standards of Performance for Petroleum Refineries (NSPS Subpart Ja). The plan provides the specifications of the flare system, documents applicability with the requirements of the regulation and outlines a compliance strategy, and included devising the best compliance strategy, calculating a baseline flare flow rate, drafting the flare gas recovery system procedures and working with process control engineers to meet flare flow monitoring requirements.
Prepare a 404 permit application to reroute an intermittent stream that was in the location of a proposed corrective measure. The permit consists of a Pre-Construction Notification and includes wetland delineation, identification of an area for wetland mitigation and preparation of a Wetland Mitigation Plan. Endangered and threatened species, and historic properties listed on the National Register of Historic Places were researched.
Prepared state and county major impact land use permit applications for a centralized E&P waste management facility, including: facility operations and contingency plans, storm water management, hydrology, geologic hazards, a sensitive area analysis with wildlife impact/habitat BMPs, land suitability and impact analysis, and property owner notifications. Analyzed potential air emissions using mass balance and modeling approaches, and prepared an air pollution emission notification.
Obtained an Underground Injection Control (UIC), Class V, Beneficial Use Permit to support bio-augmentation using periodic microbe batch injections.
Evaluated each facility for applicability and performed a gap analysis on existing plans. Used site-specific observations, measurements, maps and other documentation to address SPCC requirements. Planning distances were calculated and documented. Inspection forms, procedures and response plans were prepared based upon facility practices. SPCC plans were written to meet all new requirements while minimizing unnecessary paperwork and procedures. CADD drawings were prepared or revised to support the projects.
Rule worked with refinery Engineering, Operations, Maintenance and Environmental Departments to create a comprehensive set of underground oily water sewer maps. Flow tests using dye and volume were extensively used to document connections. Dry weather flow contributors were identified. Individual drain systems were precisely located and placed into the refinery CADD system. QQQ applicability was determined and a compliance plan was developed
Emergency response plans were written to address specific regulatory requirements under 40 CFR §112.20. Care was taken to use facility practices and procedures where possible; recommendations for satisfying data gaps were made and follow-up work completed.
Gathered data from existing refinery fuel gas flow meters and CO2 CEMS, set up a calibration schedule, drafted a Green House Gas (GHG) Monitoring Plan and prepared and submitted the annual emissions inventory. The work was completed in compliance with the Green House Gas Reporting Program (40 CFR Part 98).