. All facilities required to institute monitoring shall meet the standards described in this section.
(a) Collection and management of samples : Groundwater, soil core, vadose zone and decomposition gas samples shall be collected and managed in accordance with department guidance or equivalent methods approved by the administrator.
(b) Groundwater : - (i) Except as provided in paragraph (b)(i)(A) of this section, industrial landfills shall comply with the following groundwater monitoring requirements:
- (A) Applicability:
- (I) The administrator may suspend the groundwater monitoring requirements of paragraph (B) of this section if the owner or operator demonstrates that there is no potential for migration of hazardous constituents from the facility to the uppermost aquifer. This demonstration must be made by a qualified scientist or engineer, and must consider:
- (1.) Site-specific field measurements, and information about the specific wastes to be disposed at the facility; and
- (2.) Contaminant fate and transport predictions, including use of the hydrologic evaluation of landfill performance model, which maximize contaminant migration and consider impacts on human health and the environment.
- (II) Owners and operators of industrial landfills must comply with the requirements of paragraph (b)(i) of this section by July 1, 1998.
- (III) The administrator may establish schedules of compliance for individual existing solid waste disposal facilities with the requirement of paragraph (b)(i) of this section, provided that half of all existing facilities are in compliance by July 1, 1998 and all are in compliance by July 1, 1999. The administrator shall consider potential risks to human health and the environment in establishing an alternate schedule of compliance for an individual facility.
- (IV) Once established at a facility, the ground-water monitoring program shall be conducted throughout the active life and post-closure care period for the facility, unless modified by the administrator under paragraphs (b)(i)(D) or (b)(i)(E) of this section.
- (V) The administrator may establish an alternate schedule for compliance with any deadline specified in paragraphs (b)(i)(B), (b)(i)(C), (b)(i)(D), or (b)(i)(E) of this section, or Section 8(c) of this chapter.
- (VI) The groundwater monitoring requirements of paragraph (b)(i) of this section do not apply to:
- (1) Industrial landfills which ceased receiving wastes before January 1, 1998, or
- (2) Industrial landfills which do not receive conditionally exempt small quantity generator (CESQG) hazardous wastes, or
- (3) Industrial landfills which accept for disposal less than twenty tons of waste per day (annual average), have no evidence of existing groundwater contamination, serve communities that have no practicable waste management alternatives and are located in an area that receives less than or equal to twenty-five (25) inches of precipitation annually.
- (B) Groundwater monitoring systems:
- (I) A groundwater system must be installed which consists of a sufficient number of wells to monitor water from the uppermost aquifer which may be affected by leakage from the facility. The system must be capable of monitoring background and downgradient water quality. Well locations must be approved by the administrator, and downgradient wells shall be placed in locations as close as possible but in no case greater than 150 meters from the disposal facility waste boundary on land owned, leased, or otherwise controlled by the operator.
- (II) The administrator may approve a groundwater monitoring system designed to monitor groundwater from the facility, in lieu of individual waste disposal trenches, if the system is determined to be capable of adequately detecting groundwater pollution. In approving a facility-wide groundwater monitor system, the administrator shall consider:
- (1.) Number, spacing, and orientation of the individual waste units at the facility;
- (3.) Site history and design; and
- (4.) Type of waste accepted at the individual waste units at the facility.
- (III) The design of the groundwater monitoring system must be based on site-specific information on aquifer thickness, aquifer properties, groundwater flow direction and rate (including seasonal variations), and on geologic information on the soils, any aquitards, aquicludes, or confining formations, at the site. The design of the system must be approved by the administrator. The owner or operator must include the system design information in the facility operating record, within fourteen (14) days of the date of approval of the system design by the administrator.
- (C) Groundwater sampling and analysis requirements:
- (I) Each facility must have an approved groundwater sampling and analytical plan and maintain that plan as a part of the facility permit application. The plan must address:
- (2.) Sample preservation and shipment;
- (3.) Analytical procedures;
- (4.) Chain of custody control; and
- (5.) Quality assurance and quality control.
- (II) The groundwater sampling and analysis methods must be appropriate and accurate. Sample handling procedures shall be as required by the administrator. Groundwater samples shall not be field filtered prior to laboratory analysis.
- (III) Groundwater elevations must be measured in each well prior to purging for sample collection, each time groundwater is sampled. The owner or operator must determine groundwater flow direction at each sampling event. The owner or operator must measure or calculate groundwater flow rate(s) as appropriate to establish an adequate groundwater monitoring system, or when requested to do so by the administrator.
- (IV) The owner or operator must establish background water quality in a hydraulically upgradient or other background well approved by the administrator.
- (V) Prior to conducting the statistical analysis of groundwater data, the owner or operator shall collect a sufficient number of samples to meet the requirements of the statistical analysis procedure selected under paragraph (b)(i)(C)(VI) of this section.
- (VI) The owner or operator must include in the permit application a description of the statistical method to be used to evaluate groundwater quality data. The statistical test shall be conducted separately for each hazardous constituent in each well. The owner or operator may select any of the following statistical analysis procedures:
- (1.) A parametric analysis of variance followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method must include estimation and testing of the contrasts between each compliance well's mean and the background mean levels for each constituent;
- (2.) An analysis of variance based on ranks followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method must include estimation and testing of the contrasts between each compliance well's median and the background median levels for each constituent;
- (3.) A tolerance or prediction interval procedure in which an interval for each distribution of the background data, and the level of each constituent in each compliance well is compared to the upper tolerance or prediction limit;
- (4.) A control chart approach that gives control limits for each constituent; or
- (5.) Another statistical method approved by the administrator.
- (VII) Any statistical method chosen under paragraph (b)(i)(C)(VI) of this section shall comply with the following performance standards:
- (1.) The method shall be appropriate for the distribution of chemical parameters or constituents. If the distribution is not normal, then the data should be transformed or a distribution-free theory test should be used. If the distributions for different constituents differ, more than one statistical method may be needed;
- (2.) If an individual well comparison procedure is used to compare an individual compliance well constituent concentration with background constituent concentrations or a ground-water protection standard, the test shall be done at a Type I error level no less than 0.01 for each testing period. If a multiple comparisons procedure is used, the Type I experiment-wise error rate for each testing period shall be no less than 0.05; however, the Type I error of no less than 0.01 for individual well comparisons must be maintained. This performance standard does not apply to tolerance intervals, prediction intervals, or control charts;
- (3.) If a control chart approach is used to evaluate groundwater monitoring data, the specific type of control chart and its associated parameter values must be approved by the administrator;
- (4.) If a tolerance interval or a predictional interval is used to evaluate groundwater monitoring data, the levels of confidence and, for tolerance intervals, the percentage of the population that the interval must contain, shall be approved by the administrator;
- (5.) Any data reported as below detection limits shall be entered into the statistical analysis as a value equal to one-half the practical quantitation limit (PQL) for the constituent. The PQL shall be the lowest concentration level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions that are available to the facility; and
- (6.) If approved by the administrator, the statistical method may include procedures to adjust data to account for seasonal and spatial variability, as well as temporal correlation.
- (VIII) The owner or operator must determine whether or not there is a statistically significant increase over background values for each parameter or constituent required in the particular groundwater monitoring program that applies to the facility under paragraph (b)(i)(D) or (b)(i)(E) of this section, as follows:
- (1.) The owner or operator must compare the groundwater quality of each parameter or constituent at each monitoring well using the approved statistical method; and
- (2.) Within thirty (30) days after completing sampling and analysis, the owner or operator must determine whether there has been a statistically significant increase over background at each monitoring well.
- (D) Detection monitoring:
- (I) Each facility shall institute a detection monitoring program by sampling each well at least semiannually, and testing each sample for the constituents specified in Appendix A, unless the administrator:
- (1.) Deletes a constituent because the owner or operator shows that it is not likely to be present in the waste disposed at the facility;
- (2.) Establishes an alternate list of inorganic constituents which provide a reliable indication of inorganic releases from the facility, considering the following factors:
- a. The types, quantities, and concentrations of constituents in wastes managed at the facility;
- b. The mobility, stability, and persistence of waste constituents or their reaction products in the unsaturated zone beneath the facility;
- c. The detectability of indicator parameters, waste constituents, and reaction products in the groundwater; and
- d. The concentration or values and coefficients of variation of monitoring parameters or constituents in the groundwater background; or
- (3.) Determines a different, but no less frequent than annual, monitoring schedule is appropriate, considering the following factors:
- a. Lithology of the aquifer and unsaturated zone;
- b. Hydraulic conductivity of the aquifer and unsaturated zone;
- c. Groundwater flow rates;
- d. Minimum distance between the edge of the waste boundary at the facility and the downgradient monitor well(s); and
- e. The classification of the aquifer under Chapter 8 of the Water Quality Rules and Regulations.
- (II) A minimum of four (4) individual samples is required to be collected and analyzed from each well (background and downgradient ) during the first year of sampling. At least one (1) sample must be collected and analyzed from each well during subsequent sampling events, which must be conducted on the sampling frequency determined under paragraph (b)(i)(D)(I) of this section.
- (III) If a statistically significant difference in water quality between background and any downgradient well is detected, the operator must:
- (1.) Notify the administrator and place a note in the facility operating record within fourteen (14) days and start assessment monitoring within ninety (90) days as provided in paragraph (b)(i)(E) of this section; or
- (2.) Demonstrate to the administrator that the statistically significant water quality difference is not due to the solid waste disposal facility, but that the difference is due to another source of pollution, error in sampling, analysis or statistical evaluation, or natural variation in groundwater quality. The owner or operator shall prepare a report documenting this demonstration, and following approval by the administrator, place the report in the operating record for the facility. If the report is approved, the owner or operator shall continue detection monitoring as required in paragraph (b)(i)(D) of this section. If, after ninety (90) days, a successful demonstration is not made, the owner or operator must initiate an assessment monitoring program as required in paragraph (b)(i)(E) of this section.
- (E) Assessment monitoring:
- (I) Assessment monitoring is required whenever a statistically significant increase over background water quality has been detected under paragraph (b)(i)(D) of this section.
- (II) Within ninety (90) days of triggering an assessment monitoring requirement, and annually thereafter, the owner or operator must sample and analyze all downgradient monitor wells for all Appendix B constituents. A minimum of one (1) sample from each downgradient well must be collected during each annual sampling event. If any Appendix B constituent is detected in any downgradient well, the owner or operator must promptly collect a minimum of four (4) additional independent samples from each background and downgradient well. These samples must be analyzed for each Appendix B constituent which was detected in the initial assessment monitoring sampling event.
- (III) The administrator may specify an appropriate subset of wells to be sampled and analyzed during assessment monitoring, and may delete Appendix B constituents from the monitoring requirements if it can be shown that the deleted constituents are not reasonably expected to be in or derived from the waste contained in the facility. The administrator may also specify an appropriate alternate frequency for the collection of the additional independent samples under paragraph (b)(i)(E)(II) of this section, considering the following factors:
- (1.) Lithology of the aquifer and unsaturated zone;
- (2.) Hydraulic conductivity of the aquifer and unsaturated zone;
- (3.) Groundwater flow rates;
- (4.) Minimum distance between the facility and the downgradient monitor well(s);
- (5.) Classification of the aquifer under Chapter 8 of the Water Quality Rules and Regulations; and
- (6.) Nature (fate and transport) of any constituents detected under assessment monitoring.
- (IV) After obtaining the results from any sampling event under paragraph (b)(i)(E)(II) of this section, the owner or operator must:
- (1.) Within fourteen (14) days, notify the administrator and place a notice in the operating record identifying the Appendix B constituents that have been detected;
- (2.) Within ninety (90) days, and on at least a semiannual basis thereafter, resample all wells, conduct analyses for all constituents required under detection monitoring [paragraph (b)(i)(D) of this section], and for all Appendix B constituents which have been detected under assessment monitoring [paragraph (b)(i)(E)(II) of this section], and record their concentrations in the operating record. At least one (1) sample must be collected from each well during each sampling event under this paragraph. The administrator may approve an alternate sampling frequency, no less than annual, considering the factors in paragraph (b)(i)(E)(III) of this section;
- (3.) Establish background concentrations for any constituents detected pursuant to paragraph (b)(i)(E)(II) or (b)(i)(E)(IV)(2.) of this section; and
- (4.) Establish groundwater protection standards for all constituents detected pursuant to paragraph (b)(i)(E)(II) or (b)(i)(E)(IV)(2.) of this section. The groundwater protection standards shall be established in accordance with paragraphs (b)(i)(E)(VIII) or (b)(i)(E)(IX) of this section.
- (V) If the concentrations of all Appendix B constituents are at or below background values using the approved statistical procedures, for two (2) consecutive sampling events, the owner or operator must notify the administrator and may return to detection monitoring under paragraph (b)(i)(D) of this section.
- (VI) If the concentrations of any Appendix B constituents are above background values, but all concentrations are below the groundwater protection standard established under paragraphs (b)(i)(E)(VIII) or (b)(i)(E)(IX) of this section, using the approved statistical procedures, the owner or operator must continue assessment monitoring under paragraph (b)(i)(E) of this section.
- (VII) If one (1) or more Appendix B constituents are detected at statistically significant levels above the groundwater protection standard established under paragraphs (b)(i)(E)(VIII) or (b)(i)(E)(IX) of this section in any sampling event, the owner or operator must, within fourteen (14) days of this finding place a notice in the operating record identifying the Appendix B constituents, notify the administrator and all appropriate local government officials, and:
- (1.) Characterize the nature and extent of the release by installing additional monitor wells as necessary;
- (2.) Install at least one (1) additional monitor well at the facility boundary downgradient of the release and sample the well in accord with paragraph (b)(i)(E)(IV)(2.) of this section;
- (3.) Notify all persons who own or reside on the land that directly overlies any part of the plume of contamination, if that plume has migrated off-site; and
- (4.) Initiate an assessment of corrective measures as required by Section 8(a) of this chapter within ninety (90) days; or
- (5.) Demonstrate to the administrator that the contamination was caused by another source, resulted from an error in sampling, analysis or statistical evaluation, or from natural variation in groundwater quality. If a successful demonstration is made, the owner or operator must continue monitoring under the assessment monitoring program as required by paragraph (b)(i)(E) of this section, or may return to detection monitoring if all Appendix B constituents are at or below background as specified in paragraph (b)(i)(E)(V) of this section. Until a successful demonstration is made, the owner or operator must comply with paragraph (b)(i)(E)(VII) of this section including initiating an assessment of corrective measures under Section 8(b) of this chapter.
- (VIII) The owner or operator must establish a groundwater protection standard for each Appendix B constituent detected in the groundwater. The groundwater protection standards shall be:
- (1.) For constituents where a maximum contaminant level (MCL) has been promulgated, the MCL for that constituent;
- (2.) For constituents for which MCL's have not been promulgated, the background concentration established from wells in accordance with paragraph (b)(i)(B)(I); or
- (3.) For constituents for which the background level is higher than the MCL or health-based levels identified under paragraph (b)(i)(E)(IX) of this section, the background concentration.
- (IX) The administrator may establish an alternative groundwater protection standard for constituents for which MCL's have not been established. These groundwater protection standards shall be health-based levels meeting the requirements of Chapter 8 of the Water Quality Rules and Regulations.
- (ii) Industrial landfills excluded from groundwater monitoring requirements under paragraph (b)(i)(A)(VI) of this section, shall, if required by the administrator, comply with the following groundwater monitoring and corrective action requirements:
- (A) Well placement: All facilities required to install monitoring wells shall place them in accordance with the department's requirements. Following initial placement of the wells, the operator shall confirm that the wells are capable of measuring groundwater quality that is representative of conditions hydraulically upgradient and downgradient of the solid waste disposal facility.
- (B) Well design, construction/installation and abandonment: All wells shall be designed, constructed and installed in accordance with the Water Quality Division Chapter 11 requirements. All abandoned monitoring wells shall be plugged and sealed in accordance with the Water Quality Division Chapter 11 requirements.
- (C) Permits required: Prior to well installation, the monitoring well design, construction and location specifications shall be approved by the administrator. A construction permit under Chapter 3 of the Water Quality Division rules and regulations is not required. All monitoring wells shall be permitted by the Wyoming State Engineer's Office.
- (D) Analyses:
- (I) Baseline monitoring: The initial groundwater samples shall be analyzed for pH, Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), Ammonia as N, Nitrate as N, Bicarbonate, Carbonate, Chloride, Fluoride, Calcium, Magnesium, Potassium, Sodium, Sulfate, Copper, Iron, Manganese, Nickel, Zinc, Arsenic, Barium, Cadmium, Chromium, Cyanide, Lead, Mercury, Selenium, and Silver. Additionally, water temperature, specific conductance, pH and static water level shall be measured in the field during each baseline monitoring event. The length of this baseline monitoring period shall not exceed one (1) year, and samples shall be obtained at least quarterly during this period.
- (II) Detection monitoring: Following the initial baseline monitoring period, the administrator may specify a reduced set of sampling parameters to be analyzed at least semi-annually. The reduced set of parameters shall include, at a minimum: pH, temperature, static water level, Total Dissolved Solids (TDS), Chlorides, Ammonia (as N), Iron, Hardness, and Total Organic Carbon (TOC). Additionally, water temperature, specific conductance, pH and static water level shall be measured in the field during each routine monitoring event.
- (III) Assessment monitoring: Should groundwater monitoring data cause the administrator to determine the facility may be impacting groundwater quality, additional wells, a revised set of sampling parameters and revised sampling schedule may be required by the administrator to define the nature and extent of contamination.
- (IV) The administrator may specify alternative or additional water quality parameters for analyses, including organic chemical constituents, based on its review of the wastes likely to be disposed at any specific solid waste disposal facility.
- (E) Corrective actions: Whenever there is a release of contamination which adversely impacts groundwater quality, the operator shall institute corrective actions approved by the administrator, as specified in Section 8 of this chapter.
- (iii) If designated by the administrator, operators of industrial landfill which have three (3) or more groundwater monitoring wells designated for monitoring potential impacts from the facility may be required to submit groundwater monitoring data on magnetic media or electronically transmitted files in a format which is specified by the administrator. Alternatively, these operators may submit hard copies of these data in a tabular format which is approved by the administrator in order to facilitate electronic scanning by the administrator.
(c) Methane : - (i) Methane probe system design: Methane probe design, construction, installation and location shall be adequate to monitor compliance with the appropriate standards specified in Sections 4 and 5 of this chapter.
- (ii) Abandonment of methane probe boreholes: Abandoned methane probe boreholes shall be plugged and sealed in accordance with department recommendations.
- (iii) Analyses: Methane analyses shall be conducted at least quarterly, should the administrator determine methane monitoring is required. Analyses shall be conducted using a gas-scope and/or organic vapor analyzer, using the manufacturer's recommended procedures.
(d) Air : Air monitoring, if required, shall be conducted in accord with Air Quality Division regulations.
(e) Soil core : Soil core monitoring, if required, shall be conducted in accord with a plan approved by the administrator.
(f) Vadose zone : Vadose zone monitoring, if required, shall be conducted in accord with a plan approved by the administrator.
(g) Reporting of environmental monitoring data : On an annual basis, operators of all facilities shall provide the administrator with copies of all required environmental monitoring data. An analysis of environmental monitoring data shall also be submitted as follows: - (i) Operators of facilities which are subject to the groundwater monitoring requirements of Section 6(b)(i) of this chapter shall provide copies of all required statistical analyses;
- (ii) Operators of all facilities may be required to submit supporting charts and/or maps which represent the data.