Code of Maine Rules
06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION
096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL
Chapter 405 - Solid Waste Management Rules: Water Quality Monitoring, Leachate Monitoring, and Waste Characterization
Section 096-405-2 - Water Quality Monitoring

Universal Citation: 06 ME Code Rules ยง 096-405-2

Current through 2024-38, September 18, 2024

The monitoring program approved for a solid waste facility must be capable of detecting any changes in ground water quality in the vicinity of the solid waste facility and/or any changes in surface water quality in the vicinity of the solid waste facility.

A. Standards for Ground Water Monitoring. The objective of a ground water monitoring program is to detect changes in the quality of ground water due to a solid waste facility. To accomplish this, downgradient and upgradient (or background) ground water monitoring wells must be placed in sufficient numbers to meet the standards of this chapter as determined through a hydrogeological investigation of the facility site. Areas where public health concerns or nearby sensitive receptors are threatened or have been affected may be subject to more intensive ground water monitoring requirements than provided below.

(1) Number and location of ground water monitoring wells. The number and placement of ground water monitoring wells at new or altered solid waste facilities, or existing active, inactive or closed solid waste facilities required to implement a new ground water quality monitoring program or add additional monitoring wells, must conform to the standards listed below. Where the location of existing active, inactive or closed solid waste facilities (including alterations) make it impossible to locate wells upgradient of the waste handling area, other locations for characterizing background ground water quality may be proposed for review by the Department:
(a) Horizontal well spacing must be based on site-specific conditions including ground water flow direction and rate, estimated dispersion, proximity to sensitive receptors and the nature of wastes disposed of, stored, processed or beneficially used at a solid waste facility. For landfills, it must also be based on the proposed or existing design of the landfill liner and leachate management systems. The number and location of the downgradient monitoring wells or well clusters will depend on the size of the waste handling area and the length of its downgradient perimeter. Monitoring wells must be established in sufficient numbers to detect any contamination emanating from the waste handling area.

(b) Vertical well locations must be chosen to ensure that each hydrogeologic unit is monitored.

(c) At new or expanded landfills, a minimum of two upgradient and three downgradient wells or well cluster locations must be provided. At landfills where more than five wells or well clusters are necessary, the ratio of upgradient (or background) wells to downgradient wells must be sufficient to support valid statistical analyses.

(d) At existing facilities, or where ground water contamination is suspected, the Department may require the use of geophysical techniques to aid in establishing appropriate well locations and screen elevations for additional ground water monitoring points.

(e) The downgradient monitoring wells must be located as close as practical to the solid waste boundary(s) of landfills, or the waste handling area of solid waste facilities that are not landfills, but in no case greater than 100 feet away, unless placing some of the wells at greater distances enhances the ability to detect a release from the facility. In such a case, placement of wells more than 100 feet distant may be proposed for approval by the Department

(f) All upgradient and background monitoring wells must be placed so as to avoid any facility-derived impacts both during the operating life of the facility and after closure.

(2) Sampling, Handling and Analysis of Ground Water. The ground water monitoring program must include consistent sampling procedures that are designed to ensure monitoring results that provide an accurate representation of ground water quality at all monitoring wells installed at a solid waste facility. The approved sampling protocol must be followed throughout the monitoring period of the facility so that data acquired can be compared over time and accurately represent changes in ground water quality. The following procedures must be followed during purging and sampling of monitoring wells, and the handling and analysis of the collected samples:
(a) Prior to purging. Prior to purging the well, static water level must be measured to the nearest 100th of a foot using standard techniques. If a protocol other than low flow sampling is used, well depth must be measured at least annually, or more often if suspended solids in the sample suggest that the well integrity has been impaired. Also, the ground water quality monitoring plan must include the following provisions for detecting immiscible fluids, and explosive or organic vapors, when applicable.
(i) In areas where the presence of explosive or organic vapors is suspected, appropriate instruments must be used to test and identify any constituents in the air in the well prior to purging. Results must be recorded on the field sheet.

(ii) For wells at which ground water contamination has been documented, or where contamination by non aqueous phase liquids is suspected, standing water in the well must be checked for immiscible layers or other contaminants that are lighter or heavier than water, prior to purging the well. If present, these liquids must be sampled and analyzed separately by a method described in the facility ground water monitoring plan.

(b) Purging and Sampling. Wherever possible, purging and sampling must be accomplished at low flow rates using a pump. The pump intake must be within the screened interval of the well, and the purging and sampling procedure must minimize drawdown in the well in order to minimize both the creation of artificial gradients in the vicinity of the well and the introduction of stagnant water into the well screen.
(i) Purge methods, including type of pump, pumping rate, and depth of pump intake must be included in the ground water monitoring plan.

(ii) Dissolved oxygen, pH and Eh must be measured inline at the discharge of the pump, in a closed flow cell.

(iii) purge stabilization criteria. Sample collection at the same flow rate used to purge the well may occur when the following stabilization criteria are met:
a. Specific conductance, dissolved oxygen and turbidity stabilize within 10% of the reading range for 3 consecutive readings;

b. The pH is within 0.1 standard unit; and

c. Water level is stabilized.

(c) Order of Sampling. An order for the sampling of monitoring wells must be included in a monitoring program which uses non-dedicated equipment; any changes in the sampling order must be approved by the Department.
(i) The order in which monitoring wells in the program will be sampled must consider the likelihood for contamination in each well in the respective well network. Wells at locations least likely to be found contaminated must be sampled first.

(ii) The order in which samples will be collected from each monitoring well must remain consistent over time and must be based on the parameter's volatility. The United States Environmental Protection Agency (US EPA) provides the following guidelines on order of sample collection:
a. Volatile Organic Compounds (VOCs);

b. Total Organic Carbon (TOC);

c. Total Organic Halogens (TOX);

d. Any samples approved by the Department for field filtration;

e. Samples for field parameter measurement (usually Temperature, Dissolved Gases, Alkalinity and Specific Conductance);

f. Large-volume samples for Extractable Organic Compounds;

g. Samples for Total Metals; and

h. Samples for Nutrient Anion Determinations.

(d) Except as otherwise approved by the Department based on site-specific characteristics, all samples must be whole and unfiltered and must be collected in a manner which produces the least possible sampling-induced turbidity.

(e) Field Analyses. All field test equipment must be calibrated at the beginning of each sampling day and checked and re-calibrated according to the manufacturer's specifications. Calibration data must be reported with the analytical results.

(f) Quality Assurance/Quality Control
(i) Blanks and Duplicates. Unless otherwise approved by the Department based on site-specific characteristics, the following schedule for the collection and analysis of blanks and duplicates must be followed:
a. One trip blank per cooler or shipping container for VOCs each time VOCs are taken to the lab;

b. One equipment blank (final rinsate blank) per sampling event. For each piece of non-dedicated sampling equipment used, the equipment blank must be taken at the end of the sample event; and

c. One duplicate for every tenth sample obtained over the course of consecutive sampling events. The duplicate sample identification must be coded such that its origin is unknown to the laboratory.

(ii) Continuous chain of custody documentation must be maintained for each sample. Sample containers, preservation methods and maximum holding times must be appropriate for each parameter and method involved in the monitoring program, and must be specified in the sampling and analytical work plan for the facility.

(iii) The analytical methods used to analyze samples must be chosen in accordance with State or Federal guidance documents. Analytical methods used must, where possible, have detection limits which do not exceed one half the maximum contaminant level (MCL) or the maximum exposure guideline (MEG) for each respective parameter.

(3) Additional Standards for the Sampling of Water Supply Wells. When the sampling of water supply wells is conducted, documentation of the well location, design and sampling procedures must be provided.
(a) Location and construction records for the wells
(i) A description of each well, including its installation, history, and treatment must be provided to the Department. A template for a "Well Description" is contained in Appendix B of this chapter.

(ii) A map, identifying the location of the disposal facility, and of all water supply wells sampled.

(b) Sampling procedures for the wells
(i) Samples should be collected directly from the well, where possible. Otherwise, samples must be collected as near to the well as possible and before the water is softened, filtered or heated.

(ii) If possible, samples must be collected before the water enters the pressure tank; otherwise the water must be run long enough to flush water stored in the tank and pipes.

(iii) If samples are collected from a tap, aerators, filters or other devices must be removed before sampling.

B. Standards for Surface Water Monitoring. The objective of a surface water quality monitoring program is to detect direct or indirect discharges to a classified body of water, or to detect improvements in surface water quality. Information gathered during hydrogeologic investigations, preparation of an application and ongoing monitoring of a facility must be considered in locating surface water monitoring points.

(1) Number and Locations of Surface Water Monitoring Points. For solid waste facilities at which surface water monitoring is required, a minimum of three surface water sampling locations must be established:
(a) At the locations of likely discharges;

(b) Upstream or sufficiently distant so as not to be affected by any discharges from the facility; and

(c) Downstream of the facility.

(2) Sampling, Handling and Analysis of Surface Water. The surface water monitoring program must include consistent sampling procedures that are designed to ensure results that provide an accurate representation of surface water quality at both upstream (background) and downstream monitoring points for a solid waste facility. The approved sampling protocol must be followed throughout the monitoring period of the facility so that data acquired can be compared over time and accurately represent surface water quality.
(a) Collection of Samples
(i) Samples collected from shallow water should not include bottom sediment. In shallow moving water, downstream samples must be collected first to avoid disturbing the bottom sediments.

(ii) Any sample point at which water is over ten feet deep must be checked for stratification using the field parameters conductivity, pH, temperature and dissolved oxygen. Each stratum so identified must be sampled and analyzed separately.

(iii) Except as otherwise specified by the Department, all samples must be whole and unfiltered and must be collected in a manner which produces the least possible turbidity.

(b) Blanks and Duplicates. Unless otherwise approved by the Department, the following schedule for the collection and analysis of blanks and duplicates must be followed:
(i) One trip blank per cooler or shipping container for VOCs each time VOCs are taken to the lab.

(ii) One equipment blank (final rinsate blank) per sampling event. The equipment blank must be taken at the end of the sample event for each piece of non-dedicated sampling equipment used.

(iii) One duplicate for every tenth sample obtained over the course of consecutive sampling events. The duplicate sample identification must be coded such that its origin is unknown to the laboratory.

(c) Sample Handling. Continuous chain of custody documentation must be maintained for each sample. Sample containers, preservation methods and maximum holding times must be appropriate for each parameter and method involved in the monitoring program, and must be specified in the sampling and analytical work plan for the facility.

(d) Laboratory Analyses. The analytical methods used to analyze samples must be chosen in accordance with State or Federal guidance documents. Analytical methods used must, where possible, have detection limits which do not exceed one half the MCL or the MEG for each respective parameter.

C. Types of Water Quality Monitoring Programs. The information below describes the various types of monitoring programs and when they must be implemented. The detection and assessment parameters to be analyzed at a landfill must be based upon those found to be present during characterization of the leachate generated by the solid waste facility, those found to be present through ground and/or surface water characterization monitoring, and those identified by the Department as reliable indicator parameters. For a solid waste facility other than a landfill, the water quality monitoring program must be based on the specific types of wastes handled at the facility.

The parameter list for water quality monitoring is found in Appendix A of this chapter.

(1) Site Characterization Monitoring. A site characterization monitoring program must be conducted at any new, expanded or existing active, inactive or closed solid waste landfill at which water quality monitoring is required, to establish the parameters to be monitored, and their concentrations as currently found in ground and surface water in the vicinity of the solid waste facility. At existing landfills, site characterization monitoring is required prior to performing detection monitoring. Existing landfills which have previously conducted site characterization monitoring and have ongoing ground and surface water quality monitoring programs found by the Department to have met the applicable water quality monitoring requirements of the May, 1989 solid waste regulations, are exempt from the ground and surface water characterization requirements of this subsection. The site characterization monitoring program at solid waste facilities other than landfills must be determined on a case-by-case basis based on the siting, design, and operations plan, and the physical and chemical characteristics of wastes to be handled at each solid waste facility.
(a) Four or more independent samples from each ground and surface water sample point approved by the Department for the characterization program are required for proper characterization of water quality. The actual number of independent samples required for water quality characterization at a sample point must be based on the rate of ground water flow, data quality and/or variability of results. Sampling events must include the extremes of seasonal water level fluctuation (yearly high and low ground water).

(b) For existing solid waste landfills which accept exclusively MSW, characterization analyses of samples from the first two sampling rounds must be conducted for the Appendix A of this chapter, Column 2 parameters. Subsequent sampling rounds must be for the Column 1 parameters, plus any Column 2 parameters detected in the first two sampling rounds.

(c) For all other existing solid waste landfills, characterization analyses for the first two sampling rounds must be conducted for the Column 2 parameters, less any Column 2 parameters demonstrated by analyses not to be present in or derived from leachate generated at the facility which is being characterized. Such demonstration must consist of "non-detect" results, using laboratory methods approved by the Department for the given parameter(s) for the four most recent sampling rounds of analyses for representative and independent samples of leachate generated by the solid waste facility. For landfills without the capability of monitoring a leachate detection system and/or a leachate collection system, characterization analyses for the first two sampling rounds must be conducted for the Column 2 parameters.

(d) For proposed solid waste landfills, analyses must be conducted for the Column 2 parameters during the first two sampling rounds. Subsequent sampling rounds must be for the Column 1 parameters plus any Column 2 parameters detected in the first two sampling rounds. Results of these analyses must be submitted with the application.

(e) For a solid waste facility, other than a landfill, that is required to have a water quality monitoring program, analyses must be conducted during the first two sampling rounds for the Column 2 parameters reasonably expected to be present in any wastes to be handled at the solid waste facility in a manner which could allow leachate to enter ground or surface water. Subsequent sampling rounds must be for the Column 1 parameters plus any Column 2 parameters detected in the first two sampling rounds.

(2) Detection Monitoring. The data obtained through the site characterization monitoring program and, for landfills, the nature of leachate generated by the same or a similar landfill, must be used to establish the list of detection parameters for the solid waste facility. The purpose of detection monitoring is to detect changes in water quality throughout the active life of the facility and through the closure and post closure periods.
(a) Detection monitoring at a landfill must be conducted for the parameters listed in Column 1 of Appendix A of this chapter, plus any Column 2 parameters determined to be present during leachate characterization, site characterization monitoring, and as required in subparagraph (e) or (f), below.

(b) Detection monitoring at a solid waste facility other than a landfill must be conducted for the parameters listed in Appendix A of this chapter, Column 1 plus any Column 2 parameters determined to be present during site characterization monitoring.

(c) Sampling frequency for detection monitoring at an active solid waste facility must include three sampling events per year collected during spring (March/April), summer (July/August) and fall (October/November), unless an alternative frequency is approved or required by the Department, based on site-specific characteristics.

(d) Sampling frequency may be reduced to twice yearly (spring and fall) at an active solid waste facility at which ground water velocity is calculated to be less than 10 feet/year using conservative assumptions. Conservative assumptions must include the steepest gradient observed for the hydrogeologic unit, the maximum hydraulic conductivity measured in the hydrogeologic unit, and a maximum effective porosity for flow of 0.1, unless site-specific information or other pertinent data exists to establish a greater porosity.

(e) A landfill without the capability of monitoring a leachate detection system and/or a leachate collection system must include annual monitoring of the Column 2 parameters in the landfill's detection monitoring program.

(f) A landfill having the capacity to monitor a leachate detection system and/or a leachate collection system must monitor the leachate for the Column 2 parameters in the facility's leachate detection system and/or leachate collection system at least annually.

(g) Parameters consistently undetected in a facility's leachate, or in results from its ground water monitoring network, may be deleted from detection monitoring upon approval by the Department. Certain major ions and complex ions (sodium, potassium, magnesium, calcium, iron, bicarbonate, sulfate, and chloride) may not be deleted from a detection monitoring program.

(h) Sampling frequency and parameters for detection monitoring at a landfill which does not qualify for closure under the reduced closure procedure of 38 M.R.S.A. §1310-E-1(2) or the alternative closure procedure of 38 M.R.S.A. §1310-E-1(3) must continue as previously approved for the facility, unless an alternative program is established in the closing plan and post-closure care approval for the landfill. The sampling frequency and parameters for closed landfills are expected to decrease throughout the post-closure period.

(i) If the results of detection monitoring indicate a possible deterioration in water quality at one or more ground water monitoring wells or surface water monitoring points, the owner/operator of the solid waste facility shall initiate an evaluation of the causes of the deterioration in water quality within 30 days of its receipt of the laboratory results. A report of the evaluation, prepared and sealed by a qualified professional, must be submitted to the Department for review and approval within 90 days of the date the evaluation is initiated. The report may be a part of the regular monitoring report or a separate document. The evaluation must include the following:
(i) A statistical analysis of the data from the monitoring program, performed in accordance with section 3;

(ii) An evaluation of sources other than the solid waste facility which may have caused or contributed to the possible deterioration in water quality, such as natural variation in water quality or another development;

(iii) An evaluation of possible errors, such as errors in sampling, analysis, or mathematical problems with the monitoring data. If resampling of monitoring points is performed, the samples must be independent of the previous sample; however, the sample must be collected within the same season as the original sample; and

NOTE: Staff consider "possible deterioration" to mean a change in data values that appears significant after considering normal variations in the historical database and any acute events that might have triggered short-term water quality changes.

(j) Assessment monitoring must be initiated within 90 days of the date the report required by section 2(C)(2)(i), above, is submitted, unless the Department concurs that a source other than the solid waste facility is the likely source of the deterioration in water quality. Assessment monitoring must be conducted in accordance with a plan approved by the Department.

(3) Assessment monitoring. The purpose of assessment monitoring is to determine the nature and extent of a release of contaminants to ground or surface water.
(a) Proposed changes to the facility's water quality monitoring plan, prepared in accordance with the applicable rules, must be submitted at least 15 days prior to the first scheduled assessment monitoring event.

(b) Assessment monitoring frequency must include three sampling events per year collected during spring (March/April), summer (July/August) and fall (October/November) at each sample point where it is documented by a statistically significant change in concentration of a parameter that deterioration of water quality has occurred, and at its upgradient or upstream counterpart(s).

(c) Samples taken during the first two rounds of assessment monitoring must be analyzed for the Column 3 parameters. After the submission of the results from the first two rounds of assessment monitoring, an owner/operator may submit a proposal to eliminate parameters based on an analysis of those results.

(d) Assessment monitoring must continue until the Department concurs that successful corrective action, as defined in 06-096 CMR ch. 400, section 1, has been demonstrated.

(e) As part of assessment monitoring, monitoring wells must be installed and sampled downgradient of (and in the same hydrogeologic unit as) the affected monitoring well(s) in sufficient numbers to identify the magnitude and extent of the plume. All additional wells installed under this section become part of the assessment monitoring network, but may not be required to be part of the detection monitoring network.

(4) Alternative Ground Water Monitoring Programs. After ground water quality is established at a solid waste facility, the Department will consider proposals for alternative forms of monitoring, such as leachate accounting or geophysical surveys, in lieu of or in conjunction with sampling and analysis of some of the wells required by this section. At a minimum, the applicant must submit the following documentation to justify a proposed alternative:
(a) A complete description of the proposed alternative ground water monitoring program, including a demonstration that the hydrogeological characteristics of the facility site have been considered during the development of the proposal;

(b) A discussion of the benefits of the proposed alternative ground water monitoring program;

(c) A discussion of the drawbacks and limitations of the proposed alternative ground water monitoring program;

(d) A comparison of this proposal and similar applications of alternative ground water monitoring programs;

(e) A demonstration that the proposed alternative ground water monitoring program will provide equal or superior protection of human health and the environment;

(f) A protocol for maintaining the viability of the ground water monitoring well network;

(g) A proposal for, at a minimum, annual sampling of all monitoring wells; and

(h) A proposed trigger which would require the resumption of routine detection monitoring of all wells in the monitoring network.

D. Corrective Action Plans. Any solid waste facility that has implemented a corrective action plan previously approved by the Department must complete the actions specified in that plan. For all other solid waste facilities, within 90 days of the date that verification, through statistical analyses on the relevant historical database, including the two assessment monitoring events, that a statistically significant change has occurred indicating contamination of ground water or surface water, the owner/operator of the facility must complete and submit to the Department for review and approval a plan which includes evaluation of potential corrective actions and a proposal to initiate the chosen corrective action(s). The corrective actions must be designed to minimize the discharge of pollutants from the facility. An evaluation of the plan must be updated and resubmitted annually until successful corrective action has been demonstrated. The plan must include:

(1) Immediate Corrective Actions Needed. An analysis of the time frame, potential effectiveness, performance, risks and costs of the corrective actions immediately available or necessary to prevent significant threats to the environment or public health, and a schedule for implementation of those actions;

(2) Analysis of Long-Term Corrective Actions. A detailed evaluation must be completed of potential long-term corrective action(s) necessary to achieve compliance with all ground water and surface water requirements and standards to protect human health and the environment, and to control sources of releases so as to reduce or eliminate, to the maximum extent practicable, releases of Appendix A of this chapter, Column 3 constituents that may pose a threat to human health or the environment. The evaluation must, at a minimum, address the following:
(a) The performance, reliability, ease of implementation and potential impacts of each potential remedy identified, based on:
(i) The magnitude of existing and residual risks in terms of the likelihood of further releases due to waste remaining following implementation of a remedy;

(ii) The type and degree of long-term operation and maintenance required;

(iii) Short-term and long-term health, safety, and environmental risks that each potential corrective action could pose to people and the environment; and

(iv) Long-term reliability of the engineering and institutional control;

(b) The time required to begin and complete each potential remedy and when full protection would be achieved;

(c) The projected costs associated with the implementation of each potential remedy; and

(d) Any federal, state or local licenses or permits required to be obtained prior to the implementation of each potential remedy.

NOTE: The potential long-term corrective actions for a solid waste facility are site-specific and will vary significantly depending on the design and age of the solid waste facility, the completeness of the facility's historical records, the nature and extent of contaminants found in the ground or surface water, the complexity of the site hydrogeology, and the facility's proximity to sensitive receptors or other natural resources.

(3) Selection of Corrective Actions. The facility owner and/or operator, as part of the corrective action plan, shall submit to the Department a written proposal for corrective action(s) to be taken at the facility. This proposal must detail:
(a) A correction action program, and the basis for the selection of that program, including a basis for measuring and documenting the effectiveness of the proposed program. This report must include:
(i) The extent to which different corrective actions would reduce further releases; and

(ii) The ease or difficulty of implementing proposed remedies. This analysis must include the following factors: constructing the technology, operational reliability and availability of necessary equipment and specialists, and the available capacity and location of needed treatment, storage, and disposal services; and

(b) A schedule for implementation of the proposed corrective action program based upon the potential risks to human health and the environment, ground water use and contamination considerations, extent and nature of the contamination, and availability of treatment and/or disposal capacity for the wastes to be removed.

(4) Implementation of Corrective Action. The facility owner and/or operator shall initiate corrective action immediately upon the Department's approval of their corrective action plan and approval of the individual actions to be taken. The owner/operator shall propose, and, upon Department approval, take any interim measures necessary to ensure protection of human health and the environment based upon the time required to develop and implement long-term corrective actions, the threat to water resources, and weather conditions that may cause pollutants to be released or migrate from the facility site.

(5) Completion of Corrective Action. The facility owner/operator shall continue corrective action and assessment monitoring until the Department finds that successful corrective action has occurred.

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