Re: UniFirst Corporation, Docket No. WQ-97-07 (Appeal of DEC Permit #3-1435), Findings of Fact, Conclusions of Law, and Order (May 7, 1998) State of Vermont WATER RESOURCES BOARD FINDINGS OF FACT, CONCLUSIONS OF LAW, AND ORDER RE: UniFirst Corporation Docket No. WQ-97-07 P.O. Box 205 (Appeal of DEC Permit #3-1435) Brush Hill Road Williamstown, Vermont 05679 This decision pertains to an appeal from the Department of Environmental Conservation's ("DEC") issuance of DEC Permit #3-1435 to UniFirst Corporation ("UniFirst") pursuant to 10 V.S.A.  1259 and  1263 ("Permit"). The Permit, issued on September 26, 1997, authorizes the discharge of treated groundwater from a proposed new groundwater treatment facility in Williamstown, Vermont ("Project") to an unnamed tributary of Rouleau Brook. I. BACKGROUND DEC issued the Permit pursuant to 10 V.S.A.  1259 and  1263, and Section 402 of the federal Clean Water Act (33 U.S.C.  1342). The Permit authorizes UniFirst to discharge treated tetrachloroethylene contaminated groundwater from outfall S/N 001 at its facility located at Brush Hill Road in Williamstown into an unnamed tributary of Rouleau Brook, a waterbody classified by the Water Resources Board ("Board") as a Class B water. The tributary into which the discharge has been authorized is characterized by DEC as an "ephemeral" (otherwise known as intermittent) stream. The discharge limitations in the Permit are derived from the Vermont Water Quality Standards ("VWQS") applicable to this proceeding which are those effective April 21, 1997. The VWQS provide both a "consumption of water and organisms" standard for tetrachloroethylene of 0.8 g/l, as well as an "organisms only" standard of 8.85 g/l. It is the latter standard which is applicable to this proceeding. The Permit also limits UniFirst's discharge in accordance with several special conditions as well as the limitations and monitoring requirements set forth on the following page: EFFLUENT DISCHARGE MONITORING CHARACTERISTICS LIMITATIONS REQUIREMENTS Annual Maximum Sample Sample Average Day Frequency Type Flow 0.033 MGD 0.288 MGD Continuous Daily Total Tetrachloroethylene 8 g/l 1 x per week Grab pH 6.5 to 8.5 S.U. 1 x per week Grab The Permit provides a more detailed description of both the allowed discharge as well as the above-noted limitations, conditions and monitoring requirements attendant to the discharge. In addition, the Permit explains the procedures for monitoring and reporting. On October 24, 1997, Joyce Day and Alvin W. Day, Jr. ("Appellants"), appealed DEC's issuance of the Permit pursuant to 10 V.S.A. 1269. A prehearing conference was held on November 24, 1997 at the Board's office in Montpelier. On December 12, 1997, the Board issued a Prehearing Conference Report and Order outlining the issues and the schedule for this proceeding. No party objected to the Prehearing Order. Pursuant to Water Resources Board Rule of Procedure ("WBR") 24(B), such orders shall control the subsequent course of the proceeding, unless modified at the hearing to prevent manifest injustice. No modifications to the Prehearing Order have been made. The issues in this appeal were stated with specificity at Section II of the Prehearing Order. Those issues are repeated herein and will be specifically addressed in the Board's Conclusions of Law. On February 4, 1998, this proceeding was joined with a pending proceeding before the Environmental Board for purposes of a coordinated presentation of evidence relative to both the above- captioned appeal and the appeal of Land Use Permit Application #5R0072-2-EB. All parties agreed that with respect to both the present appeal and the Act 250 appeal, there was a significant overlap of water quality issues and the Boards recognized the administrative efficiency of proceeding in a coordinated manner. On March 10, 1998, the Boards conducted a site visit and convened the hearing at the Barre Town Offices in Websterville, Vermont. II. FINDINGS OF FACT The Present Condition of Groundwater at the Site 1. UniFirst formerly operated a dry cleaning and washing facility located in Williamstown, Vermont near the site of the proposed discharge under the terms of Land Use Permit #5R0153 issued on October 6, 1972. 2. In 1983 it became apparent that several private residences in the vicinity of UniFirst's facility had contamination present in their bedrock drinking water supply wells. Residential drinking water supplies that were affected were replaced with hookups to the municipal water supply system. Investigations by the State of Vermont as to the source of the contamination continued through 1984. 3. UniFirst's facility was determined to be a cause of the contamination and ceased dry cleaning operations in 1984. 4. The Groundwater Rule and Protection Strategy ("Groundwater Rules") applicable to this proceeding are those effective September 29, 1988. The groundwater enforcement standard for tetrachloroethylene that is set forth in the applicable Groundwater Rules is 0.7 g/l. 5. The groundwater underlying both UniFirst's facility and the receiving site is classified by the ANR as Class III groundwater. 6. The level of tetrachloroethylene contamination in the affected groundwater is at or near 80 g/l, well in excess of the applicable standard, and thus, the groundwater is substandard. 7. According to ANR testimony, the determination that an area of groundwater is substandard is not determined by a formal process. Areas are substandard because they do not meet the uses defined for that particular class of groundwater. 8. The Groundwater Rules were recently amended and thus the September 29, 1988 Groundwater Rules are not the current rules. If the Board were to consider the current groundwater enforcement standard of 5 g/l, the current level of groundwater contamination would still be substandard. 9. Between 1984 and 1986, UniFirst constructed two groundwater collection and pumping systems and a groundwater treatment system. One of the collection systems is located primarily on UniFirst property and the second is uphill and to the north of (behind) the Elementary School, parallel to Construction Hill Road. 10. UniFirst installed a groundwater treatment facility within the boiler room of the UniFirst plant building and began continuous operation on January 1, 1986. The facility was designed to discharge treated groundwater to the municipal sewer collection system. 11. In January, 1986, UniFirst entered into a Consent Decree (Orange Superior Court, Docket No. S53-840eC) with the State of Vermont and the Town of Williamstown to address contamination arising from operations of its Williamstown facility. That Decree set out the process by which remedial action would continue for the next ten years. 12. In 1990, UniFirst constructed a third groundwater collection drain, known as the "Duff Drain," which is located at the foot of the hill between 2 residences and the UniFirst property to the East. The flow from this third drain is also directed into the pump station which, under the existing system, pumps to the groundwater treatment system. 13. In 1996, the original Elementary School drain became fouled by root growth. This drain line was rebuilt in its entirety and enlarged from a 4- inch diameter pipe to an 8-inch diameter pipe. The improvements to the efficiency of this drain system further increased the amount of water that is being collected, treated and discharged to the Williamstown municipal sewage treatment plant. 14. The Court entered a second Consent Decree effective March 24, 1997 with a thirty year duration. Among other things, the 1997 Consent Decree directed UniFirst to seek a surface water discharge and any necessary permits for the discharge of the treated groundwater. The Project is an attempt to comply with that directive. 15. The Town of Williamstown has issued a prohibition of continuing discharge from the UniFirst treatment system to the municipal treatment plant effective December 31, 1998. The Project 16. The Project is comprised of four main components. These consist of: a. Drains - a groundwater collection system comprised of three large drains wherein contaminated groundwater underlying the UniFirst and Williamstown Elementary School, as well as the area between two nearby residences and the eastern portion of the UniFirst property, will be collected; b. Subsurface Pipes - extension and/or improvement of existing drainage pipes from the collection drains to the carbon filtration system at a site substantially down gradient from the drains to allow the use of gravity to force inflow through the filters; c. A Filtration System - construction and ongoing maintenance of a filtration system building which will contain two fully redundant treatment trains that will receive inflow by gravity feed from the drainage pipes. Each of the treatment trains will house two carbon adsorption filters within cylindrical canisters. The filters will measure approximately nine feet in height and six feet in diameter; and d. An Outfall Pipe - an outfall pipe which will discharge the treated wastewater to a location identified as S/N 001 and which is the upstream most point of the Affected Reach discussed below. 17. The design capacity of the proposed filtration system will be 200 gallons per minute. 18. The proposed treatment system will be a significant improvement over the existing system in several respects. Among the benefits of the proposed system are the following: a. the system relies on gravity to direct inflow to the filtration system without the need to employ pump stations to create "head" or elevation gain; b. the drains and pipes are significantly improved to ensure more comprehensive collection of contaminated groundwater; c. the filtration system employs larger, more efficient silt collecting "prefilters;" d. the filtration system is fully redundant in that it has two independent treatment trains either of which can be brought online at any time offering the same level of treatment; e. the filtration system is to a large extent a self-balancing system; and f. because the filtration system has a tendency to self-balance, during periods of high inflow to the system the collection drains effectively back up with groundwater as the capacity of the pipes, filters, and discharge per day allowance of 288,000 gallons is approached. Even when the collected groundwater backs up several feet or more, there would be no added health risk. 19. Each treatment train in the system houses two filters in sequence. There is a primary filter and an identical backup filter. Continuous monitoring enables UniFirst to detect the breakthrough of contaminants through the primary filter, and after such detection the inflow is diverted to the other treatment train. Even in the case where breakthrough of contaminants through the primary filter is either not immediately detected, or is detected but not immediately acknowledged by UniFirst's engineers or operators, the backup filter ensures that the contaminant will not penetrate the system. 20. Provided that both backup filters are routinely checked for their ability to remove contaminants, the proposed operation of the filtration system is sufficiently reliable to ensure that no untreated effluent will be discharged. 21. Replacement of spent filters must occur expeditiously after the first detectable contaminants have penetrated the spent filter. At most times, all four filters will be functional and housed within the system. 22. The filters consist of granulated activated carbon. The treatment of tetrachloroethylene (PCE) contaminated groundwater by granulated activated carbon is the best available technology (BAT). 23. Filtration of the contaminated groundwater through UniFirst's proposed treatment system will achieve levels of tetrachloroethylene in the effluent that are in the non-detectable range. Characteristics of the Receiving Site 24. The Receiving Site is the specific location of the discharge from the Project. The Receiving Site is an ephemeral stream - also known as an intermittent stream. 25. The stream is an unnamed tributary of Rouleau Brook in Williamstown, Vermont. Rouleau Brook and its tributaries are classified by the Board as Class B waters. 26. From its confluence with Rouleau Brook upstream to the point of the discharge ("the Affected Reach"), the tributary has variable stream bed characteristics and, depending primarily on the time of year, it is either a losing stream (i.e. it loses surface water to groundwater) or a gaining stream (i.e. groundwater contributes to the instream flow). 27. The Affected Reach is approximately 110 feet in length. 28. Children occasionally play in or around both Rouleau Brook and the Affected Reach. 29. The stream is typical of many streams found in Vermont. Its flow is comprised of surface water runoff from an approximately 61 acre watershed. 30. During the drier months of the year, there is a reduction in surface water runoff from the surrounding watershed. In addition, much of the water which does enter the stream during these dry periods is "lost" before the surface water flow from the tributary reaches Rouleau Brook. Such loss to groundwater occurs through the highly porous gravelly deposits which are present in certain segments of the Affected Reach. 31. In such losing periods the stream bed sometimes appears to be completely dry, as is typical of an ephemeral or intermittent stream. 32. Despite periods when there is little or no streamflow in the Affected Reach, the tributary's shape is easily identifiable at all times of the year with clearly- defined banks and other obvious indicators of a streambed. 33. When the Project is operating it will consistently contribute a flow of treated groundwater to the Affected Reach on an annualized average of 33,000 gallons per day - approximately 23 gallons per minute - with the maximum allowable daily volume not to exceed 288,000 gallons. 34. During the driest months of the year, typically from mid-July through September, when there is a reduction of surface water runoff and limited, if any, seepage of groundwater into the Affected Reach, the effluent from the discharge will constitute a significant percentage of the total streamflow in the Affected Reach. 35. As noted in Finding 30, there may be a loss of some portion of the treated groundwater through the highly porous streambed found in several locations of the Affected Reach. Even without dilution, the treated groundwater would filter back into the groundwater at a level that complies with the water quality standards and which is significantly less contaminated than the existing concentrations of tetrachloroethylene in the receiving substandard groundwater. 36. Effluent treated to 8 g/l of tetrachloroethylene would not pose any additional risk to human health or to aquatic biota beyond that which presently occurs due to the effects of previous groundwater contamination. 37. When effluent is discharged pursuant to UniFirst's proposal, it will contain levels of tetrachloroethylene in the non-detectable range, and will consistently be well below the applicable VWQS criterion, and also below the groundwater standard for Class III groundwaters (0.7 g/l). Such discharge would pose no risk. The Discharge 38. The effluent from the treatment facility will exit the outfall pipe at an average of 33,000 gallons per day. The maximum daily limitation is 288,000 gallons per day. 39. The effluent will flow from the outfall, through the Affected Reach, downstream approximately 110 feet into Rouleau Brook. From there, the waters will flow downstream to the confluence with Stevens Branch and then to the Winooski River. 40. No other contaminants of concern have been addressed in this proceeding, nor is the Board aware of any other contaminants of concern pertaining to the Project. III. CONCLUSIONS OF LAW A. Recitation of Issues as Stated in the Prehearing Order II. ISSUES A. Defining the Site of the Discharge 1. Whether the site at which UniFirst will release waste (hereinafter called "Receiving Site"), characterized in the permit as an ephemeral stream which is a tributary of Rouleau Brook , constitutes "waters" as that term is defined in 10 V.S.A. 1251(13) and 1-01(B)(38) of the Vermont Water Quality Standards ("VWQS"). 2. Whether, for purposes of 10 V.S.A. 1263(a), the Receiving Site can be characterized as "waters of the state." 3. Whether it is relevant for purposes of 10 V.S.A. 1263 to determine if the Receiving Site is a "watercourse" as that term is defined in 10 V.S.A. 1002(10), and if so, whether the Receiving Site constitutes a "watercourse." 4. Independent of the issue whether or not the Receiving Site constitutes waters of the state or a watercourse, whether the Receiving Site constitutes "waters of the United States" as that term is defined in 40 C.F.R. 122.2 (1995) and incorporated by reference in 1-01(A)(2) of the VWQS. B. Jurisdiction 1. If the Receiving Site does not constitute waters of the state, whether it is appropriate to issue a discharge permit pursuant to 10 V.S.A. 1263, which by its own terms requires a permit to be secured only by those persons who "intend[] to discharge waste into the waters of the state..." 2. If the Receiving Site does not constitute waters of the state under 10 V.S.A. Chapter 47, but it does constitute waters of the United States for purposes of the CWA and the VWQS, whether a discharge permit may nonetheless issue under the agency's delegated NPDES permitting authority because the contemplated discharge is to a water of the United States. C. Consistency between Waters of the State and Waters of the United States 1. Although not raised in the Notice of Appeal, the following issue is one which may be raised in the context of interpreting the multitude of statutes and regulations (both state and federal) which direct the administration of the NPDES program, to wit: whether, for purposes of ensuring consistency among the state and federal statutes and regulations governing the direct or indirect discharge of wastes, generally, and the NPDES program set forth at 33 U.S.C. 1342 (CWA 402) specifically, the Board should determine the state definitions of "waters" of the state to be coextensive with the federal definition of "waters of the United States" as referenced in 1-01(A)(2) of the VWQS. Parties are encouraged to submit testimony and file briefs on this issue. D. Compliance with Vermont Water Quality Standards 1. Whether the discharge as proposed, violates 10 V.S.A. 1259(e), especially subsection 1259(e)(4) which prohibits the secretary of the ANR from issuing a permit for on-site disposal of sewage into Class B waters, unless the applicant demonstrates by clear and convincing evidence, and the secretary finds, that the discharge will not cause a violation of the VWQS. 2. In particular, whether the discharge violates VWQS 1-03(B)(2), 1-04, 2-02 and 2-03. 3. Whether a discharge permit under 10 V.S.A. 1263 may be issued to authorize the discharge of waste where the Receiving Site is often dry or has little or no waterflow and no mixing zone in fact. E. Determining Other Applicable Regulations 1. If any portion of the Receiving Site does not constitute waters of the United States, whether in addition to meeting the applicable standards for discharges to waters, the appropriate federal regulations pertaining to the land application of pollutants (i.e. waste) set forth at 40 C.F.R. 122.50 have been complied with. 2. If any portion of the Receiving Site does not constitute waters of the United States, whether in addition to meeting the applicable standards for discharges to waters, the appropriate state regulations for the land application of waste, including those set forth 10 V.S.A. Chapters 47 and 159, as well as Chapter 14 of the ANR's Environmental Protection Rules have been complied with. 3. Assuming that the Receiving Site constitutes either "waters" as defined in 10 V.S.A. Chapter 47, a "water of the United States," or both, and where an assessment of both stream hydrology and the groundwater characteristics (including soil permeability) demonstrate that the discharge will impact groundwater resources, whether a permit authorizing a discharge to those surface waters also requires the applicant to demonstrate, and the Secretary of the ANR to conclude, that the discharge conforms with those provisions of 10 V.S.A.  1390-1394 pertaining to groundwater protection. 4. If the Board finds that the policy of 10 V.S.A. 1390 is applicable to the proposed discharge, whether the proposed discharge violates the groundwater resources policy as set forth in 10 V.S.A. 1390 and more particularly, whether the discharge violates the Class III groundwater standards set forth at  12-503 and 12-702 of the Groundwater Rule and Protection Strategy effective September 28, 1988. F. Prohibitions on the Discharge of Hazardous Materials 1. Whether the proposed discharge contains a "hazardous material" for purposes of 10 V.S.A. 1281. 2. If the pollutants constitute hazardous materials, whether the discharge violates any rule of the ANR enacted pursuant to 10 V.S.A. 1281 prohibiting or otherwise regulating the discharge of hazardous materials either directly or indirectly into waters of the state. B. Defining the Site of the Discharge Section II.A of the Prehearing Order sets forth four issues which address the question of whether the Receiving Site is an appropriate location for the discharge of wastes - essentially asking the question of whether the tributary in question constitutes a surface water into which a discharge is allowable. The Receiving Site constitutes waters of the United States as that term is defined at 40 C.F.R. 122.2 ("federal definition") and incorporated into the VWQS at Section 1-01 (A)(2). Specifically included in the federal definition is a reference to intermittent streams. Subparagraph C of Chapter 122.2 of 40 C.F.R. reads in part: "all other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, "wetlands," slews, prairie potholes, wet meadows, etc.." Emphasis added. The tributary to which the effluent will be discharged is an ephemeral or intermittent stream and it is a water of the United States occurring in Vermont. The Board finds no basis upon which to interpret the statutory definition of waters less broadly than the federal definition. "Waters" are defined at 10 V.S.A.  1251(13) and  1-01 (B)(38) of the VWQS. The definition of waters"includes all rivers, streams, creeks, brooks . . . springs and all bodies of surface waters, artificial or natural, which are contained within, flow through, or border upon the state." Emphasis added. With respect to Issue II.C.1, the Board concludes that in light of the foregoing, the term "waters" should be read to be coextensive with the federal definition. Having determined that the Receiving Site is a water into which a discharge may be permitted, Issues II.B.1 and 2 and II.E.1 and 2 as stated in the Prehearing Order are mooted. C. Compliance with the VWQS Having determined that the Receiving Site constitutes waters, the central issue before the Board is whether the discharge, as proposed, complies with the applicable provisions of 10 V.S.A.  1263 and with  1-03 (B)(2), 1-04, 2-02 and 2-03 of the VWQS. 10 V.S.A.  1263(c) states that "[i]f the secretary determines that the proposed discharge will not reduce the quality of the receiving waters below the classification established for them and will not violate any provisions of state and federal laws or regulations [s]he shall issue a permit containing terms and conditions as may be necessary to carry out the purposes of this chapter and of applicable federal law." The principal regulations to which the statute makes reference are the VWQS. The Affected Reach is a portion of a tributary to Rouleau Brook. Both Rouleau Brook and its tributaries have been classified by the Board as Class B waters. The underlying groundwater is Class III and has been demonstrated to be "substandard" as that term is used in the applicable Groundwater Rules. The VWQS set forth a standard for the issuance of discharge permits within the context of the Anti-degradation Policy under the category "Protection of Existing Uses." Specifically,  1-03(B)(2) states that "[t]he Secretary may only issue a discharge permit pursuant to 10 V.S.A.  1263 . . . when the Secretary finds that: (a) [t]he existing water use involves use of the water body by aquatic biota, fish or wildlife, and the proposed activity would not have a significant impact on those values." The discharge does not violate  1-03(B)(2) of the VWQS. The filtered groundwater will not have a significant impact on the use of the water body by aquatic biota, fish or wildlife. Based on the evidence submitted in this proceeding, the Board concludes that the discharge of treated groundwater containing nondetectable levels of tetrachloroethylene will have only a de minimis impact on the Affected Reach, on Rouleau Brook and on other downstream waters. The existing uses of the Affected Reach and the downstream sections of Rouleau Brook potentially affected by this discharge include only incidental recreational contact from time to time. The Board concludes that the levels of contamination in the effluent will consistently be well below the applicable limitation for tetrachloroethylene and the discharge will not result in significant degradation of the existing use of primary contact recreation. Fishing, water supply or commercial enterprises that depend directly on the preservation of an existing level of water quality are not existing uses of either the Affected Reach or the portion of Rouleau Brook potentially affected by the discharge. Section 1-04 of the VWQS sets forth a Discharge Policy concerning both discharge criteria and assimilative capacity. With respect to 1-04(A), wherein the VWQS set forth discharge criteria, only Paragraphs 1, 2, 3, 6, and 7 are in issue in this case. With regard to 1-04(A)(1), the Appellants have not directed the Board to any other applicable section of the VWQS not specifically addressed herein, and there has been no allegation that the proposed discharge is inconsistent with the Class B classification of the waters in issue. Section 1-04(A)(2) requires that "new discharges of waste may be allowed only when . . . [t]here is no alternative method of, or location for, waste disposal that would have a lesser impact on water quality including the quality of groundwater, or if there is such an alternative method or location, it would be clearly unreasonable to require its use." Emphasis added. The proposed discharge is to a surface water. All parties agree, however, that at certain times of the year, the discharge will effectively be apportioned between the surface water of the tributary and the groundwater underlying the Affected Reach. This phenomenon is not peculiar to the case at hand - but it is accentuated by the fact that the proposed discharge is to an intermittent waterbody. The Board concludes that a discharge directly to Rouleau Brook, or the Stevens Branch, or some other surface water that is not ephemeral or intermittent, or to a stream with a less porous streambed, might have a lesser impact on the quality of groundwater. To require such an alternative in this case, however, would be clearly unreasonable. UniFirst and the Williamstown Elementary School have coordinated to create significant improvements to both the collection facilities and the filtration system of the Project. UniFirst has simplified the Project such that it is not only extremely reliable, but it will ensure that the contaminants that penetrate the filtration system are consistently at nondetectable levels. Moreover, the site of the proposed discharge allows flow to be reintroduced within the watershed from which it was collected. The Project, as proposed, is constrained by certain engineering considerations - one of which is a requirement that the elevation difference between the collection drains and the treatment trains allow for sufficient head to force water through the system. This allows the system to operate without the use of electrical pumps thereby adding to the reliability of the system. This design also creates a tendency for the filtration system to self-balance in periods of increased groundwater flow. Alternatives to the Project were considered and dismissed, partially in light of these engineering considerations and also in view of the combined land ownership of UniFirst and the School. The Board concludes that any de minimis improvements to the groundwater quality extant at the site that may be achieved by requiring the effluent to be discharged elsewhere would effect only marginal improvements to groundwater that is currently well in exceedence of the applicable groundwater enforcement standard for tetrachloroethylene. In the context of this case, where the potential discharge to groundwater is associated with a project to remediate existing groundwater quality, the Board is also guided by the language of 12-503 (6) of the Groundwater Rule which addresses In Situ Remediation in Class III Areas. 12-503(6) states: When approved by the Secretary, the in situ remediation of contaminated ground water involving discharges of partially treated groundwater may be construed as posing acceptable risk. Here, as discussed above, the discharge of treated groundwater back into substandard groundwater will only occur during limited periods of the year over a portion of the Affected Reach. Although it might be characterized as "partially treated" groundwater, the groundwater will contain non-detectable levels of tetrachloroethylene. The Board concludes that such discharge, limited in both extent and duration, to an area of Class III groundwater that is considerably in excess of the applicable enforcement standard would pose an acceptable risk - and indeed, would not pose any additional risk, beyond that which is currently present. Rather, when assessed in light of the current condition of the groundwater, rather than solely with reference to the applicable enforcement standard, the proposed treatment facility will achieve a significant reduction in the health risk posed. Section 1-04(A)(3) requires the design and operation of any waste treatment or disposal facility to be adequate and sufficiently reliable to protect all beneficial values and uses and to insure compliance with these rules and with all applicable state and federal treatment requirements and effluent limitations. The reliability of the proposed system has been discussed in detail, above, and the Board concludes that it is an extremely reliable system. The adequacy of the system is measured primarily by its ability to achieve the applicable effluent criteria. In this case, the criterion established for the surface water discharge of tetrachloroethylene (also called PCE) is set forth in the VWQS as 8.85 g/l. The proposed treatment system is adequate to meet this criterion even without accounting for dilution which is discussed in more detail below. Sections 1-04(A)(6) and (7) concern the allocation or availability of assimilative capacity in the receiving waters to accommodate the proposed discharge. As discussed below, because the Affected Reach is intermittent and the availability of receiving waters with which to assimilate the discharge is extremely limited and at times, non-existent, UniFirst has proposed its design without reliance upon receiving waters with which to assimilate the waste. With respect to wasteload allocation, and  1-04(A)(7), no other discharges to the Affected Reach or to Rouleau Brook have been identified. In any event, UniFirst's proposed discharge does not rely on any assimilative capacity; therefore, the proposed discharge would not interfere with any allocation of available assimilative capacity. The permit limitation of 8 g/l, established without reliance upon assimilative capacity, satisfies both  1-04(A)(6 ) and (7). Similarly, with respect to  1-04(B) concerning assimilative capacity,  2-02 regarding flow conditions of the receiving stream, and  2-03 pertaining to mixing zones, the establishment of the appropriate effluent limitations will account for the flow conditions at the location of the proposed discharge. With respect to the flow in the receiving water, since the flow in the channel of the Affected Reach is ephemeral near the location of the proposed discharge, no instream dilution will be provided for in this discharge. Consequently, the effluent limitation for tetrachloroethylene will be established at 8 g/l, or approximately 90% of the allowable concentration in the instream water quality criteria. Because the effluent limitation is set at a value lower than the instream water quality criteria, compliance with the water quality criteria can be attained even with the absence of additional flow in the stream. Therefore, the issues of assimilative capacity and mixing zones are moot. D. Other Applicable Law and Regulations Appellants have questioned whether a permit authorizing the discharge to the Affected Reach also requires the Board to determine that the discharge conforms with those provisions of 10 V.S.A.  1390-1394 pertaining to groundwater protection, and to determine whether the discharge conforms with the Class III groundwater standards set forth at  12-503 and 12-702 of the Groundwater Rule and Protection Strategy effective September 28, 1988. In support of this argument, Appellants note that some groundwater infiltration will occur during periods in which the Affected Reach loses flow to groundwater. Appellants also cite the fact that while the applicable VWQS criterion for tetrachloroethylene is 8.85 g/l - whereas the groundwater enforcement standard is 0.7 g/l. If the Project were proposed to discharge at the 8 g/l allowed by the permit to an area of groundwater not demonstrated to be substandard, this might violate the applicable enforcement standard for some indefinite period of the year. Such is not the case, however. Rather, UniFirst will consistently achieve nondetectable levels of tetrachloroethylene in the effluent. Further, as discussed above, the applicable Groundwater Rules specifically address situations such as this one involving in situ remediation. In order to demonstrate compliance in this context, the Secretary (here, the Board) may allow a treated or partially treated discharge of wastewater which does not meet the otherwise applicable groundwater enforcement standard provided that the discharge poses an acceptable risk. As discussed above, the risk associated with this discharge is acceptable. The numeric criterion which applies to the proposed discharge is that which pertains to tetrachloroethylene, "organisms only," in Appendix C of the VWQS - 8.85 g/l. The proposed discharge will meet this criterion throughout the Affected Reach. While the Appellants have searched for a technical violation of the Groundwater Rules, the Board concludes that no such violation will result from a permit limitation of 8 g/l. The Board further concludes that the discharge of tetrachloroethylene at non-detectable levels will effect a significant improvement of the quality of groundwater in the area of the discharge. Finally, Issues II.F.1 and 2 concern whether the proposed discharge involves a hazardous material for purposes of 1281 and if so, whether the discharge violates any ANR rule enacted pursuant to 10 V.S.A. 1281, prohibiting or otherwise regulating the discharge of hazardous materials either directly or indirectly into waters of the state. The definition of "hazardous materials" for the purposes of 10 V.S.A. 1281 is defined at 10 V.S.A. 1251(5) as follows: Hazardous material' means any material determined by the Secretary to have an unusually harmful effect on water quality if discharged to the Waters of the State. Tetrachloroethylene is a known carcinogen. Were it disposed of in a manner inconsistent with the VWQS, it has a propensity to have unusually harmful effects upon water quality. Disposal in a manner consistent with the limits established by the Permit, however, are set at approximately 90% of the VWQS limitation for tetrachloroethylene. In addition, the proposed Project will achieve non-detectable levels of tetrachloroethylene. Accordingly, the discharge does not contain, or constitute a "hazardous material." IV. ORDER 1. Permit #3-1435 is hereby reinstated with the substitution of the following language for the existing language of Part I.A.2. relating to special conditions: 2. Special Conditions a. Upon detection of breakthrough of tetrachloroethylene from the first carbon treatment canister in the treatment train in use, the permittee shall immediately cease operation of that treatment train and place the reserve treatment train in operation. The carbon canister which has experienced breakthrough shall be replaced as soon as possible, but in no event later than 45 days after detection of breakthrough, and this treatment train shall then be held in reserve until needed. The dates of carbon canister replacement shall be noted on the monthly discharge monitoring report. b. Also on the monthly discharge monitoring report, the permittee shall log the number of hours that the backup canister was used after breakthrough and before the alternate treatment train was put into operation. A running total of hours in which the backup canister has been employed shall be kept by the Agency. Based on information derived from estimating the useful life of canisters which have experienced breakthrough, the Agency shall require that the backup canister be replaced as soon as it poses a risk of breakthrough. c. The discharge shall not contain a visible sheen, foam, or floating solids or cause a visible discoloration of the receiving water. d. The discharge shall not cause a violation of Water Quality Standards in the receiving water. 2. Discharge Permit #3-1435 shall be modified to incorporate the language cited above and shall set forth a date of issuance of May 7, 1998 with appropriate modification of the date by which the permit shall be renewed set forth in Part I.B. 3. Jurisdiction is hereby returned to the Agency of Natural Resources. Dated at Montpelier on this 7th day of May, 1998. WATER RESOURCES BOARD /s/ William Boyd Davies Concurring: Ruth Einstein Gerry Gossens Gail Osherenko Jane Potvin