Full opinion text
FINDINGS OF FACT, CONCLUSIONS OF LAW, AND ORDER JOSEPH F. ANDERSON, Jr., District Judge. I. INTRODUCTION Laidlaw Environmental Services (TOC), Inc. (“Laidlaw”), owns and operates a hazardous waste incinerator in Roebuck, South Carolina. As part of that facility, Laidlaw maintains a wastewater treatment plant for water used in the incineration process. Laidlaw discharges the treated wastewater into the North Tyger River pursuant to a National Pollutant Discharge Elimination System (“NPDES”) permit issued by the South Carolina Department of Health and Environmental Control (“DHEC”). Plaintiffs Friends of the Earth (“FOE”) and Citizens Local Environmental Action Network, Inc. (“CLEAN”) brought this action on June 12,1992 against Laidlaw pursuant to the citizen suit provision in section 505 of the Federal Water Pollution Control Act Amendments of 1972, commonly known as the Clean Water Act, 33 U.S.C. § 1365. The Plaintiffs seek to enforce Laidlaw’s NPDES permit and request declaratory and injunc-tive relief, the imposition of civil penalties, and the award of costs, including attorneys’ fees and expert witness fees. On July 1, 1992, the Defendant moved to dismiss the Plaintiffs’ action, arguing that their citizen suit is barred by section 505(b)(1)(B) of the Act, 33 U.S.C. § 1365(b)(1)(B), because DHEC had previously brought, and settled, a lawsuit against Laidlaw for the same alleged violations of its permit. The Plaintiffs responded by arguing that DHEC’s lawsuit did not preclude the citizen suit because, inter alia, DHEC did not “diligently prosecute” its action against Laidlaw. The court heard oral argument on the Defendant’s motion to dismiss at the University of South Carolina School of Law on November 19, 1992. In its order of December 14, 1992, the court denied the Defendant’s motion to dismiss, but ruled that the determination of whether DHEC’s action constituted diligent prosecution sufficient to bar the Plaintiffs’ citizen suit involved disputed factual matters. Accordingly, the court decided to conduct a separate evidentiary hearing on the preliminary issue of whether the Plaintiffs’ citizen suit could proceed. The court received a total of seven days of testimony on this matter in October, November, and December of 1993. Thereafter, the court requested the United States Department of Justice to file a brief as amicus curiae setting forth the position of the United States Environmental Protection Agency (“EPA”) on the issues raised at the hearing. The Department of Justice submitted, on behalf of the United States, two amicus briefs that generally supported the Plaintiffs’ position. After receiving all of the testimony, argument, and memoranda from the parties, as well as the submissions from the Department of Justice as amicus curiae, and after studying the applicable law, the court makes the following findings of fact and conclusions of law pursuant to Fed.R.Civ.P. 52. To the extent that any of the following findings of fact constitute conclusions of law, they are adopted as such, and to the extent that any conclusions of law constitute findings of fact, they are so adopted. II. FINDINGS OF FACT A Parties The Plaintiffs, FOE, CLEAN, and the Sierra Club, are non-profit corporations which bring this action on behalf of their members to protect their environmental, health, economic, recreational, and aesthetic interests in the quality of the North Tyger River and waters downstream. The Defendant, Laidlaw, is a South Carolina corporation which owns and operates a hazardous waste incinerator (hereinafter “the facility”) in Roebuck, Spartanburg County, South Carolina. As part of the facility, the Defendant operates a wastewater treatment plant to treat water used in the incineration process before discharging the wastewater into the North Tyger River. B. Chronology of Laidlaw’s Operation of Roebuck Facility The Defendant purchased the facility from ABCO Industries, Inc. (“ABCO”) in January 1986. During most of 1986, after it purchased the facility from ABCO, Laidlaw did not have its own NPDES wastewater discharge permit; rather, Laidlaw operated the facility temporarily under the permit that had been issued to ABCO. On December 15, 1986, pursuant to section 402 of the Clean Water Act, 33 U.S.C. § 1342, DHEC issued to Laidlaw NPDES permit number SC0040517, effective January 1, 1987, for the facility’s wastewater treatment plant. The permit authorized the Defendant to discharge limited quantities of pollutants into the North Tyger River in accordance with the conditions set forth in the permit. The permit limited the Defendant’s discharge of antimony, arsenic, cadmium, chromium, copper, lead, mercury, nickel, total organic carbon, and zinc. The permit also limited the flow, temperature, and pH of the effluent from the Defendant’s facility. In addition, the permit imposed on the Defendant several monitoring and reporting obligations, such as the requirement to maintain discharge monitoring reports (“DMRs”) and laboratory reports. Several of the effluent limits in Laidlaw’s initial permit were more stringent than those under ABCO’s permit. The most significant reduction was in the mercury limit, which DHEC proposed to reduce from 20 parts per billion (“ppb”) under ABCO’s permit to 1.3 ppb. Because Laidlaw’s permit contained such a dramatic reduction in the mercury limit, DHEC imposed an interim mercury limit of 10 ppb from January 1, 1987 to December 31, 1987, which decreased to 1.3 ppb on January 1, 1988. In connection with the interim mercury limit, the permit directed Laidlaw to conduct feasibility studies to determine whether the 1.3 ppb limit could be achieved. In addition, DHEC allowed Laidlaw the option of requesting a higher, site-specific mercury limit upon completion of these feasibility studies. Faced with a drastic reduction in the mercury limit, Laidlaw contracted with Environmental Technology Engineering, Inc. (“ETE”), an environmental consulting firm, in December 1986 to conduct an engineering feasibility study to determine the best technological approach to achieving the strict 1.3 ppb mercury limit. ETE initially evaluated eight possible technologies and narrowed the focus to two technologies — activated carbon and ion exchange — for bench and pilot scale testing. ETE tested these technologies between June and December 1987 and recommended the installation of a second carbon adsorption unit to be run in series with Laid-law’s existing carbon unit. When the Defendant’s permit was issued in December 1986, the facility’s wastewater treatment plant consisted of a neutralization system, a carbon adsorption filter, and a cooling system. In early 1988 the Defendant installed the second carbon adsorption unit. Because of ETE’s recommendation that the second carbon unit should enable Laidlaw to meet the 1.3 ppb mercury limit, the Defendant chose not to exercise its option of requesting a higher mercury limit at that time. Despite ETE’s testing, the additional carbon unit did not allow the Defendant’s facility consistently to achieve the 1.3 ppb mercury limit. The Defendant’s continuing problem with mercury excursions came to a head in May 1988 after a fish kill on the North Tyger River downstream of Laidlaw’s facility. DHEC investigated the incident and determined that the fish kill was caused by a pH upset at the Defendant’s facility. Thereafter, DHEC initiated an administrative enforcement action, which culminated in a consent order with Laidlaw on September 7, 1988. The consent order required the Defendant to investigate treatment technologies that would enable it to comply with the pH limits in its permit. In addition, DHEC imposed on the Defendant a $20,000 penalty and required the Defendant to replace the killed fish. In response to the September 1988 consent order, Laidlaw contracted with RMT, Inc., another environmental consulting firm, to reevaluate the facility’s wastewater treatment system and to make recommendations for correcting the problems Laidlaw was continuing to have with mercury and other metals excursions. During the latter part of 1988, RMT investigated four conceptual approaches to treating the effluent from the Defendant’s facility. In December 1988, RMT submitted a preliminary engineering report to DHEC recommending the testing of three metals removal systems, trade named Unipure, Lancy, and Mem Tek, each of which employed a different technology for metals removal. During 1989, Laidlaw and RMT conducted bench and pilot scale tests on these three wastewater treatment systems. Also during 1989, Laidlaw applied for and received approval from DHEC to replace its two existing cooling towers with a single, more advanced cooling system. The new cooling system was necessary to eliminate occasional temperature excursions that the Defendant experienced during the summer months. On December 28, 1989, Laidlaw submitted to DHEC the results of RMT’s pilot testing. These results showed that, among the three systems tested, the Lancy system was the most likely to achieve the Defendant’s NPDES permit limits for all metals, including mercury. As a result, Laidlaw selected the Lancy system and requested approval from DHEC for its installation. DHEC approved the Defendant’s request and issued a construction permit on July 10, 1990. During the latter half of 1990 and the first two months of 1991 the Lancy system was constructed and installed at the Defendant’s facility. Between February and July 1991, the Defendant began full scale operation of the Lancy system. The Lancy system brought the Defendant into compliance with the non-mercury metals limits in the Defendant’s permit. However, at least by April 1991, it was clear that the Lancy system would not enable the Defendant to comply with its mercury limit. In responding to the continuing problems with mercury, the Defendant worked with DHEC and Lancy to make operational adjustments to the system in an effort to achieve compliance with the mercury limit. When it ultimately became apparent that mercury excursions were continuing to occur, the Defendant put pressure on the manufacturer of the Lancy system to correct the problem. Lancy responded by recommending numerous testing procedures, including the addition of varying amounts of iron sulfate, copper sulfate, and free sulfide. These tests were unsuccessful, however, in reducing the mercury content below the NPDES limit. Lancy thereafter determined that achieving the 1.3 ppb limit was problematic because it appeared that the level of metals being introduced to the wastewater treatment system was simply too low for the system to work effectively on mercury. Because meeting the strict mercury limit continued to be problematic, on June 26, 1991, the Defendant filed with DHEC a request for a higher, site-specific limit for mercury. During the latter part of 1991, and continuing into the early part of 1992, Laid-law both pursued its request for a higher mercury limit and continued to perform tests and otherwise investigate ways to achieve the 1.3 ppb limit. To support its request for a higher mercury limit, the Defendant commissioned a study of mercury levels in fish in the North Tyger River. DHEC found the Defendant’s study to be inconclusive, however, and informed the Defendant that the study did not meet EPA criteria. DHEC enforcement officials testified that they began to consider taking additional enforcement action in early 1992, after a series of abnormally high mercury violations at the Defendant’s facility in December 1991. However, DHEC did not commence its enforcement action until May 1992. On April 10, 1992, the Plaintiffs sent a letter to the Defendant, to the EPA, and to DHEC, informing them that the Plaintiffs intended to file a citizen suit against Laidlaw under section 505 of the Clean Water Act after sixty days, or on or after June 10,1992. DHEC initiated a formal enforcement action on May 21,1992 by issuing to the Defendant a Notice of Enforcement Conference. The fact sheet attached to the Notice of Enforcement Conference stated that since April 1991 the Defendant had committed 225 violations of the mercury limit in its permit and two violations of the permit limit for antimony. DHEC was unaware of any violations of the Defendant’s permit other than those set forth in the fact sheet. The violations set forth in the fact sheet were based on the monthly DMRs submitted by Laidlaw. DHEC was unaware of any violations of the monitoring or reporting requirements of the Defendant’s permit. On June 5, 1992, DHEC held an enforcement conference with the Defendant. Subsequent meetings and telephone conferences to negotiate a consent agreement occurred later in the day on June 5,1992, as well as on June 8, 1992. The parties reached a final consent agreement on June 8,1992. On June 9,1992, the Defendant filed a judicial complaint in the Court of Common Pleas in Spartanburg County, South Carolina, on behalf of DHEC. On June 10, 1992, a state circuit judge approved the settlement of the DHEC lawsuit. The Plaintiffs filed the instant lawsuit against Laidlaw on June 12, 1992. The Plaintiffs have compiled lists of the Defendant’s alleged permit violations from the Defendant’s DMRs and laboratory reports. The Plaintiffs allege that Laidlaw has had a long history of violations of its permit limits for metals and pH. According to the Plaintiffs, since the Defendant obtained its NPDES permit for the Roebuck facility it has committed at least 1,044 discharge violations, some of which allegedly continued until March 1993. The Plaintiffs’ lists of alleged violations show that the Defendant’s most frequent violations have been of its limit for mercury. The Defendant’s permit requires it to monitor for mercury every day that the incinerator is in operation. The Plaintiffs allege that the Defendant violated its mercury limit on almost a daily basis from early 1991 until June 18, 1992. The Plaintiffs also contend that the Defendant committed at least 31 discharge violations after the Consent Order with DHEC was entered. In addition, the Plaintiffs allege at least 676 violations of the permit’s monitoring requirements and 615 violations of the permit’s reporting requirements. After the Consent Order with DHEC was entered, Laidlaw continued to explore additional technologies that might help to remedy the mercury problems. The Defendant experimented with various operational changes to the system and performed various tests utilizing chemicals and technologies both recommended by Laidlaw’s consultants and developed internally by Laidlaw personnel. As the mercury problems continued to be investigated, the Defendant had to simply shut down the incinerator altogether for substantial periods of time in July, August, September, and November 1992, in an effort not to violate either its mercury parameter or the judicial consent order with DHEC. The solution to meeting the 1.3 ppb limit was ultimately achieved by Laidlaw personnel through experimentation utilizing activated carbon, microfiltration, and ion exchange. The Defendant discovered that adding activated carbon filters at the end of the Lancy system effectively reduced the mercury level below 1.3 ppb, so long as the Defendant limited the feed rate of mercury-containing waste into the incinerator. The only problem encountered with this configuration occurred when the carbon adsorption filters were backwashed, as this procedure tended to release extremely fine particulates into the wastewater stream. Since any mercury-containing particulate would likely violate the 1.3 ppb limit, Laidlaw added both a microfilter and an ion resin exchange unit after the carbon filters to remedy this problem. The addition of the new equipment, combined with the Lancy system and the other components of the wastewater treatment system, has enabled the Defendant consistently to achieve full compliance with all of the parameters contained in its NPDES permit. Following an extended period of demonstrated full compliance, DHEC agreed to allow the judicial consent order to expire. DHEC so notified the state court in a letter dated August 6, 1993 from DHEC attorney William Ready. C. DHEC’s Judicial Enforcement Action 1. Decision to file judicial action DHEC’s original intent in prosecuting the Defendant for NPDES violations was to bring an administrative enforcement action against the Defendant. In fact, DHEC’s usual approach in bringing a formal enforcement action is to issue a notice of enforcement conference and negotiate an administrative consent order. After receiving the Plaintiffs’ sixty-day notice letter, however, Ralph Mellom, the Defendant’s outside counsel, called Russell Sherer, Chief of DHEC’s Bureau of Water Pollution Control, and inquired whether DHEC would consider filing an action in court against the Defendant. Sherer informed Mellom that DHEC had no interest in filing a judicial action instead of proceeding with an administrative action. Sherer stated, however, that DHEC would agree to file an action in court if the Defendant would expend any additional resources necessary to file a judicial action. On June 5, 1992, following the DHEC enforcement conference, counsel for the Defendant telephoned DHEC and requested that the agency file a judicial action instead of proceeding with an administrative action. The Defendant’s reason for requesting that DHEC file a judicial action was to bar the Plaintiffs’ proposed citizen suit in federal court. DHEC does not normally file judicial actions to enforce NPDES permits. Indeed, Sherer testified that DHEC had filed judicial actions in only two cases prior to filing the judicial action against the Defendant and that, in each of the previous cases, the defendant had requested that a judicial action be filed. Earl Hunter, the Director of the Division of Water Quality Assessment and Enforcement in DHEC’s Bureau of Water Pollution Control, testified that if the Plaintiffs had not sent a sixty-day notice letter, DHEC probably would not have filed a judicial action. Since DHEC must go to court to enforce either an administrative order or a judicial consent decree, DHEC gains no advantage by filing a judicial action instead of proceeding with an administrative action. DHEC filed a judicial action against the Defendant solely because counsel for the Defendant requested that DHEC file a judicial action instead of an administrative action, 2. Procedural aspects of DHEC’s judicial action At the direction of Mellom, Phillip Connor, an associate with Mellom’s law firm, drafted the initial version of the DHEC Complaint and of the Consent Order. On June 9,1992, the sixtieth day after the Plaintiffs sent their sixty-day notice letter, Connor obtained the signatures from DHEC on the Complaint and Consent Order and signed the Consent Order for the Defendant. He then drove the Complaint and the Consent Order to the courthouse in Spartanburg, where he filed the Complaint and paid the filing fee for DHEC. He left the Consent Order in the judge’s chambers, and the judge signed it the next day. The Consent Order was entered at 9:34 a.m. on June 10, 1992. DHEC and the Defendant reached a settlement agreement pertaining to the DHEC lawsuit on Monday, June 8, 1992, just one business day after the initial enforcement conference. The time period from the enforcement conference to the final settlement agreement was, by DHEC’s standards, “exceedingly fast.” The usual time period from the date of the enforcement conference to the date of a consent order is thirty to forty-five days. Robert Knauss, the DHEC enforcement officer with responsibility for the Defendant’s facility, testified that none of the cases in which he has been involved has moved as quickly to final settlement as DHEC’s action against the Defendant. Similarly, William Krecker, the Section Manager of the Enforcement Division of DHEC’s Bureau of Water Pollution Control, testified that, of the 100 to 200 enforcement cases he had been involved in, none has been resolved as quickly as DHEC’s action against the Defendant. Hunter testified that the reason for the swiftness of the DHEC proceeding was the Defendant’s request that DHEC file a judicial action and the deadline imposed by the Plaintiffs’ sixty-day notice letter. Sherer testified in 1990, in another ease, that citizen suits help bring about compliance and that DHEC’s policy was not to file an action in court when requested to do so by a defendant in order to bar a citizen suit. DHEC’s action in this case violates this policy. 3. Substantive aspects of Consent Order DHEC initially sought a penalty of $120,-000 from the Defendant. Knauss determined that DHEC would seek a penalty of $120,000, because that amount was consistent with past penalties obtained by DHEC. He testified that he determined in his head the amount of the penalty to seek from the Defendant and that he made no written record of how he arrived at the figure of $120,000. Both Hunter and Krecker approved the $120,000 penalty amount; however, neither of them personally involved himself in the computation of the penalty amount, each deferring to Knauss regarding the details of the penalty proposal. Hunter and Krecker also approved the $100,000 penalty ultimately included in the Consent Order. DHEC’s uniform enforcement policy, which was approved by the DHEC board in December 1991, sets forth several factors that may be considered in the assessment of civil penalties, including “[e]conomic benefit as a result of noncompliance.” DHEC, Uniform Enforcement Policy, at 3, ¶ 3(d) (Dec. 12, 1991) (Pl.Ex. 10). In addition, DHEC’s Bureau of Water Pollution Control has a guidance document that recommends a penalty of $1,000 for each discharge violation. DHEC Bureau of Water Pollution Control, Penalty Assessment Guidance, at 4 (Pl.Ex. 92). This amount may be adjusted upward or downward depending on various mitigating factors, such as mechanical problems, vendor problems, or inability to pay. Id. at 4-5. No evidence has been presented that any of these mitigating factors applied in this case. If a penalty of $1,000 per violation had been imposed in this ease, the penalty based on the number of violations listed in the fact sheet accompanying DHEC’s Notice of Enforcement Conference would have been $227,000. In considering the seriousness of a permit-tee’s violations, DHEC uses the standard of whether the violations were more than 1.4 times the permit limit. Knauss was aware that most of the Defendant’s mercury violations were greater than 1.4 times its permit limit for mercury. The DHEC penalty guidance and policy documents were available to enforcement staff at the time of the DHEC lawsuit. DHEC made no attempt to calculate the Defendant’s economic benefit from noncompliance. Krecker testified that he had no reason to believe that the Defendant had enjoyed any economic benefit and that economic benefit was not a factor in Knauss’s consideration. Also, Hunter testified that Knauss considered, but did not calculate, economic benefit. However, no DHEC enforcement personnel obtained the information necessary to make an economic benefit calculation. DHEC did not determine the capital costs or the operation and maintenance costs of the wastewater treatment equipment installed by the Defendant. According to Krecker, DHEC does not normally make an economic benefit calculation in proceedings to enforce NPDES permits. Hunter testified that DHEC considers economic benefit in conjunction with good-faith attempts at compliance and that “economic benefit is usually derived from someone that just ignores environmental laws and doesn’t want to place equipment in place.” In this case, although the Defendant had been in violation of its permit for five years by the time DHEC brought it enforcement action in 1992, Krecker testified that he did not consider the Defendant to have obtained any significant economic benefit because the Defendant installed pollution control equipment with the intent of being in compliance. Since DHEC believed that the Defendant was attempting in good faith to comply with its permit, DHEC did not deem economic benefit to be an important consideration in calculating a penalty against the Defendant. On June 9, 1992, DHEC and the Defendant entered into a Consent Order in which the Defendant agreed to pay a penalty of $100,000. The Consent Order contains no injunction requiring the Defendant to comply with its permit, but requires only that the Defendant make “every effort” to comply. Consent Order and Decree, at 5, ¶ 10 (June 9, 1992) (Def.Ex. 167). Also, the Consent Order provides that “[t]he sums to be paid under the terms of this Consent Order shall constitute full settlement and shall completely discharge Defendant from any and all liability ... arising from ... (c) any and all violations occurring during the period covered by this Consent Order.” Id. at 6, ¶ 14. The Consent Order further provides that it “shall automatically terminate and expire if and when Defendant achieves compliance with any new permit limit based on number 8 above or upon submittal of the additional plans, if necessary, and achieve[s] the limits for mercury referred to in paragraph 10 above.” Id. at 6, ¶ 15. Knauss testified that the Consent Order covered violations that occurred after the date it was entered. Krecker testified that DHEC’s normal practice is that violations which occur after the date of a consent order are subject to additional enforcement action. He further testified that he is aware of only one case other than DHEC’s case against the Defendant, in which DHEC’s settlement covered future violations. In that case, however, the consent order provided for stipulated penalties for future violations. William Ready, DHEC’s attorney who worked on this ease, testified that it is not DHEC’s practice to settle future violations “except on the basis of stipulated penalties.” He also testified that DHEC attempted to include stipulated penalties in the Consent Order for permit violations that occurred after the Consent Order was entered, but did not insist them. With the exception of Knauss, DHEC personnel testified that they did not interpret the Consent Order to cover permit violations that occurred after the date of the consent order. Ready testified that he believed that DHEC could seek penalties for violations occurring after the date of the Consent Order based on paragraph 10 of the Consent Order, which requires that the Defendant make “every effort” to comply with its mercury limit. However, Ready admitted that, if paragraphs 14 and 15 of the Consent Order were interpreted to settle violations occurring after the date of its entry but prior to its expiration, the Defendant would have obtained a benefit that is not extended to other dischargers in South Carolina. The Consent Order also required the Defendant to complete a fish tissue study. However, before the Consent Order was entered, the Defendant was already planning to conduct the fish tissue study to support its request for a higher mercury limit. DHEC had no interest in having the Defendant perform the fish tissue study. All of the foregoing factors provide some evidence that DHEC did not diligently prosecute its action against Laidlaw. D. Economic Benefit of Noncompliance The Defendant, as a holder of an NPDES discharge permit, should not profit from noncompliance with that permit. If DHEC assessed a penalty that was below the Defendant’s economic benefit of noncompliance, DHEC would not have penalized the Defendant at all; instead, the Defendant would have been rewarded for noncompliance with its permit. Economic benefit is the after-tax present value of avoided or delayed expenditures on necessary pollution control measures. Economic benefit represents the opportunity a polluter had to earn a return on funds that should have been spent to purchase, operate, and maintain appropriate pollution control devices. To determine a company’s economic benefit from noncompliance with its permit, one must compare the company’s cash flows associated with the delayed permit compliance measures to what those cash flows would have been if the company had obtained the necessary pollution control equipment on time. EPA describes the nature of the economic benefit enjoyed by a firm that delays compliance with pollution control laws as follows: An organization’s decision to comply with environmental regulations usually implies a commitment of financial resources; both initially, in the form of a capital investment or one-time expenditure, and over time, in the form of annual, continuing expenses. These expenditures might result in better protection of public health or environmental quality; however, they are unlikely to yield any direct economic benefit (i.e., net gain) to the organization. If these financial resources were not used for compliance, they presumably would be invested in projects with an expected direct economic benefit to the organization. This concept of alternative investment; that is, the amount the violator would normally expect to make by not investing in pollution control, is the basis for calculating the economic benefit of noncompliance. As part of the Civil Penalty Policy, EPA uses the Agency’s penalty authority to remove or neutralize the economic incentive to violate environmental regulations. In the absence of enforcement and appropriate penalties, it is usually in the organization’s best economic interest to delay the commitment of funds for compliance with environmental regulations and to avoid certain other associated costs, such as operating and maintenance expenses. EPA, BEN User’s Manual 1-6 (July 1990) (Pl.Ex. 91). Economic experts for both parties in this action testified that whether a permittee proceeded in good faith is irrelevant to economic benefit analysis. According to penalty guidelines promulgated by both the EPA and DHEC, good faith is a separate penalty factor to be considered when one determines what the appropriate civil penalty should be. Present-value analysis of economic benefit allows one to express all cash flows as of a given date by accounting for the time value of money — i.e., the fact that a dollar today is worth more than a dollar tomorrow. To determine by how much the value of a dollar of one year exceeds the value of a dollar of another year, one must use a discount rate to calculate the present value of money from the various time periods. The discount rate, or “opportunity cost,” represents the return the Defendant had the opportunity to obtain by investing the funds it delayed or avoided spending on pollution control measures. This rate can be used to move dollars through time and determine the Defendant’s economic benefit as of a given date. The court adopts the capital-asset pricing model as the appropriate method for determining the Defendant’s benefit of noncompliance. Under the capital-asset pricing model, the discount rate is computed by using a risk-free component, which is based on short-term United States Treasury Bills, and a near-constant risk premium. Using the capital-asset pricing model, Dr. Michael Ka-vanaugh, the Plaintiffs’ economic expert, determined that the appropriate discount rate for this case 15.25%. The court finds that the economic benefit the Defendant enjoyed by its failure to make timely expenditures for pollution control equipment is substantially in excess of the $100,000 penalty amount as of July 1, 1992, the approximate date of the Defendant’s penalty payment to DHEC. Although the court accepts Dr. Kavanaugh’s methodology of using the capital-asset pricing model to determine a violator’s economic benefit of noncompliance, the court declines, at this time, to make a specific finding on the precise amount of the Defendant’s economic benefit. The court’s preliminary determination that the penalty imposed by DHEC in the June 9, 1992 Consent Order failed to recover the Defendant’s economic benefit of noneompliance is based on the following delayed or avoided expenditures. 1. Neutralization and pH control equipment The neutralization and pH control equipment that the Defendant had in 1987 was inadequate, according to both Dr. Bruce A. Bell, the Plaintiffs’ wastewater treatment expert, and Dr. Thomas Keinath, the Defendant’s wastewater treatment expert. By late 1988, the Defendant had replaced its neutralization system with adequate neutralization tanks, a pH control system, and freeze protection. The neutralization and pH control system that the Defendant installed was necessary for it to comply with both the metals and pH limits in its permit that became effective on January 1, 1987. This system is necessary for compliance with the metals limits because the removal of metals is dependent on adequately controlling the pH levels in the wastewater. As Dr. Bell testified, the technology for neutralization and pH control has been available at least since the 1960s. Therefore, the court finds that the changes the Defendant made to its neutralization system in 1988 should have been made in time to comply with its metals and pH permit limits that went into effect on January 1, 1987. 2. Lancy system Dr. Keinath testified that the dual carbon filter system that the Defendant had in place prior to 1991 did not enable the Defendant to comply with the metals limits in its permit. Dr. Keinath further testified that some metals which are regulated in the Defendant’s permit, such as arsenic and antimony, are not easily removed with carbon treatment. As noted earlier, the Defendant decided in late 1989 or early 1990 to install the Lancy system. The Defendant began operating the Lancy system in March 1991. The Lancy system consists of equalization, neutralization, sulfide addition, a retention tank, an adsorption filter, and final pH control. According to both Dr. Keinath and Dr. Bell, the Lancy system consists entirely of technology that was available prior to 1987. Dr. Bell testified that the Lancy system has been commercially available since at least 1984. Dr. Keinath testified that, according to the 1985 text, Industrial Wastewater Treatment Technology by Dr. James Patterson, the technologies available for treatment of mercury in 1985 were carbon adsorption and ion exchange. However, Dr. Patterson’s chapter on mercury removal lists several technologies other than carbon adsorption and ion exchange that were available for mercury removal in 1985. The first technology that Dr. Patterson notes as being available for mercury removal is sulfide addition, which, he writes, can be combined with filtration. Sulfide addition and filtration are the basic technologies underlying the Lancy system. In addition, Dr. Keinath testified that he believed that the Lancy system was unproven technology for mercury removal in 1987. In fact, as both Dr. Keinath and Dr. Bell testified, the Lancy system was unable by itself to remove enough mercury to allow the Defendant to meet the 1.3 ppb mercury limit. However, Dr. Keinath also testified that the Lancy system “could well have been utilized” in 1987 for treatment of metals other than mercury. Dr. Keinath further testified that the Lancy system had in fact been installed by other dischargers before the Defendant installed the Lancy system. The court recognizes that the Lancy system was not available for off-the-shelf purchase in 1986, nor is it currently available for off-the-shelf purchase; rather, the Lancy system consists of technology which must be engineered and manufactured specifically for the purchaser. Nevertheless, according to both Dr. Keinath and Dr. Bell, the Lancy system or its functional equivalent was necessary for the Defendant to comply with the non-mercury metals limits in its permit that went into effect on January 1, 1987. The Lancy system or its functional equivalent also would have enabled the Defendant to comply with the 10 ppb mercury limit that was in effect from January 1,1987 to December 31, 1987. Therefore, the court finds that the Defendant should have installed the Lan-cy system or its equivalent by January 1, 1987. 3. Additional mercury-removal equipment As noted previously, the Lancy system brought the Defendant into compliance with the non-mercury metals limits in its permit, but was unable to achieve the 1.3 ppb mercury limit. In 1992 and 1993, the Defendant installed additional equipment, including carbon adsorption equipment, prefilters, ion exchange equipment, and microfiltration, to remove mercury from its wastewater. In July 1992, the Defendant installed new carbon adsorption equipment. Also, in January 1993, the Defendant installed prefilters, which are necessary to protect the carbon adsorption equipment. Finally, in April 1993, the Defendant installed ion exchange equipment, as well as microfiltration equipment to remove small particulate mercury formed during the sulfide precipitation process in the Lancy system. Dr. Keinath testified that he believes that the Defendant could comply with its permit with only the Lancy system and microfiltration and that the carbon adsorption filters and ion exchange equipment that the Defendant installed were “redundancies.” However, Dr. Keinath also testified that both carbon adsorption and ion exchange equipment remove some mercury, that the Defendant’s mercury violations continued until after this equipment was in place, and that he was uncertain whether the Defendant could actually comply with its permit without the carbon adsorption and ion exchange equipment. When the Defendant applied for a permit to construct activated carbon equipment, it stated that such equipment would “further reduce mercury concentrations to below 1.3 ppb in the wastewater discharge.” The Defendant’s activated carbon equipment in fact worked well to remove mercury from the Defendant’s wastewater. Furthermore, when the Defendant applied for a permit to construct ion exchange equipment, it stated that, in conjunction with microfiltration, such equipment “will ensure compliance” with the Defendant’s mercury limit. The Defendant’s ion exchange equipment also worked well to remove mercury from the Defendant’s waste-water. The carbon adsorption filters and ion exchange equipment are designed to remove soluble mercury from the Defendant’s waste-water. A test conducted by the Defendant on actual effluent from the Lancy system showed that soluble mercury in concentrations greater than the Defendant’s permit limit for mercury sometimes passes through both the Lancy system and the microfiltration equipment. The carbon adsorption and ion exchange equipment are therefore necessary to enable the Defendant to comply with its permit limit for mercury. All of the mercury removal equipment that the Defendant installed in 1992 and 1993 was necessary to ensure the Defendant’s compliance with the 1.3 ppb mercury limit. All of this mercury removal technology was commercially available before the Defendant purchased the facility in 1986. Therefore, the court finds that the Defendant should have installed the additional mercury removal equipment by January 1, 1988, in order to satisfy the mercury limit in its permit. In summary, to comply with its permit the Defendant should have installed by January 1, 1987 all of the equipment that is currently in place, or its functional equivalent, with the exception of the equipment that was designed specifically for mercury removal. The Defendant should have installed the remaining mercury removal equipment, or its functional equivalent, by January 1, 1988. The Defendant realized a significant economic benefit by taking seven years to achieve compliance with its NPDES permit limits. Although Dr. Keinath testified that the each of the individual wastewater treatment measures undertaken by the Defendant was logical, the Defendant profited by operating its facility for seven years despite continuing permit violations. In other words, the Defendant is better off now, even after paying the $100,000 penalty, than it would have been had it made the expenditures necessary to comply with its permit in a timely fashion or had it simply shut down the facility until compliance were possible. III. CONCLUSIONS OF LAW Congress enacted the Clean Water Act (“CWA” or “the Act”) in 1972 “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” 33 U.S.C. § 1251(a). To achieve the stated goals of the Act, section 301(a) makes unlawful the discharge of any pollutant into any navigable waters, except as specifically authorized by certain enumerated sections of the Act. 33 U.S.C. § 1311(a). One of these exceptions is section 402, 33 U.S.C. § 1342, which establishes the National Pollutant Discharge Elimination System (“NPDES”). Pursuant to section 402(a), or pursuant to a state program authorized under section 402(b), the appropriate regulatory authority may issue permits that allow the holder to discharge pollutants in accordance with the conditions and limitations set forth in the permit. The holder of an NPDES permit who fails to comply with the conditions of its permit may be subject to administrative, civil, or criminal sanctions. 33 U.S.C. § 1319. Permits issued under a state NPDES program are subject to both federal and state enforcement actions. See id.; 33 U.S.C. § 1342(b)(7). In addition, section 505 of the CWA authorizes private citizens, under certain circumstances, to bring civil actions to enforce any effluent standard or limitation under the Act, including NPDES permits. 33 U.S.C. § 1365(a)(1). Section 505(b)(1) provides two significant limitations on a citizen’s right to bring a citizen enforcement suit under the CWA. First, under section 505(b)(1)(A), the citizen must provide notice of the alleged violation to the Administrator of the EPA, to the state enforcement agency of the state in which the alleged violation occurs, and to the alleged violator at least sixty days before the citizen may file a citizen suit. 33 U.S.C. § 1365(b)(1)(A). Second, section 505(b)(1)(B) provides that no citizen suit may be commenced “if the Administrator or State has commenced and is diligently prosecuting a civil or criminal action in a court of the United States, or a State to require compliance with [the same NPDES permit].” 33 U.S.C. § 1365(b)(1)(B). In the matter currently before the court, the Defendant contends that section 505(b)(1)(B) precludes the Plaintiffs’ lawsuit because, it argues, DHEC “diligently prose-cut[ed]” an enforcement action against Laid-law in South Carolina state court on June 9, 1992, which action was settled by judicial consent order on June 10, 1992. The Plaintiffs raise several arguments in opposition to the Defendant’s contention that their citizen suit is barred under section 505(b)(1)(B) by DHEC’s lawsuit against the Defendant. The Plaintiffs initially argue that section 505(b)(1)(B) bars the commencement of a citizen suit only while a state or federal enforcement action is pending, but not after that action has been concluded. In other words, the Plaintiffs urge the court to interpret section 505(b)(1)(B) only to prohibit citizen suits and federal or state enforcement suits from proceeding simultaneously. The Plaintiffs assert that section 505(b)(1)(B) does not bar their action because DHEC’s action against Laidlaw in June 1992 was settled before the Plaintiffs filed their suit. The Plaintiffs base their argument on a plain reading of section 505(b)(1)(B), which provides that no citizen suit may be commenced if the enforcement agency “has commenced and is diligently prosecuting” a judicial action against the alleged violator. 33 U.S.C. § 1365(b)(1)(B) (emphasis added). Section 505(b)(1)(B) obviously contemplates a situation in which a citizen proposes to file a private enforcement suit contemporaneously with an ongoing governmental enforcement suit. Indeed, as one district court recognized, “the purpose underlying the ‘diligent prosecution’ provision [is] that a defendant not be subjected simultaneously to multiple suits, and potentially to conflicting court orders, to enforce the same statutory standard.” Connecticut Fund for the Environment v. Contract Plating Co., 631 F.Supp. 1291, 1293 (D.Conn.1986). Moreover, the provision in section 505(b)(1)(B) that allows any citizen to intervene as of right in any enforcement action brought in federal court clearly envisions the governmental action pending at the time of the attempted citizen suit. However, it is doubtful that Congress intended the preclusive effect of section 505(b)(1)(B) to expire once the government has concluded its diligent prosecution of a particular violator. As the Defendant observed in response to the Plaintiffs’ argument, reading section 505(b)(1)(B) only in the present tense would allow citizens to bring a private enforcement action against any alleged violator, as long as the citizen waited until the conclusion of the governmental action before bringing the citizen suit. Such a result would be contrary to the United States Supreme Court’s declaration in Gwaltney of Smithfield, Ltd. v. Chesapeake Bay Found., 484 U.S. 49, 108 S.Ct. 376, 98 L.Ed.2d 306 (1987), that “citizen suits are proper only ‘if the Federal, State, and local agencies fail to exercise their enforcement responsibility.’ ” Id. at 60, 108 S.Ct. at 383 (quoting S.Rep. No. 414, 92d Cong., 1st Sess. 64 (1971), reprinted in 1972 U.S.C.C.A.N. 3668, 3730). Thus, although the “diligent prosecution” condition in section 505(b)(1)(B) is phrased in the present tense, the court has determined that Congress intended to prohibit citizen suits where the governmental enforcement agency is diligently prosecuting or has diligently prosecuted a judicial action to enforce the same alleged violations of a particular permit, standard, or limitation. Therefore, the critical issue presently before the court is whether DHEC’s June 9, 1992 lawsuit against Laidlaw constitutes diligent prosecution sufficient under section 505(b)(1)(B) to bar the Plaintiffs’ citizen suit. This inquiry is guided by several principles that have been developed in the caselaw interpreting the citizen-suit provisions of the CWA. First, the citizen-plaintiffs bear the burden of proving that the state agency’s prosecution was not diligent. This burden is a heavy one because diligence on the part of the enforcement agency is presumed. See Connecticut Fund for the Environment v. Contract Plating Co., 631 F.Supp. at 1293. As several courts have recognized, “the state [enforcement] agency must be given great deference to proceed in a manner it considers in the best interests of all parties involved.” Arkansas Wildlife Fed’n v. ICI Americas Inc., 842 F.Supp. 1140, 1147 (E.D.Ark.1993), aff'd, 29 F.3d 376 (8th Cir.1994), cert. denied, — U.S. -, 115 S.Ct. 1094, 130 L.Ed.2d 1062 (1995). Deference to governmental enforcement agencies is appropriate because the CWA delegates the primary enforcement responsibility to designated state and federal agencies. For example, the requirement in section 505(b)(1)(A) that a citizen must file a notice letter sixty days before bringing a private enforcement suit clearly was designed to give the governmental agencies the “first shot” at enforcement. As the Supreme Court stated in Gwaltney, “the citizen suit is meant to supplement rather than to supplant governmental action.” 484 U.S. at 60, 108 S.Ct. at 383. Appropriate limitations on citizen suits generally “allow for smoother operation of ordinary enforcement mechanisms” and encourage out-of-court settlements between agencies and polluters. Connecticut Coastal Fishermen’s Ass’n v. Remington Arms Co., 177 F.Supp. 173, 179, 186 (D.Conn. 1991), aff'd in part, rev’d in part, 989 F.2d 1305 (2d Cir.1993); cf. Supporters To Oppose Pollution, Inc. v. Heritage Group, 973 F.2d 1320, 1324 (7th Cir.1992) (in action under the Resource Conservation and Recovery Act (RCRA), stating: “An Administrator unable to make concessions is unable to obtain them. A private plaintiff waiting in the wings then is the captain of the litigation.... To say ... that the EPA is not ‘diligently prosecuting’ the action if it does not sue the person, or use the theories, the plaintiff prefers would strip EPA of the control the statute provides.”). On the other hand, Congress certainly intended to provide private citizens with significant opportunities to participate in the enforcement of the CWA. See S.Rep. No. 414, supra, at 72, reprinted in 1972 U.S.C.C.A.N. at 3738 (“An essential element in any control program involving the nation’s waters is public participation. The public must have a genuine opportunity to speak on the issue of protection of its waters.... The scrutiny of the public ... is extremely important in insuring expeditious implementation of the authority and a high level of performance by all levels of government and discharge sources.”). As the United States Court of Appeals for the Second Circuit stated, “ ‘Congress made clear that citizen groups are not to be treated as nuisances or troublemakers but rather as welcomed participants in the vindication of environmental interests.’ ” Friends of the Earth v. Consolidated Rail Corp., 768 F.2d 57, 63 (2d Cir.1985) (quoting Friends of the Earth v. Carey, 535 F.2d 165, 172 (2d Cir.1976) (referring to citizen suit provision of the Clean Air Act)). In addition to authorizing citizen suits under section 505, the CWA provides several opportunities for citizens to participate in governmental enforcement activities. Indeed, as noted previously, the last phrase of section 505(b)(1)(B) provides that if a citizen suit is barred by the EPA’s or the state’s diligent prosecution of a judicial action, “in any such action in a court of the United States any citizen may intervene as a matter of right.” 33 U.S.C. § 1365(b)(1)(B). Also, section 309(g) contains provisions for public participation in administrative actions brought by the EPA. Section 309(g)(4)(A) requires the EPA to provide public notice of and reasonable opportunity to comment on the proposed issuance of any order assessing civil administrative penalties under section 309(g). 33 U.S.C. § 1319(g)(4)(A). In addition, section 309(g)(4)(B) provides that anyone who comments on the proposed assessment of an administrative penalty shall be notified of the hearing and “shall have a reasonable opportunity to be heard and to present evidence.” 33 U.S.C. § 1319(g)(4)(B). Any person who comments on the proposed assessment of civil penalties may obtain judicial review of such assessment. 33 U.S.C. § 1319(g)(8). Moreover, the federal regulations that list the requirements for state enforcement authorities administering NPDES programs provide, in part: Any State administering [an NPDES] program shall provide for public participation in the State enforcement process by providing either: (1) Authority which allows intervention as of right in any civil or administrative action to obtain remedies specified in paragraphs (a)(1), (2) or (3) of this section by any citizen having an interest which is or may be adversely affected; or (2) Assurance that the State agency or enforcement authority will: (i) Investigate and provide written responses to all citizen complaints submitted pursuant to the procedures specified in § 123.26(b)(4); (ii) Not oppose intervention by any citizen when permissive intervention may be authorized by statute, rule, or regulation; and (iii) Publish notice of and provide at least 30 days for public comment on any proposed settlement of a State enforcement action. 40 C.F.R. § 123.27(d). In addition, the importance of public participation in the enforcement of the CWA has been recognized by several courts interpreting section 309(g)(6)(A). That section provides, in part, that “any ... violation with respect to which a State has commenced and is diligently prosecuting an action under State law comparable to this subsection ... shall not be the subject of a civil penalty action under [section 1319(d) ... or section 1365 of this title [the citizen suit provision].” 33 U.S.C. § 1319(g)(6)(A). One issue that has repeatedly arisen in citizen suit litigation is whether a state’s scheme for administrative enforcement actions is “comparable to” the federal provisions, sufficient under section 309(g)(6)(A) to preclude a citizen suit. In making this determination, courts often focus on whether the state’s enforcement mechanisms contain provisions to ensure adequate participation by private individuals in administrative enforcement actions. See, e.g., Arkansas Wildlife Fed’n v. ICI Americas, Inc. 29 F.3d 376, 381 (8th Cir.1994) (holding that, to be comparable to federal law for purposes of section 309(g)(6)(A), state law must “provide[ ] interested citizens a meaningful opportunity to participate at significant stages of the decision-making process, and adequately safeguard^ their legitimate substantive interests”), cert. denied, — U.S. -, 115 S.Ct. 1094, 130 L.Ed.2d 1062 (1995); North & South Rivers Watershed Ass’n v. Scituate, 949 F.2d 552, 556 n. 7 (1st Cir.1991) (“So long as the provisions in the State Act adequately safeguard the substantive interests of citizens in enforcement actions, the rights of notice and public participation found in the State Act are satisfactorily comparable to those found in the Federal Act.”); Atlantic States Legal Found, v. Universal Tool & Stamping Co., 735 F.Supp. 1404, 1415 (N.D.Ind.1990) (“ ‘[I]n order to be comparable, a State law must provide for a right to a hearing and for public notice and participation procedures similar to those set forth in section 309(g)(quoting 133 Cong.Rec. S737 (daily ed., Jan. 14, 1987)). Thus, the issue presently before the court involves a delicate balance between the Act’s preference for governmental enforcement efforts and the recognized policy of allowing private citizens to participate in the enforcement process. Of course, the overriding concern is to assure vigorous enforcement of the CWA to achieve the stated goals of the Act. The Plaintiffs argue that DHEC’s prosecution of Laidlaw in June 1992 was not sufficiently diligent under section 505(b)(1)(B) to preclude their citizen suit. The Plaintiffs challenge both the procedural aspects of the DHEC lawsuit and also the substance of the settlement agreement. In determining whether DHEC’s lawsuit against Laidlaw was diligently prosecuted, the court will analyze the Plaintiffs’ allegation of lack of diligence “against the background of the agency action.” S.Rep. No. 414, supra, at 80, reprinted in 1972 U.S.C.C.A.N. at 3746; see also SPIRG v. Fritzsche, Dodge & Olcott, Inc., 579 F.Supp. 1528, 1535 (D.N.J.1984) (“An evaluation of ‘diligence’ measures comprehensively the process and effects of agency prosecution.”), aff'd on other grounds, 759 F.2d 1131 (3d Cir.1985). The Plaintiffs allege several procedural defects to support their claim that the DHEC action should not preclude their citizen suit. First, DHEC filed its complaint and consent order in state court on the very last day of the statutory sixty-day notice period during which it was possible under section 505(b) for a state-court action to preclude a citizen suit. Second, the complaint was filed at the Defendant’s request, solely to accommodate the Defendant’s desire to bar a citizen suit. The Plaintiffs contend that the judicial action served no purpose of DHEC beyond that provided by the usual administrative enforcement action. Third, Laidlaw drafted the state-court complaint and settlement agreement, filed the lawsuit against itself, and paid the filing fee. And finally, the settlement agreement between DHEC and Laidlaw was entered into with unusual haste, without giving the Plaintiffs the opportunity to intervene. Although the procedural aspects of DHEC’s June 9, 1992 action against the Defendant are somewhat suspect, they do not, in and of themselves, establish a lack of diligent prosecution. Cf. Atlantic States Legal Found. v. Universal Tool & Stamping Co., 735 F.Supp. at 1416 (finding that state’s prosecution was not diligent because, inter alia, counsel for the defendant “walked through” the interlocutory consent decree for approval in the offices of the state agency in a single day; procedure was highly unusual as the approval and signing of such decrees usually requires four to six weeks). The court is quite concerned, however, that because DHEC settled its action against Laid-law only one day after the lawsuit was filed, the Plaintiffs simply had no chance to intervene. See Love v. New York State Dep’t of Envtl. Conservation, 529 F.Supp. 832, 843—44 (S.D.N.Y.1981) (in holding that state failed to diligently prosecute an administrative action, the court cited, inter alia, the lack of opportunity for the citizen plaintiffs to intervene); Sierra Club v. SCM Corp., 572 F.Supp. 828, 830-31 (W.D.N.Y.1983) (holding that “where settlement of permit violations is achieved as a result of enforcement proceedings in which plaintiffs, as members of the public, lacked the opportunity to be heard on the merits of the proposed consent order, a citizens suit pursuant to 33 U.S.C. Section 1365(a)(1) may properly be entertained by a federal district court”). Because of the importance of public participation in the enforcement processes of the CWA, as discussed above, the absence of a meaningful opportunity for the citizen plaintiffs to intervene in this case triggers a heightened scrutiny into the settlement of the underlying case between DHEC and Laidlaw. In examining the totality of the circumstances surrounding DHEC’s prosecution of Laidlaw, the court is compelled to conclude that this procedural deficiency weighs in favor of the Plaintiffs. The Plaintiffs also contend that the substantive provisions of the Consent Order between DHEC and Laidlaw demonstrate that DHEC’s state-court action was not diligently prosecuted. The Plaintiffs identify several aspects of the Consent Order that they allege demonstrate a lack of diligence on the part of DHEC. First, the Consent Order did not provide that the court’s jurisdiction would continue in order to enforce the decree, but only that the Defendant’s violations of the order’s terms would subject it to “additional enforcement action.” Consent Order and Decree, at 5, ¶ 13 (June 9, 1992) (Def.Ex. 167). The Consent Order also provides that DHEC’s complaint be dismissed. Id. at 4, ¶ 1. In addition, DHEC did not obtain an injunction requiring the Defendant to comply with its permit; instead, the Consent Order merely required the Defendant to “use every effort” to comply with its mercury limit. Id. at 5, ¶ 10. Furthermore, the Consent Order did not contain stipulated penalties for future violations of the Defendant’s permit. The Consent Order provides: This Consent Order constitutes a full, fair, reasonable, and complete settlement of the allegations contained in the complaint. filed in this ease, and all other claims covered by this Consent Order, including all claims Plaintiff [DHEC] might have arising out of or in any way connected with alleged violations of NPDES Permit No. SC00W517. Id. at 4, ¶ 4 (emphasis added). The Consent Order further provides that the Defendant will be discharged from liability for “any and all violations occurring during the period covered by this Consent Order.” Id. at 6, ¶ 14. Finally, the Consent Order extended for an indefinite period into the future, until the Defendant demonstrated compliance with the mercury limitation of its permit. Id. at 6, ¶ 15. The mere fact that a settlement reached by the state is less burdensome to the defendant than the remedy sought in the complaint in the citizen suit does not establish that the state failed to prosecute its action diligently. See Connecticut Fund for the Environment v. Contract Plating Co., 631 F.Supp. at 1294. However, the lack of substantial relief in a settl