Hypothetical Variance Scenarios
For Rule-Making Workgroup Discussion
October 19, 2009
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Factors Applicable to All Human Health Criteria Variances:
❖ An applicant for a water quality standards variance must submit a request for a variance to the Department. The application must include all relevant information showing that the requirements for a variance have been satisfied. The burden is on the applicant to demonstrate that attaining the designated use is not feasible for one of the reasons specified in OAR 340-041-0061(2).
❖ Variances will be granted for the minimum amount of time needed. This will be determined based on the justification provided by each applicant and subsequent DEQ approval. In no case, shall the Department authorize a variance period greater than 10 yrs. The applicant must either meet the standard upon the expiration of this time period or must make a new demonstration pursuant to OAR 340-041-0061(2).
❖ Each variance request is subject to public notice requirements; DEQ anticipates that the public comment opportunity will be concurrent with the opportunity to comment on the draft permit.
❖ A variance is granted for a specific pollutant(s) and does not otherwise modify the water quality standards for the water body.
❖ A variance does not exempt the discharger from compliance with applicable technology-based limits or water quality-based limits for other pollutants.
❖ Sources shall continue to achieve the lowest effluent concentration possible under their current operations and treatment. Where pollutant minimization plans are expected to result in improved effluent quality, milestones and/or more stringent effluent quality requirements will be incorporated as part of the variance.
❖ Based upon a case-by-case determination, the applicant may also be required to develop a pollution minimization plan to identify reasonable and cost effective measures for reducing or eliminating pollutant loading. Measures may include, but are not limited to the following: treatment optimization, investigating inflow and infiltration issues; exploring alternate source waters; or examining pre-treatment local limits. Other measures could include trading or offsets. Milestones will be established for pollutant minimization plans to ensure implementation of the measures described in the plan.
❖ The requirements of the variance will be included as conditions of the NPDES permit.
❖ The variance is effective only after EPA approval.
❖ There could be further variations to each scenario given below, or other scenarios that warrant a variance. These variations/variances would be approached on a case by case basis.
Scenario 1
Description: Scenario 1 describes an industrial facility where water from the receiving stream is used for non-contact cooling. The ambient background concentration of 2 ug/L of Pollutant X-- a legacy pollutant (e.g. PCB/DDT)--is higher than the human health criterion of 1 ug/L. The facility does not add any mass of Pollutant X as part of their process. Evaporative processes from cycling of the non-contact cooling water reduces water quantity, and therefore increases the concentration of Pollutant X in the effluent to 3 ug/L when compared with the ambient background concentration upstream at 2 ug/L. Upon complete mixing with the stream, there is no more than a de minimus increase (need to define, e.g. 1%?) in pollutant concentration in-stream.
Variance Justification for HHC: Human-caused conditions or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place.
In this scenario the facility is using multiple-pass cooling, which is environmentally preferable to single-pass cooling when considering water conservation, temperature, and other adverse effects that can occur with the intake of cooling water. The facility could reduce the number of passes to decrease concentrations in its effluent, but it may come at other environmental costs. This analysis is focused on these issues as described below.
Supporting Information and Rationale:
➢ Sufficient monitoring data from intake source, upstream and downstream receiving waterbody, and effluent samples shall be collected to adequately assess ambient background levels of pollutant, as well as the downstream ambient concentration after mixing.
➢ Documentation demonstrating that treatment more advanced than that required by sections 301(b)(l)(A) and (B) and 306 of the Clean Water Act (i.e. Technology Based Requirements) has been carefully considered and that alternative effluent control strategies have been evaluated. Environmental benefits, such as water conservation practices used for non-contact cooling, could be part of this analysis.
➢ DEQ determination that effluent concentration would not be expected to increase the risk to human health above what would already be present in the waterbody absent the facility’s discharge.
Interim Conditions and Requirements of a Variance:
➢ Variance requirements which allow no increase in effluent concentration above that of current operation. In this scenario, it has been determined that the current effluent concentration will not increase the ambient pollutant concentration more than a de minimis amount.
➢ In this case, a pollution minimization plan would most likely not be warranted. However, if feasible pollutant reduction actions were identified, these measures would be incorporated into the variance.
Precedence for EPA Approval: NY is currently looking at human caused conditions as a justification supporting a Hg multiple discharger variance.
Scenario 2
Description: The City of Petersville located in the State of Oregon operates a sewage treatment plant (STP) which discharges to the Blue River.
• The Blue River upstream of the STP’s discharge has ambient concentrations of arsenic (2 ug/L) below the applicable human health water quality criterion (2.7 ug/L).
• The City of Petersville STP has a high level of arsenic in its discharge effluent (6 ug/L) that causes it to exceed the applicable human health water quality criterion for the Blue River after complete mixing.
• Influent data for this facility indicates that there is a high concentration of arsenic flowing into the treatment plant (7 ug/L).
The City of Petersville has a formal pretreatment program with the Oregon Department of Environmental Quality (ODEQ), and is has developed local limits (1.5 ug/L) for industrial facilities that discharge to the STP to minimize sources of arsenic where that pollutant may be present. Therefore, these industries are not the source of concern.
A substantial portion of the City of Petersville is built upon soils that have naturally elevated concentrations of arsenic. This includes the collection system for the STP, which is old and believed to be cracked in places. The ground water in the area, which contains natural levels of arsenic, enters the cracked collection system piping and is carried as influent to the treatment plant, along with the domestic untreated sewage entering the system (also as influent). This suggests that the inflow and infiltration problem is likely a significant contribution of the arsenic loading into the treatment plant.
Without additional controls for removal of arsenic, the effluent from the City of Petersville STP would not meet the water quality-based NPDES permit limits for arsenic. In order to meet water quality-based NPDES permit limits, the City of Petersville STP would need to reduce the arsenic concentration by approximately 55%. In order to accomplish these reductions, the facility will need to make improvements to the collection system to reduce seepage into the pipes along with the installation of expensive arsenic removal treatment.
Variance Justification for HHC: Economic Justification - Controls more stringent than those required by sections 301(b) and 306 of the Act would result in substantial and widespread economic and social impact.
In this scenario, the facility has opportunities to improve its water quality, but implementation of those measures will occur over time and the ultimate water quality that the facility is capable of achieving is uncertain. In the short term (within 5-10 years), while the facility may begin implementing improvements, the facility cannot economically achieve limits based on the arsenic criterion.
Supporting Information and Rationale:
➢ Analyses regarding the source and quantity of arsenic in the facility’s influent and effluent, ambient concentrations and river and effluent flow volumes, and mixing analysis.
➢ Documentation on the source of arsenic that supports the conclusion that it is from I&I and there are no other significant sources that could be controlled or reduced.
➢ Analyses related to the improvements that are planned or could be implemented to address I&I. This would include cost, timing, and expected water quality improvement.
➢ Information on whether there is a community drinking water supply intake downstream from the discharge and, if so, whether the STP discharge is impacting the level of arsenic in the water supply.
➢ Estimated costs for the treatment(s) and alternative effluent control strategies have been considered.
➢ Documentation that treatment more advanced than the applicable technology based requirements (sections 301(b)(l)(b) and 306 of the Clean Water Act) has been carefully considered.
➢ Economic analysis based upon the least cost alternative evaluated using EPA’s 1995 Interim Economic Guidance.
Interim Conditions and Requirements of a Variance :
➢ Requirements based on the pollutant minimization plan. In this scenario, the source could demonstrate that inflow and infiltration improvement measures would result in a reduction of arsenic entering the treatment system over time.
➢ Based on the analyses related to improvements to the collection system to control I & I, either require maintenance of current discharge levels and incorporate milestones related to the capital improvements to the collection system, or, if the expected improvement in water quality is quantifiable, include requirements for discharge levels that reflect the expected improvement during the term of the variance. For example, the variance could include a requirement that X feet of leaking pipes would be replaced, or that X% of capital improvements would be made over a certain time period.
➢ Incorporate any other interim milestones based on implementation measures identified in the plan, as appropriate (e.g., if alternatives to existing treatment technologies has been identified).
Precedence for EPA Approval: ID case example where the discharge from 3 municipal facilities exceeded the criteria associated with an aquatic life designated use for Cd, Pb, and Zn for the SF Coeur d’Alene River.
Scenario 4
Scenario 3
Description: Scenario 3 describes a situation where the facility’s effluent is contributing to a Pollutant X concentration (3 ug/L) in the receiving stream. Ambient concentration of Pollutant X is 0.5 ug/L and the human health water quality criterion applicable to Pollutant X in the receiving stream is 1 ug/L.
Cost-effective feasible treatment technologies that can remove Pollutant X to the level of their calculated water quality-based effluent limitation do not exist. While treatment technologies theoretically exist, implementation of such controls would cause substantial and widespread social and economic impact and may have other associated undesirable environmental effects (e.g., require huge amounts of energy, produce brine that would need to be disposed of).
Variance Justification for HHC: Economic Justification - Controls more stringent than those required by sections 301(b) and 306 of the Act would result in substantial and widespread economic and social impact.
In this scenario, cost-effective treatment technologies are not available that would reduce the human health pollutant to levels that would be required to meet water quality standards. In this instance, an evaluation of potential treatment technologies, what water quality can be achieved (even if it is short of the water quality-based effluent limit), and an evaluation of other reduction measures both within the facility and elsewhere through trading or offsets would guide the development of the variance and associated requirements.
Supporting Information and Rationale:
➢ Sufficient ambient monitoring data from receiving stream, as well as effluent concentrations after treatment and mixing analysis must be collected and submitted to DEQ.
➢ Develop a pollution minimization plan and evaluate options such as treatment optimization/enhancement, source reduction efforts (e.g. take back programs for Hg), and opportunities for trading or offsets.
➢ Evaluation of treatment options and effluent control strategies (including treatment more advanced than the applicable technology based requirements). The analysis must also include estimated costs for the treatment(s) and alternatives.
➢ Economic analysis based upon the least cost alternative evaluated using EPA’s 1995 Interim Economic Guidance.
➢ Information evaluating potential human health or environmental impacts.
Interim Conditions and Requirements of a Variance:
➢ If analyses demonstrate that treatment or alternative effluent control strategies are likely to improve water quality, those improvements will be included as part of the variance requirements as either milestones or water quality requirements or both.
➢ Where improvements in effluent quality are unlikely, the variance would require no increase in effluent concentration based on current operation.
➢ Requirements based on the applicant’s pollution minimization plan, such as treatment optimization/enhancement, source reduction efforts (e.g. take back programs for Hg), and opportunities for trading or offsets.
➢ Interim milestones would be established based on implementation measures identified in the plan. For example, the facility may be able to optimize its current treatment technology thereby reducing Pollutant X by Y% in 3 years. In addition, they may agree to provide funding for source reduction programs.
Precedence for EPA Approval: Examples have not been identified.
Scenario 4
Description: Scenario 2 describes a situation where contaminated ground water is being extracted and treated prior to discharge to a waterbody. The ground water also contains naturally occurring Pollutant X at 3 ug/L. The human health criterion for Pollutant X is 1 ug/L, while the natural background concentration of the waterbody is 2 ug/L. The treatment facility effluent with a concentration of 2 ug/L does not increase the concentration of Pollutant X naturally present in the receiving waterbody.
Variance Justification for HHC: The primary justification would be based on the naturally occurring presence of a pollutant, although there could be a secondary justification based on economic impacts.
Supporting Information and Rationale:
➢ Sufficient ambient monitoring data from GW and SW, as well as effluent concentrations after treatment and mixing analysis must be collected and submitted to DEQ.
➢ Analysis supporting the conclusion that the ground water pollutant concentrations are naturally occurring must be submitted to DEQ.
➢ Documentation demonstrating that treatment more advanced than that required by sections 301(b)(l)(A) and (B) and 306 of the Clean Water Act has been carefully considered and that alternative effluent control strategies have been evaluated.
➢ Facility should coordinate with DEQ clean-up program, which has conducted risk and treatment feasibility studies in developing the clean-up requirements.
Interim Conditions and Requirements of a Variance:
➢ Variance requirements which allow no increase in effluent concentration above that of best achievable operation of the current treatment system.
➢ In this case, a pollution minimization plan would most likely not be warranted; however, the facility should reference requirements specified under their clean-up plan.
Precedence for EPA Approval: Arizona case example where a treatment facility was extracting ground water contaminated with PCE and BTEX and treating with GAC prior to discharge. Discharge exceeded the Boron criterion associated with an agricultural DU. Variance justification was based on naturally occurring ground water concentrations.