The findings of a recent study conducted by EPA indicate that discharge of CERCLA wastewater to a POTW can be a feasible and effective part of a Superfund response action, and that currently, the option of discharging to a POTW is under-utilized. This guide provides quick reference to the statutory, policy, administrative, and technical factors involved in discharging aqueous wastes generated during Superfund response actions to a POTW. Additional guidance on evaluating the use of POTWs can be found in three documents "CERCLA Site Discharges to POTWs-- Guidance Manual" (EPA/540/G-90/005, August 1990), "Treatability Manual" (EPA/540/2-90/007, August 1990), and "CERCLA Sue Sampling Program Detailed Data Report" (EPA/540/2-90/008, August 1990) United States Office of A9ency Emergency Response March 1991 SEPA Guide to Discharging CERCLA Aqueous Wastes to Publicly Owned Treatment Works (POTWs) Office of Emergency and Remedial Response Hazardous Site Control Division 0S-220W Quick Reference Fact Sheet The discharge of aqueous wastes to a publicly-owned treatment works (POTW) as part of a Superfund response action generally is considered to be an off-site activity, even if a CERCLA waste is first pretreated in a wastewater facility located on site. Consequently, all discharges to a POTW still have to be in compliance with the off-site policy, ie., any facility accepting the waste must have no relevant violations, uncontrolled releases, or other environmental conditions that pose a significant threat to human health, welfare, or the environment, or otherwise affect the satisfactory operation of the facility. In addition, site managers must comply with both substantive and administrative requirements (e.g, permits) of Federal, State, and local laws and regulations. EVALUATING THE POTW OPTION Determining the feasibility of utilizing a POTW as a discharge option should begin as early in the remedial process as possible, i.e., once it is known that wastewater streams generated during site characterization, treatability studies, and/or response actions will require treatment. Wastewater streams at CERCLA sites that may be suitable for treatment in a POTW include ground water, leachate, surface runoff, or process streams generated by remedial activities (eg., wastewaters from treatment processes) The necessary steps involved in evaluating the POTW option are outlined below. 1. Identify and Characterize CERCLA Wastewater Discharge In order for a POTW to accept a CERCLA discharge, it will require data on the nature of the discharge, including the constituents within the wastestream. Therefore, data necessary to characterize wastestreams and determine whether a POTW can receive the discharge should be identified and collected as early in the remedial process as possible (e.g., during the sampling phase(s) of the Remedial Investigation/Feasibility Study) A POTW generally will require sampling information on all Target Compound List (TCL) constituents before it can accept a waste. [The TCL is a list of 152 volatile and semi-volatile organic compounds, pesticides, polychlorinated biphenyls (PCBs), and inorganics used in the contract laboratory program (CLP) under CERCLA.] In addition, POTWs usually require information about conventional pollutants in the wastestream, such as the five-day suspended solids, nitrite-nitrate, total Kjeldahl nitrogen, total phosphorus, oil and grease, total dissolved solids, color, total sulfides, and pH. The wastestream to be discharged also should be characterized in terms of quantity, i.e., as a function of time or expressed in terms of daily average and daily maximum flows and size and frequency of batch discharges. ------- Lastly, because of the potential applicability of RCR.A requirements to a POTW and the waste management requirements that may be trjggered dunng transportation and storage of the wasies, site mihagers should determine whether a CERCLA astewater is a, RCRA hazardous waste. If the CERCLA wastestream is considered a RCRA hazardous waste, site matiagers .need tO determine whether the Domestic Sewage Exclusion (D,SE) applies to the discharge of that waste to a POTW The, .CRA DSE exempts domestic sewage, ari i mixture of domestic sewage, and other wastes, that pass through a sewer system to a POTW for treatment from classification as a solid waste and, therefore as a RCRA hazardous waste. [ The Domestic Sewage Exclusion applies only to the actual point discharge; it does not exclude industrial wastewaters while they are being collected, stored, or treated before discharge; sludges that are generated by industrial wastewater treatment; or wastes received within the POTW’s property boundary by truck, rail, or dedicated pipe.) 2. Identify Local POTWs Once CERCLA wastestreams have been characterized, site managers should identify existmg POTWs within a delineated geographic area in which it is technically feasible to transport the CERCLA wastestream Factors for evaluating the feasibility of transport to a POTW include • The distance to the POTW or its existing sewer lines; • The volume of the wastewater; • The viscosity or percent solids of the wastewater, • Topography of the area; • The need to obtain right-of-way permits; and • Cost of transportation. 3. Evaluate Regulatory Status If the determination is made that the discharge of CERCLA aqueous wastes to a POTW is technically feasible, site managers should begin evaluating the regulatory status of the POTW potentially receiving the wastes. One important source of information about the regulatory status and facility-specific acceptance requirements are the municipal authonties responsible for technical and administrative oversight of each POTW. The National Pollutant Discharge Elimination System (NPDES) authority (State or Regional Office of Water) can provide additional information concerning the level of treatment, capacity, operating history, and collection system that will be helpful for screening POTWs. If the CERCLA waste stream is considered a RCRA hazardous waste and the DSE does not apply, site managers should determine whether the POTW meets RCRA Permit-by-Rule requirements POTWs operating under an NPDES permit issued before November 8,1984 currently must be operating under a valid permit and be in compliance with the permit, including RCRA manifesting and reporting requirements. (In addition, the waste must meet all Federal, State, and local pretreatment requirements that would apply to the waste if it were discharaed through a sewer, pipe, or similar conveyance The necessary “POTW-spectfic” analyses of pretreatment requirements are discussed later under step 5) If the POTW is operating under a permit issued or renewed after November 8, 1984, it also must comply with RCRA corre tive action requirements under 40 CFR 264.101. Site managers should identify the operations and responsibilities of the POTW and the regulations that apply to these activities to ensure compliance with RCRA pernut-by-rule requirements. It is important to involve P01W personnel to ensure that accurate and complete information is received and evaluated As an additional check, site managers can review EPA’s Quarterly Noncompliance Report that includes a listing of all POTW facilities that are in significant non- compliance. 4. Evaluate Technical/Administrative Feasibility If a POTW is determined to be in compliance with its NPDES permit and is technically capable of accepting the waste (see Highlight 1), it should be determined whether acceptance of the CERCLA waste is administratively feasible. Negotiations between EPA and the POTW authority concerning administrative feasibility should consider the permitting process and effects of existing local ordinances. If pollutants exist in the CERCLA wastewater that the POTW did not previously handle, the NPDES permit may require modifications, the pretreatment program may require revisions to regulate the new pollutant or increased discharges. In such cases, the P01W may be unwilling to have the changes made, or the required changes may not be feasible in a timely manner. Similarly, local ordinances may include prohibitions that make it illegal for the POTW to ------- accept the CERCLA wastes, (e.g., restrictions on accepting only domestic discharges). Consequently, it i necessaiy to ensure compliance with these laws and regulations or to see if the possibility of obtaining variances exists. There also may be liability issues associated with a POTW’s accepting Superfund wastes. Section 107 of CERCLA states that whenever there is a release or a threatened release of a hazardous substance, the responsible parties can be held liable for the costs of cleanup of that release. Potentially responsible parties (PRPs) include current owners and operators of the facility, those who owned and operated the facility at the time of the release, persons who transported the substances and selected the disposal facility, the generators of the waste, and the persons who arranged for disposal or treatment of the hazardous substances. Under CERCLA Section 107(j), federally permitted releases as defined in Section 101 (10) are not subject to such liabilities. These releases include discharges covered by an NPDES permit, permit application, or permit administrative record. These releases also include the introduction of any pollutant into a POTW when such pollutant is specified in (and in compliance with) pretreatment standards, and a pretreatment program has been submitted to EPA for approval Therefore, local limits should be established for all of the pollutants that exist in the CERCLA wastewater to eliminate the possibility of the POTW’s being held liable for the release of hazardous wastes. Section 119 of CERCLA does not authorize indemnification from liability to facilities regulated under RCR.A. including RCRA Permit-By-Rule POTWs. At this time, EPA believes that an extension of indemnification to POTWs, even those not subject to RCRA regulations, would be inconsistent with Congressional intent. 5. Evaluate POTW Pretreatment Requirements Once the best candidate(s) for receiving the discharge has been determined using the four steps outlined above, a POTW-specific analysis 01 pretreatment requirements designed to prevent pass through, inhibition, and sludge contamination at a POTW should be conducted to ensure that CERCLA discharges are in compliance. Section 307(b) of the CWA established the National Pretreatment Program, which specifies three types of pretreatment standards. general prohibitions, national categorical standards, and local limits (see Highlight 2). General prohibitions are intended to address site- specific problems at POTWs and to apply a broad baseline level of control to all industrial users discharging to any POTW. National categorical standards are technologically-based effluent limits that must be achieved prior to introduction into a POTW of wastes generated by particular categories of industry, such as leather tanning and metal finishing. [ EPA however, has not promulgated specific national categorical pretreatment standards that govern the discharge of CERCLA wastes to a POTW. As a result, CERCLA wastes are treated as non-domestic wastestreams, and are subject to the general pretreatment regulations.] Local limits are specific requirements developed and enforced by individual POTWs to implement the national general prohibitions and categorical standards. Highlight 1 TECHNICAL FACTORS AFFECTING THE FEASIBILITY OF DISCHARGING TO A POTW • The POTW’s hydraulic and organic load capacity; • The suitability of the POTW’s unit operations for treatment of contaminants; • If the CERCLA wastestream will be discharged to a sewage collection system, whether that system is separate from or combined with the storm drain system, and the capacity of that system to provide proper containment of the wastestream; • Whether there are combined sewer overflows between the site and the POTW, • The adequacy of the capacity and age of the sewer piping system for the CERCLA discharge flow rate; • The sludge disposal processes currently employed by the POTW; and • The likelihood that the POTW could treat the CERCLA wastestreani for the duration required ------- POTWs also may have a State-approved pretreatment program and be required to have mechanisms in place to ensure that dischargers comply with applicable pretreatment standards and requirements. Most POTWs likely will require some type of self-monitonng program and submission of monhtonng results to the POTW on a periodic basis. An approved pretreatment program for a POTW may not address all of the constituents of the CERCLA discharge, in which case the site manager must proceed as though an approved pretreatment program did not exist, i.e., site managers must determine whether sufficient mechanisms exist to enable the POTW to ensure compliance with appropriate pretreatment requirements. Whether an approved pretreatment program exists or not, compliance with applicable regulations must be achieved. If an approved program exists, the evaluation of a POTW’s pretreatment requirements consists of obtaining the local limits enforced by the POTW to prevent pass through, inhibition, and sludge contamination If an approved program does not exist or if the pretreatment program does not address all of the components of the CERCLA waste, local limits must be estimated by calculating the mass balances of the wastestream to be disposed. Estimating Local Limits to Meet Standards Ideally, the POTW will have existing local limitations for all of the contaminants present in the CERCLA discharge. However, in many cases, the POTW will not have local limitations for all of the contaminants in the CERCLA discharge or existing limits may need to be changed as a result of the discharge. In this case, the limits must be developed by the POTW or estimated by the site managers so that pretreatment alternatives may be evaluated. Promulgated national categorical pretreatment standards can he used in calculating local limits for the CERCLA wastewater constituents where limits do not already exist. When the estimation of local limitations is necessary, the following measures may be taken: • Obtain Pertinent Regulatory Criteria to Ensure Compliance of Estimated Limits With the Criteria In estimating local limits it is necessary to comply with limits that have been established on the Federal and State levels. Furthermore, consulting these limits can give necessary guidance for establishing limits on the local level. • Calculate a mass balance for each Compound detected in the CERCLA waste using treatabilitv The purpose of the mass balance is to calculate the general treatment efficiency of the POTW and identify which POTW removal mechanisms will be impacted by the removal of each constituent from the CERCLA wastestrearn. There are several options for calculating the mass balance of a particular contaminant, including the use of POTW-specific or published treatability data and the use of computer models. • Evaluate the impact of each contaminant on air emissions, treatment plant operations, sludge disposal. and effluent air quality : Data exists (for most contaminants) that makes it possible to calculate the concentration of those contaminants in air emissions, sludge, and also the amount that will be biodegraded by certain operations. Highlight 2 PRETREATMENT STANDARDS SPECIFIED tSNDER THE OVA General Prohibitions - Nationat prohibitions that are applicable to nondomestic uses that control the introduction of contaminants into POTWs to (a) prevent interference (i e, a discharge that inhibits or disrupts a FOTW causing a violation of its t4PDES permit or other requirements) with the operations of a P0Th’, and (b) prevent pass through (i e, any discharge to a POTW in concentrations thai cause a violation of any requirement of the POTW’s NPDES permit) of contaminants through the POTW • National Categoilcal Standards National prohibitions that apply to all non-domestic users and protect against (a) fire or explosion hazard in the sewers or POTWs (b) corrosive structural damage to the POTW, (c) obstruction of flow in ihe sewer system, (d) interference due to the pollutants’ high concentration or flow rate, or (e) an increase in temperature ot wasiewater entering the POTW that inhibits biological activity resulting in interference • Local Limits. Specific requirements that are developed and enforced by individual POTWs to implement the national general and specific prohibitions States and localities also may impose more su-ingent requirements than the national limits on disdiargers to their regulated facilities • Estimate local limits and the expected level of ------- pretreatment necessary to ensure continu i compliance with NPDES permit limits and applicable air emission standards, avoiding any exceedance of State water quality standards and maintaining acceptable levels of sludge quality . Using the local limits and the composition of the CERCLA wastewater, determine if and when additional pretreatment is necessaiy to ensure compliance with the POTW’s pretreatment requirements. (Eventually, the estimated limits must be transferred by the P01W mw enforceable limits. Because this process may take tune and cause a delay in the evaluation process, site managers should begin this evaluation as early as possible). Determining Pretreatment Options Generally, site managers will have several pretreatment options to achieve the identified limits in effect at a POTW: - Treatment technologies--(e.g., aerobic biological treatment, precipitation, and oxidation), • Separation technologies--(e.g., clarification, filtration, and oil and grease separation); • Polishing technologies--(e.g., carbon adsorption and ion exchange). [ Note: in many cases, these technologies may have already been evaluated as pan of other alternatives not involving discharge to a POTW.] Once possible treatment technologies are identified based on the nature of the CERCLA wastes and the pretreatment requirements of the P01W, it is necessary to develop a pretreatment program that will result in CERCLA wastewater that complies with the POTW’s pretreatment requirements. The key steps in the process for evaluating the feasibility of discharging CERCLA wastes to a POTW are summarized in Highlight 3. Highlight 3 PROCESS FOR EVALUATING CERCLA DISCHARGES TO POTWs L- . 1 W i....lu . • ldenti?y the slt. .wecrlc cERct.A Wret er dIsctra, es • Determine data requirements arid coOed data to fulfill these requirements • Evaluate all ava1Ia 4 data to th eda.want • Determine if the CERCLA t er a RCPA ha2ar j3 2. Id.l Iy Local PO1Ws • Determine geoQraphlc area to bo • Consider methods ransporting the eal.am to the P01W • identify potentIal PO1Ws arid g Ier Ev*iat, ‘J. R.guiatory Stabs. • tv oalIgate the compliance ataru, ot the P01W • if cERc*.A waaiettream Is a hazardous waate determine If Domestic Sewage Earfuslon Is applicable If not. determine Permit - by - Rule requirements Evabset. Tsctelcd 4 • Contoct the P01W to determine if they are willing to occagt a CEACLA eeneim • Evaluate the P01Ws ability to handle and ppert treat the CEACLA wast Tsarn • Address and discuss me PO1W8 potential liability a onTed with occepllng a CER A wesreaneam • Evaluate the current permits ot the P01W and determine changes required and rer permte needed Evabiet. Prebeabew* 5 • Oblain or estimate the local limItS eryfo, ..U by tha P01W to present p thmugli Innlbflicn and sludge comamthabon • Compare CERCLA dIscharge ctiarscterlstlcs to local Ittst odeterminewiiicf i contaminants muirepretreatmeru • identify pocaible pretreatment technologies • Develop a pretreatment pm a train to properly pretreat th. CERCLA w esseam ------- |