The statement of scope for this rule, SS 121-19, was approved by the Governor on December 5, 2019, published in Register No. 768A2 on December 9, 2019, and approved by the Natural Resources Board on May 27, 2020. This rule was approved by the Governor on December 16, 2021. ORDER OF THE STATE OF WISCONSIN NATURAL RESOURCES BOARD
CREATING RULES
The Wisconsin Natural Resources Board adopts an order to create NR 220.02 (13m) and 229 relating to regulation of wastewater discharges from dental offices to sanitary sewers and affecting small business. |
WY-14-19
Analysis Prepared by the Department of Natural Resources
2. Statutory Authority: The department is required to promulgate by rule effluent limitations, standards of performance for new sources, toxic effluent standards or prohibitions and pretreatment standards for any category or class of point sources established by the U.S. environmental protection agency and for which that agency has promulgated any effluent limitations, toxic effluent standards or prohibitions or pretreatment standards for any pollutant under s. 283.11 (1), Wis. Stats. 3. Explanation of Agency Authority: Section 283.001 (2), Wis. Stats., allows the department to establish, administer and maintain a state pollutant discharge elimination system in order to regulate the discharge of pollutants within the state. Section 283.001 (2) states in part, “The purpose of this chapter is to grant to the department of natural resources all authority necessary to establish, administer and maintain a state pollutant discharge elimination system.” Section 283.13 (2), Wis. Stats., requires that point sources of pollutants other than publicly owned treatment works (POTWs) and storm water dischargers are required to implement application of the best practical control technology to reduce the discharge of pollutants from point sources, specifically those categorized as toxic. Section 283.13 (2) reads in part: “The discharge from any point source, other than a publicly owned treatment works or a source of storm water permitted under s. 283.33, shall comply with the following requirements: (a) Best practicable technology. The application of the best practicable control technology currently available.
(b) Requirements for certain pollutants. For pollutants identified under pars. (c), (d) and (f):
1.
a. The application of the best available technology economically achievable for a point source or a category or class of point sources which will result in reasonable further progress toward the national goal of eliminating the discharge of all pollutants as stated in the federal water pollution control act, as amended, 33 USC 1251 to 1376; or b. The application of the best available technology which will result in the elimination of the discharge of all pollutants if the department finds on the basis of information available to it that the elimination is technologically and economically achievable for a category or class of point sources.
2. The application of any applicable pretreatment requirements or any other requirements under s. 283.21 to any point source discharging pollutants into a publicly owned treatment works. (c) Certain toxic pollutants; compliance by July 1, 1984. Compliance with the effluent limitations under par. (b) with respect to all toxic pollutants referred to in table 1 of committee print number 95-30 of the committee on public works and transportation of the U.S. house of representatives by no later than July 1, 1984.
(d) Other toxic pollutants; compliance within 3 years after limitations are established. Compliance with effluent limitations under par. (b) with respect to all toxic pollutants included on the list promulgated under s. 283.21 (1) (a) but which are not included in the table referred to under par. (c) not later than 3 years after the date the effluent limitations are established.” Section 283.21, Wis. Stats., establishes effluent standards for pretreatment of wastewater and the discharge of toxic pollutants. This section requires the department to establish a list of toxic pollutants, promulgate effluent standards for those pollutants, and establish pretreatment standards for pollutants introduced into publicly owned treatment works that would ordinarily not be treated or would have a negative effect on the facility.
(b) Effluent standards. The department may promulgate by rule an effluent standard, which may include a prohibition, establishing requirements for a toxic pollutant which, if an effluent limitation is applicable to a class or category of point sources, is applicable to that category or class of point sources only if this effluent standard imposes more stringent requirements than are imposed under s. 283.13 (2) (b). An effluent standard promulgated under this section shall take into account the toxicity of the pollutant, its persistence, degradability, the usual or potential presence of affected organisms in any waters, the importance of affected organisms, the nature and extent of the effect of the toxic pollutant on these organisms and the extent to which effective control is being or may be achieved under other regulatory authority.” Section 283.21 (2) (a) reads: “The department shall by rule promulgate pretreatment standards to regulate the introduction into publicly owned treatment works of pollutants which are not susceptible to treatment by such treatment works or which would interfere with the operation of such treatment works.” 4. Related Statutes or Rules: Chapters NR 211, 215, 661, and 662, Wis. Adm. Code. Chapter NR 211, Wis. Adm. Code, establishes requirements for POTWs and point source dischargers of pollutants to POTWs to prevent the discharge of pollutants that would interfere with the operation of the treatment works, pass through treatment works insufficiently treated, or impair the use or disposal of the sludge generated by treatment works. Chapter NR 215, Wis. Adm. Code, is the list of toxic, conventional, and nonconventional pollutants required under s. 283.21, Wis. Stats. Mercury, which is a significant component of dental amalgam, is included on that list under s. NR 215.03 (6) (j), Wis Adm. Code. Chapter NR 220, Wis. Adm. Code, establishes a list of industrial categories for which effluent limitation guidelines and/or pretreatment standards apply and provides for the incorporation of effluent limitations into discharge permits. Chapters NR 221-297, Wis. Adm. Code, contain effluent limitation guidelines for industrial categories of dischargers, just as this proposed rule will for dental offices. Effluent limitation guidelines are typically promulgated by the U.S. Environmental Protection Agency (EPA) and adopted into this range of administrative code chapters, just as is the case with this proposed rule. Chapter NR 661, Wis. Adm. Code, in part identifies solid wastes subject to regulation as hazardous wastes under ch. NR 662, Wis. Adm. Code. Mercury is specifically listed in ch. NR 661 Appendix VIII, HAZARDOUS CONSTITUENTS. Chapter NR 662, Wis. Adm. Code, establishes requirements for storage, transport, disposal, and recordkeeping related to hazardous wastes. Mercury collected in an amalgam separator is classified as a solid hazardous waste under ch. NR 661, Wis. Adm. Code. 5. Plain Language Analysis: The proposed rule requires dental offices to control the discharge of mercury and other metals in dental amalgam to POTWs based on the best available technology or best available demonstrated control technology. Specifically, the requirements are based on the use of amalgam separators and best management practices recommended by the American Dental Association (ADA). The best management practices (BMPs) are:
—prohibiting the discharge of waste (or “scrap”) amalgam; and
—prohibiting of the use of line cleaners that are oxidizing or acidic and that have a pH higher than 8 or lower than 6.
Amalgam separators are a practical, affordable, and readily available technology for capturing mercury and other metals before they are discharged into sewers that drain to POTWs. The mercury collected by these separators can be recycled. This rule also includes a provision to significantly reduce and streamline the oversight and reporting requirements in pretreatment regulations that would otherwise apply as a result of this rulemaking. The rule requires dental offices to meet a performance standard that includes BMPs and the use of an amalgam separator(s) compliant with the 2008 International Organization for Standardization (ISO) 11143 standard (ISO, 2008), or the American National Standards Institute (ANSI)/ADA Specification 108 for Amalgam Separators (2009) with Technical Addendum (2011), (ANSI/ADA, 2009; ANSI/ADA, 2011). ISO, a voluntary standard setting organization, established a standard for measuring amalgam separator efficiency by evaluating the retention of amalgam solids using specified test procedures in a laboratory setting. In order to meet the ISO standard, a separator must achieve 95 percent removal or greater of total solids. The standard also includes requirements for instructions on the use, operation, and maintenance of amalgam separators (see proposed s. NR 229.03 (a) (1) 4., Wis. Adm. Code).
