Section 11-55-41 - Zones of mixing(a) Zones of mixing are defined and authorized for use in discharge permits in section 11-54-1. Zones of mixing allow for dilution of wastes before compliance with the applicable water quality criteria must be met. Zones of initial dilution are a subset of zones of mixing that are applied to toxic pollutants.(b) Establishment, renewal, and termination. (1) Application for establishment of a zone of mixing shall be made concurrently with any discharge permits whenever applicable and the conditions of a zone of mixing shall be incorporated as conditions of the discharge permits. Every application for a zone of mixing shall be made on forms furnished by the director and shall be accompanied by a complete and detailed description of present conditions, how present conditions do not conform to standards, and other information as the director may prescribe.(2) Each application for a zone of mixing shall be reviewed in light of the descriptions, statements, plans, histories, and other supporting information as may be submitted upon the request of the director, and in light of the effect or probable effect upon water quality standards established pursuant to chapter 11-54.(3) Whenever an application is approved, the director shall establish the zone of mixing, taking into account the environmental impact, including but not limited to factors such as the protected uses of the body of water, existing natural conditions of the receiving water, character of the effluent, and the adequacy of the design of the outfall and diffuser system to achieve maximum dispersion and assimilation of the treated or controlled waste with a minimum of undesirable or noticeable effect on the receiving water.(4) Approval of a zone of mixing shall be made either after a public hearing is held by the director in the county where the source is situated, in accordance with chapters 91 and 92, HRS and the rules of practice and procedures of the department, or after the public notification and comment process duly established for a discharge permit in the case when the zone of mixing is being considered concurrently with the discharge permit.(5) No zone of mixing shall be established by the director unless the application and the supporting information clearly show that: (A) The continuation of the function or operation involved in the discharge by the granting of the zone of mixing is in the public interest;(B) The discharge occurring or proposed to occur does not substantially endanger human health or safety;(C) Compliance with the existing water quality standards from which a zone of mixing is sought would produce serious hardships without equal or greater benefits to the public; and(D) The discharge occurring or proposed to occur does not violate the basic standards applicable to all waters, will not unreasonably interfere with any actual or probable use of the water areas for which it is classified, and has received (or in the case of a proposed discharge will receive) the best degree of treatment or control.(E) The capacity of the receiving water to dilute a pollutant or assimilative capacity is available in the receiving water for the pollutant in which a zone of mixing is being requested.(6) Any zone of mixing or renewal thereof shall be established within the requirements of this section and for time periods and under conditions consistent with the reasons within the following limitations:(A) If the zone of mixing is established on the grounds that there is no reasonable means known or available for the adequate prevention, control, or abatement of the discharge involved, it shall be allowed only until the necessary means for prevention, control or abatement become practicable, and subject to the taking of any substitute or alternative measures that the director may prescribe. No renewal of a zone of mixing established under this subsection shall be allowed without a thorough review of known and available means of preventing, controlling, or abating the discharge involved;(B) The director may issue a zone of mixing for a period not exceeding five years;(C) Every zone of mixing established under this section shall include conditions requiring the applicant to perform effluent monitoring, at a minimum, for pollutants with effluent limitations established in the permit, and receiving water quality monitoring, at a minimum, for pollutants for which a zone of mixing is established. Additional effluent and receiving water monitoring, including monitoring of bottom biological communities, may be required as appropriate. The results of all required monitoring shall be reported to the director. A program of research to develop reasonable alternatives to the methods of treatment or control in use by the applicant may be required if research is deemed prudent by the director; and(D) In order to prevent high temperature discharges from violating section 11-54-04 (a) (4), no new or increased domestic, industrial, or other controllable source shall discharge at a maximum temperature which will cause temperatures to exceed three degrees Celsius above ambient, or thirty degrees Celsius, whichever is less, within one meter of the bottom within a zone of mixing. For discharges with or without submerged outfalls, the director may make a limited allowance for higher discharge temperatures if there is satisfactory demonstration that the elevated temperature will not cause damage to the local aquatic community. (7) Any zone of mixing established pursuant to this section may be renewed from time to time on terms and conditions and for periods not exceeding five years which would be appropriate on initial establishment of a zone of mixing, provided that the applicant for renewal meets the requirements in section 11-55-41. The renewal shall provide for the discharge not greater in quantity of mass emissions than that attained pursuant to the terms of the immediately preceding zone of mixing at its expiration, unless such an increase is in accordance with state and federal anti-degradation and anti-backsliding regulations as applicable. Any new zones of mixing or requests for zone of mixing renewals for wastewater treatment plants performing primary treatment shall comply with section 301(h) of the Federal Water Pollution Control Act of 1972 (33 U.S.C. 1251) . No renewal shall be allowed except upon application. Any renewal application shall be made at least three hundred and sixty days prior to the expiration of the zone of mixing.(8) No zone of mixing established pursuant to this part shall be construed to prevent or limit the application of any emergency provisions and procedures provided by law.(9) Each mixing zone may be subject to revocation, suspension, or modification if, after notice and opportunity for a hearing pursuant to chapter 91, HRS and the rules of practice and procedures of the department, the director determines that the terms specified in section 342D-6, HRS have been violated. In taking any action, the director may consider operating records, compliance investigations, or other information regarding discharge quality or impact on receiving waters. The action shall be effected by giving written notice to the permittee, which shall contain the reasons for the action.(10) The director shall be notified within thirty days of the permanent discontinuance of a discharge. The zone of mixing shall terminate thirty days after such notification has been received.(11) Upon expiration of the period stated in the designation, the zone of mixing shall automatically terminate and no rights shall become vested in the designee. [Eff and Comp OCT 22 2021] (Auth: HRS §§ 342D-1, 342D-4, 342D-5) (Imp: HRS §§ 342D-4, 342D-5)