Hawaii Administrative Rules › Title 11 - DEPARTMENT OF HEALTH › Subtitle 1 - GENERAL DEPARTMENTAL PROVISIONS › Chapter 55 - WATER POLLUTION CONTROL › Section 11-55-41 - Zones of mixing

Current through June, 2024
(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.