Michigan Administrative Code › Department - Environmental Quality › Water Resources Division › Water Resources Protection › Part 22 - GROUNDWATER QUALITY › Section R. 323.2216 - Permits for specific discharges

Current through Vol. 24-12, July 15, 2024
Rule 2216.
(1) A
				  wastewater described in this rule may be discharged under a permit issued by
				  the department in compliance with R 323.2217 if the conditions of R 323.2204
				  are met.
(2) A person may discharge
				  less than 20,000 gallons per day of sanitary sewage that has been treated by a
				  system described in subdivision (a) or (b) of this subrule if the treatment
				  system is operated to achieve optimum treatment efficiencies for the specified
				  design as follows:
(a) The discharge receives
				  treatment by a constructed wetland and associated treatment system that meets
				  all of the following requirements:
(i) A
				  minimum of 2 septic tanks installed in series precedes the constructed wetland.
				  The septic tanks shall have a minimum combined volume of 2 times the daily
				  design flow. The outfall to the constructed wetland shall be equipped with a
				  septic tank effluent filter.
(ii)
				  The system shall have a treatment process to enhance nitrification prior to
				  discharge to the constructed wetland.
(iii) If the discharge is expected to have
				  high concentrations of oil and grease, such as sanitary sewage from a food
				  service establishment, then the discharge shall be treated to remove oil and
				  grease.
(iv) The system shall have
				  a minimum of 2 wetland cells to allow for isolation or maintenance of
				  individual cells.
(v) Each wetland
				  cell shall have an aspect ratio, which is length to width ratio, of between 2:1
				  and 4:1.
(vi) The constructed
				  wetland shall have a composite bottom liner in compliance with R 323.2237. The
				  bottom of the wetland cell shall be constructed to be level.
(vii) The wetland cell filter media shall
				  consist of &frac12-inch to 1-inch washed gravel with 100% passing the
				  1.0-inch sieve and a maximum of 3% passing the 1/2-inch sieve.
(viii)The filter media shall not be less than
				  18 inches or more than 30 inches in depth.
(ix) The effective water depth in the wetland
				  cell shall be maintained between a range of 2 to 6 inches below the filter
				  media surface.
(x) The constructed
				  wetland shall be insulated with at least 6 inches of mulch or other comparable
				  substitute and designed to protect against freezing.
(xi) The filter surface area hydraulic
				  loading rate is not more than 1.2 gallons per square foot per day.
(xii) The design retention time shall not be
				  less than 7 calendar days.
(xiii)Indigenous or sterile wetland
				  vegetation, such as bulrushes, common reeds, and cattails, shall be planted on
				  a 1-foot grid across each wetland cell.
(xiv) Wetland vegetation shall be cultivated
				  to maximize the rooted depth throughout the gravel filter media.
(xv) The system shall have the capability to
				  recirculate effluent back into the influent end of the system when additional
				  flow is needed into the system.
(xvi) The wetland cell shall discharge to a
				  tile field designed and constructed in accordance with the provisions of the
				  publication entitled "Michigan Criteria for Subsurface Sewage Disposal," April
				  1994, and approved by the county, district, or city health department that has
				  jurisdiction. Copies of the criteria may be obtained without charge at the time
				  of adoption of these rules from the Michigan Department of Environmental
				  Quality, Drinking Water and Radiological Protection Division, P.O. Box 30630,
				  Lansing, Michigan 48909. If the county, district, or city health department
				  that has jurisdiction chooses not to review the tile field design, then the
				  department shall review and approve the system under this subrule.