Florida Administrative Code › 62 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 62 - Departmental › Chapter 62-610 - REUSE OF RECLAIMED WATER AND LAND APPLICATION › Part IV - RAPID-RATE LAND APPLICATION SYSTEMS (RAPID INFILTRATION BASINS AND ABSORPTION FIELDS) › Section 62-610.523 - Design and Operation Requirements

Current through Reg. 50, No. 138; July 16, 2024
(1) Hydraulic
				  loading rates shall be developed on the basis of representative percolation
				  tests (drainfield percolation tests described in Chapter 64E-6, F.A.C., are
				  inappropriate) which simulate actual loading conditions that will prevail
				  during the design life of the rapid-rate system. This shall involve bench-scale
				  or pilot-scale hydraulic testing with either the actual reclaimed water to be
				  applied, or other water properly adjusted to correspond to the composition of
				  the reclaimed water to be applied. The design loading rate shall allow for the
				  expected gradual reduction in percolation rate due to long-term application of
				  reclaimed water.
(2) The design
				  hydraulic loading (and application) rate shall be related to the hydraulic
				  conductivity and transmissivity and of the geologic formations at the project
				  site which shall be evaluated in-depth by the permittee, with assistance from
				  organizations or individuals qualified by training or experience in soil
				  science, geology, and hydrology.
(3) Initial average annual hydraulic loading
				  rates shall be limited to 3 inches per day, or 1.9 GPD/FT2, as an annual
				  average where hydrogeologically feasible and as applied to the total bottom
				  area of rapid infiltration basins, percolation cells, or absorption fields. For
				  absorption fields, the bottom area shall be calculated by multiplying the
				  bottom width of the absorption field trench by the length of the absorption
				  field application/distribution lines. An applicant may request higher average
				  annual loading rates based on justification provided in the engineering report,
				  but such rates shall not exceed 9 inches per day (5.6 GPD/FT2), unless the
				  requirements of Rule  62-610.525, F.A.C., are met. The
				  average annual hydraulic loading rate shall be related to the clear water
				  saturated vertical hydraulic conductivity for the most restrictive layer in the
				  unconsolidated medium underlying the site. However, application rates during
				  the loading cycle for individual rapid infiltration basins, percolation cells,
				  or portions of the absorption field comprising the system will depend on the
				  average annual hydraulic loading rate and the loading/resting cycle for the
				  system. Application rates during the loading cycle shall be conservative and
				  shall not exceed 25 percent of the documented vertical hydraulic conductivity,
				  as described above, to control ground water mounding and ensure hydraulic
				  performance of the system. Application rates during the loading cycle may
				  exceed the maximum average annual hydraulic loading rates specified above.
				  Justification for the use of selected design hydraulic criteria shall be
				  required in the engineering report. These design criteria shall be based on the
				  pollutant load in the reclaimed water to be applied, the characteristics of the
				  underlying soil and aquifer system, loading and resting cycles to be used, and
				  other process design considerations (including denitrification reactions that
				  may be incorporated into the facility's design).
(4) Hydraulic loading and resting cycles
				  shall be developed so as to restore operating percolation rates of the pond
				  system to design levels by the end of the resting period. Hydraulic loading
				  periods of 1-7 days with resting periods of 5-14 days to dry the cell bottoms
				  and enable scarification or removal of deposited solids are required. Design
				  loading and resting cycles and other maintenance measures required to ensure
				  system performance shall be described in the engineering report. Systems which
				  achieve restoration of design operating percolation rates on a diurnal cycle
				  shall meet the requirements of Rule
				   62-610.525, F.A.C. Loading and
				  resting cycles are required for absorption fields. Loading and resting periods
				  for absorption fields may vary from the requirements for rapid infiltration
				  basins, if the applicant provides an affirmative demonstration that the
				  alternative loading and resting cycle will enable compliance with the ground
				  water criteria at the edge of the zone of discharge.
(5) A ground water mounding analysis based on
				  site-specific information shall be included in the engineering report. This
				  analysis shall demonstrate acceptable long-term hydraulic performance of the
				  system. The ground water mounding analysis shall demonstrate that the ground
				  water mound will not intercept the ground surface during any portion of the
				  loading cycle during any time of the year. The ground water mounding analysis
				  shall demonstrate that increases in ground water elevations shall not interfere
				  with reasonable uses of adjacent properties.
(6) Rapid infiltration basins, percolation
				  ponds, basins, trenches, or cells shall be routinely maintained to control
				  vegetation growth and to maintain percolation capability by scarification or
				  removal of deposited solids.
(7)
				  Rapid infiltration basin, percolation pond, and trench bottoms shall be
				  designed, constructed, and maintained to be level.
(8) Provisions shall be made in the design to
				  ensure reasonably uniform distribution of reclaimed water across the entire
				  bottom area of rapid infiltration basins, percolation ponds, basins, or cells.
				  Multiple discharge points (normally three or less) may be needed to accomplish
				  this. Elaborate sprinkler distribution systems shall not be required for rapid
				  infiltration basins. Absorption fields shall be designed and constructed to
				  ensure reasonably uniform distribution of reclaimed water across each portion
				  of the absorption field system.
(9)
				  The physical characteristics of unconsolidated materials overlying the bedrock
				  shall be such that direct rapid movement (short-circuit) of the applied
				  reclaimed water to underlying aquifers does not occur, unless the requirements
				  of Rule  62-610.525, F.A.C., are
				  met.
Rulemaking Authority
						403.051,
						403.061,
						403.087 FS. Law Implemented
						403.021,
						403.051,
						403.061,
						403.062,
						403.085,
						403.086,
						403.087,
						403.088
						FS.
New 4-4-89, Amended 4-2-90, Formerly 17-610.523, Amended
						1-9-96, 8-8-99, 4-1-21.