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(A) Except as provided in paragraphs (A)(1) to (A)(5) of this rule, the minimum design flows and waste strengths in table A-1 of this rule shall be used to design a treatment works sized for one hundred thousand gallons per day or less. The design flow and the waste strength shall be based on the existing and proposed services at the facility, and the justification for the proposed design flow and the proposed waste strength shall be submitted with the permit to install application. In addition to table A-1 of this rule, the director may also consider additional relevant engineering data, including flow monitoring data, computer flow modeling data, flow equalization facilities, potential impacts to upstream sewers and sampling data for waste strength characterization.
(1) Flow monitoring. The director may consider flow monitoring data in addition to the minimum design flow requirements in table A-1 of this rule when evaluating the design of a treatment works sized for one hundred thousand gallons per day or less, provided that the flow monitoring data is obtainable and documented on a daily basis.
(a) The flow monitoring data shall be submitted with the permit to install application and shall:
(i) Be from the facility for which the treatment works is being designed, and be representative of the range of operating conditions that are expected to occur, which includes considering the months, days and hours of operation; or
(ii) Be from a place of like kind, like usage, and located in a similar climate, and be representative of the range of operating conditions that are expected to occur, which includes considering the months, days and hours of operation.
(b) For facilities that operate year-round, at least twelve months of flow monitoring data shall be provided. For seasonal facilities, flow monitoring data shall be provided for the entire operational period within a calendar year.
(2) Computer flow modeling. The director may consider computer flow modeling data in addition to the design flow requirements in table A-1 of this rule when evaluating the design of a treatment works sized for one hundred thousand gallons per day or less. The computer flow modeling data shall be submitted with the permit to install application.
(3) Flow equalization facilities. The director may consider flow equalization facilities at the treatment works or upstream of the treatment works in addition to the design flow requirements in table A-1 of this rule, when evaluating the design of a treatment works sized for one hundred thousand gallons per day or less. The flow equalization data shall be submitted with the permit to install application.
(4) Potential impacts to upstream sewers. The director may consider potential impacts to upstream sewers in addition to the design flow requirements in table A-1 of this rule when evaluating the design of a treatment works sized for one hundred thousand gallons per day or less. Any information regarding the potential impacts to upstream sewers shall be submitted with the permit to install application.
(5) Sampling data for waste strength characterization. The director may consider sampling data in addition to the five day minimum biochemical oxygen demand (BOD5) loading rates in table A-1 when evaluating the design of a treatment works sized for one hundred thousand gallons per day or less, provided that the sampling data is collected daily and that the daily raw data, the seven-day averages (otherwise referred to as average-weekly limits) and thirty-day averages (otherwise referred to as average-monthly limits) are submitted with the permit to install application. The sampling data shall also:
(a) Be from the facility for which the treatment works is being designed, and be representative of the range of operating conditions that are expected to occur; or
(b) Be from a place of like kind, like usage, and located in a similar climate, and be representative of the range of operating conditions that are expected to occur.
[Comment: The NPDES regulations at paragraph (d) of 40 CFR 122.45 (effective July 1, 2005) require that all permit limits be expressed, unless impracticable, as both average-monthly limits (AMLs) and maximum-daily limits (MDLs) for all discharges other than publicly owned treatment works (POTWs), and as average weekly limits (AWLs) and AMLs for POTWs. The MDL is the highest allowable discharge measured during a calendar day or twenty-four-hour period representing a calendar day. The AML is the highest allowable value for the average of daily discharges obtained over a calendar month. The AWL is the highest allowable value for the average of daily discharges obtained over a calendar week.]
[Comment: “C.F.R” refers to the federal “Code of Federal Regulations,” which can generally be found in public libraries and electronically online, and can be purchased from “U.S. Government Printing, Superintendent of Documents, Mail Stop: SSOP, Washington, DC 20402-9328.”]
Table A-1 for Design Flow Requirements
See Table A-1 at http://www.registerofohio.state.oh.us/pdfs/3745/0/42/3745-42-05_PH_FF_N_RU_20060810_1312.pdf
Effective: 11/01/2006
R.C. 119.032 review dates: 11/01/2011
Promulgated Under: 119.03
Statutory Authority: 6111.03, 6111.04, 6111.44, 6111.45, 6111.46
Rule Amplifies: 6111.03, 6111.04, 6111.44, 6111.45, 6111.46