§ 1147.07. Method of determining wastewater strength characteristics.

(a)

Volume of discharge shall be determined as provided in Section 1147.14 of the Columbus City Codes, 1959.

(b)

Concentration of wastewater.

(1)

Monitored discharge. Monitoring on a periodic basis through direct sampling, utilizing recognized field techniques, equipment and procedures will be used for all major contributors. The BOD ₅ test shall be considered the standard test, however, COD or TOC tests may be substituted in cases where it has been determined by the Director that the BOD ₅ test is not representative of actual wastewater loading. Wastewater characteristics shall be determined by the Division of Sewerage and Drainage on the basis of monitored wastewater discharged, a certified statement from the user, or on the best available data, as to the characteristics of such discharges.

(2)

Any change in the ongoing process(es) employed by a user contributing industrial waste which results in a variation of more than twenty-five (25) percent in one or more of the effluent loading concentrations shall be reported to the division of sewerage and drainage within thirty (30) days of said change.

(3)

If it is determined through monitoring that a significant variation exists between the users certified data and the discharge characteristics monitored by the division of sewerage and drainage, surveillance section, the city may adjust sewer charges based on the monitored data from the original date of certification unless written communication has occurred notifying said division of changes in loading and giving specific dates of changes.

(4)

Designated Discharge. Where sampling and gauging of a specific user or user class is not practical for physical, economic, safety, or other reasons; the division of sewerage and drainage may designate values for concentrations of the wastes discharged into the sewerage system for all users in the same standard industrial classification or subclassification. The designated concentrations may be determined by sampling the waste discharges of one (1) or more typical firm(s) in the same classification or by other appropriate means. The resultant designated concentration may serve as the value for all users in a particular classification. Extra strength user wastewater concentrations may be adjusted for an entire classification or for individual users upon determination that the previously assigned concentration was inappropriate. Initially, all users who are placed in a designated user class shall be assigned wastewater concentrations. An annual evaluation may be made for each specific SIC subclass by the division of sewerage and drainage to substantiate the future assignment of specific strengths for similar users in that particular industrial group.

(Ord. 1980-77.)