(a) Any significant industrial user discharging industrial or commercial wastes into the sewer system shall construct and maintain at his expense a suitable control manhole, or pump station wetwell downstream from any treatment, storage or other approved works to facilitate observation, measurement and sampling of all wastes, including all domestic sewage from the establishment. The control manhole or wetwell shall be constructed at suitable and satisfactory locations either on public or private property and shall be built in a manner approved by the city. If any establishment wishes to meter its waste discharge into the sewer system to verify the end product, water retention or other uses of metered flow, the establishment may install a metering device as approved by the city. The control manhole shall be accessible to city personnel at all times for sampling. Construction shall be completed within three months following written notification by the city.

(b) Where, in the opinion of the city manager in concert with the city's consulting engineer, the potential exists for contamination of groundwater surrounding any establishment, the city may require to be installed at the owner's expense one or more observation or monitoring wells. The well shall be constructed at a suitable and satisfactory location and installed in a manner approved by the city. The monitor well shall be accessible to city personnel at all times for sampling.

(c) All authorized city employees shall be permitted, upon suitable notice to the user, to enter upon all properties for the purposes of inspection, observation, measurement, sampling and testing and shall have the authority to inspect records in accordance with this division.

(d) Every noncompliant and significant industrial user shall file a discharge monitoring report every three months with the city. The report shall include a brief description or listing of in-process modifications or pretreatment processes which were employed during the reporting period to reduce pollutant concentrations and discharge rates. Where the industry is involved in material processing or manufacturing, the report shall also include production quantities (raw material and/or product) and hours of operation, both to be recorded for each day of the report period. Information concerning discharge quantity and rate and the concentration of controlled pollutants shall be included for all significant industrial users. Quarterly reporting periods will end on the last day of the months of March, June, September and December and must be submitted to the city within 15 days following those dates.

(e) Every significant industrial user shall maintain such records of production quantities, discharge volumes, discharge rates and pollutant amounts or concentrations as are necessary to demonstrate that his operation and discharge of waste does not adversely affect operation of the city's wastewater treatment system. Where specific pretreatment requirements and discharge limitations have been adopted, whether by the federal government, the state or the city, a significant industrial user to whom the adopted requirements and limitations apply shall maintain sufficient additional records as are necessary to demonstrate compliance according to the following:

(f) Compliance determinations with respect to sections 78-96 and 78-98 shall be made on the basis of the inspection, monitoring, sampling and analysis procedures described as follows:

(g) Samples shall be obtained at a minimum frequency of once a month during each quarterly reporting period on and during a workday which typically represents the user's activity. The sample shall be a 24-hour composite sample which will be representative of the discharge occurring throughout the duration of the workday. Samples shall be analyzed by a reliable and recognized testing laboratory using procedures stipulated in Standard Methods or other methods acceptable to the U.S. Environmental Protection Agency.

(h) For all significant industrial users, samples shall, at a minimum, be analyzed for the following pollutants:

(i) Where specific user class pretreatment requirements and discharge limitations have been adopted by the federal government, the state or the city, additional analyses shall be performed for any additional pollutants which are to be limited or prohibited. Other types of analyses may also be specified by the city if considered necessary to demonstrate compliance with section 78-96.

(j) The results of sample analyses shall be submitted to the city with the quarterly discharge report, together with any pertinent information concerning the discharge flow rate and production quantities and any other internal factors that may have directly affected pollutant concentrations during the particular days that samples were taken. If required for compliance determination, the city may direct that additional samples be obtained at the user's expense. Alternately, the city may elect to obtain and have analyzed supplemental samples at its own expense.