A. General Requirements: Permittees and nonpermitted industrial users specified by the public works director shall monitor industrial waste discharges into public sewers. Such monitoring shall accurately characterize the discharge and shall be performed in accordance with all applicable provisions of these rules and any permit issued thereunder. Such monitoring information shall be submitted to the public works director in a self-monitoring report. At a minimum, a summary report shall be prepared quarterly and submitted to the superintendent.
B. Monitoring Point:
1. Required: Each permittee shall have an approved monitoring point provided at the permittee's expense. Liquid waste haulers and specific industrial users, may be exempted by permit from portions of this chapter.
2. Criteria For Approval: An approved monitoring point shall meet the following criteria:
a. The wastewater flow is visible and accessible for inspection and monitoring purposes;
b. Adequate safeguards are in place to protect BPUC personnel from accident or injury;
c. The wastewater flow has appropriate velocity and is well mixed to yield representative samples;
d. The wastewater flow at the monitoring point conveys all of the permittee's industrial waste;
e. The monitoring point is large enough or space is provided nearby to allow for monitoring equipment placement; and
f. The total wastewater flow of the permitted facility, if exceeding twenty five thousand (25,000) gallons per day, can be measured using an open channel or other acceptable measuring device.
3. Deadline For Installation: All permittees shall have an approved monitoring point within twelve (12) months of the effective date of this chapter.
4. Design Plans: Design plans for constructing a monitoring point shall be submitted to the superintendent for approval sixty (60) calendar days prior to any construction necessary to meet the criteria specified in this chapter. All new installations shall be in accordance with provisions of the Minnesota plumbing code.
5. Maintenance: Each permittee is responsible for all maintenance on the approved monitoring point, including routine cleaning.
C. Representative Sampling: Representative samples shall be collected by permittees at an approved monitoring point. Sampling shall be conducted on a normal operating day and in accordance with standard monitoring techniques described herein. The samples shall accurately characterize the discharge, taking into account batch discharges, daily production variations, downtime, cleanup and other operating conditions. Each permittee shall accurately determine wastewater flow volumes during periods of sample collection. Flow proportional compositing may be required. Samples shall be collected in a well mixed region of the wastewater. In order to avoid collecting nonrepresentative amounts of sediment or floating material, the intake of the sampling device shall be placed appropriately. When using an automatic sampler, the intake line velocity shall be sufficient to ensure representative sampling of suspended solids. The minimum intake velocity should be two feet (2') per second, the minimum automatic sampler intake line inside diameter shall be one-fourth inch (1/4"). When feasible, the automatic sampler intake shall be downstream of the primary flow device.
D. Grab And Composite Samples: Samples shall be collected as specified in the permit or as determined by the public works director. Grab and/or composite samples may be required. A series of at least four (4) grab samples is required when analyzing wastewater for pH, grease and oil, cyanide, volatile organics, total phenols, and sulfides. For other parameters, grab samples may be required when the wastewater flow is not continuous or when necessary to determine the instantaneous wastewater characteristics. Grab samples can be taken manually or automatically. Composite samples are formed by combing discrete samples collected either manually or by an automatic sampler. Each discrete sample shall have a minimum volume of at least one hundred milliliters (100 ml). Discrete samples can be composited using any of the following methods: 1) equal time intervals and equal volume samples; 2) equal time intervals and unequal volume samples; or 3) unequal time intervals and equal volume samples. Flow proportional composite sampling is the designated method for sample collection for industrial permit holders. Equal time/equal volume composition may only be utilized if the hourly waste flow volumes are nearly constant during the sampling period.
E. Sample Handling Procedures: All samples shall be contained, preserved and held in accordance with code of federal regulations, part 136. The sample temperature shall be maintained at four degrees Celsius (4°C), if necessary, from the time of collection until sample analysis is performed. When applicable, additional preservation shall be performed upon sample collection.
F. Test Procedures For Analysis Of Pollutants: All measurements, tests, and analysis of the characteristics of the industrial wastewaters shall be determined in accordance with the latest edition of "standard methods for the examination of water and wastewater", published by the American public health association. The permittee or the contracted monitoring service and/or commercial analytical laboratory shall document analytical procedures, including, but not limited to, quality control and, if applicable, chain of custody procedures conducted on each sample. The public works director may require that any sample analysis data submitted to fulfill requirements of these rules or any permit issued thereunder be obtained from a laboratory appropriately certified by the Minnesota department of health.
G. Wastewater Flow Measuring: Wastewater volumes discharged by permittees to public sewers shall be accurately determined during sampling periods using metered water supply or wastewater flow measuring devices or both. Metered water supply may be used to determine reporting period discharge volumes if the public works director determines that operating day losses can be accounted for. Operating day losses include, but are not limited to, lawn sprinkling, loss to product, or evaporation. Water meters used for wastewater discharge volume determinations shall be maintained in good operating condition. The public works director may require outside calibration of such meters. In the event that the public works director determines that operating day losses cannot be accounted for, or that the hourly water meter volumes do not correlate with the monitoring point hourly volumes, continuous flow measuring of industrial waste discharges to public sewers shall be required. All continuous flow measuring installations shall meet the following requirements;
1. Primary Flow Device: Primary flow devices including, but not limited to, weirs and flumes, shall be installed such that proper hydraulic conditions exist. Factors used to determine the type, size, and location of a primary flow device include:
a. Flow rate and velocity;
b. Pipe configuration and slope;
c. Turbulence;
d. Presence of nearby tributary flows;
e. Solids concentration; and
f. Other factors.
The primary flow device shall accommodate the maximum expected flow. The primary flow device shall be properly leveled and sealed.
2. Flow Level Sensing Device: The flow level sensing device shall be installed at a proper distance upstream of the primary flow device and in a location where excessive turbulence is not created.
3. Continuous Recording Device: All continuous flow measuring installations shall include a continuous recording device.
4. Maintenance: All continuous flow measuring installations shall be maintained in good operating condition. Records of all maintenance conducted on flow measuring installations shall be kept. Maintenance includes, but is not limited to, the removal of sediment from upstream and downstream of the primary device, and the calibration of the flow meter.
H. Inspections; Access: The public works director shall inspect the facilities of any user to ascertain whether the purpose of this chapter is being met and all requirements are being complied with. Persons or occupants of premises where wastewater is created or discharged shall allow the public works director ready access at all reasonable times to all parts of the premises for the purposes of inspection, sampling, records examination or in the performance of any of their duties. The public works director, MPCA and EPA shall have the right to set up on the user's property such devices as are necessary to conduct sampling, inspection, compliance monitoring and metering operations. Where a user has security measures in force which would require proper identification and clearance before entry into their premises, the user shall make necessary arrangements with any security guards so that upon presentation of suitable identification, the public works director, MPCA and EPA will be permitted to enter, without delay, for the purposes of performing their specific responsibilities.
I. Confidential Information: Information received from a user shall be treated as public unless requested by the user in accordance with section 8-2-9 of this chapter, and in any event in accordance with applicable law.
J. Self-Monitoring Reports:
1. Required: Permittees shall submit complete and accurate self- monitoring reports to the public works director at a frequency stated in the permit.
2. Required Information: Permittees shall use report forms provided by the public works director. Self-monitoring reports may require the permittee to disclose the following information for each reporting period:
a. General facility data;
b. Operational data;
c. Source and volume of all water supplies;
d. Volumes of water used or lost;
e. Use and volume of wastewater discharged to public sewers;
f. Analytical results from wastewater monitoring;
g. Description of sampling and analytical methods; and
h. Other information as is relevant to determining compliance with these rules.
3. Frequency Of Reports: The frequency of routine reporting shall be based on the reporting schedule included in the individual permit. The minimum reporting frequency shall be quarterly. Industrial waste discharges subject to a strength charge or a cumulative annual metal limit shall report monthly. Liquid waste haulers shall report monthly. Refer to section 8-2-14 of this chapter for additional sampling and reporting requirements.
4. Modification Of Reporting Schedule: The public works director may modify the above reporting schedule for any permittee based on the permittee's industrial waste characteristics or any other relevant consideration.
5. Compliance With Regulations: Permittees subject to categorical pretreatment standards shall submit self-monitoring reports and other required reports to the BPUC in accordance with the general pretreatment regulations established under the act and any requirement of a categorical pretreatment standard.
6. Due Dates: Permittees shall submit complete self-monitoring reports to the public works director such that the public works director has received such reports on or before the thirtieth calendar day of the month following the end of each applicable reporting period. (2002 Code)