Sample reporting terms

The following apply to all dischargers: (1) Calculate Average Concentration (in mg/lL or ug/lL) as the sum of the sample concentrations taken (and analyzed) during the month divided by the number of samples analyzed. Report average concentrations on the SMR/DMR form if numerical limitations are given or reporting is required by the permit. (2) Calculate Average Limitations as follows: (A) "7-day average" or "weekly average", other than for bacteria, is the arithmetic mean of the daily values for all effluent samples collected during a calendar week, calculated as the sum of all daily discharges measured during a calendar week divided by the number of daily discharges measured during that week. The "7-day average" for bacteria is the geometric mean of the values for all effluent samples collected during a calendar week. (B) "30-day average" or "monthly average", other than for bacteria, is the arithmetic mean of the daily values for all effluent samples collected during a calendar month, calculated as the sum of all daily discharges measured during a calendar month divided by the number of daily discharges measured during that month. The "30-day average" for bacteria is the geometric mean of the values for all effluent samples collected during a calendar month. (3) The Daily Average Concentration means the arithmetic mean (weighted by flow value) of all the daily determinations of concentration made during a calendar month. Daily determinations of concentration made using a composite sample must be the concentration of the composite sample. When grab samples are used, the daily determination of concentration must be the arithmetic mean (weighted by flow value) of all the samples collected during that calendar day. (4) The numerical limitations listed under Maximum Allowable Concentration (in mg/lL or ug/lL) represent the highest level of the pollutant which is allowed to be discharged to a receiving water under any flow conditions of the effluent. The permittee must report the highest single concentration for all samples analyzed during the month on the SMR/DMR form if numerical limitations are given or reporting is required by the permit. (5) The Daily Maximum Concentration means the highest daily determination of concentration for any calendar day. (6) Determine the Daily Average Discharge by calculating the total discharge by weight during a calendar month divided by the number of days of operation in the month. Where less than daily sampling is required by the permit, the daily average discharge must be determined by the summation of all the measured daily discharges by weight divided by the number of days during the calendar month when the measurements were made. (7) The Daily Maximum Discharge means the total discharge by weight during any calendar day. (8) The loading (in lbs/day) is calculated by multiplying each sample concentration (in mg/lL) by 44 the simultaneous effluent flow rate (in mgdMGD) with a conversion factor of 8.34 stated in the equation: Loading (in lb/day) = Concentration (in mg/lL) x Simultaneous Effluent Flow Rate (in mgdMGD) x 8.34. (9) Determine the Average Loading by the sum of all the loadings divided by the number of loadings calculated. (10) The Maximum Loading is reported as the highest single loading for all samples analyzed during the month.