34. (1) Subject to subsection (6), for the purposes of this section, a volume of effluent for a stream for a day is the volume that flowed past the sampling point established under section 8 on the stream during the 24-hour period preceding the pick-up of the first sample picked up from the stream for the day. (2) Each discharger shall determine in cubic metres a daily volume of effluent for each process effluent monitoring stream at the discharger’s plant for each day on which a sample is collected under this Regulation from the stream, by integration of continuous flowrate measurements. (3) Despite subsection (2), where a process effluent monitoring stream discharges on an intermittent basis, the daily volumes for the stream may be determined either by integration of continuous flowrate measurements or by the summation of the individual intermittent volume measurements. (4) Each discharger shall use flow measurement methods that allow the daily volumes for process effluent monitoring streams to be determined to an accuracy of within plus or minus 15 per cent. (5) Each discharger shall determine in cubic metres a batch volume of effluent for each process effluent batch monitoring stream at the discharger’s plant, for each batch of effluent for which a sample is collected under this Regulation from the stream, by integration of continuous flowrate measurements. (6) For the purposes of subsection (5), a batch volume of effluent for a process effluent batch monitoring stream for a batch is the volume of effluent that flows past the process effluent batch sampling point established under section 8 on the stream throughout the period of flow of the batch. (7) Each discharger shall use flow measurement methods that allow the batch volumes for process effluent batch monitoring streams to be determined to an accuracy of within plus or minus 15 per cent. (8) Each discharger shall determine in cubic metres a daily volume of effluent for each merged effluent monitoring stream at the discharger’s plant for each day on which a sample is collected under this Regulation from the stream. (9) Each discharger shall use flow measurement methods that allow the daily volumes for merged effluent monitoring streams to be determined to an accuracy of within plus or minus 20 per cent. (10) Each discharger shall determine in cubic metres a daily volume of effluent for each cooling water effluent monitoring stream at the discharger’s plant for each day on which a sample is collected under this Regulation from the stream. (11) Each discharger shall use flow measurement methods that allow the daily volumes for cooling water effluent monitoring streams to be determined to an accuracy of within plus or minus 20 per cent. (12) Each discharger shall, no later than the day that this section comes into force, determine by calibration or confirm by means of a certified report of a registered professional engineer of the Province of Ontario that, (a)  each flow measurement method used under subsections (2) and (3) meets the accuracy requirements of subsection (4); (b)  each flow measurement method used under subsection (5) meets the accuracy requirements of subsection (7); (c)  each flow measurement method used under subsection (8) meets the accuracy requirements of subsection (9); and (d)  each flow measurement method used under subsection (10) meets the accuracy requirements of subsection (11). (13) Where a discharger uses a new flow measurement method or alters an existing flow measurement method, the discharger shall determine by calibration or confirm by means of a certified report of a registered professional engineer of the Province of Ontario that each new or altered flow measurement method meets the accuracy requirements of subsection (4), (7), (9) or (11), as the case may be, within two weeks after the day on which the new or altered method or system is used. (14) Each discharger shall develop and implement a maintenance schedule and a calibration schedule for each flow measurement system installed at the discharger’s plant and shall maintain each flow measurement system according to good operating practices. (15) Each discharger shall use reasonable efforts to set up each flow measurement system used for the purposes of this section in a way that permits inspection by a provincial officer.  O. Reg. 63/95, s. 34. Calculation of Plant Volumes