Summary of OPPC Sampling Requirements – Process Operations
Discharge Type | Permitted Monthly Average Concentration of Dispersed Oil | Sampling of Discharges | Quantification of Volume/Weight Discharged | Quantification of Dispersed Oil Discharged | Additional Analysis Required? | Reporting |
Produced Water – routine discharges > 2 tonnes dispersed oil per annum: | 30 mg/l(not to exceed 100 mg/l at any time) | Samples to be taken at least twice daily at equal intervals at sample points detailed in permit schedule. | Volume of produced water discharged shall be measured or calculated to +/- 10% accuracy on volume. | Each dispersed oil analysis result (mg/l) shall be multiplied by the volume of the produced water discharged between samples. If samples taken more than required sampling frequency, all analysis results should be used.Monthly average dispersed oil concentrations (mg/l) shall be calculated by dividing the total weight (tonnes) of dispersed oil discharged each calendar month by the total volume of produced water discharged during the same period.Annual average dispersed oil concentration (mg/l) shall be calculated by summing the total weight (tonnes) of dispersed oil discharged each month over the calendar year, and dividing by the total volume of produced water discharged during the same period. | Yes(biannual) | Monthly report to be submitted by 16th of the month for each preceding calendar month. Reporting via EEMS. |
Produced water – routine discharges < 2 tonnes per annum: | Samples to be taken at least monthly at equal intervals at sample points detailed in permit schedule. | |||||
Produced water – batch discharges: | Number of samples will be detailed in permit schedule. If each batch discharge continues for >12 hours, sampling required at least twice per day at equal intervals at sample points detailed in permit schedule. | |||||
Produced water – contingency discharge (e.g. if PWRI down): | At least one sample to be taken during each contingency discharge. If contingency discharge continues for >12 hours, sampling required at least twice per day at equal intervals at sample points detailed in permit schedule. | Yes(on at least one occasion during each contingency discharge up to a maximum two occasions per year or as directed by DECC) | ||||
Produced water – injection and re-injection: | N/A | Minimum of one sample of re-injected produced water per calendar month at equal intervals at sample points detailed in permit schedule. | Volume of produced water re-injected shall be measured or calculated to +/- 10% accuracy on volume. | As above for produced water discharges. | No | Annual report by 31st January. Report to DECC. |
Displacement water: | 40 mg/l(not to exceed 100 mg/l at any time) | At least one sample to be taken during each discharge. If discharge continues for >12 hours, sampling required at least twice per day at equal intervals at sample points detailed in permit schedule. | Volume of displacement water discharged shall be measured or calculated to +/- 10% accuracy on volume. | As above for produced water discharges. | No | Monthly report to be submitted by 16th of the month for each preceding calendar month. Reporting via EEMS. |
Hazardous and non-hazardous drainage: | 40 mg/l(not to exceed 100 mg/l at any time) | Samples to be taken at a frequency to ensure that a representative sample is achieved. Additional samples to be taken as directed by DECC to demonstrate sampling frequency is representative. | N/A | N/A | No | N/A (records to be maintained for 2 years) |
On-line backwashing of produced sand and scale: | As agreed with DECC | Sampling strategy as agreed with DECC and detailed in permit schedule. | Quantity (kg) of sand and scale discharged to be measured or calculated on a monthly and annual basis. | The monthly total of oil discharged shall be calculated by averaging the results of the oil on sand/scale analysis undertaken during that month, and multiplying the average by the total sand/scale discharge quantity during same period.Annual quantity of oil on sand/scale discharged should be calculated by summing the monthly values. | No | Annual report by 31st January. Report to DECC. |
Off-line backwashing of produced sand and scale(life permit): | No | |||||
Off-line backwashing of produced sand and scale(term permit): | Quantity (kg) of sand and scale discharged during term operation to be measured or calculated. | Calculation of quantity of oil discharged during term operation to be undertaken by averaging the results of the oil on sand/scale analyses undertaken and multiplying average by total sand/scale discharged during same period. | No | Report one calendar month after end of discharge operation. Report to DECC. |