Quick answer
- Every company that discharges wastewater needs a discharge permit: either to the sewerage system (system operator or local council) or to the environment (Catalan Water Agency, Agència Catalana de l'Aigua).
- The permit sets limit values for each parameter and a programme of self-monitoring at a set frequency.
- Analyses must be carried out by laboratories accredited by ENAC, the Spanish accreditation body, and the results are submitted to the competent authority.
- A result above the limit is not the end of the story: there are deadlines and corrective measures that need to be managed properly.
The discharge permit and its conditions
The discharge permit or authorisation is the document that sets out what your company may discharge, where and with what characteristics. If the discharge goes to the sewer network, it is granted by the operator of the sewerage system (in Catalonia, under the Regulations on public sewerage services, Reglament dels serveis públics de sanejament); if it goes directly to a watercourse or the sea, by the Catalan Water Agency. In addition, companies that use water and discharge it periodically file the DUCA (Water Use and Pollution Declaration).
The permit includes emission limit values (pH, conductivity, COD, suspended solids, oils and greases, metals, nitrogen, phosphorus, etc.) and a self-monitoring programme: which parameters to measure, how often and how to report the results.
How to carry out self-monitoring that is fit for purpose
- Representative sampling. At the control point set in the permit, under normal production conditions and with a documented chain of custody. Poor sampling invalidates the analysis.
- Accredited laboratory. Analyses must be carried out by laboratories accredited by ENAC for those parameters and those matrices. Otherwise, the authorities may refuse to accept the results.
- Reporting on time. Results are reported to the competent authority at the frequency set in the permit. Failing to report them is a breach even if the values are compliant.
- Interpretation. Compare each parameter with its limit and with the historical record. An upward trend gives warning before the breach actually occurs.
If a parameter exceeds its limit
The first step is to confirm the result (duplicate sample or repeat analysis) and look for the cause: a new process, a fault in the treatment plant, a different chemical product. The next step is to make the required notifications and propose corrective measures with deadlines. In inspections involving sampling, the permit holder is entitled to a duplicate sample: having it analysed in parallel is the only way to challenge a result.
Our sampling and analysis service
- On-site sampling
We collect the samples at your plant and transport them to the laboratory with a documented chain of custody. - Accredited analysis
Laboratories accredited by ENAC for the parameters in your permit. - Submission of self-monitoring results
If the analysis fulfils a self-monitoring requirement, we submit it to the competent authority on your behalf. - Compliance report
We assess each parameter against its limits and tell you where you have margin and where the risk lies. - Duplicate samples and advice
We analyse inspection duplicate samples and advise you in the event of a breach.
Not sure whether it affects you?
If you need to meet a self-monitoring requirement in your licence, or simply want to know what is going down your drain, call us on 934 09 80 30 and we will arrange the sampling.