Whilst mentoring a food processing client in Ireland on ISO14001 implementation we expressed concern over phosphate levels in waste water being discharge to a lake. These levels were in breach of the Consent to Discharge which was set at 2 mg/L. We lead a review of all processes including the use of detergents and no reason could be identified for the elevated levels.
The client was adamant that the detergents used were phosphate free and a review of the data sheets confirmed this impression. As there was no other explanation for the elevated phosphate levels we advised independent testing of the detergents by a UKAS accredited lab. The results were a surprise, the phosphate levels in the allegedly phosphate free detergents were significant. In all nine different ‘phosphate free’ detergents were analysed at their recommended working dilutions, seven of these had orthophosphate concentrations of greater than 2 mg/L. One particular ‘phosphate free’ detergent had an orthophosphate level of 12 mg/L at the recommended dilution.
The take away from this tale is to never take anything at face value when investigating the root cause of a non-conformance.