Monitoring of urban waste water treatment
Monitoring must be implemented, and Member States must provide the Commission with all relevant information concerning the monitoring method used. Flow-proportional or time-based 24-hour samples shall be collected “at the same well-defined point in the outlet and if necessary in the inlet of the treatment plant in order to monitor compliance with the requirements for discharged waste water laid down in this Directive.” The minimum annual number of samples shall be determined according to the size of the treatment plant and be collected at regular intervals during the year in compliance with a table, and depending on the level of p.e. (Annex I-D).
According to the CJEU, while these provisions refer to “a continuing obligation aimed at ensuring that discharges satisfy ‘over time’ the quality requirements which they must have satisfied since the entry into operation of the treatment plant”, they do not require that samples be collected over a full year, and “where a Member State is able to submit a sample meeting the requirements set out in Annex I.B to Directive 91/271, the obligations arising under Article 4 of that directive must be deemed to be satisfied.” (Case C-398/14 Commission v Portugal).
Discharge of industrial waste-water into collective systems and urban waste-water treatment plants are subject to regulations and/or prior authorisations pursuant to further requirements (Article 11). They must most notably be subject to a pre-treatment in order to: protect the health of staff working in collecting systems and treatment plants, ensure that collecting systems, waste water treatment plants and associated equipment are not damaged, that the operation of the waste water treatment plant and the treatment of sludge are not impeded, that discharges from the treatment plants do not adversely affect the environment, or prevent receiving water from complying with other EU Directives, and that sludge can be disposed of safety in an environmentally acceptable manner (Annex I-C).
Biodegradable waste-water from certain food-processing industries must also comply with conditions established in prior regulations and/or specific authorisations on the basis of specific requirements (Article 13).