COUNCIL DIRECTIVE of 21 May 1991 concerning urban waste water treatment (91/271/EEC)

‘urban waste water’ means domestic waste water or the mixture of domestic waste water with industrial waste water and/or run-off rain water;

‘domestic waste water’ means waste water from residential settlements and services which originates predominantly from the human metabolism and from household activities;

‘industrial waste water’ means any waste water which is discharged from premises used for carrying on any trade or industry, other than domestic waste water and run-off rain water;

‘agglomeration’ means an area where the population and/or economic activities are sufficiently concentrated for urban waste water to be collected and conducted to an urban waste water treatment plant or to a final discharge point;

‘collecting system’ means a system of conduits which collects and conducts urban waste water;

‘1 p.e. (population equivalent)’ means the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day;

‘primary treatment’ means treatment of urban waste water by a physical and/or chemical process involving settlement of suspended solids, or other processes in which the BOD5 of the incoming waste water is reduced by at least 20 % before discharge and the total suspended solids of the incoming waste water are reduced by at least 50 %;

‘secondary treatment’ means treatment of urban waste water by a process generally involving biological treatment with a secondary settlement or other process in which the requirements established in Table 1 of Annex I are respected;

‘appropriate treatment’ means treatment of urban waste water by any process and/or disposal system which after discharge allows the receiving waters to meet the relevant quality objectives and the relevant provisions of this and other Community Directives;

‘Sludge’ means residual sludge, whether treated or untreated, from urban waste water treatment plants;

‘eutrophication’ means the enrichment of water by nutrients, especially compounds of nitrogen and/or phosphorus, causing an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned;

‘estuary’ means the transitional area at the mouth of a river between fresh-water and coastal waters. Member States shall establish the outer (seaward) limits of estuaries for the purposes of this Directive as part of the programme for implementation in accordance with the provisions of Article 17 (1) and (2);

‘coastal waters’ means the waters outside the low-water line or the outer limit of an estuary.