Different effluent charges by country

Dear all, after my first post “Different discharge limits by country”, I´d like to get some integrations/comments about the following:

even if the maximal admittable discharged concentrations are practically the same, in Europe effluent charges for industrial polluters are applied in very different ways, being also under discussion inside some of those countries.

For example, in Germany the taxes on industrial wastewater discharges are applied on quantity and quality of direct discharges to surface water bodies (that means often discharges of public wastewater treatment plants), while in Italy, the fees are proportional to the indirect charges sent to sewer (that means before entering the public wastewater treatment plants). The same in UK, where analyses of discharges into sewer are the main factor influencing industrial wastewater fees.

Also the basic (without considering metals or recently recognised micropollutants) controlled parameters are not at all the same: the more common ones are Flow and COD, Germany adds as common also Nitrogen and Phosphorus, while UK in the standard Mogden Formula has neither Nitrogen nor Phosphorus, but differently from Germany considers Suspended Solids too. Italy is using as usual control parameters Flow, COD, Nitrogen, Phosphorus and Suspended Solids.

In the specific, for Italy, the weights used to add up the influence of the single quality parameters on the global costs of the wastewater treatment are respectively 52% for COD, 28% for SST, 15% for Nitrogen and 5% for Phosphorus. In the last years the unitary wastewater fee and related calculation coefficients, locally set in a new legislation dating back to the year 2020, are periodically updated and normally increased to reflect the effect of increased investments by managing utilities and so on. For the standard pollutants the reference wastewater effluent, to which are compared the measured wastewater concentrations for the calculation of the variable part of the fee, has the following composition: 160 mg/l for COD, 80 mg/l for SST, 10 mg/l for Nitrogen and 1 mg/l for Phosphorus. Even if normally a wastewater treatment plant is treating the wastewater collected in the sewer, the above set benchmarking concentrations are already those fixed from Italy for industrial discharge into surface water body (for COD and SST: see attached table) and into sensitive areas (for Nitrogen and Phosphorus: see values from my first post).

For Germany the main used weights are 50% for COD, 25% for Nitrogen and 3% for Phosphorus. Here the unitary wastewater tax has not been changed since 1997, but a reform process is about to be carried out; moreover, up to now is not used a reference wastewater effluent for the calculation of the tax, instead are normally considered the concentrations set by the discharge permit. These concentrations cannot in any case be bigger than those set into the German Wastewater Ordinance, according to the dimension of the corresponding wastewater treatment plant (as from values in my first post).

Would be interesting to know more deeply what other countries, not only in Europe, do for the wastewater tax in terms of quality and quantity and if the majority is applying fees to discharges into sewer (easier to apply the polluter pays principle) or into superficial waters (probably easier to calculate cuz normally referring only to the wastewater treatment plants and not to each single industrial polluter). An exchange of experiences may also help to improve existing models, maybe to lighten them, however always with the aim of protecting more and not less the natural environment, also in view of the new pollutants that are being discovered/regulated.

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