|Plants with over 10,000 population equivalents||99.3%||99.2%||99.0%|
|Plants with less than 10,000 population equivalents||99.0%||99.2%||99.5%|
The 2015 and 2016 data have been aligned with the calculation criteria used for 2017
Considering the 10,811 analyses carried out in 2017 on 229 treatment plants, in 99.1% of the cases the results were compliant with the regulatory limits.
The final values for this indicator in 2017 show a very satisfactory situation with extremely encouraging percentages of the total checks found compliant. The only cases that exceeded the authorized limits were in relation to purely incidental situations, largely compatible with the variability of the incoming quantities, the operating conditions and the structural condition of the plants.
Wastewater treatment quality can also be identified by monitoring the upgrade trends of urban areas, defined as areas in which population and production activities are concentrated to the extent that it is technically and economically acceptable to build an independent sewage treatment system. As set out by Directive 91/271/EEC, Legislative Decree 152/2006, and by the Water Protection Plan of the Regional Government of Emilia-Romagna, compliance requires that at least 95% of wastewater must be collected and the capacity of the treatment plants must exceed the requirement for the population equivalents of the urban area with secondary or tertiary treatment (where necessary).