(7)Significant investments will be necessary to implement the new requirements introduced by this Directive. It is therefore necessary to take into account the specific situation of each Member State and, where appropriate, adapt the deadlines for the implementation of certain demanding requirements. For instance, Member States having a large number of small agglomerations concerned by the new requirements of this Directive in terms of collection and treatment of urban wastewater for agglomerations of between 1 000 and 2 000 p.e., should be allowed to extend the deadlines for compliance with those new requirements in their first national implementation programme. This should also be the case for Member States having a large number of facilities, for example above 50 %, that need to be upgraded to tertiary treatment in line with the new requirements of this Directive. Agglomerations of below 2 000 p.e. where collecting systems are already in place and discharging urban wastewater into treatment plants located in a different agglomeration should not be counted in the calculation of percentages for the purposes of the derogations from those deadlines. Moreover, the three Member States that acceded to the Union most recently, namely Bulgaria, Croatia and Romania, had to make recent investments to implement the requirements of Directive 91/271/EEC. Furthermore, those Member States are characterised by high amounts of rural areas with a high outflux of population, in addition to an ageing rural population. It is therefore necessary to take into account the specific situation of those Member States by allowing them to extend the deadlines for compliance with those new requirements in their first national implementation programme.