(9)Where it can be demonstrated that the establishment of an urban wastewater collecting system or the connection to a collecting system would produce no benefit for the environment or human health, would not be technically feasible or would involve excessive costs, and only in those cases, Member States should be allowed to use individual systems to collect, store and/or treat urban wastewater, provided that they ensure the same level of protection of the environment and human health as secondary and tertiary treatment. Individual systems can include different types of collection, storage or treatment system, such as nature-based solutions, small-sized treatment systems, or temporary tanks combined with regular evacuation to treatment plants. Member States should also exchange best practices on the use and operation of individual systems.