The production facility of the Healthcare Europe plant in Ruma has been expanded by another production hall and a retention pool, which serves as a wastewater collector in the production facility. A retention basin is a reinforced concrete facility for receiving and equalizing the amount of water in a sewer network with the pumping of water further. The walls of the tank are 30cm thick and 4m high. The concrete tank has penetrations through which the intended equipment passes. The building is mostly buried, it is based on a 60cm thick concrete slab and 30cm thick slab above. The lower panel is on a downward slope to direct the water to the inner walls by a zigzag path to the outlet of the reservoir.