With the highest inflow of any Nordic plant, the Ryaverket wastewater treatment plant near Gothenburg needs to be efficient. Its location next to the coast means that high environmental standards must also be applied to its treatment processes. To meet these demands an innovative disk filter system was procured, turning effluent into recoverable byproducts. The criteria applied in the tender for mechanical equipment looked at the life-cycle environmental impact and energy consumption of the proposed systems. The contract clauses also included requirements for environmental management.