The plant itself meets its own energy needs. This was made possible by the installation of a sludge treatment process to produce biogas. This biogas is then used to provide heat and electricity. The treatment also includes a production facility of natural fertiliser. Sludge, or 'sewage sludge', is a residual, organic material that is produced during the treatment of wastewater. Its use as a fuel for the plant’s operations, which require a large amount of energy, is therefore both a cost efficient and a long-term sustainable solution.