The reliability of supply. The period over which supply can be guaranteed. C1.1.2 Municipal wastewater Municipal wastewater treatment plants are generally large facilities with substantial energy demands. Aerobic treatment processes take up substantial areas of land, and produce large quantities of sludge that needs to be disposed. Aeration is energy intensive.
Anaerobic processes have a smaller footprint and produce smaller quantities of sludge.
They are more effective in converting the biological load of the wastewater to gases, predominantly methane, and residual sludge. In the case of selling biogas, whether a gas user is located in close proximity to the plant, and whether expenditures need to be incurred on upgrading the gas. In the case of selling electricity, the buy back rates offered by local utilities or whether an energy recovery project developer is willing to develop the project. The period over which supply can be guaranteed The extent to which the plant can be adapted to maximise biogas recovery. The savings in purchased energy that can be achieved.