Environmental protection through self-powered plants for isolated communities

The possibility exists of creating wastewater treatment systems with very low levels of energy consumption for areas with particularly high requirements from the environmental standpoint. One low energy system for small communities capable of meeting effluent standard involves the use of an Imhoff tank followed by a rotating biological contactor (RBC) and by anothe settling tank. In such a system, the only energy consumption involved is connected with the rotation of the biological contactor disks. This energy requirement can be met by a systme transforming solar energy into electricity by menas of photovoltaic cells. The other phases of treatment involve gravity flow and settling and hence require no further energy, it being possible to harness gravity also for the extraction of sludge to be dried on drying beds. One further advantage of such a unit lies in the reduced environmental impact involved, making an attractive option for use in parks or protected areas.