Cleaning wastewater by 90-95 %-only biological cleaning systems are capable. In this case, biologically active substances, specially added microorganisms — simply naturally participate in the decomposition of organic elements in wastewater. That is, after a septic tank, cleansed of large fragments of garbage, wastewater is transmitted to another container — air tank. Here, with the participation of the activity of active silt, deep cleaning occurs. At the end — water passes through the filter.