The MBBR technology (Moving Bed Bio Reactor), where the biomass development is carried out in plastic supports (carriers) which are suspended in the mixed liquor of the biological reactor. These carriers enable growth of more microorganisms per unit of volume than a conventional system. Oxygen needed for wastewater treatment, is supplied through a blower and an air distribution system. After the biological reactor, water is introduced into the lamellar decanter. The sludge is collected in the bottom of the decanter, while clarified water is collected at the top.