The block-modular biological treatment plants PlanaOS-B are based on MBBR technology (Moving Bed Biofilm Reactor). The plants are equipped with a process automation systems, equipment for mechanical cleaning and reagent treatment of wastewater, biological treatment reactors, sections for additional treatment on pressure filters, UV disinfection units and a bag sludge dewatering units. The plants provide purification of domestic wastewater according to the indicators of SS, COD, BOD, nitrogen group and phosphorus to the standards of «fish farming». The tank equipment of the plants is made of stainless steel.