The article deals with the issues of quality requirements and operation of treatment facilities and devices of enterprises of the pulp and paper industry. The possibilities of expanding the tasks solved from the position of automatic control on the basis of the achievements of the theory of automatic control, methods of mathematical modeling and optimization of technological processes have been studied. The scheme of wastewater treatment of a pulp and cardboard mill, which consists of a multitude of observed objects, the technological processes of control of which is carried out using multiparameter search systems, is presented. According to the approach proposed by the authors, to correct the estimates of the state of each object after receiving the next observation, are used not one, but all measurements of this observation, taken with certain weights.