There were conducted the researches to identify new correlation between traditional controlling process indicators of cleaning stock water from phosphates and concentration of phosphates in purified water that can be used for the development of new techniques. Analytical laboratory data of the current purification station were carried out with the use of the Pearson correlation coefficient to detect a connection between concentration of phosphates in the purified water and four kinds of hydrobiological data using Microsoft Excel a computer program with functions Corel batch analysis. The most informative for monitoring of purification from the phosphates is the indicator of the number of types of hydrobionts. Change of concentration of phosphates goes in antiphase to the amount of types of hydrobionts. Therefore, for the convenience of the users there was completed the visualization of the existing trend using the introduced by the authors index-modified number of hydrobionts. There was presented an algorithm monitoring the process of sewage purification from phosphates, which requires the creation of a database and preliminary plotting of dependence of phosphates Sf concentration on the number of hydrobionts NG. The further displaying of laboratory data indicator NG on the schedule allows to predict the expected concentration of phosphates Sf in purified sewage and in case of poor forecast to carry out operational actions. The survey is based on the basis of a new methodology, which was transferred for the introduction to "Chernihivodokanal" (Chernihiv, Ukraine)