Research of sewage intake of small settlements in dry weather

Introduction. Attempts to apply classical wastewater treatment technologies to small volumes are often impossible due to the high irregularity of wastewater inflows, and fundamental fluctuations in the composition of wastewaters, which are very diverse in comparison with medium and large cities. At three sites located in the Leningrad Region, full-scale measurements of wastewater discharges from settlements with a population of 1000 people and an industrial enterprise were carried out in order to determine the irregularity coefficients of wastewater during the dry season. The irregularity coefficients used in the design practice for such objects differ greatly in their values, as determined in the process of analyzing the literature data, which, when designing head sewage treatment plants, can lead to significant errors in calculations. Materials and methods. Measurement of a daily consumption of sewage flowmeters counters, elimination of improbable values, definition of consumption in dry weather, comparison of these various objects. Results. Mathematical dependences are proposed for describing fluctuations in the daily coefficient of irregularity of waste during the year. It was proposed to describe the weekly fluctuation of expenses with the help of the weekly coefficient of non-uniformity and its values were determined for the studied objects. A method has been developed for determining estimated costs for small objects with a population of 1000 people. Conclusions. The developed technique allows to predict the size of coefficient of daily unevenness within a year in dry weather for small settlements with number of inhabitants of 1000 people and a small share of production drains. It is possible to recommend values of coefficients of week unevenness.