Оценка агрономических критериев почв после орошения сточными водами от муниципальных очистных сооружений

Abstract

The aim of the study is to assess the impact of irrigation with wastewater of various degrees of treatment from urban wastewater treatment plants on agrochemical indicators of soils. As materials for the study, samples of wastewater of various degrees of treatment were selected (stage 1 – mechanical treatment, stage 2 – biological treatment) from the Kadamovsky treatment facilities of LLC “Ecological Technologies” in Novocherkassk. The selected samples were evaluated according to the main irrigation indicators: irrigation coefficient, sodium adsorption coefficient and the danger of magnesium salinization. Under laboratory conditions, alfalfa seeds were grown in vessels against the background of irrigation with tested waters. Agrochemical indicators of soils were evaluated in comparison with the approved standards for soils of the Rostov region. The control sample was watered with water from the Don River. Irrigation characteristics of the selected wastewater samples demonstrate their suitability for irrigation in all controlled parameters. In both types of treated wastewater, there is an excess of the content of phosphates by more than 30 times compared to the established norms, sulfates – by more than 4 times. As a result of the soil assessment, the following data were obtained: the humus content after irrigation with wastewater that has undergone only mechanical treatment increased slightly, in other cases the amount of humus decreased, and in the control variant by 1.5 times, and in the variant with water after biological treatment by only 6%; in all variants, when irrigation with wastewater, it is noted accumulation of nitrogen, as well as in all variants, there is a decrease in the content of phosphates and potassium in soils. The change in electrical conductivity indicates the leaching of easily soluble salts from soils against the background of irrigation, and to the greatest extent when watering with water that has passed the 2nd stage of treatment. In general, according to all indicators, the most suitable for irrigation is water after biological treatment