Transformation Stages of the Cleaning Capacity of Agricultural Irrigation Fields by Wastewater from a Gas-Processing Plant

The dynamics of the cleaning capacity of agricultural fields irrigated with wastewater from a gas-processing plant is studied. It is shown that 5–7 irrigations at a rate of 480 m 3 /ha annually bring 2.98–4.17 t/ha of pollutants into the soil, and these pollutants are retained in the soils of the aeration zone and contribute to their salinization and alkalinization and, as a consequence, lead to a reduction in crop yields. In addition, calcium is carried from upper soil layers to deeper horizons, thereby forming a new geochemical barrier. Under conditions of a weak outflow of groundwater, we recorded a growth in its level, an accumulation of salts carried with wastewater, and an increase in the total mineralization of wastewater. It is established that the agricultural irrigation fields used for over 20 years undergo three transformation stages: adaptation stage (3–4 years); stable functioning of the geoecosystem utilizing industrial waste waters from the gas-processing plant (7–10 years), and the stage of the critical state of the geoecosystem due to the loss of the cleaning capacity by the soils and the necessity of soil-improving remediation activities.