INVESTIGATION OF REPROCIAL INFLUENCE OF WASTEWATER INFILTRATION ON N, P, K, ORGANIC MATTER AND SALT CONTENT OF VARIOUS SOIL TYPES

In this study, four soil types (clay (C), sand (S), clay-sand mixture (SC), and calcareous loam (CA)) in western Catania province, Italy were selected to observe their responses to treated wastewater infiltration for 8 months. To investigate their significance, reveal correlation between them and develop appropriate models to represent reciprocal aspect of treated wastewater effect on soil and soils on wastewater, obtained data were analyzed thoroughly. Significant findings were attained through the experiments. Firstly, the leaching action of applied water at high-frequency made some elements'levels (nitrogen (N), phosphorus (P), potassium (K), sodium (Na)), and electrical conductivity (EC) of the studied soil more desirable. Particularly, in calcareous soil, where EC was relatively high, the level was reduced to about half the initial value after treatment. Secondly, interaction between leached wastewater and soils were discovered with acceptable accuracy and some empirical models were generated to investigate it. Detecting nitrogen and sodium content after leaching was demonstrated as the most accurate model for drained water, while determining variations in EC and organic matter content was considered the best model for soils. Through various chemical and physical parameters, the response of four soils to daily applications of treated wastewater about the rate of 2 L day(-1) was assessed. Three simple empirical models representing alterations in soil nitrogen, EC and organic matter with wastewater application were investigated.