Influência da água residuária na uniformidade de aplicação do sistema de irrigação por gotejamento

Abstract

The use of domestic sewage treated in irrigated agriculture has been intensified in recent years due to the water crisis that has driven the search for alternative sources of water, as well as the environmental and nutritional question of treated domestic effluent. However, analyzing the problems related to the use of residual water in the irrigation system is essential for economic and technical recommendation. In this way, the objective was to evaluate the uniformity of water application of an irrigation system operating with treated domestic sewage in comparison to another system operating with potable water. The study was carried out in the experimental area of the Sewage Treatment Station (ETE) belonging to the Water and Sewage Company of the State of Ceará (CAGECE) located in the municipality of Tianguá - CE. It was used the methodology that recommends the obtaining of flow in four points along the lateral line, that is, of the first dripper, the drippers located 1/3 and 2/3 of the length of the lateral line and the last dripper. The lateral lines selected along the line of derivation shall be the first, those situated 1/3 and 2/3 of the length of the branch line and the last lateral line. The performance of the system was analyzed through the Uniform Distribution Coefficient (CUD), the Uniformity Coefficient of Christiansen (CUC), the Statistical Uniformity Coefficient (CUE), and the application efficiency. In the irrigation system (S1), the CUC, CUD and CUE were above 90%, being classified as "excellent" in all evaluations. The irrigation system (S2), CUC, CUD and CUE were below 90%, being classified as "good". Regarding the efficiency of the irrigation system, S1 was above 80%, while in S2 below 80%. The quality of the wastewater affected the uniformity of application and the efficiency of the application of the system, as well as the service pressure.