A technical model for reclaimed water reuse in agricultural irrigation: a case study in Kordkuy, Iran

This study aims at developing a systematic and holistic logical decision-making model to assess technical feasibility of reclaimed water reuse in agriculture. The hypothesis of algorithm was based on the basic conditions recommended by Food and Agriculture Organization of the United Nations which are required to make irrigated farming a success. The model innovatively integrates technical aspects by using a hierarchical modular structure consisting of three modules to tackle an unstructured assessment process. Reusability analysis module is concerned with determining the restrictions imposed on effluent quality, selection of suitable types of crops as well as the best available irrigation method. In order to select crops, a framework of potential restrictions was developed to match effluent, soil and types of crops, simultaneously, with a high level of intricacy as well as adaptability to any cases. Supply–demand analysis module provides an estimation of reuse potential in terms of quantity and irrigated area based on the water requirements of selected crops and the volume of produced treated wastewater. Module of field management practices aims at controlling adverse impacts of prolonged irrigation by effluent on the environment. The compatibility with different guidelines and regulations, the simplicity achieved by a series of logical steps and the integration of modules are the main features of the algorithm. To test algorithm robustness, it was successfully applied in Kordkuy, Iran. As a result of model performance, the water reuse scheme can annually save up to 718,560 m3 of freshwater by planting soybean and rapeseed as the most suitable crops in the region.