Soil aquifer treatment (SAT) is a practice used to enhance groundwater storage through intermittent percolation of treated wastewater effluent in designated infiltration basins. Due to proximity to urban regions, land availability for SAT infiltration basins is a limiting factor. Furthermore, with the growing population, SAT systems are faced with an increase in effluent volumes meant for recharge. The present study experimentally explores, for the first time, the feasibility of the short-term flooding of a citrus orchard with secondary effluent, as an alternative for an additional dedicated infiltration area for SAT, namely agricultural soil aquifer treatment (Ag-SAT). Orange trees were planted in two different agricultural setups, on flat soil and atop a ridge. Sporadic intermittent winter flooding experiments, lasting 24 and 48 h, were conducted. Volumetric water content (VWC) and oxidationreduction conditions were continuously monitored. Concurrently, water samples were collected and analyzed for total organic carbon and nitrogen species, along with leaf health measurements. Results were compared to an adjacent control plot, where no flooding with effluent was applied. Contaminant removal rates under the ridge setup resembled active SAT basins. Moreover, chemical analysis of the water samples and VWC readings demonstrated that higher water quality and faster root zone aeration (following flooding) were obtained under the ridge, which appears to be the better Ag-SAT setup. According to a principal component analysis (PCA), the dissolved oxygen explains 75% of the variability of effluent chemistry under the ridge, illustrating that oxic conditions prevailed in this setup. This study demonstrates that while many other concerns still need to be addressed, using agricultural plots as recharge basins for SAT during the winter appears to be a promising way to supplement recharge basins while having no impact on tree health.

Water is a limiting factor for economic and social development in most arid and semi-arid regions on Earth. The deliberate recharge of depleted aquifer storage and later recovery, known as managed aquifer recharge (MAR), is an important tool for water management and sustainability. Increasing stresses on groundwater and subsequent overdrafts have sparked the development of several advanced MAR technologies, including soil aquifer treatment (SAT). SAT is a method that recharges wastewater effluent through intermittent percolation in infiltration basins. Another emerging MAR approach currently explored is the off-season flooding of agricultural lands, known as agricultural MAR, or Ag-MAR. Utilizing agricultural fields as temporary infiltration basins during periods of dormancy increases the availability of land resources for groundwater recharge, rather than designating land explicitly for MAR. As land resources for SAT become limited and the amount of available treated wastewater (TWW) increases, we propose the idea of agricultural SAT, or Ag-SAT, as a combination of SAT and Ag-MAR. This review paper aims to provide an in-depth look into the approach and application of Ag-MAR and the possibilities of integrating Ag-MAR with SAT. Ag-SAT comprises the off-season flooding of agricultural land using TWW for groundwater recharge and subsequent reuse. Ag-SAT could provide alternative infiltration sites for SAT where available surface area dedicated to infiltration is becoming a limiting factor. Additionally, the treated wastewater could potentially provide nutrients to agricultural fields during the flooding cycles. Potential advantages, disadvantages, and knowledge gaps related to Ag-SAT are presented and discussed.