**Abstract**

This chapter is the result of a research conducted in the experimental area of the Department of Rural Engineering, School of Agronomic Sciences, São Paulo State University, Botucatu, São Paulo, Brazil, for 165 days, between the months of February and August 2018, with the objective to evaluate the performance of a wastewater treatment plant (WWTP) at a pilot-scale composed of six anaerobic filters (tank-in-series), filled with gravel #1 in the treatment of domestic wastewater (DW) for agricultural reuse. The parameters were monitored was: pH, electrical conductivity, total suspended solids, biochemical oxygen demand, chemical oxygen demand, total nitrogen, total phosphorus, and potassium. The results indicate that the WWTP performed satisfactorily and provided treated wastewater (TWW) with acceptable quality for agricultural reuse in irrigation of vegetable crops. It was observed that the mean concentrations of the pollutants decreased as wastewater advanced through the filters stage, presenting high removal efficiency at the 6th filter (TWW 6) than the 3rd filter (TWW 3), with statistical analysis corroborating that there are significant differences between the quality of TWW 3 and TWW 6 for most of the parameters evaluated, suggesting that the increase of the number of filters in this treatment system proposed improves the treated wastewater quality.

**Keywords:** agricultural irrigation, agricultural wastewater reuse, wastewater reuse, wastewater treatment, water scarcity
