Effect on the Yield of Crops Irrigated With Water Treated in a Passive System and Advanced Purification

ABSTRACT Population growth and drought reduce water availability for agriculture, making alternative water sources crucial. This study evaluated the effect of irrigating radish and coriander with domestic wastewater treated in a passive system (PS) and further advanced purification (PS + A). PS water met local irrigation quality standards featuring (per litre) 2.0 mg of fat, oil and grease (FOG), 33.5 mg of chemical oxygen demand (COD), 31 mg of total inorganic nitrogen (TIN) and 2700 E. coli most probable number, among other variables. PS + A showed reduction of 80% FOG, 42% COD, 20% TIN and 95% E. coli present in PS water. Irrigation with PS, PS + A and tap water led to yields of 3.9 ± 4.2 g, 4.8 ± 3.9 g and 0.4 ± 0.3 g per radish plant, and 2.4 ± 1.2 g, 1.9 ± 1.0 g and 0.2 ± 0.1 g per coriander plant, respectively. Number of coriander plants with leaves larger than 40 mm was significantly different irrigating PS (22) or PS + A (13). No size difference was observed in radish leaves or roots using PS or PS + A. In soil, no differences in pH, water holding capacity, cation exchange capacity and proportion of silt, clay and sand were found after irrigation with PS, PS + A or tap water after 35 days.