Wastewater treatment plant effluent inputs influence the temporal variability of nutrient uptake in an intermittent stream

Abstract Wastewater treatment plant (WWTP) effluents alter water chemistry and in-stream nutrient uptake rates of receiving freshwaters, thus changing the magnitude fate nutrients exported. In Mediterranean regions, dilution capacity streams can vary strongly over time due to seasonal occurrence floods droughts, causing temporal variability uptake. We assessed patterns controlling factors net in an intermittent stream WWTP effluent inputs. compiled longitudinal concentration profiles ambient dissolved inorganic nitrogen (DIN) soluble reactive phosphorus (SRP) along a 800 m reach on 47 sampling dates between 2001 2017, encompassing wide range hydrological conditions. estimated stream. 72% dates, high ammonium co-occurred with releases either nitrate or nitrite. This pattern suggests that has nitrification capacity. Conversely, 75% did not show any SRP concentration, suggesting release processes for this element were counterbalanced both occurred at very low rates. Finally, was when had (< 40%) high. Overall, we demonstrate consideration stream’s is imperative management freshwaters guarantee adequate inputs avoid saturation under flow conditions urban landscapes.