## 2 Materials and Methods
### Analytical Methods  
Total suspended solids (TSSs) have been measured using Method 8006 [21]. The biochemical oxygen consumption was determined after a period of 5 days (BOD\({}_{5}\)) using a membrane electrode to estimate the initial and post-incubation dissolved oxygen concentration and estimate the consumed oxygen according to the Standard Methods for the Examination of Water and Wastewater [22]. The COD was analyzed with Hach kits (150-1000 mg L\({}^{-1}\) O\({}_{2}\)), which provided all reagents after proper dilutions of the initial sample were made (Hach Company, Loveland, CO, USA) [23]. To reduce the analytical error, after filtration (pore size, 0.45 \(\upmu\)m), interference from chlorides was ruled out by verifying that the chloride concentration was lower than the maximum accepted by the method (1500 mg L\({}^{-1}\)). A total of 2 mL of sample was injected into the cuvette and heated in a HACH HT 200 S (Hach Company, Loveland, CO, USA) for 15 min, then a HACH DR-5000 (Hach Company, Loveland, CO, USA) was used for the spectrophotometric measurements, respectively.  
A Hach-Lange IL 550 TOC-TN device (Hach Company, Loveland, CO, USA), which operates on the principle of oxidation pyrolysis (800 \({}^{\circ}\)C), was used to determine total nitrogen (N\({}_{\rm tot}\)). In this case, samples were digested using thermocatalytic high-temperature oxidation (800 \({}^{\circ}\)C and platinum as catalyst), and nitrogen was evaluated using a CLD chemiluminescence detector.  
Total phosphorous (P\({}_{\rm tot}\)) was analyzed with Hach kits (Hach Company, Loveland, CO, USA), which provided all reagents after proper dilutions of the initial sample were made. A total of 5 mL of sample was injected into the cuvette and one potassium persulfate pillow was added to the cuvette. Then, the cuvette was heated in a COD Reactor 115/230 VAC (Hach Company, Loveland, CO, USA) for 30 min, and 2 mL of 1.54 N Sodium Hydroxide was added. Then, one PhosVer 3 pillow was added, and the cuvette was analyzed by a Molybdenum DR 6000 (Hach Company, Loveland, CO, USA) [24]. P-PO\({}_{4}\)\({}^{3-}\) was measured using Hach kits (Hach Company, Loveland, CO, USA), which provided all reagents after proper dilutions of the initial sample were made. A total of 5 mL of sample was injected into the cuvette, then analyzed by a Molybdenum DR 6000 (Hach Company, Loveland, CO, USA) [25].  
Temperature and pH were monitored using a portable multiparameter instrument (WTW 3410 SET4, Xylem Inc., Washington, DC, USA) and the probe WTW-IDS Model SenTix(r) 940 (Xylem Inc., Washington, DC, USA), while conductivity was measured using the probe TetraCon(r) 925. A HACH 2100Q turbidimeter (Hach Company, Loveland, CO, USA) was used to quantify turbidity.  
For each sampling activity, one sample was taken, and all the measurements and analyses were performed immediately. Possible sources of analytical error in the use of the kits could be the inoculation of an incorrect volume, possible turbidity that alters the spectrophotometric measure, the presence of interfering substances, and failure to respect the reaction times and temperatures [26]. For COD and Ptot, to be sure that the results were robust, each analysis of the same sample was conducted in triplicate to verify the difference is less than 10%. These values are presented in the results as the mean, along with their 95% confidence interval.