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A quality evaluation of wastewater in Quito's metropolitan area for environmental sustainability

Abstract:

The demand for water in recent years has increased rapidly, it is for this reason that wastewater recycling becomes an integral part of its management. This promotes the conservation of freshwater supplies with high quality standards. In addition, pollutants and cost in their final treatment are reduced. It is in this way that this research reports the quality of a domestic residual effluent from residential washing machines. Treated gray water can be used as a substitute for fresh water for non-potable end uses, helping to overcome water shortages worldwide. The effluent studied has an average outlet temperature of 21 °C and a pH of 7.4. By means of analytical techniques the alkalinity and acidity of this were determined (228.20 mg/L CO3; 1651.80 mg/L HCO3 and 0.00053 mg/L). The total hardness is 395.09 mg/L (369.44 mg/L Mg and 25.65 mg/L Ca). When making a comparison with the parameters allowed for sewage discharges and water quality values for irrigation, in order to possible reuse. The effluent evaluated has an extremely high alkalinity, this causes precipitation of calcium and magnesium ions such as carbonates. This effluent cannot be discharged directly to the sewer without prior treatment. Like it cannot be reused as irrigation water in crops because of its hardness and nitrate content.