Final answer:
To satisfy EPA standards with a nitrate limit of 50 mg/L, calculate the flow rates from a well with 15 g/m³ nitrate and a reservoir with 5 g/m³ nitrate to provide a total flow of 2.0 m³/s. Use algebraic equations to find the correct blending proportions, then multiply by the total needed flow rate.
Step-by-step explanation:
To meet the EPA drinking water standard while minimizing the use of more expensive reservoir water, you would blend water from both the local well with a nitrate concentration of 15 g/m³ and the reservoir water with 5 g/m³ nitrate concentration. First, you must determine the maximum allowable nitrate concentration, which according to the EU is 50 mg/L. You can achieve the desired concentration by mixing certain proportions of well water and reservoir water to ensure that the blend does not exceed this limit.
To calculate the specific flow rates needed from each source, you would set up an equation based on the desired flow rate and nitrate concentrations. This is a typical dilution problem which can be solved using algebra. Once you find the correct proportions, you multiply these by the total required flow rate of 2.0 m³/s to get the individual flow rates from each source.