2.Cotton, polyester, nylon, rayon or can also be made by wool
Explanation:
Drinking water requirement in town 2.0 m^3/s of water per second
nitrate in local well nitrate per 15
of water
nitrate in distant reservoir 
Let the flow rate of well
flow rate of reservoir 
Drinking water requirement is
or 
therefore, the total flow of drinking water
This could be wrong but I am giving a decent suggestion: All ions are atoms with a negative charge.