A wastewater stream has a flow of 70,000 m3/day and an average nitrate concentration of 10 mg NO3/L. The nitrate in the wastewater stream can be removed by denitrification with electron donors such as methanol (CH3OH). The prices of methanol is US$260 per metric ton. Calculate the daily cost of supplying methanol to completely remove nitrate from the wastewater stream. The balanced equation for denitrification with methanol as electron donor is: 5CH3OH + 6NO3 - + 6H+ 3N2 + 5CO2 + 13H2O