A wastewater contains ammonia nitrogen (calculated on nitrogen)
A wastewater contains ammonia nitrogen (calculated on nitrogen) 150 mg/L, BOD5 210 mg/L, and its pH value is 7.5. The Nitrification-Denitrification two-stage activated sludge process is chosen to treat this wastewater, and methanol is used as the additional carbon source for denitrification. Assuming that the removal efficiencies for ammonia nitrogen and BOD5 in the first Nitrification tank are both 95%; and removal efficiency for the nitrate nitrogen in the second Denitrification tank is 90%. Please calculate that: the dosage of methanol to the second Denitrification tank is _____ mg/L.