A landfill is located 500 km from a river whose surface elevation is 40 m lower than the ground elevation at the landfill. After several years it is discovered that leachate from the landfill, with a COD of 1300 mg/L, is leaking into the river. The river with a flow of 150 m3/min has an upstream COD of 5 mg/L. The COD immediately downstream from the point where leachate enters the river is 100 mg/L. What volume of leachate is being added to the river each day? What effects could this have on the river?