Patent ID: 9328005
Filing Date: 2016-05-03
CPC Classification: C02F,Y02W

Claim Text:
1. A method for conducting a denitrification process in water that includes a total nitrogen content, comprising the steps of: a) mixing water having a total nitrogen concentration of less than 30 mg/l and a biochemical oxygen demand measured 5 days after the start of incubation of less than 30 mg/l with a sufficient amount of dissolved carbohydrate to cause reduction of the total nitrogen in the water, the ratio of dissolved carbon-to-nitrogen being in a range of between about two and a half to ten milligrams per liter of dissolved carbon of Chemical Oxygen Demand to about one milligram per liter of total nitrogen; and b) intermittently percolating the water and the dissolved carbohydrate through a stratified fixed bed, wherein the stratified fixed bed includes a packed bed filter of layers separated by nonwoven filter cloth, whereby the amount of dissolved carbohydrate is metabolized by bacteria in the stratified fixed bed by a denitrification process, thereby reducing the total nitrogen in the water.