Patent ID: 6599425
Filing Date: 2003-07-29
Classification: B09C,C02F

Abstract:
A method for biological denitrification of groundwater in situ in an aquifer under substantially anaerobic conditions, comprising(a) providing a network, including an extraction well for removal of groundwater from the aquifer and a plurality of injection wells for returning groundwater to the aquifer, the injection wells being arranged in a line substantially perpendicular to the direction of groundwater flow, the extraction well being located downstream or upstream of the line of injection wells, and the spacing of the wells and the number of injection wells being determined by the mathematical relationship J=Cp+nC1W&RightArrow;min(1)where J is the cost of treatment, CP and CI are the costs of extraction and injection wells, respectively; n is the number of injection wells, and W is the distance across the protected area, and wherein the water stream is evenly distributed between injection wells, according to the relationship: Fi=Fe/n=const â€ƒâ€ƒ(2) where F is the water flow rate (eâ€”extraction well, iâ€”injection well) and n is the number of injection wells, (b) removing groundwater from the aquifer by the extraction well, (c) adding a carbon source to the groundwater in a controlled manner, (d) returning the carbon source amended groundwater to the aquifer by the injection wells in even distribution, the water flow rate being controlled, and (e) monitoring the nitrate concentration of the groundwater removed from the extraction well, a decrease in nitrate concentration being indicative of denitrification.