A method for injecting water into a hydrocarbon-producing-reservoir to enhance oil recovery, the method comprising deaerating a feed seawater stream containing an oxygen, an air, a nitrogen and/or a carbon dioxide, wherein the method comprises: a. providing a rotating packed bed device comprising one or more rotatable packing rings disposed within a housing wherein the one or more rotatable packing rings define an interior region; a liquid inlet in the housing for feeding a liquid into the interior region, the liquid inlet in communication with an exit port disposed in the interior region for infusing the liquid into the interior region; a gas outlet in the housing for accepting a gas which has at least partially passed radially inwardly through the one or more rotatable packing rings and removing the gas from the interior region; a liquid outlet in the housing for removing a deaerated seawater stream from the housing; a rotatable shaft coupled to the one or more rotatable packing rings for causing the one or more rotatable packing rings to rotate; and a motor coupled to the rotatable shaft for driving the rotatable shaft; b. infusing the feed seawater stream by way of the exit port into the interior region, wherein the feed seawater stream passes radially outwardly through each of the one or more rotatable packing rings thereby forming the deaerated seawater stream having a lower concentration of the oxygen, the air, the nitrogen and/or the carbon dioxide therein than the feed seawater stream and a gas stream comprising the oxygen, the air, the nitrogen and/or the carbon dioxide having been removed from the feed seawater stream; c. removing the deaerated seawater stream from the housing through the liquid outlet; and d. removing the gas stream having at least partially passed through the one or more rotatable packing rings from the interior region through the gas outlet wherein the rotating packed bed device further comprises a gas inlet in the housing in fluid communication with the one or more rotatable packing rings and wherein the method further comprises injecting a gas stream essentially free of oxygen through the gas inlet, wherein a ratio of the gas stream to the feed seawater stream is from 1 to 10 standard cubic feet (0.028 to 0.28 cubic meters) of the gas stream per standard cubic feet (0.028 cubic meter) of the liquid, and the feed seawater stream and the gas stream pass through each of the one or more rotatable packing rings; the method further comprising: injecting the deaerated seawater stream into the hydrocarbon-producing-reservoir using a water injection means connected to the liquid outlet of the rotating packed bed device; providing a separator in fluid communication with the hydrocarbon-producing-reservoir, wherein the separator comprises at least an inlet, a separator gas outlet and a produced water outlet; separating produced fluids from the hydrocarbon-producing-reservoir in the separator into an oil phase, a gas phase and an aqueous phase; passing the gas phase from the separator gas outlet of the separator to the gas inlet of the rotating packed bed device such that the gas phase is received as the gas stream essentially free of oxygen; passing the aqueous phase from the produced water outlet of the separator to a filter for removing salts from the aqueous phase; and passing the aqueous phase from the filter to the water injection means. a. providing a rotating packed bed device comprising one or more rotatable packing rings disposed within a housing wherein the one or more rotatable packing rings define an interior region; a liquid inlet in the housing for feeding a liquid into the interior region, the liquid inlet in communication with an exit port disposed in the interior region for infusing the liquid into the interior region; a gas outlet in the housing for accepting a gas which has at least partially passed radially inwardly through the one or more rotatable packing rings and removing the gas from the interior region; a liquid outlet in the housing for removing a deaerated seawater stream from the housing; a rotatable shaft coupled to the one or more rotatable packing rings for causing the one or more rotatable packing rings to rotate; and a motor coupled to the rotatable shaft for driving the rotatable shaft; b. infusing the feed seawater stream by way of the exit port into the interior region, wherein the feed seawater stream passes radially outwardly through each of the one or more rotatable packing rings thereby forming the deaerated seawater stream having a lower concentration of the oxygen, the air, the nitrogen and/or the carbon dioxide therein than the feed seawater stream and a gas stream comprising the oxygen, the air, the nitrogen and/or the carbon dioxide having been removed from the feed seawater stream; c. removing the deaerated seawater stream from the housing through the liquid outlet; and d. removing the gas stream having at least partially passed through the one or more rotatable packing rings from the interior region through the gas outlet wherein the rotating packed bed device further comprises a gas inlet in the housing in fluid communication with the one or more rotatable packing rings and wherein the method further comprises injecting a gas stream essentially free of oxygen through the gas inlet, wherein a ratio of the gas stream to the feed seawater stream is from 1 to 10 standard cubic feet (0.028 to 0.28 cubic meters) of the gas stream per standard cubic feet (0.028 cubic meter) of the liquid, and the feed seawater stream and the gas stream pass through each of the one or more rotatable packing rings;