Sewage Irrigation and Recharge Consequences, Oahu

By the year 2000 the island of Oahu, Hawaii, is projected to have a water demand that equals its fully-developed freshwater (essentially ground-water) supply. columns appears that reuse and reclamation are presently the most feasible means of water supplementation for the island. Recently completed field projects on Oahu, covering a 7-year period, involving the application of secondary sewage effluent to grassland and sugarcane revealed that: (1) It does not have a detrimental effect on the vegetation or public health; (2) it serves as a fertilizer source and a sewage disposal method; (3) the quality of the leachate below the root zone is similar to that produced by agriculture practices; and (4) at least 50 percent of the applied liquid reaches the ground water when the ridge and furrow method of irrigation is employed.