Wasterwater Reclamation and Recharge, Bay Park, N.Y.

About 600,000 gal/day (0.03 m³/s) of effluent from an activated-sludge type sewage treatment plant was further purified by clarification, filtration, activated-carbon adsorption, and chlorination. Significant quality parameters of the reclaimed water and their usual concentrations were: Chemical oxygen demand approx. 10 mg/l; phosphorus approx. 0.1 mg/l; methylene blue active substances <0.1 mg/l; and turbidity <1 mg/l. Reclaimed water was injected intermittently in a series of tests into the Magothy aquifer through a well screened at a depth of 418 ft to 480 ft (127 m to 146 m) below land surface. The rate of excessive head buildup observed during the recharge of 41,700,000 gal (158,000 m³) averaged 3 ft (0.9 m)/1,000,000 gal (4,000 m³). Operation and maintenance costs (1972) of further purifying the secondary-stage effluent to rechargeable quality, but without nitrogen removal, are estimated to be about –0.27 per 1,000 gal (3.785 m³) on a 3-mgd (0.13-m³/s) scale. Operation and maintenance of recharge wells should be on the order of –0.04 to –0.05/1,000 gal (3.785 m³).