Mobilization of iron in water in the Magothy aquifer during long-term recharge with tertiary-treated sewage, Bay Park, New York

Tertiary-treated sewage (reclaimed water) has been recharged by well into the Magothy aquifer at Bay Park, N. Y., intermittently since 1968. The longest of 13 recharge tests, the subject of this report, lasted 84.5 days. This was sufficient time for the reclaimed water to reach an observation well 200 ft (61 m) from the recharge well. Although the iron concentrations of the reclaimed water and the native water were less than 0.4 mg/l, the iron concentrations of samples from observation wells 20, 100, and 200 ft (6, 30, and 61 m) from the recharge well at times approached 3 mg/l. Source of the ii'on is pyrite that is native to the aquifer.