ABSTRACTThe Lake George Village sewage treatment plant has been discharging trickling filter effluent onto natural delta sand beds for a period of 35 years. The applied sewage apparently appears near the banks of West Brook approximately 600 m (2000 ft) from the lower sand beds. Wells have been placed between the recharge beds and the appearance of the seepage at West Brook. The quality of the water in the wells has been evaluated over the period of slightly over one year.The ground water appears to be aerobic at all times indicating that the oxygen demand of the applied effluent has been adequately reduced before it reaches the ground water. This should afford adequate and proper tertiary treatment for the applied effluent.The phosphorus concentration was significantly reduced at the first well downstream (ground water) approximately 150 m (500 ft) from the sand beds. The phosphorus in well 2 approximately 600 m (2000 ft) from the lower sand beds reached a high value of 150 μg/l during the late fall but was less than 100 μg/l during the rest of the year.Some of the nitrogen in the applied effluent was apparently oxidized to nitrate which was very little removed by the sand system. The highest nitrate concentration found was 14 mg N/l in well 3C during the Spring, whereas well 3A had almost consistently the lowest concentration of nitrat