EFFECTS OF THREE SEWAGE TREATMENT PLANTS ON WATER QUALITY OF THE LACKAWANNA RIVER (LACKAWANNA COUNTY, PENNSYLVANIA)

We studied six water quality variables including temperature, dissolved oxygen, pH, ammonia-nitrogen, nitrate-nitrogen and phosphate-phosphorus, above and below three major sewage treatment plants (STP) on the Lackawanna River, a major tributary of the Susquehanna River in northeastern Pennsylvania, during 1990-91. Study sites included STPs at Scranton, Throop and Archbald located 12.6 km, 24.2 km and 37.8 km, respectively, upstream of the confluence with the Susquehanna. The Scranton STP, with the largest capacity, had a significant effect on all six variables causing a decrease in dissolved oxygen and increases in temperature, pH, ammonia, nitrates and phosphates. The Throop and Archbald STPs, with 15-25% of the capacity at Scranton, affected fewer variables although effects on individual variables were of similar or greater magnitude. Significant increases in the concentrations of nitrates (Scranton and Throop) and phosphates (all three plants) are likely to have the most deleterious effects on water quality in the Lackawanna River and, ultimately, the Susquehanna River.