Evaluation of BOD, SS, N and P loadings into Lower Hudson River Basin from point and non-point sources

Abstract

This study showed that municipal point source wastewater flows to the lower Hudson River basin increased from 32 MGD (121 x 10⁶ Lid) in 1900 to 266 MOD (1,007 x 10⁶ L/d) in 1993. BOD and suspended solids loadings increased since 1900 and reached a high of 187,182 lbs/day (84,904 kg/day) and 146,736Ibs/day (66,558 kg/day) respectively in 1970 and decreased to 23,778 lbs/day (10,785 kg/day) and 29,659Ibs/day (13,453 kg/day) respectively in 1993. The BOD per capita loading rate from municipal discharges decreased from 0.15 lbs/day (68 g/d) in 1900 to 0.015 lbs/day (6.8 g/d) in 1993. Nitrogen and phosphorus loads reached a high in 1980 and also decreased in the past decade but not as dramatic as BOD and suspended solids. In 1993, 36,974Ibs/day (16,771 kg/day) of total nitrogen and 14,483 lbs/day (6,569 kg/day) of total phosphorus were discharged from municipal point sources into the lower Hudson River basin.

Most of the current BOD and 55 loadings into the lower Hudson River basin are from the upstream and non-point source discharges. Current nitrogen loads from municipal, upstream and non-point source areas are each significant inputs into the basin while the majority of the phosphorus load is from municipal discharges. This information makes it possible to evaluate the effectiveness of past water pollution control programs and to set directions for existing and future programs.

Pollutant discharges into the Hudson River basin have been studied in the past but results obtained from these studies are based on different physical boundaries, waste dischargers (municipal/ industrial) and discharge type (point/non-point) which made comparing results difficult. A look at pollutant loadings over time into the lower Hudson River basin from point and non-point sources was performed to analyze for trends and relative relationships between the different pollutant discharges.