USGS Banner

Title: Nitrogen and Phosphorus in D.C. Waterways

Focus Categories: WW, WQL, NU, NC

Keywords: Wastewater, Nitrate, Phosphate, Water Quality

Duration: May 15, 2000 - May 14, 2001

FY 2000 Federal Funds: $ 11,570

FY 2000 Non-Federal Funds: $42,303

Principal Investigator:

Charles C. Glass
Assistant Professor,
Department of Civil Engineering
Howard University
2300 6th Street, N.W.
Washington D.C. 20059

Congressional District: District of Columbia

Problem and Research Objectives

he two major rivers that flow through boundaries of D.C. are the Anacostia and the Potomac rivers. These two water bodies have several contamination issues, especially the Anacostia, including higher nutrient concentrations. The major influences on the concentrations of nitrogen and phosphorus to the waterways in D.C. are from nonpoint source runoff upstream in the Potomac, the effluent from the Blue Plains Wastewater treatment plant, and combined storm sewer overflows. Currently the Blue Plains Wastewater Treatment Plant is adding the process of denitrification to increase the removal of nitrate from the plants effluent. The nutrient load from the plant is predicted to be greatly decreased when denitrification reactors are on-line.

The objective of this research will be to compile data on the nitrogen and phosphorus species in the Potomac and Anacostia Rivers and to compare this data with effluent data from the wastewater treatment plant as upgrades to nutrient removal are made.

Statement of Results and Benefits

The results of this research will give a clear representation of the extent to nitrogen and phosphorus contamination in the two rivers inside the boundaries of D.C. The comparisons of the contributions to nitrogen and phosphorus in the rivers from the wastewater treatment plant, nonpoint source runoff and storm sewer overflows will be made with the data that results from this research.

Nature, Scope and Objectives of the Research

This study will focus on the chemical measurement of nitrogen and phosphorus species in the Potomac and Anacostia rivers within the boundaries of the District of Columbia. The plan for this study is to gain a thorough understanding of the sources of nitrogen and phosphorus to the two rivers and how activities in D.C. affect the concentrations of nitrogen and phosphorus. Water samples will be taken from the middle of the rivers throughout their lengths and tested in the laboratory for various nitrogen and phosphorus species. Blue Plains is believed to contribute 95% of the nitrogen and 53 % of the phosphorus from DC to the Potomac river (EPA, 1999). Data from the Blue Plains Wastewater treatment plant and any other sources that are made available will be analyzed to evaluate the fluctuating concentrations throughout the two rivers. The effect of changing treatment processes at the wastewater treatment plant on nitrogen and phosphorus concentrations in the water will be evaluated.

Methods, Procedures and Facilities

During the course of this study weekly water samples will be taken from the rivers from May to September in the year 2000 and compared with daily data from the Blue Plains wastewater treatment plant throughout the same time period. The data will be used to determine if there are any concentration gradients prior to the samples taken downstream of the wastewater treatment plant. There are points along the Anacostia and the Potomac that may increase the nutrient concentrations during dry and wet weather, including Rock Creek stream and the Kenilworth aquatic gardens and storm sewers along the Anacostia. Quality assurance and quality control procedures will be followed in accordance with Standard Methods for the Examination of Water and Wastewater, 20th Edition. Nitrate, nitrite, ammonia and total Kjedhal nitrogen will be measured as well as total phosphorus and total soluble phosphorus following Standard Methods. Through contacts at the wastewater treatment plant data will be gathered on the effluent concentrations during the study to compare with sampling from the rivers.

The environmental laboratories in the Department of Civil Engineering here at Howard University are fully equipped with the necessary analytical equipment to perform this study. The majority of the sampling will be performed using a general water quality portable laboratory available from the HACH Company, Loveland CO. The laboratory at Howard in Civil Engineering has gas chromatographs (GC) (Hewlett-Packard 6980 and 5890A, a gas chromatograph/mass spectrophotometer (GC-MS) (Hewlett-Packard 5890A with a Hewlett Packard 5971 MSD), a high performance liquid chromatograph (HPLC) (Hewlett Packard 1050), and an ion chromatograph (IC) (Dionex Model 300 DX). Phosphate, nitrate and nitrite will be measured using ion chromatography. IC's are accurate to part per billion concentrations when measuring these anions and sample manipulation for systems of this type has been performed before (Glass and Silverstein, 1998, 1999).

Related Research

Previous and current research by the Principal Investigator has focused on nitrogen species found in wastewater treatment and their conversion by denitrification in engineered systems (Glass et ai., 1997, Glass and Silverstein, 1998, 1999). The reaction in the natural environment are identical to those that occur in engineered systems, they just occur at faster rates in engineered systems.

Literature Cited

APHA, AWWA, WEF, (1998) Standard Methods for the Examination of Water and Wastewater. l9th Ed. APHA, Washington, DC.

Glass, C, Silverstein, J., and Oh, J. (1997). "Inhibition of Denitrification in Activated Sludge by Nitrite". Water Environment Research, 69:6, 1086-1093.

Glass, C. and Silverstein, J. (1998a) "Denitrification Kinetics of High Nitrate Concentration Water: pH effect on inhibition and nitrite accumulation". Water Research, 32:3, 831-839.

Glass, C. and Silverstein, J. (1999) "Denitrification of High-Nitrate, High-Salinity Wastewater". WaterResearch, 33:1, 223-229.

U.S. Department of the Interior, U.S. Geological Survey
Maintained by: John Schefter
Last Updated: Tuesday October 25, 2005 4:31 PM
Privacy Statement || Disclaimer
|| Accessibility