Patapsco Wastewater Treatment Plant’s origins essentially began in 1918, when 60.2 square miles was annexed to the City of Baltimore. This increase in the size of the City resulted in a section of South Baltimore being without sewage treatment facilities. By reason of the topography, the sewage from this section could not drain by gravity to the Eastern Avenue Pumping Station, or to the outfall sewer discharging at Back River Sewage Treatment Works. Therefore a study was made in 1921 of the available shorefront property in the Brooklyn-Curtis Bay Area, suitable for a sewage treatment plant.

Studies were also made of the currents in the Patapsco River to determine the most desirable location to discharge the treatment plant effluent. Afloat, lighted by means of a storage battery, was used to make the current studies. At first, two oil lanterns were used on the float, but they were discarded when it was found that the wind increased the speed of travel of the float, and the speed of the float was quite different when one or two lanterns were used.

In 1923, a general survey was made of all the industries in the Brooklyn-Curtis Bay and Fairfield areas to determine the nature and the quantity of their sanitary and industrial wastes. After a careful review of all the factors involved, it was decided to purchase the present site of the Patapsco Wastewater Treatment Plant. The property, which has a land area of 29.04 acres, and a total area of 38.74 acres, was purchased in 1924 for $115,000.

There then followed a period of study and a determination to serve an ultimate population of 100,000. Construction finally began on June 14, 1937, and was completed on June 26, 1940, with the plant placed in service on November 12, 1940. Unfortunately, the original plant, modern for its time, was capable of only removing approximately one-third of the pollutants flowing through the plant, with the remaining two-thirds being discharged to the Patapsco River and out into the Chesapeake Bay.

That problem had to be resolved. Beginning in 1958 the Southwest Diversion Project was to change the future of the Patapsco plant. This was to provide major sewerage facilities for conveying wastewater from the western part of Baltimore, principally the Gwynns Falls sewershed, and from the Patapsco River Basin sewershed to the Patapsco Wastewater Treatment Plant. In addition to providing needed system capacity for West Baltimore, the project would also relieve portions of the East Baltimore system flowing to the Back River Wastewater Treatment Plant.

Subsequent actions led to the Master plan Report of 1968, and then in 1970 the overall planning and design criteria for the present plant began. The ultimate goal was to provide additional capacity and to upgrade the plant’s discharge to meet more stringent water quality requirements for the Patapsco River and the Chesapeake Bay.

The formal opening on June 29, 1985, therefore, was the culmination of the efforts of many people, over a long period of time, who sought and are now seeing the achievement to provide protection to the waters of the State of Maryland.

Currently under construction are additional facilities to further remove the quantity of nutrients being discharged to the receiving waters. No longer is there only just one-third of the pollutants being removed by the plant, but rather today in excess of ninety percent of the pollutants are being removed and the City achieves its commitment to meeting the stringent federal and state discharge parameters.

The Facility

The Patapsco Wastewater Treatment Plant is a secondary treatment facility with enhanced nutrient removal (ENR), chlorination and de-chlorination, situated on 69 acres on the Patapsco River at Wagner’s Point.

The plant has grown from 5 million gallons per day (MGD) capacity in 1940 to its present-day 63.0 MGD. It serves an area of approximately 184 square miles and an estimated population of approximately 450,000. The plant employs approximately 180 people to treat wastewater generated from Baltimore City, as well as Baltimore, Howard, and Anne Arundel counties. Wastewater treatment at Patapsco consists of grit removal, screening out large solid materials, settling out solids during an hour’s retention, and removal of suspended and dissolved materials. These processes remove almost all of the pollutants that enter the treatment facility.

The goal of the Patapsco Wastewater Treatment Plant is to remove the pollutants from the incoming wastewater that is received daily and return it to the environment without detrimental effects to the aquatic life of the Patapsco River and the Chesapeake Bay.