When you think about the plethora of remarkable places in Washington, D.C., what pops into your head? You may have thought of the Washington Monument, the world’s tallest obelisk, or maybe the numerous memorials of famous figures like Martin Luther King, Jr. and President Lincoln. If someone were to ask you whether the D.C. Water’s Blue Plains Advanced Wastewater Treatment Plant came to mind, many of you would most likely say it did not. However, this nearby plant is actually the largest thermal hydrolysis facility in the world as of 2016, and on February 11th of 2026, the AP Environmental Science (APES) class, here at BASIS Independent McLean (BIM), got the chance to go see it in person.

First, to familiarize ourselves with wastewater treatment plants, let’s focus on what they do. In general, these plants clean wastewater from households, businesses, and industries before returning it to the environment, free of harmful pollutants, bacteria, and debris. According to the U.S. Environmental Protection Agency (EPA), there are several ways among treatment plants to clean the water, but the following are all specific to (but not unique to) Blue Plains: 

Primary/Physical Treatment: separates solids that float to the top or settle to the bottom; uses raw wastewater pumping, grit removal, grease separation, and primary sedimentation; then, treats the removed solids through digestion, elutriation, and dewatering.

Secondary/Biological Treatment: converts suspended or dissolved solids into separable form. Blue Plains achieves this using a modified-aeration step-feed activated sludge process. Also reduces carbon and phosphorus via course bubble diffused aeration and chemical precipitation, respectively.

Advanced/Chemical Treatment (which may but is not required to include): Biological Nitrogen Removal, Nitrification, Denitrification, Multimedia Filtration, Solids Process, Chemical Addition, Odor Control, Settleability Enhancement, Phosphorus Removal, Metal Salts, pH, Foam Control, Disinfection, Dechlorination, Solids Processing, etc.

Upon finishing treatment, the water is released into a body of water (in Blue Plains case, the Potomac River) to protect the connected larger ecosystem (the Chesapeake Bay) against pollution.

According to the EPA, here are some facts and statistics about the significance and accomplishments of Blue Plains in its entirety:

• Upon opening in 1937, originally as only a primary treatment facility, Blue Plains now covers 150 acres, with a design capacity of 370 million gallons per day (mgd), and a peak capacity of 1,076 million gallons per day.
• Its collection system includes 1,800 miles of sanitary and combined sewers, 22 flow-metering stations, nine off-site wastewater pumping stations, and 16 storm water pumping stations within the District, more prevalent in the older systems, such as the downtown area.
• The plant serves the District of Columbia; portions of Montgomery and Prince George’s Counties in Maryland; and Fairfax and Loudoun counties in Virginia. So, depending on where you live, this plant may very well be treating your household water!
• 58 Combined Sewer Overflow outfalls (CSOs) and two discharge points, mainly flowing into the Potomac River.

Now that we know more about the location of the fieldtrip, it’s time for some opinions from the people who experienced the tour. After an interview with Drema Khraibani, the teacher of the APES course, we learn that this is not her first time visiting Blue Plains, seeing as she went there when she was a high school student at a different high school, “It’s not a new field trip in APES tradition,” she said. When asked if she would host this field trip again, Mrs. Khraibani says she “absolutely” would. “The first-hand experience that the students are able to gain from this trip is so wonderful,” she remarks, differentiating this venture from anything a student might learn from just sitting in a classroom reading a textbook.

Although the plant is not actually open to the public, there is a visitors center where anyone can learn more about Blue Plains as a whole. Many of the BIM high school APES students that went on this field trip considered it an eye-opening and delightful experience. This field trip was a learning moment in showing students how things work, where things work, and the significance of those things.