By Jan Peelen
Advisor Infrastructure & the Environment
Royal Netherlands Embassy, Washington, D.C.
Ever wonder what happens to all the water we flush down the toilet or that drains out of the washing machine after doing a load of laundry?
Well, the wastewater is not just dumped into the river. It has to be treated in wastewater treatment plants before it is clean enough to discharge into creeks or rivers.
A more sustainable operation
In Washington, D.C., that treatment happens in the District of Columbia Water and Sewer Authority’s Blue Plains Advanced Wastewater Treatment Plant, the largest of its kind in the world. Since the Royal Netherlands Embassy promotes the circular economy and the development of smart city technology, we just had to visit this innovative facility in our backyard to see how they applied the latest technologies to make their operation more sustainable.
Our friends at DC Water gave us a warm welcome at the Blue Plains plant and explained a bit what they are doing. Every day they receive and treat more than 330 million gallons of raw sewage from 2.2 million people in the District of Columbia, Maryland and Virginia at the Blue Plains plant, where it is cleaned, and all the organic waste is removed before it is released into the Potomac River.
Traditionally, the DC Water and Sewer Authority needs 25 megawatt of electricity to treat all this wastewater, making it the biggest user of electricity in the District of Columbia.
Reducing the carbon footprint
However, DC Water and Sewer Authority has been reducing Blue Plains’ energy bill and carbon footprint drastically. They added a thermal hydrolysis system that basically pressure cooks the organic material before entering an anaerobic digester, where microbes convert the organic matter into methane.
This gas powers turbines that generate enough energy to provide about one-third of Blue Plains’ energy needs. In addition, heat is recovered and converted into steam, which is used to heat the thermal hydrolysis process, so that there is no external energy needed for the project.
The development of 150 acres of solar panel canopies on top of its facilities will add another 10 megawatts of onsite power.
Smart and circular facility
Besides generating energy, the DC Water and Sewer Authority is also creating soil conditioner. With the thermal hydrolysis system in place, the quality of the biosolids that remain after water treatment exceeds all EPA standards for soil production and use in both rural and urban settings, so it can be used for landscaping, restoration, gardening, and tree planting.
This makes Blue Plains an excellent example of a smart, circular facility!