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Energy + Water

Maximizing Energy Resources, Minimizing Costs

Upgrading the Blue Plains advanced wastewater treatment plant

The Blue Plains advanced wastewater treatment plant, operated by the District of Columbia Water and Sewer Authority (DC Water), is the largest facility of its kind in the world. The 153-acre plant has an average daily capacity of 370 million gallons per day, and a peak capacity of more than 1 billion gallons per day--an energy intensive operation.

 
The $208 million upgrade to the biosolids management process includes the world’s largest Cambi thermal hydrolysis process (THP) system, and the first Cambi THP system in the United States.  

Looking to maximize available resources and reduce its carbon footprint, DC Water is implementing an upgrade that consists of four individual projects: site preparation, main process train (MPT), combined heat and power (CHP) and final dewatering. CDM Smith, as an equal, joint-venture partner, is providing design-build services for the MPT project, which will be developed using a building information model and 3D/4D technology.

The $208 million upgrade to the biosolids management process includes the world’s largest Cambi thermal hydrolysis process (THP) system, and the first Cambi THP system in the United States. Cambi’s THP system is a high-pressure process using steam pre-treatment of biosolids prior to anaerobic digestion. CDM Smith has experience implementing Cambi THP systems in Europe, where several facilities are currently using this technology.

In addition to incorporating THP, the project will build new facilities for biosolids blending and screening, pre-dewatering and four 3.8-million-gallon digesters. Upgrades to the current process, which is producing Class B, lime stabilized biosolids, will produce Class A biosolids, reducing the overall volume of biosolids to be hauled for land application by 50 percent and reduce costs dramatically.

Meanwhile, by putting biogas to work and generating renewable energy through a separate CHP project, the updated plant will generate between 10 and 13 megawatts of power, reducing demand for energy from the grid. Reduced biosolids hauling and on-site power production is anticipated to reduce the facility’s greenhouse gas emissions by 40 percent. And in addition to reducing waste, generating energy and improving air quality the project will save residents of the district and surrounding metro areas an estimated $20 million annually—$10 million in power savings and $10 million in reduced sludge disposal costs.

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District of Columbia Water and Sewer Authority