The U.S. Patent and Trademark Office has awarded the District of Columbia Water and Sewer Authority (DC Water) a patent for a unique wastewater treatment process that achieves three specific benefits:
• It produces a low odor compost-like biosolids product
• It degrades microconstituents within biosolids
• It removes nitrogen from recycle streams
The innovation is a new aerobic digestion process following anaerobic digestion.

“DC Water is unique in the water sector for its investment in science and technology research,” said General Manager George S. Hawkins. “Our research is aimed not only at current regulations, but also emerging issues such as endocrine disruptors (estrogens), personal care products (PCPs) and flame retardants (PBDEs), along with process improvements. Our studies help advance water sector technology.”

Walter Bailey, Assistant General Manager of Wastewater Treatment, added, “We seek to understand the science behind emerging issues so that we identify, as a sector, which are the most important to address and how best to process them. Our research comes years before implementation so that by the time there are regulations in place, we know how to meet or exceed those regulations.”

This approach can also save wastewater treatment plants immensely by perfecting the technology prior to implementation and regulation. DC Water partners with prestigious universities including those in the DC metropolitan region, such as Howard University, The George Washington University, University of Maryland and Virginia Tech.

The invention is titled, “Method for Treating Raw Sludge Including Simultaneous or Pulsed Aerobic/Anoxic Digestion” and is assigned to DC Water. Bailey, Christopher Peot, PE, Biosolids Manager, and Sudhir Murthy, PhD, PE, Research and Laboratory Manager, are named as inventors. The research was conducted with Virginia Tech, whose scientist is also named as inventor.

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About the District of Columbia Water and Sewer Authority

The District of Columbia Water and Sewer Authority (DC Water), is an industry leading multi-jurisdictional regional utility that provides drinking water, wastewater collection and treatment to nearly 600,000 residential, commercial and governmental customers in the District of Columbia, and also collects and treats wastewater for a population of 1.6 million in Montgomery and Prince Georges counties in Maryland and Fairfax and Loudoun counties in Virginia.

DC Water’s service area covers approximately 725 square miles and the company operates the world’s largest advanced wastewater treatment plant with a capacity of 370 million gallons per day and has a peak capacity of 1.076 billion gallons per day.