ARMN member Louis Harrell reports on a group visit to Blue Plains. All came away with enhanced understanding of waste water treatment––and some valuable tips.
By Louis Harrell, ARMN
On May 28, 13 ARMN members traveled to Southwest D.C. to the Blue Plains Advanced Waste Water Treatment Plant for a guided tour of the facility. Blue Plains is the largest plant of its kind in the world, with the ability to treat 370 million gallons a day. Peak capacity is slightly more than 1 billion gallons per day. The facility serves Loudoun County, Fairfax County, part of Arlington County, Montgomery County, Prince George’s County, and the District of Columbia.
We saw key features of the facility and met with an engineer who answered questions about the plant and informed us about issues that Blue Plains faces.
We saw the primary and secondary sedimentation tanks, the nitrification and denitrification tanks, and the location where cleaned water is returned to the Potomac. The nitrification tanks use microbes and a large amount of aeration to oxidize the nitrogen from ammonia to nitrate. The denitrification tanks are used to convert the nitrate to nitrogen gas using microbes and methanol. Unlike the nitrification process, the denitrification tanks do not use aeration. The nitrification and denitrification steps, along with a final disinfection step, make Blue Plains into a highly advanced facility. Our guide showed us samples of the effluent and drinking water and we agreed that they both looked the same.
Some of the takeaways from our visit included:
- Blue Plains plans to start using methane captured on site to produce 10 MW of their power requirements. DC Water is the single largest consumer of electricity in the District.
- The plant produces Class A biosolids, which are presently distributed locally for free to community gardens; in the next few years they hope to market them commercially. This change will allow the plant to reduce its carbon footprint by one third.
- We learned that flushable baby wipes should not actually be flushed as they clog the pipes at the plant. Composting was also recommended.