Washington has been growing. The population boom of the past six years — when the city added as many as 1,000 residents a month — may be slowing, but it’s not stopping. D.C. Mayor Muriel Bowser in July estimated that the District’s population could top out around 800,000.
 
Can the District accommodate the population influx in an environmentally sustainable way? Lots of city departments already have plans in the works to do just that. Here are three programs that could change the way our city grows.
 
D.C.’s waste won’t go to waste
 
As the city grows it will need to handle even more of what experts call “biosolids” — and what the rest of us call poop.
 
To do that in an environmentally friendly way, Chris Peot, the director of resource recovery at D.C. Water, says we need to view biosolids not as waste, but as a resource.
 
“We think that it’s a valuable asset and we should extract as much value from it as we can,” Peot says.
 
On October 7, the city will cut the ribbon on a $470 million plant 16 years in the making. The new system at the Blue Plains Advanced Wastewater Treatment Plant in Southeast Washington is the first of its kind in North America and the largest in the world. It uses cutting-edge technology to turn Washington’s waste into two things that can make the city money — energy and topsoil.
 
For the past two decades, D.C.’s biosolids were treated with chemicals to kill pathogens. The city paid about $16 million a year for treated waste to be trucked to rural farms to be used as fertilizer.
 
“We were returning much of the carbon back to the earth,” Peot says. That was a good thing, but with one problem: “We were not extracting any of this value out of this asset ourselves.”
 
D.C Water began working in 1999 to come up with a better way to treat waste, and today, the new plan is in place. Although the ribbon-cutting is October 7, the new plant is already processing D.C.’s waste in a brand new way: Biosolids now flow into two dozen thermal hydrolysis tanks. D.C. is the first North American city to use tanks like these, which are made by a Norwegian company called Cambi. The Cambi tanks pressure cook the biosolids, so that when they’re released into the digesters, they produce methane gas. That gas is turned into electricity to power the plants itself.
 
 
“We are now producing over a third of our electrical needs on site,” Peot says. “It will reduce our carbon footprint by 55,000 tons.”
 
The remaining biosolids, now reduced by half, are blended with sand to create topsoil of higher quality than the city’s previous product. The new processing method means the product meets EPA standards for use in urban areas. So instead of trucking it to Virginia farms, the topsoil can be put to use in D.C.
 
“We can help DDOT plant trees that have a lower mortality rate because we have this high-quality soil,” Peot says.
 
The investment in the plant should pay for itself in savings: In addition to reducing D.C. Water’s Pepco bill by as much as a third, the city will save about $16 million a year by not paying truckers to take the waste away.
 
And D.C. Water built the new plant with even more growth in mind. “As the population in D.C. grows, we have room to add more digesters,” Peot says. “We have about 100 years worth of capacity.”
 
The city will lower its utility bill
 
The District’s growth has arrived during the era of big data. So one of the city’s strategies for growing green is to use that data to lower the government’s carbon footprint. That’s where the city’s BuildSmart DC program comes in.
 
“We are in a very specific fight right now to reduce the amount of carbon emissions that are fueling the city,” says Mark Chambers, director of sustainability and energy management at the Department of General Services. “There’s not a lot of folks who are doing this in the way that we are trying to do.”
 
It started a few years ago, when, after negotiating partnerships with a few utility companies, D.C. found itself in a unique position. It suddenly had access to real-time data on electricity usage, something utilities usually collect but don't share.
 
Chambers and his colleagues decided to do something unusual with all of this data: They made it public.
 
In 2013, the Department of General Services launched buildsmartdc.com, which shares utility data for nearly every building owned by the city — office buildings, schools, power stations, homeless shelters, libraries, health centers and more — about 400 in all.
 
“We knew that we wanted to be somewhat of a champion of transparency,” Chambers says. “We wanted to say, ‘Here’s almost the entirety of our building portfolio, and here’s the energy use data for that.”
 
Since the site launched two years ago, the city has boasted a 10 percent drop in electricity used in buildings in the BuildSmart portfolio.
 
Next, the team behind BuildSmart is hoping to influence the rest of the city to reduce energy use as well.
 
Chambers says the project was always intended to be a model for others, and the team is currently negotiating with other large landowners in the city — large universities and hospital centers — to let them use BuildSmart’s tools.
 
The team also redesigned the BuildSmart website this summer to make it more user-friendly. And Chambers hopes at-home data tinkerers will be able to analyze the plethora of information available to come up with new ways to reduce energy.
 
“We knew that was not just going to put pressure on ourselves to reform,” he says, “but also to give a mirror back to the public, and say, ‘These are your public buildings, if you think you can do it better, please do.’”
 
 
A new sewer will keep rivers clean
 
As Washington looks to the future, it has to come to terms with its past. And for D.C. Water, that means updating the city’s century-old sewer system.
 
“About a third of the District is served by these old antiquated sewers called combined sewers,” says Carlton Ray, director of the clean rivers project. They’re so called because they comprise a single pipe, which combines the wastewater from plumbing with the rainwater that flows off the streets and into gutters.
 
This isn’t a problem — except when it rains.
 
When there’s a downpour, sewers fill, and the sewage/rain mix threatens to back up into the streets. "Overflow points" release some of the rain and raw sewage into the Anacostia River, the Potomac River and Rock Creek, an average of 75 to 80 times a year.
 
But backups still happen. In 2012, four major rainfalls sent sewage flooding into the streets and basements of Bloomingdale and Ledroit Park.
 
“We had up to two feet of sewage rolling down through Bloomingdale,” Ray recalls. “It was just a terrible situation.”
 
It wasn’t an unusual one. “Since ‘55, every five years they would have these terrible rains where this would occur,” Ray says. Back then, the sewage would flow into people's cellars; that was bad, but now it's worse. With the recent population boom, most of those cellars have now been converted into basement apartments--so regular heavy rainfall now floods people's home with sewage every few years.
 
Even when the overflow points work, they no longer work for the environment. “Since the Clean Water Act, they've been a violation of water quality standards,” Ray says.
 
D.C. has been working on a plan to update the sewers since the 1990s, and in 2005, both the city and the Environmental Protection Agency approved a 20-year plan to fix the problem:  Enormous tunnels will capture and store the overflow — an extra 10 million gallons of storage capacity. Then, when the rain stops, the water will be released into the open tunnels and flow, as usual, to the Blue Plains treatment facility.
 
When the system is complete in 2025, the number of overflows will drop from 75 to 80 a year to 6 times a year.
 
D.C. Water is still working to make the plan greener. “In 2011, we started to tweak that plan to include example of green infrastructure,” Ray says. The city will add rain gardens, rain barrels and green roofs to try to capture water, so it never makes it to the overburdened sewer system.
 
“The goal is to slow that water down,” Ray says.
 
The entire plan will be complete by 2025, and parts of it are already coming together: The northeast boundary tunnel will be complete by 2022, a tunnel along First Street has been accelerated to relieve flooding in Bloomingdale, and a major tunnel that runs south from RFK stadium is scheduled to be completed in March of 2018. 
 
“It’s like a big symphony,” Ray says. “I guess as the conductor we’re trying to get everybody to work together to complete that by March 23, 2018.”