News / Science & Technology

Wastewater Plants Extract Nutrients from Sewage

Wastewater Plants Extract Nutrients from Sewage i
X
October 24, 2012 6:37 PM
Sewage treatment plants around the world are beginning to put value on waste, turning it into a marketable resource. Blue Plains Advanced Wastewater Treatment Plant in Washington is the largest facility of its kind in the world and is among the leaders in the effort. VOA's Rosanne Skirble reports.

Wastewater Plants Extract Nutrients from Sewage

TEXT SIZE - +
Rosanne Skirble
Sewage treatment plants around the world are beginning to put value on waste, turning it into a marketable resource.  

Blue Plains Advanced Wastewater Treatment Plant in Washington is the largest facility of its kind in the world and is among the leaders in the effort.

On an average day, 1.4 billion liters of raw sewage flow into the plant, delivered from around the city through 2,000 kilometers of underground sewer pipes and pumping stations, an amount that could fill the nearby sports stadium.  

The waste is loaded with nitrogen and other nutrients.

Wastewater - A Green Industry
Wastewater US Policy, pt. 2i
|| 0:00:00
...
 
🔇
X


General Manager George Hawkins makes sure the discharge doesn’t pollute the river on which two million people in the region depend for their drinking water.

Limited discharge

By law, Blue Plains can dump only a small percentage of those nutrients into the Potomac River.

“We know that people buy nutrients all the time," Hawkins says. "So the question is how can we take things out of the water that we’re treating here and re-use it for the resource that it is?”

  • When raw sewage comes into Blue Plains debris and grit are removed and trucked to a landfill. (Rosanne Skirble/VOA)
  • Sewage flows into primary sedimentation tanks that separate more than half of the suspended solids from the liquid. (Rosanne Skirble/VOA)
  • After primary sedimentation, the fluid flows into secondary tanks where oxygen is pumped into it so microbes can break down the organic matter. (Rosanne Skirble/VOA)
  • In a laboratory at Blue Plains, researchers are working on a cost-saving measure that would deploy a newly discovered microbe that can break down organic matter without oxygen. (Rosanne Skirble/VOA)
  • Blue Plains plans to cut its nitrogen discharges into the Potomac River by half when this expansion project is completed in 2014. (Rosanne Skirble/VOA)
  • Microbes convert ammonia into harmless nitrogen gas. (Credit: DC Water)
  • Water, percolated through sand filters, removes remaining suspended solids and then is disinfected and de-chlorinated and discharged into the Potomac River. (Rosanne Skirble/VOA)
  • Construction is underway to build giant digesters that will bake the solid waste recovered during treatment and turn it into methane gas that will in part power the plant. (Rosanne Skirble/VOA)
  • Wastewater cleansed at Blue Plains is cleaner than the Potomac River when it is discharged in the waterway. (Rosanne Skirble/VOA)
  • By 2025 a new underground tunnel system will reduce to almost zero sewage overflow into Washington, DC waterways.  (Credit: Ted Coyle, DC Water)
  • The system of pipes, valves and pumping stations that distributes water to more than two million people in Washington, DC and suburban communities is aging like this one installed in 1910. (Credit: DC Water)



A massive $4 billion environmental program is under way at Blue Plains.

Among the three projects, two are mandated by the government, including one that will cut in half the amount of nitrogen and other waste nutrients discharged into the Potomac River.

The other is an underground tunnel to prevent accidental sewage overflow from its network of ageing pipes.

Sludge power

Engineer Chris Peot heads the solid waste program at Blue Plains, which is working on making better use of the mud-like sludge components of the wastewater stream.  

He says by 2012 the four huge digesters now under construction will cook the sludge.

“The microbes in the digesters are methanogens and they help break down the organic matter and convert it into methane which can be collected and burned in a turbine which turns and creates electricity.”

The process will make enough methane gas to supply about one-third of the treatment plant’s electric power needs, a great savings given that Blue Plains is the city’s biggest electricity user.

The other half of the digested wastewater bio-solids will be sold as a nutrient-rich soil additive.

“If we blend it and make it look like a top soil we can market it to the public," Peot says. "It can certainly be a source of revenue, a source of good clean soils for restoration projects, for reducing run-off for tree planting.”

Ghana's green factory

Other sewage treatment plants in the United States and other developed countries have adopted this by-product technology, or are considering doing so. The idea is also generating interest in developing countries.  

Amit Pramanik is an environmental engineer with the Water Environment Research Foundation. In a recent trip to Ghana, West Africa, he visited Kumasi, the nation’s second largest city, where only 10 percent of the residents are connected to a central sewer system.

Wastewater Plants Extract Nutrients from Sewage Part 2i
|| 0:00:00
X
Rosanne Skirble
October 23, 2012 6:51 PM
Sewage treatment plants around the world are beginning to put value on waste, turning it into a marketable resource. Blue Plains Advanced Wastewater Treatment Plant in Washington is the largest facility of its kind in the world and is among the leaders in the effort. In the United States, however, funding for water projects has stalled. VOA's Rosanne Skirble reports.


Pramanik says the digester project under construction will help reduce waste that now flows largely into open pits or landfills. He says project managers hope it will also generate useful and commercially valuable by-products such as nutrient-rich soil additives, bio-diesel fuel and methane gas.

“Can you recover that gas and can you use that either for heating or cooking and so on?" he says. "Can you grow food crops with this? Can you recover the nitrogen and phosphorus and increase agricultural yields?”

Economically and environmentally sound

What’s attractive to the local community, Pramanik says, is the payback.  

He says the model could be adopted anywhere that waste can be marketed as a profitable community resource. “So if you can get the community involved from the beginning and see that the community is benefiting from it, and the community sees that, they will take ownership.”

Pramanik says these new green factories make good sense for the local economy, for public health and for the environment.  

Costly old infrastructure

George Hawkins at the Washington Water and Sewer Authority agrees, however he and other waste water managers in the United are faced with many challenges to put such new green factories in place.  First, he says, their current system of pipes and pumping stations is old and requires on-going maintenance.  “In most cities the system was put in at the turn of the century of the last century when cities were being formed. And, he adds, the fact is that we need a lot of revenue from our rate-payers to bring it back up to date.”

Hawkins predicts those rates will increase by double-digits annually for years to come.

Not only is this costly, but secondly operators must also comply with strict environmental rules.  Under the Clean Water Act, passed 40 years ago and widely credited with protecting public health and the environment, industries are required to limit the waste that can go into the waterways.

Financial challenge

Many cash-strapped communities are finding it difficult to meet the law’s tough new standards, for what some, as George Hawkins told lawmakers at a recent hearing on Capitol Hill, believe are marginal environmental benefits to the waterway.

“We spend one billion dollars to get one tenth the protection of what we had spent 100 million dollars for in the past," he said. "And, it’s only going to get more expensive.

Joining Hawkins at the hearing was Lima, Ohio Mayor David Berger, who said his city doesn’t have all the funds it needs to comply with the new rules.

“These are unfunded mandates," Hawkins said. "So, if the Congress has passed these as mandates and orders for us to execute, then you must join us to pay for it. If the cash isn’t there or the political will isn’t there, then regulatory relief must come, and it has to come soon.”

While Republican Congressman Bob Gibbs told Berger that he agreed, that communities with ageing water and sewer systems need to be given some flexibility in complying with the law, Congress has actually moved to reduce funds for water projects from projects from $4.7 billion in 2009 to just $690 million in 2012.

Stalled Funding

Last year Democratic Congressman Tim Bishop introduced a bi-partisan bill to expand a fund that states could use to finance water projects.  

In his remarks at the hearing, Bishop was clearly frustrated that the bill is stalled in Congress. “We’re going in the wrong direction here. And we are exacerbating a problem that all of you on the ground are trying to resolve.”

George Hawkins says he and other public utility mangers will continue to press the U.S. Congress to provide the funds they need to comply with new clean water laws and maintain aging infrastructure. In the meantime, he urges the nation’s water treatment managers to pursue creative ways to turn wastewater into an income stream.

You May Like

Multimedia Anti-Keystone XL Protests Continue

Demonstrators are worried about pipeline's effect on climate change, their traditional way of life, health and safety More

Thailand's Political Power Struggle Continues

Court gave Prime Minister Yingluck Shinawatra until May 2 to prepare her defense over abuse of power charges but uncertainty remains over election timing More

Malaysia Plane Search Tests Limits of Ocean Mapping Technology

Expert tells VOA existing equipment’s maximum operating depth is around 6 kilometers as operation continues on ocean bed for any trace of MH370 More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Pet Kangaroo Helps Spread Environmental Messagei
X
Penelope Poulou
April 22, 2014 5:53 PM
Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pet Kangaroo Helps Spread Environmental Message

Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pro-Russian Separatists Plan 'Federalization Referendum' in Eastern Ukraine

Pro-Russian separatists in eastern Ukraine say they plan to move forward next month with a referendum vote for greater autonomy, despite the Geneva agreement reached with Russia, the U.S. and Ukraine to end the political conflict. VOA's Brian Padden reports from the city of Donetsk in Eastern Ukraine.
Video

Video Pope Francis Hopes Dual Canonizations Will Reconcile Church

On April 27, two popes - John the XXIII and John Paul II - will be made saints in a ceremony at St. Peter’s Square. VOA religion correspondent Jerome Socolovsky says the dual canonization is part of the current pope’s program to reconcile liberals and conservatives in the Roman Catholic Church.
Video

Video In Capturing Nature's Majesty, Film Makes Case for Its Survival

French filmmaker Luc Jacquet won worldwide acclaim for his 2005 Academy Award-winning documentary "March of the Penguins". Now Jacquet is back with a new film that takes movie-goers deep into the heart of a tropical rainforest - not only to celebrate its grandeur, but to make the case for its survival. VOA's Rosanne Skirble reports.
Video

Video Boston Marathon Bittersweet for Many Runners

Monday's running of the Boston Marathon was bittersweet for many of the 36,000 participants as they finished the run that was interrupted by a double bombing last year. Many gathered along the route paid respect to the four people killed as a result of two bombings near the finish line. VOA's Carolyn Presutti returned to Boston this year to follow two runners, forever changed because of the crimes.
Video

Video International Students Learn Film Production in World's Movie Capital

Hollywood - which is part of Los Angeles - is the movie capital of the world, and many aspiring filmmakers go there in hopes of breaking into the movie business. Mike O'Sullivan reports that regional universities are also a magnet for students who hope to become producers or directors.
Video

Video Pacific Rim Trade Deal Proves Elusive

With the U.S.-led war in Iraq ended and American military involvement in Afghanistan winding down, President Barack Obama has sought to pivot the country's foreign policy focus towards Asia. One aspect of that pivot is the negotiation of a free-trade agreement among 12 Pacific Rim nations. But as Obama leaves this week on a trip to four Asian countries he has found it very difficult to complete the trade pact. VOA's Ken Bredemeier has more from Washington.
Video

Video Autistic Adults Face Housing, Job Challenges

Many parents of children with disabilities fear for the future of their adult child. It can be difficult to find services to help adults with disabilities - physical, mental or emotional - find work or live on their own. The mother of an autistic boy set up a foundation to advocate for the estimated 1.2 million American adults with autism, a developmental disorder that causes communication difficulties and often social difficulties. VOA's Faiza Elmasry reports.
AppleAndroid