In front of the sewage sludge biogas reactor in Walla Walla.
A new method to treat sewage can efficiently convert leftover sludge to biogas, an advance that could help communities lower their waste treatment costs while helping the environment.
Reporting in the journal, Waste Management, a Washington State University research team tested a pretreatment technology, adding an extra step to typical treatments and using oxygen-containing high pressure steam to break down sewage sludge. They found that they were able to convert more than 85% of the organic material to biogas, which can be used to produce electricity or upgraded to renewable natural gas (RNG) for the natural gas grid or for local use.
Adding the new pretreatment step improves the anaerobic conversion of sewage sludge at the wastewater treatment facility from the current less-than-50% conversion rate, and they produced 98% more methane overall compared to current practice.
“It was shown to be extremely efficient, and that’s very exciting,” said Birgitte Ahring, professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, who led the work. “This can be applicable and something we could begin to explore in Washington state. Not wasting waste but using its potential instead has major advantages.”
Sewage sludge is not a sought-after product. About half of the wastewater treatment plants in the U.S. use anaerobic digestion to reduce this waste, but the process, in which microbes break down the waste, is inefficient. The leftover sludge, called biosolids, generally ends up in landfills.
Wastewater treatment facilities also use large amounts of electricity to clean up municipal wastewater. They are often the largest user of electricity in a small community.
“If they could make their own electricity or for some of the large plants, make renewable natural gas and add it to the natural gas grid, then they can reduce the use of fossil fuels. Here we are beginning to move into the idea of the circular economy,” said Ahring, who is also a faculty member in the Bioproducts, Sciences, and Engineering Laboratory at WSU Tri-cities.
For their study, the WSU research team treated the sludge at high temperature and pressure with oxygen added before the anaerobic digestion process. The small amount of oxygen under the high-pressure conditions acts as a catalyst breaks down the polymers in the material.
The WSU researchers have been studying this pretreatment process for several years, using it to break down straw and woody materials. They weren’t sure the process would work with the different composition of sewage sludge, such as lipids and proteins, but were positively surprised.
“This is not a very high-tech solution,” Ahring said. “It’s actually a solution that can be useful even at small scale. The efficiency has to be high or else you cannot warrant adding the extra costs to the process.”
The technology could be particularly helpful for smaller communities, many of which are motivated to reduce waste and their climate impact, she added.
The WSU team is working with Clean-Vantage, a Richland-based clean technology start-up company active in the pretreatment area, as well as with Pacific Northwest National Laboratory (PNNL), which is doing a techno-economic analysis of the new process.
The researchers are now scaling up the work in their pilot facility located at WSU Tri-cities to further demonstrate the process. They are also studying how to efficiently convert the biogas to more valuable renewable natural gas by a new bioprocess. While the biogas can be used to produce electricity, producing renewable natural gas could allow rural communities to produce local transportation fuel for fueling their municipal vehicles.
Original Article: Novel waste treatment efficiently converts sewage to biogas
The Latest Updates from Bing News
Go deeper with Bing News on:
Sewage to biogas
- Ares acquires Burnham RNG
Burnham RNG (Burnham) has announced that a fund managed by Ares Management’s Infrastructure Opportunities strategy (Ares) has made a strategic investment to acquire the company from Edge Natural ...
- Burnham RNG Is Acquired by Ares Management
The asset has a 30-year wastewater treatment agreement with the City of Pasco and will sell produced RNG to Cascade Energy via a 20-year offtake agreement. In addition to PRRC, Burnham has a ...
- Orangeville water pollution control plant to undergo rehabilitation
We’ll be exploring how this biogas could be used for on-site energy recovery ... Both sections are responsible for wastewater generated by approximately 11,308 households within the Town limits. The ...
- The benefits of anaerobic wastewater treatment
Conventional wastewater treatment in many regions consists of three ... plants used to generate electricity from biogas. Using HRS G Series heat exchangers on the exhaust recovers energy that can be ...
- From trash-eating hogs to biogas: How SLO County stayed on ‘the cutting edge’ of composting
One of the projects Rizzoli helped to develop is the landfill’s compost operation. In its first year in operation in 1997, the recycling center brought in 4,000 tons of green waste from the city of ...
Go deeper with Bing News on:
Sewage pretreatment technology
- EMP Metals Announces Successful DLE Pilot Project and Production of Battery Grade Lithium Carbonate; Provides Update on PEA
CNW/ - EMP Metals Corp. (CSE: EMPS) (OTCQB: EMPPF) ("EMP Metals" or the "Company") is pleased to report significant ...
- Achieving ZLD at textiles hub through ERDs
Energy Recovery’s line of ERDs provide significant energy savings in RO wastewater treatment by capturing lost pressure energy and recycling it back into the system. Specifically, the PX is ...
- City eyes audit of north end sewage plant mega project
The most expensive infrastructure project in City of Winnipeg history could be audited next year, if council approves. In a new report, the city’s auditor proposes to complete a “limited scope ...
- Wastewater Reverse Osmosis Membrane (Cellulose Acetate, Thin Film Composite) Market - Global Forecast to 2028
Application (Residential,Commercial, Industrial), And Region (North America, Europe, APAC, South America, Middle East & Africa) - Global Forecast to 2028" report has been added to ...
- Funding approved for Sundre's wastewater technology study
SUNDRE – Town council has approved the allocation of a $25,000 commitment in a bid to secure grant funding to conduct a feasibility study on the new technology being trialled at the wastewater ...