Waste water treatment plant mud used as 'green' fuel

Jun 23, 2009
This is a cement factory. Credit: José Luis Domingo

Catalan scientists have shown that using mud from waste water treatment plants as a partial alternative fuel can enable cement factories to reduce their CO2 emissions and comply with the Kyoto Protocol, as well as posing no risk to human health and being profitable. These are the results of an environmental impact assessment.

Dependency on oil and coal could be coming to an end. Researchers from the Rovira i Virgili University (URV) have analysed the environmental and human health impacts of an alternative fuel that solves various problems simultaneously. This is the solid waste from the water treatment plants of large cities.

The scientists have carried out the first study into this method at a plant in Vallcarca (Catalonia), which has been producing cement for more than 100 years, and they confirm in the latest issue of the journal Environmental Science and Pollution Research that it is "the best option for getting rid of mud that would have had to be dumped elsewhere, while also powering the plant".

"As this mud is already waste, burning it does not enter into the atmospheric CO2 emissions assigned to each country under the ", José Luis Domingo, lead author of the study and director of the Toxicology and Environmental Health Laboratory at the URV, tells SINC.

This would enable plants producing cement, one of the most contaminating industries in terms of CO2 as well as emissions of dioxins, furans and heavy metals, to consume energy in a more environmentally-friendly way. Up to 20% of the fossil fuel energy used at the Catalan plant has now been substituted for the fuel from waste water treatment plant mud.

From an economic point of view, the scientists will not say that cement plants could increase their profits by using this method, but "they will not have to pay anything to exceed their agreed emissions", the researcher points out. The economic benefits of this system also depend on the price of fuel.

One of the most important issues for the URV scientists is the reduction in environmental impact, and consequently the health risks for people living near the plants. The experiment with the mud has led to a 140,000 tonne reduction in CO2 emissions between 2003 and 2006, and will have limited the potential deaths from exposure to chemical pollutants. In addition, the study shows that using this green fuel would reduce the cancer rate by 4.56 per million inhabitants.

The researchers say it is essential to carry out separate studies for each plant because "we still don't know whether this will be positive for the whole cement industry", according to Domingo. However, if the conditions are right, using mud from waste water treatment plants in cement factories is "a very good solution", he concludes.

More information: Nadal, Marti; Schuhmacher, Marta; Domingo, José Luis. "Cost-benefit analysis of using sewage sludge as alternative fuel in a cement plant: a case study" Environmental Science and Pollution Research 16(3):322-328, mayo de 2009.

Source: FECYT - Spanish Foundation for Science and Technology

Explore further: Hopes, fears, doubts surround Cuba's oil future

add to favorites email to friend print save as pdf

Related Stories

EPA to limit mercury from cement plants

Apr 22, 2009

The Environmental Protection Agency on Tuesday called for the nation's first limits on mercury emissions from the more than 100 cement factories across the U.S.

Rocket-fueled bacteria clean up waste

Oct 26, 2005

Bacteria that make rocket fuel as part of their metabolism are making sewage treatment less expensive and kinder to the environment, British researchers say.

Study: Drugs from sewage not dangerous

Jul 14, 2006

A Canadian study has suggested adverse effects are unlikely on aquatic life from drugs passed through human waste released from sewage treatment plants.

CO2 emissions booming, shifting east, researchers report

Sep 24, 2008

Despite widespread concern about climate change, annual carbon dioxide emissions from burning fossil fuels and manufacturing cement have grown 38 percent since 1992, from 6.1 billion tons of carbon to 8.5 billion tons in ...

Recommended for you

Rising anger as Nicaragua canal to break ground

16 hours ago

As a conscripted soldier during the Contra War of the 1980s, Esteban Ruiz used to flee from battles because he didn't want to have to kill anyone. But now, as the 47-year-old farmer prepares to fight for ...

Hopes, fears, doubts surround Cuba's oil future

Dec 20, 2014

One of the most prolific oil and gas basins on the planet sits just off Cuba's northwest coast, and the thaw in relations with the United States is giving rise to hopes that Cuba can now get in on the action.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

lengould100
not rated yet Jun 23, 2009
I'm sure much would depend on eg. the lead levels in the city's water and sewer piping systems, other sources of heavy metals contamination in wastewater, the metals loading in the city's freshwater supply, etc.

What's needed is a study of the comparative conditions of Vallcarca with other cities around the world.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.