Did you know that sewage contains 10 times the energy needed to treat it? If you think about it that way, you would wonder why we have not been actively reusing what is available in order to produce energy. With all of the talk about finding new sources of energy, such as hydrogen fuel cells or solar power, why have we not been using our own waste?

Ironically, wastewater treatment plants are some of the major users of energy. In the U.S. alone, they consume about 21 billion kilowatt hours per year. Think about it, wastewater treatment plants can use their waste directly in wastewater treatment. This would reduce the facility’s overall need for conventional electricity. Turning sludge into energy is beneficial to the environment as well. Most methods of sewage sludge disposal are harmful to the environment. Some of these methods are land filing, ocean dumping, compost, and incineration. These methods contaminate the underground water reservoirs and ocean waters.

There are different methods of turning sludge into energy. One way would be to use a low temperature thermochemical conversion from sludge to oil. In this process the sludge is dried to evaporate any unwanted water and useful materials are conserved and extracted. These useful materials are substances, such as gas, oils, and chemicals. However, companies, such as Energy Answers International, have developed technology that will co-combust the different types of sludges with municipal solid waste to form energy in combustion facilities.

There are many different groups of people all working to find new sources of energy with the focus on renewable energy. Using sludge may be one of the cheaper ways to form energy, but it is still technology that needs to be developed. Seeing that the idea of using sludge is not that new, I am curious to see if this field really will ever expand into something big, or if fuel cells and other ideas will overpower the interest in sludge.

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