'Hungry' Bacteria Can Harvest Energy in Sewage, Research Finds

Today may be a big day for scientists working on energy extraction from sewage. A team of biochemists and microbiologists from Ghent University in Belgium, in collaboration with DC Water in Washington DC, is working on a pilot project that can double the extraction of heat, biogas and electrical energy from bacteria.

According to New Atlas, sewage from bathrooms and kitchens can be a potential source of energy as it contains various organic substances in wastewater. However, a trick for a self-sustaining sewage treatment model is to find an efficient way to separate the organic water from the wastewater. This allows the water to be recycled and the organic matter to generate energy.

So far, the principle of most sewage treatment plants will try to optimize the way microorganisms like bacteria, fungi, and protozoans feed on organic matter in the wastewater. According to the Ghent University website, resulting particles will clump together and settle on the bottom of the tank, which allows a "clear" liquid to be separated and purified.

This normally uses something called "contact stabilization" which involves using two aeration tanks to ensure the microorganisms are active before introducing them to the next batch of effluent.

Today's sewage treatment process recovers around 20 to 30-percent of the organic matter. However, Francis Meerburg of the Belgian project wants to improve their approach on how bacteria captures organic metal.

It appears they can improve the yields of the contact stabilization process by ensuring the bacteria is "hungry." They do this with a kind of "fasting regimen," allowing the bacteria to gobble up organic matter and not ingest everything. Afterward, the undigested materials can be made into energy. They "starve" the bacteria once again and repeat the process.

He said this method can help them recover more than 55 percent of the organic matter from the sewage. Siegfried Vlaeminck also told New Atlas that this can result in lower energy bills. 

The researchers are currently collaborating with DC Water to implement the new process on part of the plant's full-scale water treatment installation.