New technology generates clean energy from dirty water

A new technology that harnesses the power of bacteria could transform wastewater from an "expensive problem" to a sustainable source of hydrogen and valuable chemicals, according to a new report.

Pilot studies have indicated that energy captured by the technology, known as bioelectrochemical systems, as hydrogen can greatly offset, or exceed, the energy needed to initiate the process.

Electrically-active microorganisms in bioelectrochemical systems can remove contaminants from wastewater while at the same time produce valuable commodities, such as hydrogen or caustic soda.

According to the report by the European Commission’s information service, Science for Environment Policy, wastewater treatment can be an expensive and difficult process, requiring large amounts of energy.

However, the new technology involves microorganisms that break down the contaminants of wastewater, a process that releases electrons, which then creates a current and generates electricity.

Pilot studies on domestic and industrial wastewater have shown “promising results” according to the report but the technology is yet to be used on a wide-scale.

A bioelectrochemical pilot scheme in the UK, mainly treating domestic wastewater, used hydrogen capture to recover 70% of the initial energy used.

With planned improvements, researchers predict that the scheme could become ‘energy positive’.

Other than energy efficiency and cost reduction, the report indicates that there are other advantages of bioelectrochemical systems.

Unlike conventional wastewater treatments, bioelectrochemical systems produce almost no sludge by-product, remain active at low temperatures and do not require new facilities to be built, as existing infrastructure can be modified to incorporate the systems.

However, high capital costs are proving a barrier to commercialisation but could be offset by focusing on the recovery of resources, such as hydrogen or caustic soda as these have a high economic value.

Despite these challenges, researchers are optimistic that commercial installations could be available in two to five years’ time.

Leigh Stringer

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