Solar-powered method converts sewage sludge into green hydrogen and animal feed

Scientists at Nanyang Technological College, Singapore (NTU Singapore), have developed an progressive solar-powered technique to rework sewage sludge—a by-product of wastewater remedy—into inexperienced hydrogen for clear power and single-cell protein for animal feed.

Published in Nature Waterthe sludge-to-food-and-fuel technique tackles two urgent international challenges: managing waste and producing sustainable assets. This aligns with NTU’s objective of addressing humanity’s biggest challenges, akin to local weather change and sustainability.

The United Nations estimates that about 2.5 billion extra individuals can be residing in cities by 2050. Together with the expansion of cities and industries comes a rise in sewage sludgewhich is notoriously tough to course of and eliminate as a result of its complicated construction, composition, and contaminants akin to heavy metals and pathogens.

Based on UN-Habitat, greater than 100 million tons of sewage sludge are generated globally every year, an quantity that’s growing yearly. Nonetheless, widespread disposal strategies—akin to incineration or landfill—are time-consuming, energy-inefficient, and contribute to environmental pollution.

To deal with the issue of undesirable and difficult-to-treat sewage sludge, NTU researchers created a three-step solar-powered course of that integrates mechanical, chemical, and organic strategies.

Proof-of-concept exams revealed that the NTU crew’s course of is extra environment friendly than standard strategies like anaerobic digestion—by means of which micro organism break down organic waste to provide biogas and nutrient-rich residue. It recovers considerably extra assets, fully removes heavy steel contaminants, has a smaller environmental footprint, and provides higher financial feasibility.

Lead researcher Affiliate Professor Li Hong from NTU’s Faculty of Mechanical and Aerospace Engineering (MAE) and the Vitality Analysis Institute @ NTU (ERI@N) stated, “Our method transforms waste into valuable resources, reducing environmental damage while creating renewable energy and sustainable food. This exemplifies the circular economy and contributes to a greener future.”

Co-lead researcher Professor Zhou Yan from NTU’s Faculty of Civil and Environmental Engineering (CEE) and Nanyang Surroundings and Water Analysis Institute (NEWRI) stated, “Our solar-powered process demonstrates how we can tackle multiple challenges at once—turning a difficult waste product into clean energy and nutritious protein. By integrating mechanical, chemical, and biological approaches, our method has successfully addressed pollution and resource scarcity, offering a new sustainable strategy in wastewater management.”

Three-step course of

The method begins by mechanically breaking down the sewage sludge. A chemical remedy separates dangerous heavy metals from natural supplies, together with proteins and carbohydrates.

Subsequent, a solar-powered electrochemical course of makes use of specialised electrodes to rework the natural supplies into beneficial merchandise, akin to acetic acid—a key ingredient for meals and pharmaceutical industries—and hydrogen fuel, a clear power supply.

Lastly, light-activated micro organism are launched to the processed liquid stream. These micro organism convert vitamins into single-cell protein appropriate for animal feed.

Eco-friendly, cost-effective and scalable

Lab exams confirmed the brand new technique recovers 91.4% of the natural carbon in sewage sludge and converts 63% of the organic carbon into single-cell protein with out producing dangerous by-products. As compared, conventional anaerobic digestion usually recovers and converts round 50% of natural supplies in sewage sludge.

The solar-powered course of achieves an power effectivity of 10%, producing as much as 13 liters of hydrogen per hour utilizing daylight, which is round 10% extra power environment friendly than the traditional hydrogen era strategies.

The NTU course of reduces carbon emissions by 99.5% and power use by 99.3% in comparison with conventional strategies. It additionally eliminates dangerous heavy metals from the sludge, which might in any other case be disposed with out correct remedy, making the method an environmentally pleasant selection.

First creator, Dr. Zhao Hu, Analysis fellow on the Faculty of MAE, stated, “We hope that our proposed method shows the viability of managing waste sustainably and shifts how sewage sludge is perceived—from waste to a valuable resource that supports clean energy and sustainable food production.”

The NTU analysis crew added that whereas the newly developed course of is promising, extra research are wanted to find out if it may be scaled up. A key problem is the price of utilizing an electrochemical course of to fully break down natural supplies and extract all heavy metals from waste. Moreover, designing a fancy system for a wastewater remedy facility provides to the problem.