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Researchers in China have used a global model to work out where solar-driven interfacial evaporation could supply drinking water, and how much – a promising result in which the assumptions matter as much as the headline.
Dosing iron into the digester is one of a biogas plant's main defences against hydrogen sulphide, but iron chloride, iron hydroxide and iron oxide behave very differently – and reactivity matters more than the price per kilo.
The TITAN project, funded by the EU's Horizon Europe programme, has shown that a microwave-heated fluidised reactor can produce hydrogen from raw biogas almost three times more efficiently than electrolysis – while the solid carbon by-product can be locked away in soil for the long term.
Using a two-step technology, researchers at Washington State University turn 83% of the carbon in sewage sludge into valuable, pipeline-quality renewable natural gas, while cutting treatment costs almost in half.
Aeration in activated sludge tanks accounts for 50–65% of the total energy use of conventional biological treatment plants, the most common type worldwide. The efficiency of membrane diffusers is directly linked to a plant's operating costs.