Instead of placing the raw sludge into a traditional digester, they found that heating it to body temperature first, in a small reactor tank, encouraged the growth of hydrolytic bacteria.These released enzymes that wiped out pathogens in the sludge almost completely. The process was developed and engineered in partnership with Monsal, a specialist environmental Technology Company based at Mansfield.United Utilities programme manager, Shanthi Rasaratnam, said: “For 50 years, digesters in treatment works have been used like a human stomach.“But people prepare their food for digestion by chewing it first, and our new process is like adding a mouth to existing wastewater treatment.”The sludge passes through six tanks where the enzymes remove all but a tiny fraction of the pathogens. Then it enters the digester for further treatment.Dr Son Le, who made the discovery, said: “Instead of lasting four weeks, the process takes only two. Previously, digestion in a single vessel could not kill enough pathogens to meet the new standards.“It is a bonus that more of the sludge is now converted to gas. What remains for disposal is a nutrient rich soil conditioner that could replace unsustainable chemical fertilisers, in the UK and developing nations.”Monsal, leading providers of advanced environmental and renewable energy systems to the water and waste sectors, are licensees for the new process.Aidan Cumiskey, Monsal business development director, said: “This market leading initiative is an important step forward for the industry. It places the UK at the forefront of technology developments in this area of business.”