AquaCritox : Sustainable Sludge Destruction

SCFI (Ireland) has successfully commercialised an innovative, unique technology to provide a sustainable solution for wastewater treatment and sludge disposal. Its product, AquaCritox®, delivers complete organic waste destruction that is fully sustainable, environmentally friendly, efficient and cost-effective.

AquaCritox is especially suitable for the treatment of sewage, drinking water sludge and industrial organic aqueous waste streams. It uses super critical water oxidation (SCWO) to destroy organic waste safely, without generating hazardous emissions, and is completely odourless. With payback periods of approximately five years, AquaCritox generates renewable energy and recovers valuable by-products, such as phosphorus and CO2, which can be used for resale. This proven, patented technology from SCFI is available in four sizes with hydraulic loads ranging from 1 to 20 tonnes per hour.

Comments chief operating officer David Kerr: “The by-product of wastewater treatment plants is sewage sludge; the disposal of which is a significant worldwide problem. With increasing costs and diminishing land bank availability, as well as social and legislative pressures affecting sludge generators, AquaCritox presents an attractive and sustainable alternative to other waste disposal methods available today, such as land spreading, landfill and incineration. Years of development and testing by our highly experienced team has gone into creating a technology that is proven to deliver 99.99% destruction of wet organic wastes in an economical, quick, sustainable process.”

AquaCritox technology uses super critical water oxidation, which is achieved when water temperature exceeds 374oC and is pressurised to 221 bar. This moves water into a super critical condition or ‘fourth phase,’ where the water is neither a liquid nor a gas, but a homogenous dense fluid. In its super critical state, water becomes a universal solvent for gases and organic compounds, even those that are normally insoluble in water. By adding an oxygen supply, a very rapid and complete oxidation reaction takes place, which not only generates thermal energy, but also converts all organic materials in sewage sludge into CO2, nitrogen and clean water. The nitrogen can be safely released into the atmosphere and the CO2, (which is a short cycle carbon rather than greenhouse gas), may be sold on for industrial applications or dry ice production. The inorganic materials are easily separated and treated in a separate step to recover phosphorus or in the case of drinking water sludge, coagulants.

Continues David Kerr: “AquaCritox is a full destruction rather than reduction technology, offering a significant decrease in costs with none of the hazardous by-products associated with other destruction technologies. It does not fall under the Waste Incineration Directive, so there are no onerous licensing issues to worry about. Our solution is fast, safe and environmentally friendly, producing more energy than it actually uses. This rapid reaction also means that our plants are small in actual size.”

Over $40m has been invested in the development of AquaCritox technology, including extensive testing for the last three years at SCFI’s operating facility in Ringaskiddy. The technology has been successfully processing wet waste for a number of global leaders in the wastewater treatment, pharmaceutical, chemical, oil and gas industries. SCFI has also received its first commercial order from environmental company Eras Eco to improve the sustainability credentials of wastewater treatment at the site.

SCFI has a strategic partnership with Parsons to globally market the technology to end-users, as well as design and engineer AquaCritox plants. It has also teamed with Rockwell Automation to deliver top-of-the-range automation and control software and construction. With a wealth of industry knowledge, the SCFI team will work closely with customers to identify the best, bespoke AquaCritox solution for their requirements, ensuring optimum results are achieved.