Supercritical Water Oxidation of Sewage Sludge – An Update
O’Regan, J., Dunne, A., Preston, S., SCFI Group, Ireland
(free)
Supercritical water oxidation (SCWO) is an innovative, economic and incredibly effective destruction
method for organic wastewater and sludge and is a realistic alternative to conventional methods.
From 1998 to 2007 extensive evaluations of the destruction of sewage sludge by SCWO were
performed by Chematur Engineering AB on two state of the art pilot plants. These units had
capacities of 250 kg/h and 1100 kg/h, respectively. The results achieved showed that the technology
easily gave 99.9% destruction of the organic material in the sludge and the inorganic material left in
the effluent was non leachable and is very easily settled. The very encouraging results indicated that
the technology was ready to be commercialised for treatment of sewage sludge.
In 2007 SCFI Group, acquired the patented super critical water oxidation technology (Aqua Critox®)
from Chematur Engineering AB of Sweden. Further work on design capacity and energy recovery by
SCFI Group has led to a reduction in over all build cost, a significant increase in processing capacity
and increased energy recovery in the form of electricity generation.
SCFI Group in 2008 commissioned its 250 litre per hour demonstration Aqua Critox® super critical
water oxidation demonstration plant in Cork, Ireland. Since May 2008, the plant has been subjected
to continuous operation on sewage sludge to document the long term reliability of the Aqua Critox®
SCWO technology.
KEY WORDS
Aqua Critox®, destruction, economic, reliable, SCWO, Sewage, Sludge.
