The Eco-Solids Process Alkaline Stabilization using a Tubular Plug Flow Reactor With Recycle:
Rigden, C., and Shepherd, S. Eco-Solids International
(free)
A process for converting municipal, industrial and agricultural sludge of biological solids to pathogen-free, odourless sludge
with much reduce sulphur and phosphate runoff potential by including the steps of mixing the sludge with oxide-containing
chemicals and pozzolanic materials so as to elevate a temperature of the sludge, pressurizing the mixed sludge to a pressure
of greater than 1 bar, and discharging the pressurized mixed sludge. The oxide-containing chemicals may be a mixture of
calcium oxide, potassium oxide, potassium hydroxide, sodium hydroxide with pozzolanic materials, included but not limited
by, aluminium, silicates, iron oxide derivatives including the ferrous, ferrite and ferrate forms. The sludge has a water content
of between 5 and 99 percent. The oxide-containing chemicals are reacted with the sludge so as to elevate the temperature
of the sludge to between 40 degree C. and 140 degree C. A portion of the pressurized mixed sludge is recycled to the process
inlet, while the rest of the pressurized mixed sludge is flashed across a restricting orifice or passed into a chamber having a
lower pressure. The evaporated liquid component can be condensed and used as part of the process. The oxide-containing
chemicals are mixed with the sludge in a combined amount between 2 and 70 weight percent of the sludge.
