Process for treating a waste sludge of biological solids

Abstract

A process for treating a waste sludge of biological solids including the steps of mixing the sludge with an oxide-containing chemical and sulfamic acid so as to elevate a temperature of the sludge, pressurizing the mixed sludge to a pressure of greater than 14.7 p.s.i.a., and discharging the pressurized mixed sludge. The oxide-containing chemical can be either calcium oxide, potassium oxide, or potassium hydroxide. The sludge has a water content of between 5 and 85 percent. The oxide-containing chemical and the acid are reacted with the sludge so as to elevate the temperature of the sludge to between 50.degree. C. and 450.degree. C. 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 chemical is mixed with the sludge in an amount between 5 and 50 weight percent of the sludge. The sulfamic acid is blended with the oxide-containing chemical in a weight ratio of between 0.33:1 and 1:1.

Dependencies are inferred from the claim text.