Liquefying de-watered sludge preparatory to drying

Procedure for liquefying solid sewage sludge, being sludge that has a solids content of twenty-five percent or more, including:

• raising the temperature of the sludge to at least sixty degC;
• at that temperature, shearing the sludge violently enough, and for long enough, to liquefy the sludge, whereby the sludge then has a viscosity of 12,000 centipoise or less;
• providing a liquefaction reactor, which is structurally suitable for containing the de-watered sludge;
• providing a shearing apparatus, having shearing blades and a motor;
• where the shearing apparatus is physically capable of, and suitable for, moving the shearing blades violently enough to tear open biological cells in the batch of de-watered sludge in the liquefaction reactor;
• and
• operating the motor to shear the sludge in the reactor.

A sewage sludge treatment station, wherein:

• the station is suitable for preparing sewage sludge for drying;
• the station includes a de-watering apparatus, which is effective to remove enough water from incoming sludge that the solids content level of resulting de-watered sludge is twenty-five percent or more;
• the station includes a liquefaction reactor, which is physically suitable for receiving de-watered sludge from the de-watering apparatus;
• the station includes an operable shearing apparatus, having shearing blades, which is effective, when operated, to shear sludge in the reactor;
• the shearing apparatus is physically capable of, and suitable for, moving the shearing blades violently enough to tear open biological cells in the batch of de-watered sludge in the liquefaction reactor;
• the shearing apparatus includes a motor, which is physically suitable for moving the shearing blades violently enough to tear open biological cells in the sludge in the reactor;
• the station includes a heating apparatus, which is effective to heat the de-watered sludge in the reactor to a temperature of sixty degC or hotter;
• and
• the shearing apparatus and the heating apparatus are of such structure as to be physically capable of liquefying the de-watered sludge in the reactor to a viscosity of 12,000 centipoise or less.