Abstract: In accordance with one aspect of the invention a testing procedure, a processing procedure and a resulting product are provided whereby sewage sludge is primarily or firstly pre-hydrolyzed in whole or in part by means other than alkali. The alkali is then added to the pre-hydrolyzed product. The pre-hydrolyzed product from step one has a reduced potential for further hydrolysis and is more effectively stabilized in step 2 as a liquid biosolids-containing product or BSP. As a result, in accordance with the invention less of the alkali is used up in the step 2 further alkali-based hydrolysis of the pre-hydrolyzed product. The pH of the BSP product after the step 2 alkali treatment drops less over the period of storage and the BSP product will be better preserved against microbial regrowth.

Abstract: In accordance with one aspect of the invention a testing procedure, a processing procedure and a resulting product are provided whereby sewage sludge is primarily or firstly pre-hydrolysed in whole or in part by means other than alkali. The alkali is then added to the pre-hydrolysed product. The pre-hydrolysed product from step one has a reduced potential for further hydrolysis and is more effectively stabilized in step 2 as a liquid biosolids-containing product or BSP. As a result, in accordance with the invention less of the alkali is used up in the step 2 further alkali-based hydrolysis of the pre-hydrolysed product. The pH of the BSP product after the step 2 alkali treatment drops less over the period of storage and the BSP product will be better preserved against microbial regrowth.

Abstract: Paunch-sludge from an abattoir is mixed with the fatty DAF-float from an abattoir, and placed in a shearing vessel. The mixture of the two material thickens the medium in which the matted strands are contained, enabling shearing to be more effective; so much so that paunch-sludge can now be sheared to a homogeneous liquid. The technique can be used with other sludges and other fatty waste materials.

Abstract: When liquefying sludge, e.g as in U.S. Pat. No. 6,808,636, the combination of temperature, pH, and shearing, is synergistic. Described here is a system that provides for collating test sampling and full-scale data inputs, recording achieved results and the engineering parameters that achieved those particular results. The data is presented in e.g a table format, which assists design engineers to zero-in on the combinations of parameters that will likely give the desired results.

Abstract: Hydrophobic contaminants are removed from sludge that has been liquidized by violent shearing, by stirring a hydrophobic sorbent substance material into the sludge. After a period of time in which the contaminants are sorbed into the sorbent, the sorbent substance is separated from the sludge by gravity-settling, centrifuging, etc, where the sorbent is a liquid, or by filtration etc where the sorbent is a solid. Some sorbents have a melting point such that the sorbent can be liquid for good dispersal in heated sludge, and then can be solid when the sludge has cooled, whereby the sorbent can be removed e.g by filtration. Liquefaction by violent shearing causes the biosolids in the sludge to go into solution, which leaves the hydrophobic contaminants more available to be sorbed.

Abstract: Hydrophobic contaminants are removed from sludge that has been liquidized by violent shearing, by stirring a hydrophobic sorbent substance material into the sludge. After a period of time in which the contaminants are sorbed into the sorbent, the sorbent substance is separated from the sludge by gravity-settling, centrifuging, etc, where the sorbent is a liquid, or by filtration etc where the sorbent is a solid. Some sorbents have a melting point such that the sorbent can be liquid for good dispersal in heated sludge, and then can be solid when the sludge has cooled, whereby the sorbent can be removed e.g by filtration. Liquefaction by violent shearing causes the biosolids in the sludge to go into solution, which leaves the hydrophobic contaminants more available to be sorbed.

Abstract: Paunch-sludge from an abattoir is mixed with the fatty DAF-float from an abattoir, and placed in a shearing vessel. The mixture of the two material thickens the medium in which the matted strands are contained, enabling shearing to be more effective; so much so that paunch-sludge can now be sheared to a homogeneous liquid. The technique can be used with other sludges and other fatty waste materials.

Abstract: Sewage sludge is dewatered to a cake-like state. The viscosity of the sludge is lowered by admixing a quantity of urea, urea-ammonium-nitrate, or other nitrogen-containing material, in with the dewatered sludge. The treatment also removes pathogens, and renders the product suitable for use as a fertilizer.

Abstract: Sewage sludge that has been de-watered to 25% solids is subjected to a combination of shearing and heating that liquefies the sludge, and drops its viscosity to below 12,000 cP. The fact of liquefaction prepares the sludge such that subsequent drying can be done more cost-effectively than hitherto. After drying, the dried sludge can be incinerated.

Abstract: Sewage sludge is dewatered to a cake-like state. The viscosity of the sludge is lowered by admixing a quantity of urea, urea-ammonium-nitrate, or other nitrogen-containing material, in with the dewatered sludge. The treatment also removes pathogens, and renders the product suitable for use as a fertilizer.

Abstract: Already-treated sludge is fed back into incoming sewage, and is effective to supply nutrients needed for the microbiological breakdown of the sludge. The feedback sludge has a solids content of 10% or more, and has been sheared and heated to drive its viscosity down to 10,000 cP or less. In sludge done that way, nutrients are preserved and presented to the sewage to be treated in highly liquidized and solubilized form, whereby the nutrients are very bio-available to the microbes in the sewage. Large improvements in the elimination of biomass can result.

Abstract: A method for reducing sludge viscosity of a sewage sludge having a solids concentration of at least 10% (w/w). The method comprises the steps of increasing the pH of the sludge to 9.5-12.5%, at least one step selected from subjecting the sludge to a holding step of at least one day and adding inorganic or organic chemicals to facilitate viscosity reduction, followed by incubating the sludge at temperature up to 100° C., and subjecting the sludge to a shearing or disintegration step. The method provides sludge, especially concentrated sludge, that is more readily pumped or transported.