Thermal Hydrolysis as a Profitable Way of Handling Sludge

“…HTC of municipal sewage wastes, often termed “thermal hydrolysis” in the waste processing industry, has been conducted sporadically over an extended period of time in Europe and Canada . Benefits of thermal hydrolysis conducted at temperatures of 130–175 °C are disinfection, odor improvement, greatly improved anaerobic digestion of the slurry product, and dewatering to as much as 80% . More recently, overall energy input/output determinations that indicate that conducting HTC and drying the hydrochar are more energetically favorable than drying the sludge for incineration have been reported .…”

Section: Introductionmentioning

confidence: 99%

Phosphorus Reclamation through Hydrothermal Carbonization of Animal Manures

Heilmann

Molde

Timler

et al. 2014

Environ. Sci. Technol.

219

115

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Projected shortages of global phosphate have prompted investigation of methods that could be employed to capture and recycle phosphate, rather than continue to allow the resource to be essentially irreversibly lost through dilution in surface waters. Hydrothermal carbonization of animal manures from large farms was investigated as a scenario for the reclamation of phosphate for agricultural use and mitigation of the negative environmental impact of phosphate pollution. Hydrothermal reaction conditions were identified for poultry, swine, and cattle manures that resulted in hydrochar yields of 50-60% for all three manures, and >90% of the total phosphorus present in these systems was contained in the hydrochars as precipitated phosphate salts. Phosphate recovery was achieved in yields of 80-90% by subsequent acid treatment of the hydrochars, addition of base to acid extracts to achieve a pH of 9, and filtration of principally calcium phosphate. Phosphate recovery was achieved in yields of 81-87% based on starting manures by subsequent acid treatment of the hydrochars, addition of base to acid extracts to achieve a pH of 9, and filtration of principally calcium phosphate. Swine and cattle manures produced hydrochars with combustion energy contents comparable to those of high-end sub-bituminous coals.

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“…It may be possible to solve this technological challenge by using hydrothermal treatment, in which the substance is treated in a subcritical water condition, which promotes the solubilization and liquefaction of DSSC (2) . This treatment has been reported to improve the efficiency of anaerobic digestion of DSSC (3)(4)(5)(6) , but only a small amount of research has been conducted to determine whether the dewaterability of DSSC can be improved by this treatment (7) (8) . The mechanisms of the improved dewaterability have been explained as resulting from the separation of inner water of agglomeration, cells, and gel structures in DSSC (9) .…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Treatment of Dewatered Sewage Sludge Cake for Solid Fuel Production

Namioka

Morohashi²,

Yamane

et al. 2009

JEE

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To develop a technology that can efficiently convert dewatered sewage sludge cake into solid fuel, we experimentally investigated the effects of the hydrothermal treatment on dewaterability and carbon distributions. Dewatered sewage sludge cake with a water content of about 80 wt% could not be dewatered by increasing the pressure of a mechanical press. However, after hydrothermal treatment, the sewage sludge cake could be dewatered with a mechanical press. Moisture content was negatively correlated with treatment temperature at temperatures below 473K but stayed about the same at temperatures above 473K in the range studied. Carbon contents in the residual solid after treatment with a mechanical press were negatively correlated with the reaction temperature of the hydrothermal treatment owing to the solubilization of part of the volatile carbons in the dewatered sewage sludge cake. On the basis of the above results, we proposed a novel solid fuel production system composed of the following processes: hydrothermal treatment, mechanical press treatment, concentration, and drying. The optimum operating temperature of hydrothermal treatment was 473K in the range studied, and at this temperature, we estimated that the energy input to obtain dry sewage sludge using the proposed system would be about two-thirds that of a conventional drying process.

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Thermal Hydrolysis as a Profitable Way of Handling Sludge

Cited by 12 publications

References 0 publications

Principles and potential of the anaerobic digestion of waste-activated sludge

Principles and potential of the anaerobic digestion of waste-activated sludge

Phosphorus Reclamation through Hydrothermal Carbonization of Animal Manures

Hydrothermal Treatment of Dewatered Sewage Sludge Cake for Solid Fuel Production

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