Extraction of phosphorus compounds from ashes from thermal processing of sewage sludge

As a result of the spread of sewerage systems, the management of growing quantities of sewage sludge is becoming an urgent need. As the method of sludge management, thermal processes have mostly been applied to the treatment and disposal of sewage sludge in Japan, because of the difficulty of finding final disposal sites. This paper describes the progress of thermal processing technologies, especially focusing on drying-incineration process systems and melting-slag recycling process systems.

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The Staged Thermal Conversion of Sewage Sludge in the Presence of Oxygen

Journal of Energy Resources Technology ◽

10.1115/1.4042822 ◽

2019 ◽

Vol 141 (7) ◽

Cited By ~ 7

Author(s):

Halina Pawlak-Kruczek ◽

Mateusz Wnukowski ◽

Krystian Krochmalny ◽

Mateusz Kowal ◽

Marcin Baranowski ◽

...

Keyword(s):

Energy Consumption ◽

Sewage Sludge ◽

Thermal Processing ◽

Thermal Conversion ◽

Single Step ◽

Energy Yield ◽

Mass Yield ◽

Optimal Conditions ◽

Kinetics Of ◽

By Products

This study compares a staged thermal processing of the sewage sludge, with single step, integrated thermal processing. The aim of this study is to find the optimal conditions for drying and subsequently for carbonization/torrefaction of sewage sludge, regarding the energy consumption. This study presents the results of the drying tests performed at laboratory scale convective dryer for different parameters of drying agent (air). The tests were focused on finding and developing a method of drying that allows to minimize the energy consumption. Subsequently, both dry and vapothermal torrefaction was performed in the presence of oxygen. The kinetics of drying, using low quality heat as well as the properties of products and by-products of torrefaction in both regimes were determined. The process was characterized by mass yield and energy yield in both of the cases. There has been only scarce amount of literature studies published on the torrefaction of sewage sludge so far, without a detailed study of the composition of the torgas and tars of such origin. Performed study enables a comparison of two distinct scenarios of the processing, i.e., drying followed by dry torrefaction with a single stage of vapothermal torrefaction.

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Thermal processing of sewage sludge by drying, pyrolysis, gasification and combustion

Water Science & Technology ◽

10.2166/wst.2001.0655 ◽

2001 ◽

Vol 44 (10) ◽

pp. 333-339 ◽

Cited By ~ 23

Author(s):

P. Stolarek ◽

S. Ledakowicz

Keyword(s):

Thermal Decomposition ◽

Sewage Sludge ◽

Kinetic Parameters ◽

Thermal Processing ◽

Combustion Process ◽

Order Kinetic ◽

Municipal Sludge ◽

Pyrolysis Kinetics ◽

Exponential Factor ◽

First Order

Thermal processing of sewage sludge including drying, pyrolysis and gasification or combustion may be an alternative to other ways of utilising it. In this paper thermogravimetric analysis (TGA) was employed in the investigation of thermal decomposition of sewage sludge. The kinetic parameters of drying, pyrolysis and gasification or combustion of sewage sludge have been determined in an inert-gas (argon) and additionally some series of the sludge decomposition experiments have been carried out in air, in order to compare pyrolysis and combustion. The pyrolysis char has been gasified with carbon dioxide. A typical approach to the kinetics of thermal decomposition of a solid waste is to divide the volatile evolution into a few fractions (lumps), each of which is represented by a single first-order reaction. If these lumps are assumed to be non-interacting and evolved by independent parallel reactions the first-order kinetic parameters such as activation energy Ei and pre-exponential factor Ai can be determined from mathematical evaluation of TG or DTG curves. The object of our investigations was a municipal sludge from the two wastewater treatment plants (WTP) in Poland. The experiments have been carried out in the thermobalance Mettler-Toledo type TGA/SDTA851 LF, in the temperature range 30-1,000°C. Five different values of heating rate have been applied β = 2, 5, 10, 15 and 20 K/min. The values of Ei and Ai have been determined for all recognised lumps of gaseous products. The method employed has also revealed its usefulness for the determination of kinetic parameters for municipal sludge, that possess an undefined content. An alternative route to combustion of sewage sludge is its gasification, which significantly increases the gaseous product (pyrolytic gas + syngas). Besides pyrolysis kinetics, gasification or combustion process kinetics have also been determined.

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Influence of thermal processing of FePO4 · 2H2O with Na2CO3 on solubility of phosphorus compounds in mixtures after sintering

Management of Environmental Quality An International Journal ◽

10.1108/14777830510623709 ◽

2005 ◽

Vol 16 (6) ◽

pp. 639-646

Author(s):

Zbigniew Wzorek ◽

Katarzyna Gorazda ◽

Dorota Minda ◽

Joanna Kulczycka

Keyword(s):

Thermal Processing ◽

Phosphorus Compounds

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SUSTAINABLE RECOVERY OF PHOSPHORUS COMPOUNDS FROM SEWAGE SLUDGE IN THE CIRCULAR ECONOMY APPROACH

18th SGEM International Multidisciplinary Scientific GeoConference SGEM2018, Energy and Clean Technologies ◽

10.5593/sgem2018v/4.3/s05.015 ◽

2018 ◽

Author(s):

Agata Wajda

Keyword(s):

Sewage Sludge ◽

Circular Economy ◽

Phosphorus Compounds ◽

Sustainable Recovery

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From sewage sludge ash to calcium phosphate fertilizers

Polish Journal of Chemical Technology ◽

10.2478/v10026-012-0084-3 ◽

2012 ◽

Vol 14 (3) ◽

pp. 54-58 ◽

Cited By ~ 20

Author(s):

Katarzyna Gorazda ◽

Zygmunt Kowalski ◽

Zbigniew Wzorek

Keyword(s):

Sewage Sludge ◽

Acid Leaching ◽

Selective Extraction ◽

Phosphorus Recovery ◽

Phosphorus Compounds ◽

Phosphate Fertilizers ◽

Sewage Sludge Ash ◽

Hematite Phase ◽

Mineral Acids ◽

Sludge Ash

Our work presents the results of the research on the utilization of ashes after sewage sludge combustion comprising phosphorus recovery in the form of useful products. The investigations were divided into three parts: selecting the combustion parameters of sewage sludge, examining ash leaching with mineral acids (nitric and phosphoric) to high phosphorus selectivity assuring a low content of iron and heavy metals in the extracted solutions and precipitation of CaHPO4 .2H2O. Suitable temperature of a sewage sludge combustion enables selective extraction of phosphorus compounds from ash because of hematite phase forming, insoluble in mineral acids. The extracts from phosphoric acid leaching, where the extraction of phosphorus compounds was 96.1%, have very good properties for its further use as the initial solution for CaHPO4 .2H2O with 6% lime milk. The obtained product is characterized by high purity and phosphorus availability compatible even with the feed phosphate standard.

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The change of the main agrochemical indicators of the sod-podzolic soil for the submission of the municipal wasterwater under the artichoke

PLANT AND SOIL SCIENCE ◽

10.31548/agr2021.03.066 ◽

2021 ◽

Vol 12 (3) ◽

pp. 66-75

Author(s):

V. I. Lopushniak ◽

◽

G. M. Hrytsuliak ◽

Keyword(s):

Sewage Sludge ◽

Podzolic Soil ◽

Soil Layer ◽

Fertilizer Application ◽

Mineral Nitrogen ◽

Phosphorus Compounds ◽

Nitrogen Compounds ◽

Concentration Coefficient ◽

Mobile Phosphorus ◽

Control Variant

The studies have shown that the introduction of sewage sludge and compost made on its basis, significantly affects the change in the agrochemical parameters of the sod-medium-podzolic soil, increasing the content of the alkaline hydrolysed nitrogen compounds by 2.2 – 13.4 mg/kg of the soil compared to with control and determining the size of its values at the level of 51.2 – 56.5 mg/kg of the soil in the upper (0 – 20 cm) and 27.9 – 31.6 mg/kg – in the lower (20 – 40 cm) soil layer. The content of the ammonium nitrogen compounds in the variants with the fertilizer application fluctuated in a small range of the values (16 – 21 mg/kg of soil) and increases under the influence of increasing fertilizer doses. Together with the change in the content of the nitrate nitrogen, this contributed to an increase in the content of the mineral nitrogen compounds in the soil in the range of 18.5 – 23.4 mg/kg of the soil in arable (0 – 20 cm) and 19.8 – 21.9 mg/kg of the soil – in subsoil (20 – 40 cm) layers, which by 1.7 – 2.2 mg/kg of the soil exceeded the control variant. The highest indicators of the mineral nitrogen compounds were recorded in the variant where the highest dose of the sewage sludge was applied – 40 t/ha and mineral fertilizers (N10P14K58). Despite the wide range of the nitrogen content values of the alkaline hydrolysed compounds and mineral nitrogen compounds, their ratio remained stable and was 2.3 – 2.6 in the upper and 1.3 – 1.5 in the lower (20 – 40 cm) soil layer, and also decreased with the increasing dose of the fertilizer. That is, this indicator did not change significantly depending on the fertilizer application rate. The content of the mobile phosphorus compounds in the variants with the use of the fertilizers fluctuated in the range of the values (77.5 – 98.5 mg/kg of the soil) and increased under the influence of the introduction of the sewage sludge and compost based on it, which is 14.6 – 35.6 mg/kg of the soil was dominated by the control indicators. The highest rates of the mobile phosphorus compounds were recorded in the variant where the sewage sludge were applied – 40 t/ha and N10P14K58. The introduction of the sewage sludge at a rate of 20 – 40 t/ha contributed to an increase in the content of the potassium metabolites at the level of 89.3 – 97.2 mg/kg of the soil in the upper (0 – 20 cm) and 83.1 – 93.4 mg/kg – in the lower (20 – 40 cm) layer, which exceeded the indicators of the control variant by more than 42.1 mg/kg of the soil. The content of the potassium metabolic compounds increased somewhat less with the introduction of the composts based on the sewage sludge and straw. The results of the correlation-regression analysis indicate that the phosphorus concentration coefficient in the soil largely depends on the content of its mobile compounds and is marked by the coefficient of the determination R2 = 0.70. The potassium concentration coefficient is closely (R2 = 0.91) correlated with the content of its metabolic compounds in the soil.

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