Thermochemical treatment of biogas digestate solids to produce organic fertilisers: The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value

Research output: Book/ReportPh.D. thesis

Standard

Thermochemical treatment of biogas digestate solids to produce organic fertilisers : The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value. / Pantelopoulos, Athanasios.

Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 2015. 118 p.

Research output: Book/ReportPh.D. thesis

Harvard

Pantelopoulos, A 2015, Thermochemical treatment of biogas digestate solids to produce organic fertilisers: The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value. Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen. <https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122524882105763>

APA

Pantelopoulos, A. (2015). Thermochemical treatment of biogas digestate solids to produce organic fertilisers: The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value. Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen. https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122524882105763

Vancouver

Pantelopoulos A. Thermochemical treatment of biogas digestate solids to produce organic fertilisers: The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value. Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 2015. 118 p.

Author

Pantelopoulos, Athanasios. / Thermochemical treatment of biogas digestate solids to produce organic fertilisers : The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value. Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 2015. 118 p.

Bibtex

@phdthesis{a90fd86e9e02483b9c9ffc27e2860ae0,
title = "Thermochemical treatment of biogas digestate solids to produce organic fertilisers: The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value",
abstract = "Anaerobic digestion of animal manures has been proposed as a process with twofold advantage.The production of biogas, a renewable source of energy, and the treatment of animal manures toincrease their agronomic value and reduce their environmental impact. However, the residual ofanaerobic digestion, called digestate, may need a combination of treatments to improve itsmanageability, reduce its environmental impact and facilitate the exportation of excessive nutrientsto other areas. Often, mechanical separation, is implemented as a first treatment of the digestate.The resulting solids from digestate, are acknowledged for their potential to serve as organicamendments and fertilizers however, their characteristics constitutes them prone to N losses, andtheir management (handling, storage, transportation) costly.Thermal drying of manures is known to facilitate transportation by volume reduction, nutrientconcentration and hygienization of the final product. However, thermal treatment of ammoniumrich organic wastes such as digestate solids has been linked with relative high volatilization of NH3and therefore decrease in N fertilizing value of the final product. Temperature and air velocityduring thermal treatment influence the evaporation rate of water from the manure solids. At thesame time, they also influence the ammonia emission rates,Lowering manure pH (controlling the NH4+ - NH3 equilibrium) can potentially reduce the loss rate.Furthermore, the changes occurring in the solid digestate after acidification and/or drying shouldimpact its behavior in the soil specifically, their N and P availabilityThe objective of this study was i) to assess the effects of different acidification levels (by additionof concentrated sulphuric acid) and drying conditions on solids digestate nitrogen content (Paper I),ii) determine their C and N dynamics after soil incorporation (Paper II) and iii) assess the plant Nand P uptake of ryegrass amended with different thermochemical treatments of the solids (PaperIII). For a more mechanistic understanding of the processes involved in the N cycle in the solidssoil-plant system, 15N has been utilized at the second and third study.In conclusion, drying of digestate solids resulted in an end-product with increased stability andreduced mass/volume which can facilitate its storage and transportation. Nevertheless, drieddigestate solids had low N fertilizing value due to the excessive loses of inorganic N during thedrying process. On the contrary, acidification minimized ammonia volatilization from solids duringthe thermal treatment with direct impact on the N fertilizing value of acid treated solids. In addition,acidification promoted the stability of the organic matter in the acidified solids indicating a higherpotential for C sequestration from this treatment. Phosphorus solubility increased by drying andacidification however, no significant differences in plant P uptake were detected mainly as a resultof soil properties on plant P availability.A combined acidification and drying treatment of digestate solids may be proved an interestingoption for increasing the fertilizing value of the final product and reduce the mineral fertilizingdependency of the agricultural sector. Despite the added cost of acidification, in the digestate solidsmanagement chain, the fertilizing value and stability of the end product may compensate for theacid-related expenditures. Nevertheless, alternatives to sulphuric acid should be exploited, to avoidexcessive application of sulphur via acidified treatments, in the agricultural system. For a fullutilization of acidification and drying as digestate solids treatment, a more systematic assessment ofthe effect of the thermochemical treatment on P availability is required. Moreover, the amelioratingproperties of thermo-chemically treated solids should be assessed in comparison with knownmanure stabilizing treatments i.e. composting. Finally, the energy cost associated with thermaldrying of bio-wastes is expected to largely determine the degree implementation in different areas",
author = "Athanasios Pantelopoulos",
year = "2015",
language = "English",
publisher = "Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen",

}

RIS

TY - BOOK

T1 - Thermochemical treatment of biogas digestate solids to produce organic fertilisers

T2 - The effect of acidification and drying on N losses, soil N turnover and plant fertilizer value

AU - Pantelopoulos, Athanasios

PY - 2015

Y1 - 2015

N2 - Anaerobic digestion of animal manures has been proposed as a process with twofold advantage.The production of biogas, a renewable source of energy, and the treatment of animal manures toincrease their agronomic value and reduce their environmental impact. However, the residual ofanaerobic digestion, called digestate, may need a combination of treatments to improve itsmanageability, reduce its environmental impact and facilitate the exportation of excessive nutrientsto other areas. Often, mechanical separation, is implemented as a first treatment of the digestate.The resulting solids from digestate, are acknowledged for their potential to serve as organicamendments and fertilizers however, their characteristics constitutes them prone to N losses, andtheir management (handling, storage, transportation) costly.Thermal drying of manures is known to facilitate transportation by volume reduction, nutrientconcentration and hygienization of the final product. However, thermal treatment of ammoniumrich organic wastes such as digestate solids has been linked with relative high volatilization of NH3and therefore decrease in N fertilizing value of the final product. Temperature and air velocityduring thermal treatment influence the evaporation rate of water from the manure solids. At thesame time, they also influence the ammonia emission rates,Lowering manure pH (controlling the NH4+ - NH3 equilibrium) can potentially reduce the loss rate.Furthermore, the changes occurring in the solid digestate after acidification and/or drying shouldimpact its behavior in the soil specifically, their N and P availabilityThe objective of this study was i) to assess the effects of different acidification levels (by additionof concentrated sulphuric acid) and drying conditions on solids digestate nitrogen content (Paper I),ii) determine their C and N dynamics after soil incorporation (Paper II) and iii) assess the plant Nand P uptake of ryegrass amended with different thermochemical treatments of the solids (PaperIII). For a more mechanistic understanding of the processes involved in the N cycle in the solidssoil-plant system, 15N has been utilized at the second and third study.In conclusion, drying of digestate solids resulted in an end-product with increased stability andreduced mass/volume which can facilitate its storage and transportation. Nevertheless, drieddigestate solids had low N fertilizing value due to the excessive loses of inorganic N during thedrying process. On the contrary, acidification minimized ammonia volatilization from solids duringthe thermal treatment with direct impact on the N fertilizing value of acid treated solids. In addition,acidification promoted the stability of the organic matter in the acidified solids indicating a higherpotential for C sequestration from this treatment. Phosphorus solubility increased by drying andacidification however, no significant differences in plant P uptake were detected mainly as a resultof soil properties on plant P availability.A combined acidification and drying treatment of digestate solids may be proved an interestingoption for increasing the fertilizing value of the final product and reduce the mineral fertilizingdependency of the agricultural sector. Despite the added cost of acidification, in the digestate solidsmanagement chain, the fertilizing value and stability of the end product may compensate for theacid-related expenditures. Nevertheless, alternatives to sulphuric acid should be exploited, to avoidexcessive application of sulphur via acidified treatments, in the agricultural system. For a fullutilization of acidification and drying as digestate solids treatment, a more systematic assessment ofthe effect of the thermochemical treatment on P availability is required. Moreover, the amelioratingproperties of thermo-chemically treated solids should be assessed in comparison with knownmanure stabilizing treatments i.e. composting. Finally, the energy cost associated with thermaldrying of bio-wastes is expected to largely determine the degree implementation in different areas

AB - Anaerobic digestion of animal manures has been proposed as a process with twofold advantage.The production of biogas, a renewable source of energy, and the treatment of animal manures toincrease their agronomic value and reduce their environmental impact. However, the residual ofanaerobic digestion, called digestate, may need a combination of treatments to improve itsmanageability, reduce its environmental impact and facilitate the exportation of excessive nutrientsto other areas. Often, mechanical separation, is implemented as a first treatment of the digestate.The resulting solids from digestate, are acknowledged for their potential to serve as organicamendments and fertilizers however, their characteristics constitutes them prone to N losses, andtheir management (handling, storage, transportation) costly.Thermal drying of manures is known to facilitate transportation by volume reduction, nutrientconcentration and hygienization of the final product. However, thermal treatment of ammoniumrich organic wastes such as digestate solids has been linked with relative high volatilization of NH3and therefore decrease in N fertilizing value of the final product. Temperature and air velocityduring thermal treatment influence the evaporation rate of water from the manure solids. At thesame time, they also influence the ammonia emission rates,Lowering manure pH (controlling the NH4+ - NH3 equilibrium) can potentially reduce the loss rate.Furthermore, the changes occurring in the solid digestate after acidification and/or drying shouldimpact its behavior in the soil specifically, their N and P availabilityThe objective of this study was i) to assess the effects of different acidification levels (by additionof concentrated sulphuric acid) and drying conditions on solids digestate nitrogen content (Paper I),ii) determine their C and N dynamics after soil incorporation (Paper II) and iii) assess the plant Nand P uptake of ryegrass amended with different thermochemical treatments of the solids (PaperIII). For a more mechanistic understanding of the processes involved in the N cycle in the solidssoil-plant system, 15N has been utilized at the second and third study.In conclusion, drying of digestate solids resulted in an end-product with increased stability andreduced mass/volume which can facilitate its storage and transportation. Nevertheless, drieddigestate solids had low N fertilizing value due to the excessive loses of inorganic N during thedrying process. On the contrary, acidification minimized ammonia volatilization from solids duringthe thermal treatment with direct impact on the N fertilizing value of acid treated solids. In addition,acidification promoted the stability of the organic matter in the acidified solids indicating a higherpotential for C sequestration from this treatment. Phosphorus solubility increased by drying andacidification however, no significant differences in plant P uptake were detected mainly as a resultof soil properties on plant P availability.A combined acidification and drying treatment of digestate solids may be proved an interestingoption for increasing the fertilizing value of the final product and reduce the mineral fertilizingdependency of the agricultural sector. Despite the added cost of acidification, in the digestate solidsmanagement chain, the fertilizing value and stability of the end product may compensate for theacid-related expenditures. Nevertheless, alternatives to sulphuric acid should be exploited, to avoidexcessive application of sulphur via acidified treatments, in the agricultural system. For a fullutilization of acidification and drying as digestate solids treatment, a more systematic assessment ofthe effect of the thermochemical treatment on P availability is required. Moreover, the amelioratingproperties of thermo-chemically treated solids should be assessed in comparison with knownmanure stabilizing treatments i.e. composting. Finally, the energy cost associated with thermaldrying of bio-wastes is expected to largely determine the degree implementation in different areas

UR - https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122524882105763

M3 - Ph.D. thesis

BT - Thermochemical treatment of biogas digestate solids to produce organic fertilisers

PB - Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen

ER -

ID: 160641829