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The combination of anaerobic digestion and pyrolysis technologies could be a novel energy-biochar production system to maximize energy and nutrient recovery from pulp and paper mill sludge. Herein, the life-cycle energy production and emissions reduction of sludge treatment from a typical pulp and paper mill were investigated, in which alternative uses of biogas for industrial or household application, in different regions of the world, were assessed. The three scenarios considered for different end-uses of biogas are: (A) biogas for vehicle fuel in the transportation sector in Sweden, (B) biogas for heat and electricity in the power sector in Brazil, and (C) biogas for cooking in households in China. The results of Environmental Life-Cycle Assessment (E-LCA) show that for all these three scenarios, the use of biogas and pyrolysis gas contributes most to emissions mitigation, while the dewatering and drying processes carried out on the sludge, contribute the most to the environmental emissions. Addition of biochar to the soil, contributes significantly to a reduction in global warming by sequestering carbon in the soil. Compared to scenarios B and C, Scenario A, in which biogas substitutes gasoline in transportation, and heat from combusted pyrolysis gases is used for district heating in Sweden, demonstrates the highest environmental performance for all the evaluated impact categories. [ABSTRACT FROM AUTHOR]

The Kopet Dagh is a thick-skinned, tectonically inverted mountain range situated along the Iran-Turkmenistan border. It comprises clastic and carbonate sedimentary rocks ranging in age from Jurassic to Neogene. We determine the provenance of Middle Jurassic deep marine turbiditic sandstones, Upper Jurassic-Lower Cretaceous deltaic-shelf sandstones and Paleocene continental conglomerate by describing sandstone modal framework, heavy minerals, detrital zircon U-Pb ages and in-situ Hf isotopic analyses. This work aims to determine the assemblages of source rocks of the investigated sediments and to reconstruct the tectonic setting of clastic sediment deposition. Modal sandstone framework compositions indicate that a magmatic arc and recycled deformed sediments were the main sources of Middle Jurassic-Lower Cretaceous sandstones and Paleogene conglomerate, respectively. Heavy mineral assemblages including ultra-stable and meta-stable minerals indicate magmatic rocks and recycled sediments as a main source of clastic rocks. Detrital zircon U-Pb ages (2478 measured ages) cluster in six main age groups: The oldest zircon grains in the Kopet Dagh belong to two populations peaking at 1833 Ma (Paleoproterozoic) and 643 Ma (Neoproterozoic). These grains suggest a continental crust provenance within the Central Iranian and Eurasian blocks. Detrital zircon grains of Silurian (437 Ma), Lower Carboniferous (340 Ma), Triassic (233 Ma) and Lower Cretaceous (132 Ma) are the major age population in the Kopet Dagh. Hafnium isotopic compositions in Zircons (175 measurements) indicate their origin: Silurian and Triassic zircons show a magmatic provenance, preferentially related to intracontinental rifting. Hafnium isotopic compositions of Lower Carboniferous and Lower Cretaceous zircons indicate a continental magmatic arc source. Our results indicate that Middle Jurassic-Lower Cretaceous detritus have been supplied from Silurian and Triassic rifting-related magmatic rocks and Lower Carboniferous / Lower Cretaceous continental magmatic arcs. The variety of source rocks is in concordance with rifting and an extensional regime in Kopet Dagh during Middle Jurassic time. Paleocene clastic sediments result from erosion of deformed older sedimentary rocks within the basin. This indicates that the first stage of deformation in Kopet Dagh basin took place in Paleocene time. [ABSTRACT FROM AUTHOR]

AbstractBiosludge is a solid waste of the pulp and paper industry, which is usually incinerated for energy recovery or landfilled. This study evaluates the energy balance and carbon footprint of using pulp and paper mill sludge in anaerobic digestion (AD) systems with alternative uses for the biogas, in different regions of the world, using Environmental Life Cycle Assessment (E-LCA). The digested residues from the AD are assumed to be used for biochar production, and subsequent incorporation into forest soils. Three scenarios based on alternative uses of biogas were investigated: (i) biogas for vehicle fuel in the transportation sector, (ii) biogas for heat and electricity in the power sector, and (iii) biogas for cooking in households. The E-LCA results demonstrate that both energy balance and greenhouse gas (GHG) emissions abatement of biosludge treatment in the AD systems significantly improve relative to the baseline scenario of incineration. The displacement of fossil fuel with biogas, and carbon stabilized in biochar contribute largely to the truncation of the energy and carbon footprints. Therefore, a combination of AD and pyrolysis technologies as a novel energy-biochar production system could offer an opportunity for sustainable management of pulp and paper mill sludge. Regarding biogas, the local or national infrastructure determines possible uses, and this aspect was shown to affect E-LCA results. Keywords: Biochar, biogas, digested sludge, carbon footprint, energy balance, waste treatment [ABSTRACT FROM AUTHOR]