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Microbial Degradation of Spilled Oil in Aqueous Environments: Beyond C15 Hydrocarbons
Published in Wael Ahmed Ismail, Jonathan Van Hamme, Hydrocarbon Biotechnology, 2023
Fernanda Lopes Motta, Nayereh Saborimanesh, Heather D. Dettman
In Figure 4.1, the creation of petroleum is shown to be formed with the removal of oxygen from humic substances. As degradation of petroleum after a spill occurs with the addition of oxygen, the question can be asked whether there are conditions under which the recalcitrant, partially degraded petroleum compounds can become humic substances again? Humic substances are not believed to be harmful to human health (Government of Nova Scotia, 2021), and published literature elucidates the beneficial effect of these substances in decreasing toxicity caused by other chemicals (Schnitzer and Khan, 1972). Among the various organic substances occurring naturally, humic substances are the most widespread and can be found in various environments such as soils, rivers, lakes, and sea sediment (Weber et al., 2018). In addition, humic substances have important roles in soil fertility and are considered to have primal relevance for the stabilization of soil aggregates, as well as can remove toxic metals, anthropogenic organic chemicals, and other pollutants from water (Pefia-Méndez et al., 2005). Humic substances, themselves, are extremely resistant to biodegradation, with a half-life measured in tens or hundreds of years. These substances are considered to be recalcitrant in the absence of dissolved oxygen (Stevenson, 1994) and are slowly degraded by microbial populations in aerobic environments (Wetzel, 1992; Wetzel et al., 1995).
Activated Sludge Process for Refractory Pollutants Removal
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Reyhan Ata, Gökçe Faika Merdan, Günay Yıldız Töre
HSs represent most of the organic substances found in soil, lignite, peat coal, sewage waters, spring waters, and sediments. Humic substances are divided into three categories: FAs, HAs, and humin. One of the most important parts of humic substances is humic acid. Humic acids and fulvic acids represent humus structures that dissolve in alkaline mediums. HSs can also be of industrial origin such as from the ceramic industry and pulp and paper industry. In the ceramic industry, humic substances are mainly used to increase the mechanical strength of unprocessed ceramics, to make the casting properties of ceramics efficient, to paint mud ceramics, and to prepare pottery. In addition, humic materials are used in plastic production, especially for dyeing Nylon 6 or polyvinyl chloride (PVC) plastics, to harden polyurethane foams, or as plasticizing agents for PVC plastics (Ay 2015). Humic substances are also used in the pulp and paper industry. For example, they are used in the production of paper with high tensile strength and in the recycling of paper.
Impact of waste and by-products management on soil carbon sequestration
Published in Lucjan Pawłowski, Zygmunt Litwińczuk, Guomo Zhou, The Role of Agriculture in Climate Change Mitigation, 2020
M. Pawłowska, M. Chomczyńska, M. Zdeb, G. Żukowska, M. Myszura
Waste management can have a direct and indirect impact on the C sequestration in terrestrial ecosystems. Direct impact is associated with the introduction of stable organic matter with organic waste into the surface layer of the lithosphere. Carbon is partially integrated into humic substances (HS) that are composed of slowly biodegradable, hardly soluble or insoluble in soil water solution compounds with high molecular weight (Table 1) modified during mineralization and humification processes from the plant and animal tissues. Humic substances fulfil multiple functions in soil formation and its fertility. These compounds govern the sorption properties, as well as the water and air conditions; therefore, they affect most of the soil transformations. Embedding C into some types of HS is a long-term process. Decomposition of HS in soil may take from 15 to over hundreds of years, depending on the environment conditions (Prusty & Azeez 2005). Stockmann et al. (2013) defined the soil C sequestration as long-term (i.e. >100 years) or permanent removal of CO2 from the atmosphere and its “lock up” into the soil. Some part of the C introduced into the soil along with organic waste is assimilated by heterotrophic soil microorganisms as a result of their metabolic processes. Consequently, carbon is temporarily bound in soil microorganisms. Part of that C will be released from soil due to mineralization, but the remaining part will be incorporated into humus.
Formulation and use of manufactured soils: A major use for organic and inorganic wastes
Published in Critical Reviews in Environmental Science and Technology, 2022
R. J. Haynes, Y.-F. Zhou, X. Weng
Aggregation and consequent soil structural formation are important processes that occur in natural soils but are uncommon in manufactured soils. The interaction of the soil humic component with surfaces of the mineral components is the basis for aggregate formation and is an important mechanism in the protection of organic matter from decomposition. Humic substances are formed during the decay of plant residues and are a complex system of molecules that have a wide range of generally high molecular weights. Their complex, heterogeneous structure makes them rather resistant to microbial degradation (Hayes & Swift, 2020). Interactions between organic matter and mineral surfaces occur through a multitude of mechanisms including ligand exchange, anion exchange, hydrophobic interactions, Van der Waals forces, H-bonding and through formation of electrostatic polyvalent cation bridges (Lützow et al., 2006). Organic matter can also directly complex with metal ions such as Al3+, Fe3+ and Ca2+. Both sorption of humic substances to mineral surfaces and their complexation with divalent and trivalent cations (e.g. Al3+, Fe3+ and Ca2) has been shown to reduce their rate of degradation (Lützow et al., 2006; Mikutta et al., 2006).
Advances in the agrochemical utilization of fermentation residues reduce the cost of purpose-grown phytomass for biogas production
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Josef Maroušek, Petr Bartoš, Martin Filip, Ladislav Kolář, Petr Konvalina, Anna Maroušková, Jan Moudrý, Jiří Peterka, Jiří Šál, Miloslav Šoch, Vojtěch Stehel, Otakar Strunecký, Karel Suchý, Marek Vochozka, Jaromír Vrbka, Tomáš Zoubek
The conventional agrotechnical procedures are routinely based on the results originating from the classical method of isolating humic substances (HA + FA) that is based on the alkaline extraction of the soil sample and on the precipitation of HA from the extract in an acidic environment. This classical method was used to compare the results of the newly proposed procedure. This conventional method has been used for many decades and continues to be used today, despite a great deal of justified criticism (Lehmann and Kleber 2015). As argued by its critics, the extraction fails to capture up to 50–70% of organic C which is then considered as insoluble humin (Rice 2001); the division to humic and non-humic substances has also been criticized (Horwath 2007), with a problem being posed by organic substances found at the borderline between humic and non-humic substances in the process of alkaline extraction (Knicker et al. 2008). The humification model, representing the basis of the classical method (Kononova 1961), has been criticized (Lehmann and Kleber 2015) and classical humification has been completed with selective preservation (Marín-Spiotta et al. 2014) and with the progressive decomposition model (the so-called “biopolymeric degradation“ or “degradation concept“) in recent scientific studies (Cotrufo et al. 2013). Therefore, the classical method used in this study for comparison should be taken only as roughly indicative.
Demographic responses of Cladocerans (Cladocera) in relation to different concentrations of humic substances
Published in Journal of Environmental Science and Health, Part A, 2019
Jose Luis Gama Flores, Maria Elena Huidobro Salas, S. S. S. Sarma, S. Nandini
Humification is a natural process playing a fundamental role in nutrient supply to primary producers.[1] During this process different products collectively called humic substances (HS) are liberated mainly into the water and soil.[2] Because humic substances have different functional groups, they often act as chemical stressors leading directly or indirectly to ecological problems.[1] Compared to non-humic substances such as carbohydrates and proteins which are easily degraded, humic substances are much more stable.[3] Humic substances are composed of humin (insoluble fraction), humic acid (soluble in alkaline solution), and fulvic acid (soluble in both acid and base solutions).[4] Fulvic acid, one of the components of humic substances in nature,[3] has been widely used in the agriculture sector as biostimulants.[5] Fulvic acid is also used to enhance the immunity of animals in the veterinary sector. However, in aquacultural operations, the use of humic substances has been low.[6] There is some indication that dietary intake of fulvic acid helps to enhance disease resistance in carps.[7]