A new method combining hydrothermal carbonization and mechanical compression in-situ for sewage sludge dewatering: Bench-scale verification

Quan, Cui; Li, Zongyang; Miskolczi, Norbert; Egedy, Attila

doi:10.1016/j.jaap.2019.02.003

Cited by 82 publications

(33 citation statements)

References 37 publications

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“…Obtained results, presented in Table 1, confirm the generally accepted consensus that the hydrothermal carbonization process increases the HHV of the processed material, increases carbon content, and leads to decreased oxygen content [9,11,12,20,26,43]. Additionally, the HTC process, performed at the particular process parameters, lead to a decrease in ash content.…”

Section: Resultssupporting

confidence: 72%

“…The aforementioned reactions, apart from decarbonylation, consequently cause a decrease in the O/C ratio of the solid product. The loss of functional groups, responsible for the hydrophilic nature of most biomasses not only promotes the formation of gases [9] but also makes hydrochars relatively more hydrophobic, thus leading to potential enhancement of its dewatering [9,26], leading to the energy savings when comparing to drying of unprocessed feedstock [27]. That, in turn, can improve the lower heating value (LHV) of the treated material.…”

Section: Introductionmentioning

confidence: 99%

“…This synergy can be achieved in many ways. Firstly it can enhance the dewatering of the digestate as suggested by Gao et al [26] and Wang et al [38]. Possible enhancement of the biogas production is also very appealing, as the problem of liquid by-products of hydrothermal carbonization does not have a viable technical solution for the commercial-scale reactors nowadays.…”

Section: Introductionmentioning

confidence: 99%

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Treatment of Liquid By-Products of Hydrothermal Carbonization (HTC) of Agricultural Digestate Using Membrane Separation

et al. 2020

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Agriculture affects both the quantity and the quality of water available for other purposes, which becomes problematic, especially during increasingly frequent severe droughts. This requires tapping into the resources that are typically neglected. One such resource is a by-product of anaerobic digestion, in which moisture content typically exceeds 90%. Application of hydrothermal carbonization process (HTC) to this residue could partially remove organic and inorganic material, improve dewatering, decrease the overall solid mass, sanitize the digestate, change its properties, and eliminate problems related with emissions of odors from the installation. However, a significant gap still exists in terms of the dewatering of the hydrochars and the composition of the effluents. This work presents results of experimental investigation focused on the removal of organic compounds from the HTC effluent. Results of qualitative and quantitative analysis of liquid by-products of HTC of the agricultural digestate showed that acetic acid, 3-pyridinol, 1-hydroxyacetone, and 1,3-propanediol were the main liquid organic products of the process. Application of ultrafiltration process with the use of 10 kDa membrane for liquid HTC by-product treatment allows for the reduction of chemical oxygen demand up to 30%, biological oxygen demand up to 10%, and dissolved organic carbon up to 21%.

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Section: Resultssupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Treatment of Liquid By-Products of Hydrothermal Carbonization (HTC) of Agricultural Digestate Using Membrane Separation

et al. 2020

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“…Currently, 50 million tons of sewage sludge and 1.4 billion tons of manure is produced annually in the EU (Foged et al 2012; Kelessidis and Stasinakis 2012). In China, 3.8 billion tons of manure is produced annually and sewage sludge production expected to rise to 52.92 million tons by 2020 (Gao et al 2019). These amounts are expected to further increase with global population and living standards over the next century.…”

Section: Introductionmentioning

confidence: 99%

The impact of hydrothermal carbonization on the surface functionalities of wet waste materials for water treatment applications

Niinipuu

Latham

Boily

et al. 2020

Environ Sci Pollut Res

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Hydrothermal carbonization (HTC) is an energy-efficient thermochemical process for converting wet waste products into value added materials for water treatment. Understanding how HTC influences the physicochemical properties of the resultant materials is critical in optimizing the process for water treatment, where surface functionality and surface area play a major role. In this study, we have examined the HTC of four wet waste streams, sewage sludge, biosludge, fiber sludge, and horse manure at three different temperatures (180°C, 220°C, and 260°C). The physicochemical properties of these materials were examined via FTIR, SEM and BET with their adsorption capacity were assessed using methylene blue. The yield of solid material after hydrothermal carbonization (hydrochar) decreased with increasing temperature for all samples, with the largest impact on horse manure and fiber sludge. These materials also lost the highest degree of oxygen, while HTC had minimal impact on biosludge and sewage sludge. The differences here were due to the varying compositions of each waste material, FTIR identified resonances related to cellulose in horse manure and fiber sludge, which were not detected in biosludge and sewage sludge. Adsorption capacities varied between 9.0 and 68 mg g −1 with biosludge HTC at 220°C adsorbing the highest amount. Adsorption also dropped drastically at the highest temperature (260°C), indicating a correlation between adsorption capacity and HTC conditions. This was attributed to the loss of oxygen functional groups, which can contribute to adsorption. These results suggest that adsorption properties can be tailored both by selection of HTC temperature and feedstock.

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“…This is followed by polymerization and aromatization [24,25]. A decrease in the number of OH groups is crucial in making hydrochars hydrophobic [37] and enhancing dewatering by mechanical means [25,38]. Moreover, grindability of the processed biomass can be significantly enhanced [39].…”

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confidence: 99%

HTC of Wet Residues of the Brewing Process: Comprehensive Characterization of Produced Beer, Spent Grain and Valorized Residues

et al. 2020

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Steady consumption of beer results in a steady output of residues, i.e., brewer's spent grain (BSG). Its valorization, using hydrothermal carbonization (HTC) seems sensible. However, a significant knowledge gap regarding the variability of this residue and its influence on the valorization process and its potential use in biorefineries exists. This study attempted to fill this gap by characterization of BSG in conjunction with the main product (beer), taking into accounts details of the brewing process. Moreover, different methods to assess the performance of HTC were investigated. Overall, the differences in terms of the fuel properties of both types of spent grain were much less stark, in comparison to the differences between the respective beers. The use of HTC as a pretreatment of BSG for subsequent use as a biorefinery feedstock can be considered beneficial. HTC was helpful in uniformization and improvement of the fuel properties. A significant decrease in the oxygen content and O/C ratio and improved grindability was achieved. The Weber method proved to be feasible for HTC productivity assessment for commercial installations, giving satisfactory results for most of the cases, contrary to traditional ash tracer method, which resulted in significant overestimations of the mass yield.However, for craft breweries located in big cities, disposal becomes more problematic [3]. There are also attempts to enrich food products with spent grains. Thus far, there have been trials with sausages [4] and bread [5]. However, consumers reported that such products represent a fiber aftertaste [6]. However, this is limited only to the relatively close vicinity of a brewery, due to relatively high moisture content, that could range between 70% up to 78% 70% [7][8][9]. Biological activity of these residues makes long term storage difficult. The literature reports ongoing work on various new ways of using BSG, including extraction of polyphenols [10,11], other anti-oxidants [12,13], functional cardioprotective lipids for pharmaceutic use [14], proteins [15], fodder for edible insects [16], material for disposable trays [17], natural rubber modifier [18], as well as feedstock for production of pigments [19] and biochar, for subsequent use as soil amendment [20] or sustainable material for electrodes [21].The potential use of this residue as a fuel has been suggested by several authors so far [7][8][9]22,23]. The relatively high initial moisture content of spent grain makes hydrothermal valorization techniques the most sensible choice [8,9]. Hydrothermal carbonization (HTC), also known as wet torrefaction, is a valorization process suitable for a range of low-quality solid biomass, especially with high initial moisture content [24,25]. Process temperature, reported in the literature, usually ranges between 180 • C and 260 • C [25][26][27][28][29][30]. As the process takes place in subcritical water, pressure has to be higher than saturation pressure of water for specific temperature [25][26][27][28][29][30]. In these conditions wa...

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A new method combining hydrothermal carbonization and mechanical compression in-situ for sewage sludge dewatering: Bench-scale verification

Cited by 82 publications

References 37 publications

Treatment of Liquid By-Products of Hydrothermal Carbonization (HTC) of Agricultural Digestate Using Membrane Separation

Treatment of Liquid By-Products of Hydrothermal Carbonization (HTC) of Agricultural Digestate Using Membrane Separation

The impact of hydrothermal carbonization on the surface functionalities of wet waste materials for water treatment applications

HTC of Wet Residues of the Brewing Process: Comprehensive Characterization of Produced Beer, Spent Grain and Valorized Residues

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