Mechanisms of Malodor Reduction in Dewatered Sewage Sludge by Means of The Hydrothermal Torrefaction

Namioka, Tomoaki; Morohashi, Yoshiaki; Yoshikawa, Kunio

doi:10.1299/jee.6.119

Cited by 9 publications

(7 citation statements)

References 15 publications

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“…The sensory assessment of the smell and colour of the carbonized end products recovered after the M-HTC process showed them to be similar and consistent with thermochemical conversion/transformation processes of organic biomass reported in literature involving other conventional heating methods (35,42,43,44). In essence, these similarities in the organoleptic properties of smell and colour of the end products from the M-HTC of HBW with existing methods, and the characteristic colour and smell change of end products typical of HTC processes, provide preliminary evidence that suggests M-HTC converted HBW to carbonaceous materials.…”

Section: Mechanisms Behind Smell and Colouration Changessupporting

confidence: 85%

“…The eradication of the foul odour in carbonized biowastes is primarily due to the thermal hydrolysis of these organic macromolecular components during the M-HTC process. The hydrolytic process facilitates the solubilization of compounds causing foul odour in HBW, such as the nitrogenous benzopyrrole compounds -notably indole and skatole, hydrogen sulphide, the methyl sulphides and other sulphur-containing compounds (32,33,34); and renders them nonvolatile, dissolved and trapping them in the liquid phase (35). Other reactions associated with HTC, including aromatization, may also suppress odour (36).…”

Section: Mechanisms Behind Smell and Colouration Changesmentioning

confidence: 99%

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Characterization of solid fuel chars recovered from microwave hydrothermal carbonization of human biowaste

Afolabi

Sohail

Thomas

2017

Energy

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT Highlights-Microwave hydrothermal carbonization can convert human biowaste to solid fuel chars -Physicochemical, structural, energetic and combustion properties of chars are enhanced -Higher heating value (HHV) of chars recovered increased by up to 41.5%-HHV of chars -up to 25.6MJ/kg -is greater than that of low-ranking coals/fuels -Processing human biowaste into solid fuel is promising for energy applications M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT KeywordsFaecal biomass, microwave, hydrothermal carbonization, chars, sanitation, renewable energy IntroductionTwo of the key issues facing more than 2 billion people in developing countries are poor sanitation and energy scarcity. Having missed the Millennium Development Goals' targets by wide margins, achieving access to adequate and equitable sanitation, ending open defecation/untreated faecal wastewater and increasing the share of affordable, renewable clean energy by 2030 now constitute the key targets of the recently adopted Sustainable Development Goals 6 and 7 (1). Annually, an estimated one billion tons of faecal wastewater is generated (2) and as much as 90% of this is discharged untreated (3, 4). Open defecation is still practised by almost one billion people, and about 2.4 billion people still lack access to improved sanitation (5). The consequences of poor sanitation are pervasive. Open defecation fields (which serve as breeding sites for insects, vectors/disease pathogens), odour nuisance, exposure to human faecal biowaste (HBW) during manual pit emptying and the indiscriminate disposal of this waste intosurface water, open drains, near slums and other fragile settlements constitute serious public health and environmental risks. Faecal contamination of drinking water resources is primarily responsible for the high infant mortality rates due to waterborne diseases such as diarrhoea, which kills 700,000 children per year (6). Aside the environmental and health impacts, experts estimate that lack of access to sanitation cost the global economy US$223 billion in 2015 -based on an economic valuation of the costs associated with premature death and loss in productivity, the healthcare costs of the sick and time forgone due to lack of access to improved sanitation (7).In common with poor sanitation, energy scarcity affects the least well off; an estimated 90% of people in developing economies lack access to reliable energy supplies (8). More than two billion people rely on firewood, charcoal and other related forest biomass to meet...

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Section: Mechanisms Behind Smell and Colouration Changessupporting

confidence: 85%

Section: Mechanisms Behind Smell and Colouration Changesmentioning

confidence: 99%

Characterization of solid fuel chars recovered from microwave hydrothermal carbonization of human biowaste

Afolabi

Sohail

Thomas

2017

Energy

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“…This is due to the solubility of organic and inorganic components in the pressurized subcritical water, which also decreases the amount of salts and minerals contained in the biomass [20]. Namioka et al [90] observed that in the WT of sewage sludge, thermal-odour caused from high sulfur content reduces after the treatment of WT, whereas the amount of aldehydes, light aromatics, and organic acid components increased marginally. During hydrothermal torrefaction with hot compressed water from the 200 to 265°C disintegration of hemicellulose with water occurs rapidly, whereas lignin is relatively inactive, resulting in good binding properties during pelletization [91].…”

Section: Comparison Of Torrefaction Processmentioning

confidence: 99%

Review on comparative study of dry and wet torrefaction

Acharya

Dutta

Minaret

2015

Sustainable Energy Technologies and Assessments

111

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“…Tokyo Institute of Technology has been investigating sewage sludge hydrothermal treatment system, resulted in improved natural drying performance and reduced odor [22][23][24], and recent research confirmed that NO reduction occurred on the hydrothermally treated sludge compared to untreated sludge [25]. The proposed refuse-derived fuel (RDF) production system is shown in Fig.…”

Section: Hydrothermal Treatment Of Sludgementioning

confidence: 99%

“…This experiment was conducted in northern Japan sewage sludge with characteristics shown in Table 15.6 using 3 m 3 horizontal steel vessel shown in Fig. 15.5 at 19.6 MPa and 200°C for 30 min [24]. After being treated, 150 g of each solid product sample was placed into a 5 L gas sampling bag, and 3 L of fresh air was injected into the bag.…”

Section: Changes In Product Odormentioning

confidence: 99%

Sewage Sludge Treatment by Hydrothermal Process for Producing Solid Fuel

Yoshikawa

Prawisudha

2014

Green Chemistry and Sustainable Technology

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Sludge treatment and disposal is one of the focus points in the waste treatment technology research due to the fact that sewage sludge is a form of pollution. One of the promising methods of sewage sludge treatment, considering its maximum sludge reduction and short processing time, is incineration. However, the usage of sewage sludge as fuel in incinerator is hindered by its high water content and high nitrogen content. A hydrothermal process for producing solid fuel from sewage sludge is developed by using saturated steam at 160-200°C and about 60 min holding time. It was shown that the product has improved dehydrability, but at the same time exhibiting higher solubility in the water, resulting in slightly lower calorific value due to the loss of dissolved solids, which have significant calorific value; therefore, an optimum operating condition is required to improve the dehydrability of sludge without reducing its solid content and calorific value. In the term of sewage odor, it was shown that after the hydrothermal treatment the sulfur-containing compound concentration was decreased, the same with the total odor intensity in the solid product. On the other hand, the odor intensity in the liquid and gaseous products were increased, suggesting the transfer of these compounds to the liquid and gaseous parts. During the combustion experiment, it was shown that the hydrothermally treated sludge emits lower NO emission compared to the raw sludge, promoting its possibility to be used in incinerator as direct or co-fuel without resulting in secondary pollution.

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Mechanisms of Malodor Reduction in Dewatered Sewage Sludge by Means of The Hydrothermal Torrefaction

Cited by 9 publications

References 15 publications

Characterization of solid fuel chars recovered from microwave hydrothermal carbonization of human biowaste

Characterization of solid fuel chars recovered from microwave hydrothermal carbonization of human biowaste

Review on comparative study of dry and wet torrefaction

Sewage Sludge Treatment by Hydrothermal Process for Producing Solid Fuel

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