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Bittencourt FLF, Martins MF, Orlando MTD. Integrating in-bed gas looping and CO 2 capture in the FeD-Latrine. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160133. [PMID: 36402333 DOI: 10.1016/j.scitotenv.2022.160133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Sanitation equity and climate actions are world concerns stated by the United Nations in the Sustainable Development Goals. A significant source of greenhouse gas emissions is inputted by human wastes, either in developing countries through wastewater treatment plants, or in the underdeveloped world, through anaerobic digestion of fecal sludge in pit latrines. For the first time, an integrated process for CO2 reduction and capture is implemented in a thermally sustainable, latrine-like device that destroys fresh human feces using smoldering combustion, the FeD-Latrine. A gas looping oxidizes combustible gases and creates favorable conditions to capture CO2 in bed. CH4 and H2 molar fractions are decreased around 90 % and 30 %, respectively. CaO used as a sorbent captures up to 8 mmol of CO2 per gram, forming a stable CaCO3. Compared to kinetic-dominant processes for CO2 capture, we obtain an efficiency of around 52 %. Our findings show that using the FeD-Latrine to replace typical pit latrines reduces 60 % of the CO2-eq emissions.
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Affiliation(s)
- Flávio Lopes Francisco Bittencourt
- Federal Institute of Espirito Santo, 660 Augusto Costa de Oliveira St., Piuma 29285-000, Brazil; Laboratory of Combustion and Combustible Matter, PPGEM, Federal University of Espirito Santo, 514 Fernando Ferrari Av., Vitoria 29075-910, Brazil
| | - Márcio Ferreira Martins
- Laboratory of Combustion and Combustible Matter, PPGEM, Federal University of Espirito Santo, 514 Fernando Ferrari Av., Vitoria 29075-910, Brazil.
| | - Marcos Tadeu D Orlando
- Laboratory of Combustion and Combustible Matter, PPGEM, Federal University of Espirito Santo, 514 Fernando Ferrari Av., Vitoria 29075-910, Brazil
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2
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Aalam SMM, Crasta DN, Roy P, Miller AL, Gamb SI, Johnson S, Till LM, Chen J, Kashyap P, Kannan N. Genesis of fecal floatation is causally linked to gut microbial colonization in mice. Sci Rep 2022; 12:18109. [PMID: 36302811 PMCID: PMC9613883 DOI: 10.1038/s41598-022-22626-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 10/18/2022] [Indexed: 12/30/2022] Open
Abstract
The origin of fecal floatation phenomenon remains poorly understood. Following our serendipitous discovery of differences in buoyancy of feces from germ-free and conventional mice, we characterized microbial and physical properties of feces from germ-free and gut-colonized (conventional and conventionalized) mice. The gut-colonization associated differences were assessed in feces using DNA, bacterial-PCR, scanning electron microscopy, FACS, thermogravimetry and pycnometry. Based on the differences in buoyancy of feces, we developed levô in fimo test (LIFT) to distinguish sinking feces (sinkers) of germ-free mice from floating feces (floaters) of gut-colonized mice. By simultaneous tracking of microbiota densities and gut colonization kinetics in fecal transplanted mice, we provide first direct evidence of causal relationship between gut microbial colonization and fecal floatation. Rare discordance in LIFT and microbiota density indicated that enrichment of gasogenic gut colonizers may be necessary for fecal floatation. Finally, fecal metagenomics analysis of 'floaters' from conventional and syngeneic fecal transplanted mice identified colonization of > 10 gasogenic bacterial species including highly prevalent B. ovatus, an anaerobic commensal bacteria linked with flatulence and intestinal bowel diseases. The findings reported here will improve our understanding of food microbial biotransformation and gut microbial regulators of fecal floatation in human health and disease.
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Affiliation(s)
- Syed Mohammed Musheer Aalam
- grid.66875.3a0000 0004 0459 167XDivision of Experimental Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 USA
| | - Daphne Norma Crasta
- grid.66875.3a0000 0004 0459 167XDivision of Experimental Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 USA
| | - Pooja Roy
- grid.66875.3a0000 0004 0459 167XDivision of Experimental Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 USA
| | - A. Lee Miller
- grid.66875.3a0000 0004 0459 167XDepartment of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905 USA
| | - Scott I. Gamb
- grid.66875.3a0000 0004 0459 167XMicroscopy and Cell Analysis Core, Mayo Clinic, Rochester, MN 55905 USA
| | - Stephen Johnson
- grid.66875.3a0000 0004 0459 167XDivision of Computational Biology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55905 USA
| | - Lisa M. Till
- grid.66875.3a0000 0004 0459 167XDepartment of Gastroenterology, Mayo Clinic, Rochester, MN 55905 USA
| | - Jun Chen
- grid.66875.3a0000 0004 0459 167XDivision of Computational Biology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55905 USA
| | - Purna Kashyap
- grid.66875.3a0000 0004 0459 167XDepartment of Gastroenterology, Mayo Clinic, Rochester, MN 55905 USA
| | - Nagarajan Kannan
- grid.66875.3a0000 0004 0459 167XDivision of Experimental Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 USA ,grid.66875.3a0000 0004 0459 167XCenter for Regenerative Biotherapeutics, Mayo Clinic, Rochester, MN 55905 USA ,grid.66875.3a0000 0004 0459 167XMayo Clinic Cancer Center, Mayo Clinic, Rochester, MN 55905 USA
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Rowles LS, Morgan VL, Li Y, Zhang X, Watabe S, Stephen T, Lohman HAC, DeSouza D, Hallowell J, Cusick RD, Guest JS. Financial Viability and Environmental Sustainability of Fecal Sludge Treatment with Pyrolysis Omni Processors. ACS ENVIRONMENTAL AU 2022; 2:455-466. [PMID: 36164351 PMCID: PMC9502014 DOI: 10.1021/acsenvironau.2c00022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/11/2022] [Accepted: 07/11/2022] [Indexed: 11/30/2022]
Abstract
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Omni Processors (OPs) are community-scale systems for
non-sewered
fecal sludge treatment. These systems have demonstrated their capacity
to treat excreta from tens of thousands of people using thermal treatment
processes (e.g., pyrolysis), but their relative sustainability is
unclear. In this study, QSDsan (an open-source Python package) was
used to characterize the financial viability and environmental implications
of fecal sludge treatment via pyrolysis-based OP technology treating
mixed and source-separated human excreta and to elucidate the key
drivers of system sustainability. Overall, the daily per capita cost
for the treatment of mixed excreta (pit latrines) via the OP was estimated
to be 0.05 [0.03–0.08] USD·cap–1·d–1, while the treatment of source-separated excreta
(from urine-diverting dry toilets) was estimated to have a per capita
cost of 0.09 [0.08–0.14] USD·cap–1·d–1. Operation and maintenance of the OP is a critical
driver of total per capita cost, whereas the contribution from capital
cost of the OP is much lower because it is distributed over a relatively
large number of users (i.e., 12,000 people) for the system lifetime
(i.e., 20 yr). The total emissions from the source-separated scenario
were estimated to be 11 [8.3–23] kg CO2 eq·cap–1·yr–1, compared to 49 [28–77]
kg CO2 eq·cap–1·yr–1 for mixed excreta. Both scenarios fall below the estimates of greenhouse
gas (GHG) emissions for anaerobic treatment of fecal sludge collected
from pit latrines. Source-separation also creates opportunities for
resource recovery to offset costs through nutrient recovery and carbon
sequestration with biochar production. For example, when carbon is
valued at 150 USD·Mg–1 of CO2, the
per capita cost of sanitation can be further reduced by 44 and 40%
for the source-separated and mixed excreta scenarios, respectively.
Overall, our results demonstrate that pyrolysis-based OP technology
can provide low-cost, low-GHG fecal sludge treatment while reducing
global sanitation gaps.
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Affiliation(s)
- Lewis Stetson Rowles
- Institute for Sustainability, Energy, and Environment, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Victoria L. Morgan
- Institute for Sustainability, Energy, and Environment, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Yalin Li
- Institute for Sustainability, Energy, and Environment, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Xinyi Zhang
- Department of Civil & Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Shion Watabe
- Department of Civil & Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Tyler Stephen
- Department of Civil & Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Hannah A. C. Lohman
- Department of Civil & Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Derek DeSouza
- Biomass Controls PBC, Woodstock, Connecticut 06281, United States
| | - Jeff Hallowell
- Biomass Controls PBC, Woodstock, Connecticut 06281, United States
| | - Roland D. Cusick
- Department of Civil & Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Jeremy S. Guest
- Institute for Sustainability, Energy, and Environment, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Department of Civil & Environmental Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
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Krueger BC, Fowler GD, Templeton MR, Septien S. Faecal sludge pyrolysis: Understanding the relationships between organic composition and thermal decomposition. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 298:113456. [PMID: 34364246 DOI: 10.1016/j.jenvman.2021.113456] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/26/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Sludge treatment is an integral part of faecal sludge management in non-sewered sanitation settings. Development of pyrolysis as a suitable sludge treatment method requires thorough knowledge about the properties and thermal decomposition mechanisms of the feedstock. This study aimed to improve the current lack of understanding concerning relevant sludge properties and their influence on the thermal decomposition characteristics. Major organic compounds (hemicellulose, cellulose, lignin, protein, oil and grease, other carbohydrates) were quantified in 30 faecal sludge samples taken from different sanitation technologies, providing the most comprehensive organic faecal sludge data set to date. This information was used to predict the sludge properties crucial to pyrolysis (calorific value, fixed carbon, volatile matter, carbon, hydrogen). Samples were then subjected to thermogravimetric analysis to delineate the influence of organic composition on thermal decomposition. Septic tanks showed lower median fractions of lignin (9.4%dwb) but higher oil and grease (10.7%dwb), compared with ventilated improved pit latrines (17.4%dwb and 4.6%dwb respectively) and urine diverting dry toilets (17.9%dwb and 4.7%dwb respectively). High fixed carbon fractions in lignin (45.1%dwb) and protein (18.8%dwb) suggested their importance for char formation, while oil and grease fully volatilised. For the first time, this study provided mechanistic insights into faecal sludge pyrolysis as a function of temperature and feedstock composition. Classification into the following three phases was proposed: decomposition of hemicellulose, cellulose, other carbohydrates, proteins and, partially, lignin (200-380 °C), continued decomposition of lignin and thermal cracking of oil and grease (380-500 °C) and continued carbonisation (>500 °C). The findings will facilitate the development and optimisation of faecal sludge pyrolysis, emphasising the importance of considering the organic composition of the feedstock.
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Affiliation(s)
- Benedict C Krueger
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK.
| | - Geoffrey D Fowler
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK
| | - Michael R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK
| | - Santiago Septien
- Water, Sanitation & Hygiene Research & Development Centre, University of KwaZulu-Natal, Durban, 4041, South Africa
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Bittencourt FLF, Martins MF. On the strong exothermicity of fecal matter pyrolysis under an inert atmosphere. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2020. [DOI: 10.1007/s43153-020-00052-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Soares RB, Martins MF, Gonçalves RF. A conceptual scenario for the use of microalgae biomass for microgeneration in wastewater treatment plants. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 252:109639. [PMID: 31586744 DOI: 10.1016/j.jenvman.2019.109639] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 09/13/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Microalgae are a potential source of biomass for the production of energy, which is why the amount of research on this topic has increased in recent years. This work describes the state of the art of microalgae production from wastewater treatment plants (WWTP), its potential to generate electricity and the scale in which it is possible. The methodology used was a systematic review of the gasification of microalgae from 49 articles selected. Based on the review, a conceptual scenario for microgeneration in WWTP using as feedstock microalgae for thermal gasification was developed. The most consistent assumptions for a real scale microgeneration are microalgae production in open ponds using domestic sewage as a nutritional medium; the use of the flocculation process in process of harvesting; microalgae to energy through thermal gasification process using a downdraft gasifier. Considering a WWTP with a 3000 m3/d flux capacity, 860 kg/d of dry microalgae biomass might be produced. For which, gasification has a production potential of 0.167 kWh/m3 of treated sewage, but the energy balance is compromised by the drying process. However, when the biogas produced in anaerobic treatment enter in the model, it is possible to add a surplus of electricity of 0.14 kWh/m3 of treated sewage. Finally, a cost estimate is made for the acquisition of drying and gasification-electricity generation systems. For this scenario, the results suggest that the investments may be financially returned after five years, with additional potential for further optimization.
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Affiliation(s)
- Renan Barroso Soares
- Department of Environmental Engineering, Federal University of Espírito Santo, Full Address: Avenida Fernando Ferrari, 514, Goiabeiras, CEP 29075-910, Vitória, Espírito Santo, Brazil; Federal Institute of Education of Espírito Santo, Full Address: Avenida Min. Salgado Filho, 1000, Soteco, CEP 29106-010, Vila Velha, Espírito Santo, Brazil.
| | - Marcio Ferreira Martins
- Laboratory of Combustion and Combustible Matter (LCC), PPGEM, Federal University of Espírito Santo, Full Address: Avenida Fernando Ferrari, 514, Goiabeiras, CEP 29075-910, Vitória, Espírito Santo, Brazil.
| | - Ricardo Franci Gonçalves
- Department of Environmental Engineering, Federal University of Espírito Santo, Full Address: Avenida Fernando Ferrari, 514, Goiabeiras, CEP 29075-910, Vitória, Espírito Santo, Brazil.
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