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A Simulation Study of the Effect of HCNG Fuel and Injector Hole Number along with a Variation of Fuel Injection Pressure in a Gasoline Engine Converted from Port Injection to Direct Injection. Processes (Basel) 2022. [DOI: 10.3390/pr10112389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The number of injector holes and the fuel-injection pressure in an internal combustion engine can affect engine performance and exhaust emissions. Conversion of a port-injection gasoline engine to an HCNG direct-injection engine improves engine performance and exhaust emissions. In addition, increasing the injection pressure helps to increase engine performance. In this study, AVL Fire software was used to perform simulation by certain adjustments. The injection pressure was applied in mods of 15, 20, and 25 bars, the injector holes numbers were 3 and 6, the compression ratio changed from 10:1 to 14:1, and the amount of hydrogen enrichment to natural gas was in mods of 10%, 20%, 30%, and 40%. This paper discusses the items above with regard to power, torque, combustion chamber pressure, fuel conversion efficiency, and exhaust emissions. The result determined that increasing the number of injector holes improves the performance engine and reduces CO emission so that the contour plots confirmed the balanced distribution of temperature and pressure. According to obtained results, maximum engine performance improved from 2.5% to 5% at different speeds and 30% added hydrogen, 25 bar injection pressure, and 6-hole injectors. The amount of CO decreased by approximately 30%, and NOx increased by about 10%.
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Haffiez N, Chung TH, Zakaria BS, Shahidi M, Mezbahuddin S, Hai FI, Dhar BR. A critical review of process parameters influencing the fate of antibiotic resistance genes in the anaerobic digestion of organic waste. BIORESOURCE TECHNOLOGY 2022; 354:127189. [PMID: 35439559 DOI: 10.1016/j.biortech.2022.127189] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 06/14/2023]
Abstract
The overuse and inappropriate disposal of antibiotics raised severe public health risks worldwide. Specifically, the incomplete antibiotics metabolism in human and animal bodies contributes to the significant release of antibiotics into the natural ecosystems and the proliferation of antibiotic-resistant bacteria carrying antibiotic-resistant genes. Moreover, the organic feedstocks used for anaerobic digestion are often highly-rich in residual antibiotics and antibiotic-resistant genes. Hence, understanding their fate during anaerobic digestion has become a significant research focus recently. Previous studies demonstrated that various process parameters could considerably influence the propagation of the antibiotic-resistant genes during anaerobic digestion and their transmission via land application of digestate. This review article scrutinizes the influences of process parameters on antibiotic-resistant genes propagation in anaerobic digestion and the inherent fundamentals behind their effects. Based on the literature review, critical research gaps and challenges are summarized to guide the prospects for future studies.
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Affiliation(s)
- Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Tae Hyun Chung
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Manjila Shahidi
- 4S Analytics & Modelling Ltd., Edmonton, AB, T6W 3V6, Canada
| | | | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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Dastyar W, Mohammad Mirsoleimani Azizi S, Dhadwal M, Ranjan Dhar B. High-solids anaerobic digestion of organic fraction of municipal solid waste: Effects of feedstock to inoculum ratio and percolate recirculation time. BIORESOURCE TECHNOLOGY 2021; 337:125335. [PMID: 34139557 DOI: 10.1016/j.biortech.2021.125335] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
The effects of feedstock to inoculum (F:I) ratio and percolate recirculation time (PRT) were studied for the high-solids anaerobic digestion (HSAD) of the organic fraction of municipal solid waste (OFMSW). Six mesophilic HSAD systems were operated at different F:I ratios (1 to 3 kg VS/kg VS; PRT = 2.5 h/d) and PRTs (1.5 to 3.5 h/d; F:I = 2 kg VS/kg VS). The F:I ratio of 1 provided up to 86% of the theoretical methane potential of OFMSW. In contrast, F:I ratio of 3 provided only 34% methane recovery due to volatile fatty acids (VFAs) accumulation and pH drop. Despite F:I ratio of 2 could provide 70% methane recovery, it could enable almost 45% higher organics processing capacity (VS basis) and lower solids washout during percolate recirculation, as compared to the F:I ratio of 1. However, different examined PRTs showed marginal impacts on methane yields with comparable changes in profiles of percolate characteristics.
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Affiliation(s)
- Wafa Dastyar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
| | | | - Mayank Dhadwal
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Pereira de Albuquerque F, Dhadwal M, Dastyar W, Mirsoleimani Azizi SM, Karidio I, Zaman H, Dhar BR. Fate of disposable face masks in high-solids anaerobic digestion: Experimental observations and review of potential environmental implications. CASE STUDIES IN CHEMICAL AND ENVIRONMENTAL ENGINEERING 2021; 3:100082. [PMID: 38620309 PMCID: PMC7816893 DOI: 10.1016/j.cscee.2021.100082] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/12/2021] [Accepted: 01/16/2021] [Indexed: 05/18/2023]
Abstract
Face masks became a part of our daily life amid the global COVID-19 (SARS-CoV-2) pandemic. Most of the face masks are made for single-use and primarily disposed of in garbage bins with other non-recyclable wastes. To date, little is known about how disposable face masks in municipal solid waste (MSW) would interfere with high-solids anaerobic digestion (HSAD) in waste management facilities. Here, we first report preliminary results from a lab experiment conducted with the organic fraction of municipal solid waste (OFMSW) amended with used disposable face masks. The lab-scale HSAD systems were operated with percolate recirculation comparable to commercial HSAD systems typically used for full-scale processing of OFMSW. The results suggested that the presence of face masks in OFMSW could negatively affect methane productivity and kinetics. In the digesters amended with face masks, total cumulative methane production decreased by up to 18%, along with a 12-29% decrease in maximum methane production rates than the control digester (without face masks). Moreover, lag phases increased by 7-14%. The results also suggested that the type of polymeric materials used in face masks would be more critical than their total number/loading in the digester, which warrants further investigation. The visual inspection of digestate showed that the face masks were mostly undegraded after 40 days of operation. Much remains unknown about how the undegraded face masks will affect the digestate management practices, such as composting, land application, and landfilling. However, the review of existing literature suggested that they can be a potential source of plastic and microplastic pollution and amplify transmission of antibiotic resistance genes to the ecosystem. In summary, this study underscores the importance of developing safe and reliable disposal guidelines and management plans for single-use face masks.
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Affiliation(s)
| | - Mayank Dhadwal
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Wafa Dastyar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | | | - Ibrahim Karidio
- Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Hamid Zaman
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
- Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
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Ting HNJ, Lin L, Cruz RB, Chowdhury B, Karidio I, Zaman H, Dhar BR. Transitions of microbial communities in the solid and liquid phases during high-solids anaerobic digestion of organic fraction of municipal solid waste. BIORESOURCE TECHNOLOGY 2020; 317:123951. [PMID: 32822895 DOI: 10.1016/j.biortech.2020.123951] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
This study presents a microbiological diagnosis of a mesophilic high-solids anaerobic digestion (HSAD) system with percolate recirculation. The results demonstrated a significant decrease in microbial diversity in both the solid digestate and the liquid percolate. Also, the digestate from the top and middle sections of the digester had similar diversity, whereas the digestate from the bottom of the tank had a slightly lower diversity. These results suggest that despite percolate recirculation, substrate gradients might have developed across the system. Archaeal communities showed shifts towards known hydrogenotrophic and ammonia-tolerant methanogens (genera Methanocelleus, Methanolinea, Methanosarcina, vadin CA11, etc.), which was a consequence of decreased volatile fatty acids and increased ammonia-nitrogen levels over time. Compared to initial solid and liquid inoculum, the relative abundances of some bacteria (phyla Proteobacteria and Firmicutes) and archaea of the genus Methanosarcina changed between two phases in the opposite direction, indicating a shift of microbes between two phases.
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Affiliation(s)
- Hok Nam Joey Ting
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Long Lin
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Raul Bello Cruz
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Bappi Chowdhury
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Ibrahim Karidio
- Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Hamid Zaman
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada; Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada.
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Abstract
The increasing quantity of biowaste generation and the requirements governing their ultimate disposal are of serious economic and environmental concern [...]
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