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Prof. Jonathan Woon Chung Wong
Department of Biology, Hong Kong Baptist University, Kowloon, HKSAR, Hong Kong

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0 Phytoremediation
0 composting
0 soil contamination
0 Soil plant interaction
0 Land application of organic waste

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composting
Land application of organic waste
Phytoremediation

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Journal article
Published: 16 June 2021 in Bioresource Technology
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In this research, we investigated and compared the effects of three widely used conductive materials, e.g., zero-valent iron (Fe0), magnetite (Fe3O4), and biochar on the performance, stability, and in-depth mechanism during the anaerobic co-digestion process of sewage sludge and food waste. Among the three conductive materials, Fe0 could achieve the highest cumulative methane production of 394.0 mL/g volatile solids (VS) added, which was 1.24-fold and 1.17-fold higher than that receiving Fe3O4 and biochar. The mechanistic studies indicated that compared to the Fe3O4 and biochar groups, Fe0 could significantly enhance the release of soluble protein, polysaccharide, and dissolved organic matters, the degradation of volatile fatty acids and VS, and the activities of key enzymes and direct interspecies electron transfer (DIET). Consequently, the methane yield and digestate dewaterability were notably improved. Collectively, these findings will offer suggestions of the preferable conductive materials in the anaerobic co-digestion process for decision makers.

ACS Style

Jialin Liang; Liwen Luo; Dongyi Li; Sunita Varjani; Yunjie Xu; Jonathan W.C. Wong. Promoting anaerobic co-digestion of sewage sludge and food waste with different types of conductive materials: Performance, stability, and underlying mechanism. Bioresource Technology 2021, 337, 125384 .

AMA Style

Jialin Liang, Liwen Luo, Dongyi Li, Sunita Varjani, Yunjie Xu, Jonathan W.C. Wong. Promoting anaerobic co-digestion of sewage sludge and food waste with different types of conductive materials: Performance, stability, and underlying mechanism. Bioresource Technology. 2021; 337 ():125384.

Chicago/Turabian Style

Jialin Liang; Liwen Luo; Dongyi Li; Sunita Varjani; Yunjie Xu; Jonathan W.C. Wong. 2021. "Promoting anaerobic co-digestion of sewage sludge and food waste with different types of conductive materials: Performance, stability, and underlying mechanism." Bioresource Technology 337, no. : 125384.

Review
Published: 21 May 2021 in Sensors
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This paper presents a comprehensive review of the detection of aflatoxin compounds using carbon allotrope-based sensors. Although aflatoxin M1 and its derivative aflatoxin B1 compounds have been primarily found in milk and other food products, their presence above a threshold concentration causes disastrous health-related anomalies in human beings, such as growth impairment, underweight and even carcinogenic and immunosuppressive effects. Among the many sensors developed to detect the presence of these compounds, the employment of certain carbon allotropes, such as carbon nanotubes (CNTs) and graphene, has been highly preferred due to their enhanced electromechanical properties. These conductive nanomaterials have shown excellent quantitative performance in terms of sensitivity and selectivity for the chosen aflatoxin compounds. This paper elucidates some of the significant examples of the CNTs and graphene-based sensors measuring Aflatoxin M1 (ATM1) and Aflatoxin B1 (AFB1) compounds at low concentrations. The fabrication technique and performance of each of the sensors are shown here, as well as some of the challenges existing with the current sensors.

ACS Style

Jingrong Gao; Shan He; Anindya Nag; Jonathan Wong. A Review of the Use of Carbon Nanotubes and Graphene-Based Sensors for the Detection of Aflatoxin M1 Compounds in Milk. Sensors 2021, 21, 3602 .

AMA Style

Jingrong Gao, Shan He, Anindya Nag, Jonathan Wong. A Review of the Use of Carbon Nanotubes and Graphene-Based Sensors for the Detection of Aflatoxin M1 Compounds in Milk. Sensors. 2021; 21 (11):3602.

Chicago/Turabian Style

Jingrong Gao; Shan He; Anindya Nag; Jonathan Wong. 2021. "A Review of the Use of Carbon Nanotubes and Graphene-Based Sensors for the Detection of Aflatoxin M1 Compounds in Milk." Sensors 21, no. 11: 3602.

Journal article
Published: 30 April 2021 in Bioresource Technology
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An integrated two-phase AD with acidogenic off-gas diversion from a leach bed reactor to an upflow anaerobic sludge blanket was developed for improving methane production. However, this system had its own technical limitation such as mass transfer efficiency for solid-state treatment. In order to optimize the mass transfer in this two phase AD system, leachate recirculation with various water replacement rates regulating the total solids contents (TS) at 12.5%, 15%, and 17.5% was aim to investigate its effect on methane generation. The solubilization of food waste was increased with decreasing TS content, while the enzymatic hydrolysis showed the opposite trend. A TS contents of 15% presented the best acidogenic performance with the highest hydrogen yield of 30.3 L H2/kg VSadded, which subsequently resulted in the highest methane production. The present study provides an easy approach to enhance food waste degradation in acidogenic phase and energy conversion in methanogenic phase simultaneously.

ACS Style

Liwen Luo; Guneet Kaur; Jun Zhao; Jun Zhou; Suyun Xu; Sunita Varjani; Jonathan W.C. Wong. Optimization of water replacement during leachate recirculation for two-phase food waste anaerobic digestion system with off-gas diversion. Bioresource Technology 2021, 335, 125234 .

AMA Style

Liwen Luo, Guneet Kaur, Jun Zhao, Jun Zhou, Suyun Xu, Sunita Varjani, Jonathan W.C. Wong. Optimization of water replacement during leachate recirculation for two-phase food waste anaerobic digestion system with off-gas diversion. Bioresource Technology. 2021; 335 ():125234.

Chicago/Turabian Style

Liwen Luo; Guneet Kaur; Jun Zhao; Jun Zhou; Suyun Xu; Sunita Varjani; Jonathan W.C. Wong. 2021. "Optimization of water replacement during leachate recirculation for two-phase food waste anaerobic digestion system with off-gas diversion." Bioresource Technology 335, no. : 125234.

Journal article
Published: 22 April 2021 in Journal of Environmental Management
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This work investigated the impact of the addition of different biochar types on mitigation of volatile fatty acid (VFA) accumulation, methane recovery and digestate quality in mesophilic food waste-sludge co-digestion. Four biochars derived from agricultural and sludge residues under different pyrolysis temperatures were compared. Specific biochar properties such as pH, surface area, chemical properties and presence of surface functional groups likely influenced biochar reactions during digestion, thereby resulting in a varying performance of different biochars. Miscanthus straw biochar addition led to the highest specific methane yield of 307 ± 0.3 mL CH4/g VSadded versus 241.87 ± 5.9 mL CH4/g VSadded from control with no biochar addition over 30 days of the co-digestion period. Biochar supplementation led to enhanced process stability which likely resulted from improved syntrophic VFA oxidation facilitated by specific biochar properties. Overall, a 21.4% increase in the overall methane production was obtained with biochar addition as compared to control. The resulting digestate quality was also investigated. Biochar-amended digester generated a digestate rich in macro- and micro-nutrients including K, Mg, Ca, Fe making biochar-amended digestate a potential replacement of agricultural lime fertilizer. This work demonstrated that the addition of specific biochars with desirable properties alleviated VFA accumulation and facilitated enhanced methane recovery, thereby providing a means to achieve process stability even under high organic loading conditions in co-digestions. Moreover, the availability of biochar-enriched digestate with superior characteristics than biochar-free digestate adds further merit to this process.

ACS Style

Davidraj Johnravindar; Jonathan W.C. Wong; Debkumar Chakraborty; Govardhan Bodedla; Guneet Kaur. Food waste and sewage sludge co-digestion amended with different biochars: VFA kinetics, methane yield and digestate quality assessment. Journal of Environmental Management 2021, 290, 112457 .

AMA Style

Davidraj Johnravindar, Jonathan W.C. Wong, Debkumar Chakraborty, Govardhan Bodedla, Guneet Kaur. Food waste and sewage sludge co-digestion amended with different biochars: VFA kinetics, methane yield and digestate quality assessment. Journal of Environmental Management. 2021; 290 ():112457.

Chicago/Turabian Style

Davidraj Johnravindar; Jonathan W.C. Wong; Debkumar Chakraborty; Govardhan Bodedla; Guneet Kaur. 2021. "Food waste and sewage sludge co-digestion amended with different biochars: VFA kinetics, methane yield and digestate quality assessment." Journal of Environmental Management 290, no. : 112457.

Journal article
Published: 08 April 2021 in Sustainable Chemistry
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The present work evaluates the techno-economic feasibility of a rhamnolipids production process that utilizes digestate from anaerobic digestion (AD) of food waste. Technical feasibility, profitability and extent of investment risks between fermenter scale and its operating strategy for rhamnolipids production was investigated in the present study. Three scenarios were generated and compared: production using a single large fermenter (Scenario I), using two small fermenters operated alternately (Scenario II) or simultaneously (Scenario III). It was found that all the scenarios were economically feasible, and Scenario III was the most profitable since it allowed the most optimum fermenter operation with utilization of multiple small-scale equipment to reduce the downtime of each equipment and increase the production capacity and overall productivity. It had the highest net present value, internal rate of return and shortest payback time at a discount rate of 7%. Finally, a sensitivity analysis was conducted to indicate how the variation in factors such as feedstock (digestate) cost, rhamnolipids selling price, extractant recyclability and process capacity influenced the process economics. The work provides important insights on techno-economic performance of a food waste digestate valorization process which would be useful to guide its sustainable scale-up.

ACS Style

Raffel Patria; Jonathan Wong; Davidraj Johnravindar; Kristiadi Uisan; Rajat Kumar; Guneet Kaur. Food Waste Digestate-Based Biorefinery Approach for Rhamnolipids Production: A Techno-Economic Analysis. Sustainable Chemistry 2021, 2, 237 -253.

AMA Style

Raffel Patria, Jonathan Wong, Davidraj Johnravindar, Kristiadi Uisan, Rajat Kumar, Guneet Kaur. Food Waste Digestate-Based Biorefinery Approach for Rhamnolipids Production: A Techno-Economic Analysis. Sustainable Chemistry. 2021; 2 (2):237-253.

Chicago/Turabian Style

Raffel Patria; Jonathan Wong; Davidraj Johnravindar; Kristiadi Uisan; Rajat Kumar; Guneet Kaur. 2021. "Food Waste Digestate-Based Biorefinery Approach for Rhamnolipids Production: A Techno-Economic Analysis." Sustainable Chemistry 2, no. 2: 237-253.

Review
Published: 24 March 2021 in Bioresource Technology
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Food waste digestate is a by-product of the anaerobic digestion of food waste. Presence of high ammonium nitrogen content significantly increase the nitrogen loss upon direct application on soil or by conventional composting. In this review, a comprehensive discussion regarding the effective management of food waste digestate is outlined, in which global food waste digestate production, characteristics, and composting are discussed. The nitrogen dynamics cycle considering high ammonium nitrogen content in the digestate is also evaluated, including ammonification, nitrification, denitrification, and other possible mechanisms based on the current literature. Mitigation strategies for reducing nitrogen loss via C/N ratio adjustment and the addition of physical, chemical, and microbial amendments were evaluated and estimated for 15 countries based on the available data on food waste anaerobic digestion plants. Reduced nitrogen loss and high quality compost could be produced from food waste digestate by adapting mitigation strategies.

ACS Style

M.K. Manu; Dongyi Li; Luo Liwen; Zhao Jun; Sunita Varjani; Jonathan W.C. Wong. A review on nitrogen dynamics and mitigation strategies of food waste digestate composting. Bioresource Technology 2021, 334, 125032 .

AMA Style

M.K. Manu, Dongyi Li, Luo Liwen, Zhao Jun, Sunita Varjani, Jonathan W.C. Wong. A review on nitrogen dynamics and mitigation strategies of food waste digestate composting. Bioresource Technology. 2021; 334 ():125032.

Chicago/Turabian Style

M.K. Manu; Dongyi Li; Luo Liwen; Zhao Jun; Sunita Varjani; Jonathan W.C. Wong. 2021. "A review on nitrogen dynamics and mitigation strategies of food waste digestate composting." Bioresource Technology 334, no. : 125032.

Review article
Published: 23 March 2021 in Bioresource Technology
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The advantages of anaerobic digestion (AD) technology in organic solid waste treatment for bioenergy recovery are evidenced in worldwide. Recently, more attention has been paid to on-site biogas research, as well as biogenic CO2 sequestration from AD plant, to promote “carbon neutral”. Single-phase and two-phase AD system can be incorporated with various CO2 bioconversion technologies through H2 mediated CO2 bioconversion (in-situ and ex-situ biogas upgrading), or other emerging strategies for CO2 fixation without exogenous H2 injection; these include in-situ direct interspecies electron transfer reinforcement, electromethanogenesis, and off-gas reutilization. The existing and potential scenarios for on-site CO2 bio-sequestration within the AD framework are reviewed from the perspectives of metabolic pathways, functional microorganisms, the limitations on reaction kinetics. This review concluded that on-site CO2 bio-sequestration is a promising solution to reduce greenhouse gas emissions and increase renewable energy recovery.

ACS Style

Suyun Xu; Zihao Qiao; Liwen Luo; Yongqi Sun; Jonathan Woon-Chung Wong; Xueyu Geng; Jing Ni. On-site CO2 bio-sequestration in anaerobic digestion: Current status and prospects. Bioresource Technology 2021, 332, 125037 .

AMA Style

Suyun Xu, Zihao Qiao, Liwen Luo, Yongqi Sun, Jonathan Woon-Chung Wong, Xueyu Geng, Jing Ni. On-site CO2 bio-sequestration in anaerobic digestion: Current status and prospects. Bioresource Technology. 2021; 332 ():125037.

Chicago/Turabian Style

Suyun Xu; Zihao Qiao; Liwen Luo; Yongqi Sun; Jonathan Woon-Chung Wong; Xueyu Geng; Jing Ni. 2021. "On-site CO2 bio-sequestration in anaerobic digestion: Current status and prospects." Bioresource Technology 332, no. : 125037.

Paper
Published: 05 February 2021 in Catalysis Science & Technology
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Band alignments of bulk-CN and S-CN and the photocatalytic reduction of CO2 for the production of CO.

ACS Style

Zhi Zhu; Zhixiang Liu; Xu Tang; Kumar Reeti; Pengwei Huo; Jonathan Woon-Chung Wong; Jun Zhao. Sulfur-doped g-C3N4 for efficient photocatalytic CO2 reduction: insights by experiment and first-principles calculations. Catalysis Science & Technology 2021, 11, 1725 -1736.

AMA Style

Zhi Zhu, Zhixiang Liu, Xu Tang, Kumar Reeti, Pengwei Huo, Jonathan Woon-Chung Wong, Jun Zhao. Sulfur-doped g-C3N4 for efficient photocatalytic CO2 reduction: insights by experiment and first-principles calculations. Catalysis Science & Technology. 2021; 11 (5):1725-1736.

Chicago/Turabian Style

Zhi Zhu; Zhixiang Liu; Xu Tang; Kumar Reeti; Pengwei Huo; Jonathan Woon-Chung Wong; Jun Zhao. 2021. "Sulfur-doped g-C3N4 for efficient photocatalytic CO2 reduction: insights by experiment and first-principles calculations." Catalysis Science & Technology 11, no. 5: 1725-1736.

Journal article
Published: 22 December 2020 in IEEE Access
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This paper presents the fabrication of novel flexible sensors from metalized polymer films and their subsequent utilization for environmental applications. Polyethylene terephthalate films coated with thin-film of aluminum was used as a singular material to form the sensor patches. Optimization was done on the laser parameters to form laser-inscribed interdigitated electrodes on the aluminum side of the polymer films. The sensors were then used to detect the presence of sulfate ions in the water samples. Electrochemical impedance spectroscopy was used to detect the resistive and reactive changes with respect to the corresponding changes in the concentration of the tested solutions. Experiments were conducted using five different concentrations ranging between 0.1 ppm and 1000 ppm. The sensitivity, limit of detection and response time of the salts were $0.874~\Omega $ /ppm, 0.1 ppm and one second, respectively. The repeatability of the sensors was also tested to validate their responses for the target analyte. An optimal frequency was chosen to form an IoT-based system that consisted of an impedance analyzer AD 5933, Wi-Fi embedded Arduino and 2:1 multiplexer ADG849. The interfacing of the microcontroller-sensed data was also done with the cloud server to showcase the potentiality of the developed systems as portable devices for real-time applications.

ACS Style

Shan He; Shilun Feng; Anindya Nag; Nasrin Afsarimanesh; Eshrat E Alahi; Siying Li; Subhas Chandra Mukhopadhyay; Jonathan Woon Chung Wong. IoT-Based Laser-Inscribed Sensors for Detection of Sulfate in Water Bodies. IEEE Access 2020, 8, 228879 -228890.

AMA Style

Shan He, Shilun Feng, Anindya Nag, Nasrin Afsarimanesh, Eshrat E Alahi, Siying Li, Subhas Chandra Mukhopadhyay, Jonathan Woon Chung Wong. IoT-Based Laser-Inscribed Sensors for Detection of Sulfate in Water Bodies. IEEE Access. 2020; 8 ():228879-228890.

Chicago/Turabian Style

Shan He; Shilun Feng; Anindya Nag; Nasrin Afsarimanesh; Eshrat E Alahi; Siying Li; Subhas Chandra Mukhopadhyay; Jonathan Woon Chung Wong. 2020. "IoT-Based Laser-Inscribed Sensors for Detection of Sulfate in Water Bodies." IEEE Access 8, no. : 228879-228890.

Review article
Published: 14 December 2020 in Bioresource Technology
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Management of food waste (FW) is a global challenge due to increasing population and economic activities. Presently, landfill and incineration are the keyways of FW management, while economical and environmental sustainability have been an issue. Therefore, the biological processes have been investigated for resource and energy recovery from FW. However, these biological approaches have certain drawbacks and cannot be a complete solution for FW management. Therefore, this review aims to offer a detailed and complete analysis of current available technologies to achieve environmental and economical sustainability. In this context, zero solid waste discharge for resource and energy recovery has been put into view. Corresponding to which several innovative technologies using integrated biological methods for resource and energy recovery from FW have been elucidated.

ACS Style

Anita Talan; Bhagyashree Tiwari; Bhoomika Yadav; R.D. Tyagi; J.W.C. Wong; P. Drogui. Food waste valorization: Energy production using novel integrated systems. Bioresource Technology 2020, 322, 124538 .

AMA Style

Anita Talan, Bhagyashree Tiwari, Bhoomika Yadav, R.D. Tyagi, J.W.C. Wong, P. Drogui. Food waste valorization: Energy production using novel integrated systems. Bioresource Technology. 2020; 322 ():124538.

Chicago/Turabian Style

Anita Talan; Bhagyashree Tiwari; Bhoomika Yadav; R.D. Tyagi; J.W.C. Wong; P. Drogui. 2020. "Food waste valorization: Energy production using novel integrated systems." Bioresource Technology 322, no. : 124538.

Journal article
Published: 17 July 2020 in Waste Management
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This study assessed the digester stability and overall methane production of co-digestion of sewage sludge (SS) and pig manure (PM). Four different ratios of PM were mixed with SS to reach different final concentrations of total solids (TS), i.e. 4%, 6%, 8% and 10%. Volatile solids (VS) reduction rate decreased along with an increase in TS%, and the maximum cumulative methane yield of 342 mL/g VSrem was obtained in treatment with TS of 6%. When TS was ≥ 8%, accumulation of volatile fatty acids (VFAs), free ammonium nitrogen (FAN) and total ammonium nitrogen (TAN) were observed. At a TS content of 10%, VFAs accumulated to > 20000 mg/L and the highest FAN was 481 mg/L. The suppression of methanogenesis was negatively correlated with FAN and VFA/TIC (P < 0.05). Co-digestion demonstrated to be an effective way to improve the methane yield from SS due to the enriched biodegradable organic substance and more balanced C/N ratio by incorporating PM.

ACS Style

Suyun Xu; Chongyang Wang; Yangyang Sun; Liwen Luo; Jonathan Woon-Chung Wong. Assessing the stability of co-digesting sewage sludge with pig manure under different mixing ratios. Waste Management 2020, 114, 299 -306.

AMA Style

Suyun Xu, Chongyang Wang, Yangyang Sun, Liwen Luo, Jonathan Woon-Chung Wong. Assessing the stability of co-digesting sewage sludge with pig manure under different mixing ratios. Waste Management. 2020; 114 ():299-306.

Chicago/Turabian Style

Suyun Xu; Chongyang Wang; Yangyang Sun; Liwen Luo; Jonathan Woon-Chung Wong. 2020. "Assessing the stability of co-digesting sewage sludge with pig manure under different mixing ratios." Waste Management 114, no. : 299-306.

Journal article
Published: 24 June 2020 in Bioresource Technology
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Four kinds of biochar were obtained by pyrolysis carbonization and hydrothermal carbonization from swine manure digestate, i.e. pyrochar (HC, HC-Fe) and hydrochar (HTC, HTC-Fe). Batch fermentation was conducted to compare their effects on the co-digestion of sewage sludge and swine manure. Both pyrochar and hydrochar present positive effect on methane production, nevertheless the higher methane yields were obtained in HTC and HTC-Fe digesters. No advantage was observed for the iron impregnation. The maximum methane yield was 308.4 mL/g VS in HTC digester, which was 27% and 49% higher than HC and Control, respectively. The surface functional groups of hydrochar are more abundant than pyrochar, which is favorable for promoting the syntrophic anaerobic metabolism, as revealed by the promoted substrate hydrolysis and VFAs consumption rate. Thus, it is proposed to convert swine manure digestate to hydrochar, which can be recirculated back to the AD reactor to increase the digestion efficiency.

ACS Style

Suyun Xu; Chongyang Wang; Yuting Duan; Jonathan Woon-Chung Wong. Impact of pyrochar and hydrochar derived from digestate on the co-digestion of sewage sludge and swine manure. Bioresource Technology 2020, 314, 123730 .

AMA Style

Suyun Xu, Chongyang Wang, Yuting Duan, Jonathan Woon-Chung Wong. Impact of pyrochar and hydrochar derived from digestate on the co-digestion of sewage sludge and swine manure. Bioresource Technology. 2020; 314 ():123730.

Chicago/Turabian Style

Suyun Xu; Chongyang Wang; Yuting Duan; Jonathan Woon-Chung Wong. 2020. "Impact of pyrochar and hydrochar derived from digestate on the co-digestion of sewage sludge and swine manure." Bioresource Technology 314, no. : 123730.

Journal article
Published: 26 March 2020 in Bioresource Technology
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This work investigated the effect of biochar addition to mitigate VFA accumulation and enhance methane production in mesophilic food waste/sludge co-digestion. Different types of biochar derived from agricultural and forestry residues at two pyrolysis temperatures were tested. Results showed that wheat straw biochar 550 °C supported the highest specific methane yield of 381.9 LCH4/kg VSadded and VS removal efficiency of 41.62% among all treatments. Degradation of propionic acid and long-chain fatty acids such as valeric, caproic and isovaleric acids was observed. This also corresponded to an increase in methanogenic favorable substrates including acetic acid (>40%) and butyric acid (~20%) over the control. Consequently, a 24% increase in overall methane production was obtained as compared to control. This demonstrated that biochar addition had positive effects on VFA degradation and methane production which could be a useful strategy to increase the organic loading in co-digestions without the fear of process failure.

ACS Style

Guneet Kaur; Davidraj Johnravindar; Jonathan W.C. Wong. Enhanced volatile fatty acid degradation and methane production efficiency by biochar addition in food waste-sludge co-digestion: A step towards increased organic loading efficiency in co-digestion. Bioresource Technology 2020, 308, 123250 .

AMA Style

Guneet Kaur, Davidraj Johnravindar, Jonathan W.C. Wong. Enhanced volatile fatty acid degradation and methane production efficiency by biochar addition in food waste-sludge co-digestion: A step towards increased organic loading efficiency in co-digestion. Bioresource Technology. 2020; 308 ():123250.

Chicago/Turabian Style

Guneet Kaur; Davidraj Johnravindar; Jonathan W.C. Wong. 2020. "Enhanced volatile fatty acid degradation and methane production efficiency by biochar addition in food waste-sludge co-digestion: A step towards increased organic loading efficiency in co-digestion." Bioresource Technology 308, no. : 123250.

Letters in applied microbiology
Published: 17 March 2020 in Letters in Applied Microbiology
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Indoor mould grows ubiquitously in humid areas and can affect occupants' health. To prevent indoor mould contamination, one of the key measures suggested by the World Health Organisation and United States Environmental Protection Agency is to maintain an indoor relative humidity (RH) level below 75% or at 30 - 60%, respectively. However, in tropical and subtropical areas, maintaining these suggested RH levels is equivalent to operating a 24-h air-conditioner (AC) or dehumidifier, which is energy-consuming. As a large part of building expense, the operation time of ACs has been regularly proposed to be cut down because of the requirement of building sustainability. This leads to a trade-off between sustainable building performance and indoor mould hygiene. To balance this trade-off, more sustainable alternatives such as those that target physical environments (e.g., nutrient and temperature level) or apply new surface coating technologies to inhibit mould growth, have been launched. Despite these initiatives, indoor mould contamination remains an unresolved issue, mainly because these alternative measures only exhibit limited effectiveness or require extra effort. This review aims to summarise the currently adopted mould control measures and discuss their limitations as well as the direction for the future development of sustainable mould control strategies.

ACS Style

Haoxiang Wu; Jonathan Woon Chung Wong. Current challenges for shaping the sustainable and mold‐free hygienic indoor environment in humid regions. Letters in Applied Microbiology 2020, 70, 396 -406.

AMA Style

Haoxiang Wu, Jonathan Woon Chung Wong. Current challenges for shaping the sustainable and mold‐free hygienic indoor environment in humid regions. Letters in Applied Microbiology. 2020; 70 (6):396-406.

Chicago/Turabian Style

Haoxiang Wu; Jonathan Woon Chung Wong. 2020. "Current challenges for shaping the sustainable and mold‐free hygienic indoor environment in humid regions." Letters in Applied Microbiology 70, no. 6: 396-406.

Journal article
Published: 07 January 2020 in Bioresource Technology
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In this study, the performance of UASB for treating food waste leachate was investigated, with the objective of studying the effect of conductive material on anaerobic digestion (AD) enhancement at two organic loads. Conductive and control materials (i.e. graphite and glass) were first compared for their surface porosity then dosed in UASB for side-by-side comparison of the corresponding AD performance. In the first phase (organic load of 2660 mg-COD/L), compared to glass-added UASB, 29.5% reduction of effluent COD was observed in graphite-added UASB, however, only a little biogas enhancement (2.3%) was achieved. In the second phase (organic load of 4140 mg-COD/L), the results show that it could promote better AD enhancement in graphite-added UASB, where 36% effluent COD and 38% biogas production enhancement were simultaneously observed. The overall results support that utilization of conductive material is a viable approach for enhancing biogas production in UASB, especially for high organic loads.

ACS Style

To-Hung Tsui; Hao Wu; Bing Song; Shuang-Shuang Liu; Anuja Bhardwaj; Jonathan W.C. Wong. Food waste leachate treatment using an Upflow Anaerobic Sludge Bed (UASB): Effect of conductive material dosage under low and high organic loads. Bioresource Technology 2020, 304, 122738 .

AMA Style

To-Hung Tsui, Hao Wu, Bing Song, Shuang-Shuang Liu, Anuja Bhardwaj, Jonathan W.C. Wong. Food waste leachate treatment using an Upflow Anaerobic Sludge Bed (UASB): Effect of conductive material dosage under low and high organic loads. Bioresource Technology. 2020; 304 ():122738.

Chicago/Turabian Style

To-Hung Tsui; Hao Wu; Bing Song; Shuang-Shuang Liu; Anuja Bhardwaj; Jonathan W.C. Wong. 2020. "Food waste leachate treatment using an Upflow Anaerobic Sludge Bed (UASB): Effect of conductive material dosage under low and high organic loads." Bioresource Technology 304, no. : 122738.

Journal article
Published: 11 November 2019 in Bioresource Technology
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Anaerobic hydrolysis of food wastes sourced from bakery (T1), Chinese restaurant (T2), western-style restaurant (T3), and wet market (T4) were performed in leach bed reactors under the scheme of acidogenic off-gas reuse in methanogenic reactor. Results showed that food waste in T3 achieved the highest hydrogen production of 61.0 L/kg·VSadded. Highest activity of hydrogenase in both leachate and digestate samples confirmed the superior performance of H2 production in T3. Mixed acid fermentation with domination of acetate and butyrate was observed in all four treatments, whereas variations in quantification and speciation of the acidogenic products were closely related to the composition of substrates. High volatile solids (VS) removal (76.7%) was observed in T3 while VS reduction rates of the other treatments ranged from 37 to 55%. High COD production of 0.65 gCOD /g·VSadded together with the reuse of elevated acidogenic off-gas ensured the highest specific CH4 production of 0.42 L/g·VSadded in T3.

ACS Style

Bing Hua Yan; Ammaiyappan Selvam; Jonathan W.C. Wong. Bio-hydrogen and methane production from two-phase anaerobic digestion of food waste under the scheme of acidogenic off-gas reuse. Bioresource Technology 2019, 297, 122400 .

AMA Style

Bing Hua Yan, Ammaiyappan Selvam, Jonathan W.C. Wong. Bio-hydrogen and methane production from two-phase anaerobic digestion of food waste under the scheme of acidogenic off-gas reuse. Bioresource Technology. 2019; 297 ():122400.

Chicago/Turabian Style

Bing Hua Yan; Ammaiyappan Selvam; Jonathan W.C. Wong. 2019. "Bio-hydrogen and methane production from two-phase anaerobic digestion of food waste under the scheme of acidogenic off-gas reuse." Bioresource Technology 297, no. : 122400.

Journal article
Published: 01 November 2019 in Bioresource Technology
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The aim of this study is to evaluate the effect of leachate recirculation at a ratio of 0%, 25%, 50% or 75% of collected leachate from the Leach Bed Reactor (LBR) on food waste digestion efficiency and its subsequent methane production in the second phase of a two-phase anaerobic system. Higher hydrolysis-acidogenesis efficiency and lower energy loss were achieved in LBR with higher leachate recirculation ratio. Better biochemical balance between metabolic products and microorganisms in leachate was revealed under 50% leachate recirculation ratio, which leads to the highest hydrogen production yield in LBR resulting the highest methane production yield in the corresponding methanogenic phase which was at least 15% higher than that in other conditions. This provides an easy approach to enhance the hydrolysis efficiency and in the same time a biochemical balanced leachate to enhance methanogenic reaction of a two-phase anaerobic digestion.

ACS Style

Liwen Luo; Jonathan W.C. Wong. Enhanced food waste degradation in integrated two-phase anaerobic digestion: Effect of leachate recirculation ratio. Bioresource Technology 2019, 291, 121813 .

AMA Style

Liwen Luo, Jonathan W.C. Wong. Enhanced food waste degradation in integrated two-phase anaerobic digestion: Effect of leachate recirculation ratio. Bioresource Technology. 2019; 291 ():121813.

Chicago/Turabian Style

Liwen Luo; Jonathan W.C. Wong. 2019. "Enhanced food waste degradation in integrated two-phase anaerobic digestion: Effect of leachate recirculation ratio." Bioresource Technology 291, no. : 121813.

Original article
Published: 16 October 2019 in Indoor Air
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Moisture is one of the critical abiotic factors that can affect mould growth. Indoor humidity is typically fluctuating, which renders a transient water supply for mould growth. Understanding mould growth under water dynamics and its underlying mechanisms can help in the development of novel and sustainable mould prevention strategies. In this study, pre‐germination and germinated spores of Cladosporium cladosporioides were exposed to daily wet–dry cycles with different combinations of wetting and drying duration. Afterwards, growth delay, cellular H2O2 concentration and catalase (CAT) activity were measured and compared. We found that under wet–dry cycles, the longer the growth delay was observed, the higher the cellular H2O2 concentration was detected, with the 12–12 wet–dry cycle (12‐h‐wet and 12‐h‐dry) showing the longest growth delay and highest cellular H2O2 production. A positive correlation between cellular H2O2 concentration and growth delay was suggested by Pearson correlation coefficient and linear regression analysis (p < 0.0001, R2 = 0.85). Furthermore, under wet–dry cycles, moulds derived from pre‐germination spores generally exhibited shorter growth delay, lower cellular H2O2 concentration and higher CAT activity than moulds developed from germinated spores. These results together suggest that the growth delay of C. cladosporioides under water dynamics is associated with oxidative stress.

ACS Style

Haoxiang Wu; Jonathan Woon Chung Wong. The role of oxidative stress in the growth of the indoor moldCladosporium cladosporioidesunder water dynamics. Indoor Air 2019, 30, 117 -125.

AMA Style

Haoxiang Wu, Jonathan Woon Chung Wong. The role of oxidative stress in the growth of the indoor moldCladosporium cladosporioidesunder water dynamics. Indoor Air. 2019; 30 (1):117-125.

Chicago/Turabian Style

Haoxiang Wu; Jonathan Woon Chung Wong. 2019. "The role of oxidative stress in the growth of the indoor moldCladosporium cladosporioidesunder water dynamics." Indoor Air 30, no. 1: 117-125.

Review
Published: 07 August 2019 in Waste Disposal & Sustainable Energy
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Municipal solid waste (MSW) management has emerged as probably the most pressing issue many governments nowadays are facing. Traditionally, Waste-to-Energy(WtE) is mostly associated with incineration, but now, with the emergence of the bioeconomy, it embraces a broader definition comprising any processing technique that can generate electricity/heat or produce a waste-derived fuel. Under the ambit of the circular economy many nations are looking for, additional effort must be made to be sure of acquiring the most updated information and paving a sustainable path for managing MSW in such a frame. In this regard, we have undertaken a critical review of various technologies, with their updated progress, involved in the exploitation of MSW as a renewable resource, along with the critical advantages and limitations on energy and material cycling for sustainable MSW management. Incineration, the most widely used method, is nowadays difficult to further apply due to its dubious reputation and social opposition. Meanwhile, to address the organic fraction of MSW which currently is mostly unrecycled and causes disposal issues, the biological approach presents an attractive option. The new emphasis of bioeconomy leads us to understand how environmental biotechnologies should be better connected/integrated for more sustainable MSW management. This article is concluded with advances of future prospects, which can serve as a timely reminder to encourage competent authorities/researchers to work towards further improvement of the present MSW management system.

ACS Style

To-Hung Tsui; Jonathan W. C. Wong. A critical review: emerging bioeconomy and waste-to-energy technologies for sustainable municipal solid waste management. Waste Disposal & Sustainable Energy 2019, 1, 151 -167.

AMA Style

To-Hung Tsui, Jonathan W. C. Wong. A critical review: emerging bioeconomy and waste-to-energy technologies for sustainable municipal solid waste management. Waste Disposal & Sustainable Energy. 2019; 1 (3):151-167.

Chicago/Turabian Style

To-Hung Tsui; Jonathan W. C. Wong. 2019. "A critical review: emerging bioeconomy and waste-to-energy technologies for sustainable municipal solid waste management." Waste Disposal & Sustainable Energy 1, no. 3: 151-167.

Journal article
Published: 25 June 2019 in Bioresource Technology
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This work proposes a new treatment approach involving both food waste disposal and sewerage treatment called MOWFAST i.e. Municipal Organic Waste management by combined Food wAste disposal and Sewerage Treatment. MOWFAST involves mixing of food waste directly with raw sewage instead of separate addition to sludge and their combined anaerobic digestion (AD). Compared to conventional sludge digestion, MOWFAST exhibited better digestion capability and allowed a greater degradation of organic material along with higher production of methanogenic-favourable products from the beginning of digestion. This resulted in producing higher specific methane yields (7.86 LCH4/kg VSadded versus 0.95 LCH4/kg VSadded) and 1.4-fold higher cumulative methane yield over sludge AD. Furthermore, compared with conventional food waste-sludge co-digestion, MOWFAST gave higher solubilization of organic material (0.82 g sCOD/g VSadded versus 0.23 g sCOD/g VSadded) and specific methane yields (7.86 LCH4/kg VSadded versus 3.2 LCH4/kg VSadded). This proves its feasibility for digestion and methane generation potential.

ACS Style

Guneet Kaur; Liwen Luo; Guanghao Chen; Jonathan W.C. Wong. Integrated food waste and sewage treatment – A better approach than conventional food waste-sludge co-digestion for higher energy recovery via anaerobic digestion. Bioresource Technology 2019, 289, 121698 .

AMA Style

Guneet Kaur, Liwen Luo, Guanghao Chen, Jonathan W.C. Wong. Integrated food waste and sewage treatment – A better approach than conventional food waste-sludge co-digestion for higher energy recovery via anaerobic digestion. Bioresource Technology. 2019; 289 ():121698.

Chicago/Turabian Style

Guneet Kaur; Liwen Luo; Guanghao Chen; Jonathan W.C. Wong. 2019. "Integrated food waste and sewage treatment – A better approach than conventional food waste-sludge co-digestion for higher energy recovery via anaerobic digestion." Bioresource Technology 289, no. : 121698.