Displaying publications 1 - 20 of 298 in total

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  1. Wan Ahmad WN, Rezaei J, Tavasszy LA, de Brito MP
    J Environ Manage, 2016 Sep 15;180:202-13.
    PMID: 27233046 DOI: 10.1016/j.jenvman.2016.04.056
    Our current dependency on the oil and gas (O&G) industry for economic development and social activities necessitates research into the sustainability of the industry's supply chains. At present, studies on sustainable supply chain management (SSCM) practices in the industry do not include firm-internal factors that affect the sustainability strategies employed by different functional areas of its supply chains. Our study aims to address this gap by identifying the relevant internal factors and exploring their relationship with SSCM strategies. Specifically, we discuss the commitment to and preparedness for sustainable practices of companies that operate in upstream and downstream O&G supply chain. We study the impact of these factors on their sustainability strategies of four key supply chain functions: supplier management, production management, product stewardship and logistics management. The analyses of data collected through a survey among 81 companies show that management preparedness may enhance sustainable supply chain strategies in the O&G industry more than commitment does. Among the preparedness measures, management of supply chain operational risks is found to be vital to the sustainability of all supply chain functions except for production management practices. The findings also highlight the central importance of supplier and logistics management to the achievement of sustainable O&G supply chains. Companies must also develop an organizational culture that encourages, for example, team collaboration and proactive behaviour to finding innovative sustainability solutions in order to translate commitment to sustainable practices into actions that can produce actual difference to their SSCM practices.
  2. Yew WL, Zhu Z
    J Environ Manage, 2019 Mar 15;234:28-35.
    PMID: 30599327 DOI: 10.1016/j.jenvman.2018.12.081
    Much of the environmental policy literature tends to focus on democratic contexts where environmental innovation is a product of pluralistic interactions among state and non-state actors. By bringing the (authoritarian) politics into the analysis, this article seeks to discover the processes leading to environmental innovation under nondemocratic conditions. We utilise case studies in China and then-nondemocratic Malaysia, both grappling with the twin imperatives of rapid development and social control, where the governments initiated environmental innovations to expand space for public participation and monitoring against noxious plants. We adapt the conceptual framework of "environmental innovation strategies" to illustrate the mechanisms underpinning innovative practices that address environmental issues by going beyond pre-existing public regulatory provisions. We highlight aspects distinguishing the interactive processes under authoritarianism. First, the drivers of environmental innovation are contingent on the government's role and concerns over social control and state legitimacy. Second, due to limits over political space, environmental nongovernmental organisations (ENGOs) act as issue entrepreneurs-instead of policy entrepreneurs-who turn conditions into problems deserving government attention and solution, as they engage in conflictual interactions with state authorities. Third, such innovations can strengthen nondemocratic governance while not fully plugging the gaps in existing environmental regulations. This contributes to illuminating the behaviours of state-based environmental innovators under illiberal political regimes, potentially offering lessons to activists on how to stimulate further innovations in such contexts.
  3. Li M, Badeeb RA, Dogan E, Gu X, Zhang H
    J Environ Manage, 2023 Dec 01;347:118994.
    PMID: 37722155 DOI: 10.1016/j.jenvman.2023.118994
    Global economies have recently been concerned about sustainable environmental management by reducing emissions and tackling ecological footprints. The rapid economic expansion and investment in traditional manufacturing further raises environmental degradation. China surpasses other emerging economies in the economic growth race yet has remained the top pollution-emitting economy for the last few decades, necessitating scholarly attention. This study examines the influencing factors of ecological footprints in China from the perspective of COP27. Using the extended dataset from 1988 to 2021, this study uses several time series diagnostic tests and verifies the existence of the long-run association between the study variables. Consequently, the non-linear scattered data leads to non-parametric (method of moment quantile regression) adoption. The empirical results indicate that only economic growth is a significant factor in environmental quality degradation in China. However, improving renewable energy usage, research and development, and foreign direct investment reduces the country's ecological footprint. Hence, the latter variables substantially lead to environmental sustainability. The robustness of the results is confirmed via a robust non-parametric estimator and causality test. Based on the empirical results, this study recommends increased investment in research and development, renewable production, and foreign direct investment enhancement.
  4. Pang WY, Ahmad AL, Zaulkiflee ND
    J Environ Manage, 2019 Nov 01;249:109358.
    PMID: 31450197 DOI: 10.1016/j.jenvman.2019.109358
    The aim of this study is to evaluate the performance and antifouling properties of polyethersulfone (PES) membrane incorporated with dual nanofiller, zinc oxide (ZnO) and multi-walled carbon nanotube (MWCNT). The synergistic effect of the these nanofillers in PES membrane is studied by blending different ratio of ZnO/MWCNT nanofiller into the PES membrane. The fabricated membranes were characterized in terms of cross-section and surface morphology, surface hydrophilicity, pore size and porosity. The filtration performance of the membranes was tested using 50 mg/L humic acid (HA) solution as model solution. SEM image and gravimetric evaluation reported that the incorporation of both MWCNT and ZnO into the PES membrane improved porosity significantly up to 46.02%. Lower water contact angle of PES membrane incorporated with equal ratio of MWCNT and ZnO (PES 3) revealed that it has neat PES membrane properties and more hydrophilic membrane surface than single filler. PES 3 outperform other membranes with excellent HA permeate flux of 40.00 L/m2.h and rejection of 88.51%. Due to hydrophilic membrane surface, PES 3 membrane demonstrate efficient antifouling properties with lower relative flux reduction (RFR) and higher flux recovery ratio (FRR). PES 3 also showed notable antibacterial properties with less bacterial attached to the membrane compared to neat PES membrane (PES 0).
  5. Kasan NA, Yusof SZM, Manan H, Khairul WM, Zakeri HA
    J Environ Manage, 2021 Sep 15;294:113008.
    PMID: 34119989 DOI: 10.1016/j.jenvman.2021.113008
    High nutrient loading in aquatic environment has become the main causative of harmful algae blooms (HABs) in water resources particularly pond, lake and river. HABs are mostly dominated by microalgae derived from the group of blue-green algae which are capable of releasing harmful toxins. Therefore, this study aims to investigate the inhibitory effects of thiourea derivatives on the growth of such blue-green algae. Thiourea derivatives have been proven to exhibit antifungal and antibacterial effects. However, there is still limited study had been conducted on the effect of thiourea derivatives toward blue-green algae species in recent years. In this research, a species of blue-green algae from Kenyir Lake, Terengganu, Malaysia was successfully isolated using morphological characters and molecularly identified as Synechoccus elongatus. Four new thiourea derivative compounds were also successfully synthesised. The compounds were designed with variation on different R-substitution group and characterised using Nuclear Magnetic Resonance (NMR) to confirm their molecular structure. Those compounds were characterised as 1-Benzyl-3-(3,5-dimethoxy-benzoyl)-thiourea (C1), 1-(3-Chloro-benzyl)-3-(3,5-dimethoxy-benzoyl)-thiourea (C2), 1-(3,5-Dimethoxy-benzoyl)-3-(3-methyl-benzyl)-thiourea (C3) and 1-(3,5-Dimethoxy-benzoyl)-3-(3-trifluoromethyl-benzyl)-thiourea (C4). For the inhibition assessment,S. elongatus were treated with C1-C4 for 5 day at concentration of 2, 5, 10 and 20 μg/ml, respectively. C3 compound showed the highest inhibition percentage with 98% of inhibition after 5 days treatment. By using Bradford method, protein extraction of S. elongatus was conducted at the highest inhibition percentage. Protein concentration of treated species was observed with 3.28 μg/ml as compared to protein concentration of control with 6.48 μg/ml. This result indicated the reduction of protein content after the treatment. Protein band pattern was identified intensed after the treatment SDS PAGE was carried out. The thiourea derivatives compound proved to have successfully inhibited the growth of blue-green algae. Hence, further study should be carried out to ensure the compound can be practically utilized in the pond and in natural environment.
  6. Mojiri A, Aziz HA, Zaman NQ, Aziz SQ, Zahed MA
    J Environ Manage, 2014 Jun 15;139:1-14.
    PMID: 24662109 DOI: 10.1016/j.jenvman.2014.02.017
    Sequencing batch reactor (SBR) is one of the various methods of biological treatments used for treating wastewater and landfill leachate. This study investigated the treatment of landfill leachate and domestic wastewater by adding a new adsorbent (powdered ZELIAC; PZ) to the SBR technique. ZELIAC consists of zeolite, activated carbon, lime stone, rice husk ash, and Portland cement. The response surface methodology and central composite design were used to elucidate the nature of the response surface in the experimental design and describe the optimum conditions of the independent variables, including aeration rate (L/min), contact time (h), and ratio of leachate to wastewater mixture (%; v/v), as well as their responses (dependent variables). Appropriate conditions of operating variables were also optimized to predict the best value of responses. To perform an adequate analysis of the aerobic process, four dependent parameters, namely, chemical oxygen demand (COD), color, ammonia-nitrogen (NH3-N), and phenols, were measured as responses. The results indicated that the PZ-SBR showed higher performance in removing certain pollutants compared with SBR. Given the optimal conditions of aeration rate (1.74 L/min), leachate to wastewater ratio (20%), and contact time (10.31 h) for the PZ-SBR, the removal efficiencies for color, NH3-N, COD, and phenols were 84.11%, 99.01%, 72.84%, and 61.32%, respectively.
  7. Sreenath S, Sudhakar K, Yusop AF
    J Environ Manage, 2021 Dec 01;299:113639.
    PMID: 34479146 DOI: 10.1016/j.jenvman.2021.113639
    Sustainability has become a focus area for practitioners and scholars due to the growing socio-economic issues. The sustainability of airport operations is being raised in various international platforms. This paper aims to identify the dimensions of sustainability and evaluate sustainable practices in airports of selected ASEAN countries. The various dimensions associated with the environmental aspect are energy management, emissions management, water and effluents management, solid waste management. It was understood that noise management, employee development, and community investment belong to the social dimension. Similarly, the factors such as economic contribution, passenger experience, airport safety, and security are inclined to economic dimensions of sustainability. It was found that environmentally sustainable practices have greater importance than social and economic initiatives in the airport context which provide quantifiable benefits for airports in the long term. Airport operators in South East Asia strived to mitigate carbon emissions, reduce waste and effluents, enhance the economic contribution, satisfy passengers, and meet employee needs. Compared to the total economic and social benefits obtained from these airports, the negative impacts of airport operation (such as noise emission from aircraft) are minimal but significant. The most common sustainable initiatives in airports, such as employee development, energy management, and passenger safety, supported sustainable development goals (SDG) 8, SDG 9, and SDG 11. A weak connection is observed between SDG 14 & SDG 15 and the airport's sustainable practices. The new technological innovations are concentrated in busy and profitable airports. A slow trend towards the adoption of new technologies for sustainable practices is observed in airports. The paper concludes that major airport operators in South-East Asia have effectively responded to the growing sustainability challenges in aviation markets. The sustainable dimensions and practices discussed will be valuable resource for airports striving to achieve sustainability goals.
  8. Bilad MR, Azizo AS, Wirzal MDH, Jia Jia L, Putra ZA, Nordin NAHM, et al.
    J Environ Manage, 2018 Oct 01;223:23-28.
    PMID: 29885561 DOI: 10.1016/j.jenvman.2018.06.007
    Microalgae technology, if managed properly, has promising roles in solving food-water-energy nexus. The Achilles' heel is, however, to lower the costs associated with cultivation and harvesting. As a favorable technique, application of membrane process is strongly limited by membrane fouling. This study evaluates performance of nylon 6,6 nanofiber membrane (NFM) to a conventional polyvinylidene fluoride phase inverted membrane (PVDF PIM) for filtration of Chlorella vulgaris. Results show that nylon 6,6 NFM is superhydrophilic, has higher size of pore opening (0.22 vs 0.18 μm) and higher surface pore density (23 vs 18 pores/μm2) leading to higher permeance (1018 vs 493 L/m2hbar) and better fouling resistant. Such advantages help to outperform the filterability of PVDF PIM by showing much higher steady-state permeance (286 vs 120 L/m2hbar), with comparable biomass retention. In addition, unlike for PVDF PIM, imposing longer relaxation cycles further enhances the performance of the NFM (i.e., 178 L/m2hbar for 0.5 min and 236 L/m2hbar for 5 min). Overall findings confirm the advantages of nylon 6,6 NFM over the PVDF PIM. Such advantages can help to reduce required membrane area and specific aeration demand by enabling higher flux and lowering aeration rate. Nevertheless, developments of nylon 6,6 NFM material with respect to its intrinsic properties, mechanical strength and operational conditions of the panel can still be explored to enhance its competitiveness as a promising fouling resistant membrane material for microalgae filtration.
  9. Hoo PY, Hashim H, Ho WS, Yunus NA
    J Environ Manage, 2019 Jul 01;241:603-611.
    PMID: 30616893 DOI: 10.1016/j.jenvman.2018.11.092
    Energy is widely used in industry for heating and cooling, with natural gas (NG) being the largest primary energy source in Malaysia, closely followed by coal. Renewable energy, such as biogas upgrading to biomethane, could cut the use of fossil fuels by supplementing NG usage due to their similar physicochemical and thermochemical characteristics. Biogas production plants in Malaysia are more commonly seen in waste-to-energy scenarios, with the technology anaerobic digestion, and their deployment is supported via feed-in tariffs (FiT) for power generation. Other potential applications such as the conversion of biogas into biomethane, injection into the natural gas grid or transportation through a virtual pipeline may still need further technical development. This paper presents spatial techno economic optimisation modelling using BeWhere to determine decentralised biomethane production plants using feedstock from multiple sources of biogas, including palm oil mill effluent (POME), food waste, cattle manure and chicken manure. This model considered potential configurations and sizes of the biomethane plants, the transportation of biomethane using a virtual pipeline (at 250 psig) and demand in one of the states in Malaysia, namely Johor. It was found that two to four biomethane plants with capacities ranging between 125 and 700 m3/h were located in densely populated areas or heavier industrial consumers when the carbon tax was implemented at 167.71 EUR/tCO2 (800 MYR/tCO2). Sensitivity analysis suggested that biomethane production increases with the increasing country renewable energy share target to beyond 2080 MW. It is recommended that specific policy regulations and Feed-in Tariff (FiT) mechanisms are used to expand the biomethane market share in the country.
  10. Chen SH, Yien Ting AS
    J Environ Manage, 2015 Mar 01;150:274-280.
    PMID: 25527986 DOI: 10.1016/j.jenvman.2014.09.014
    Triphenylmethane dyes (TPM) are recalcitrant colorants brought into the environment. In this study, a lesser-known white rot fungus Coriolopsis sp. (1c3), isolated from compost of Empty Fruit Bunch (EFB) of oil palm, was explored for its decolorization potential of TPM dyes. The isolate 1c3 demonstrated good decolorization efficiencies in the treatment of Crystal Violet (CV; 100 mg l(-1)), Methyl Violet (MV; 100 mg l(-1)) and Cotton Blue (CB; 50 mg(-1)), with 94%, 97% and 91%, within 7, 7 and 1 day(s), respectively. Malachite Green (MG; 100 mg l(-1)) was the most recalcitrant dye, with 52% decolorization after 9 days. Dye removal by 1c3 was presumably via biosorption, whereby the process was determined to be influenced by fungal biomass, initial dye concentrations and oxygen requirements. Biodegradation was also a likely mechanism responsible for dye removal by 1c3, occurred as indicated by the reduction of dye spectra peaks. Detection of laccase, lignin peroxidase and NADH-DCIP reductase activities further substantiate the possible occurrence of biodegradation of TPM dyes by 1c3.
  11. Ooi CH, Cheah WK, Sim YL, Pung SY, Yeoh FY
    J Environ Manage, 2017 Jul 15;197:199-205.
    PMID: 28384613 DOI: 10.1016/j.jenvman.2017.03.083
    Urea removal is an important process in household wastewater purification and hemodialysis treatment. The efficiency of the urea removal can be improved by utilizing activated carbon fiber (ACF) for effective urea adsorption. In this study, ACF was prepared from oil palm empty fruit bunch (EFB) fiber via physicochemical activation using sulfuric acid as an activating reagent. Based on the FESEM result, ACF obtained after the carbonization and activation processes demonstrated uniform macropores with thick channel wall. ACF was found better prepared in 1.5:1 acid-to-EFB fiber ratio; where the pore size of ACF was analyzed as 1.2 nm in diameter with a predominant micropore volume of 0.39 cm(3) g(-1) and a BET surface area of 869 m(2) g(-1). The reaction kinetics of urea adsorption by the ACF was found to follow a pseudo-second order kinetic model. The equilibrium amount of urea adsorbed on ACF decreased from 877.907 to 134.098 mg g(-1) as the acid-to-fiber ratio increased from 0.75 to 4. During the adsorption process, the hydroxyl (OH) groups on ACF surface were ionized and became electronegatively charged due to the weak alkalinity of urea solution, causing ionic repulsion towards partially anionic urea. The ionic repulsion force between the electronegatively charged ACF surface and urea molecules became stronger when more OH functional groups appeared on ACF prepared at higher acid impregnation ratio. The results implied that EFB fiber based ACF can be used as an efficient adsorbent for the urea removal process.
  12. Bello MO, Solarin SA, Yen YY
    J Environ Manage, 2018 Aug 01;219:218-230.
    PMID: 29747103 DOI: 10.1016/j.jenvman.2018.04.101
    The primary objective of this paper is to investigate the isolated impacts of hydroelectricity consumption on the environment in Malaysia as an emerging economy. We use four different measures of environmental degradation including ecological footprint, carbon footprint, water footprint and CO2 emission as target variables, while controlling for GDP, GDP square and urbanization for the period 1971 to 2016. A recently introduced unit root test with breaks is utilized to examine the stationarity of the series and the bounds testing approach to cointegration is used to probe the long run relationships between the variables. VECM Granger causality technique is employed to examine the long-run causal dynamics between the variables. Sensitivity analysis is conducted by further including fossil fuels in the equations. The results show evidence of an inverted U-shaped relationship between environmental degradation and real GDP. Hydroelectricity is found to significantly reduce environmental degradation while urbanization is also not particularly harmful on the environment apart from its effect on air pollution. The VECM Granger causality results show evidence of unidirectional causality running from hydroelectricity and fossil fuels consumption to all measures of environmental degradation and real GDP per capita. There is evidence of feedback hypothesis between real GDP to all environmental degradation indices. The inclusion of fossil fuel did not change the behavior of hydroelectricity on the environment but fossil fuels significantly increase water footprint.
  13. Hassan S, Duclaux L, Lévêque JM, Reinert L, Farooq A, Yasin T
    J Environ Manage, 2014 Nov 1;144:108-17.
    PMID: 24929502 DOI: 10.1016/j.jenvman.2014.05.005
    The adsorption from aqueous solution of imidazolium, pyrrolidinium and pyridinium based bromide ionic liquids (ILs) having different alkyl chain lengths was investigated on two types of microporous activated carbons: a fabric and a granulated one, well characterized in terms of surface chemistry by "Boehm" titrations and pH of point of zero charge measurements and of porosity by N2 adsorption at 77 K and CO2 adsorption at 273 K. The influence of cation type, alkyl chain length and adsorbate size on the adsorption properties was analyzed by studying kinetics and isotherms of eight different ILs using conductivity measurements. Equilibrium studies were carried out at different temperatures in the range [25-55 °C]. The incorporation of ILs on the AC porosity was studied by N2 adsorption-desorption measurements at 77 K. The experimental adsorption isotherms data showed a good correlation with the Langmuir model. Thermodynamic studies indicated that the adsorption of ILs onto activated carbons was an exothermic process, and that the removal efficiency increased with increase in alkyl chain length, due to the increase in hydrophobicity of long chain ILs cations determined with the evolution of the calculated octanol-water constant (Kow). The negative values of free energies indicated that adsorption of ILs with long chain lengths having hydrophobic cations was more spontaneous at the investigated temperatures.
  14. Jamei M, Ahmadianfar I, Karbasi M, Jawad AH, Farooque AA, Yaseen ZM
    J Environ Manage, 2021 Dec 15;300:113774.
    PMID: 34560461 DOI: 10.1016/j.jenvman.2021.113774
    The concentration of soluble salts in surface water and rivers such as sodium, sulfate, chloride, magnesium ions, etc., plays an important role in the water salinity. Therefore, accurate determination of the distribution pattern of these ions can improve better management of drinking water resources and human health. The main goal of this research is to establish two novel wavelet-complementary intelligence paradigms so-called wavelet least square support vector machine coupled with improved simulated annealing (W-LSSVM-ISA) and the wavelet extended Kalman filter integrated with artificial neural network (W-EKF- ANN) for accurate forecasting of the monthly), magnesium (Mg+2), and sulfate (SO4-2) indices at Maroon River, in Southwest of Iran. The monthly River flow (Q), electrical conductivity (EC), Mg+2, and SO4-2 data recorded at Tange-Takab station for the period 1980-2016. Some preprocessing procedures consisting of specifying the number of lag times and decomposition of the existing original signals into multi-resolution sub-series using three mother wavelets were performed to develop predictive models. In addition, the best subset regression analysis was designed to separately assess the best selective combinations for Mg+2 and SO4-2. The statistical metrics and authoritative validation approaches showed that both complementary paradigms yielded promising accuracy compared with standalone artificial intelligence (AI) models. Furthermore, the results demonstrated that W-LSSVM-ISA-C1 (correlation coefficient (R) = 0.9521, root mean square error (RMSE) = 0.2637 mg/l, and Kling-Gupta efficiency (KGE) = 0.9361) and W-LSSVM-ISA-C4 (R = 0.9673, RMSE = 0.5534 mg/l and KGE = 0.9437), using Dmey mother that outperformed the W-EKF-ANN for predicting Mg+2 and SO4-2, respectively.
  15. Bhagat SK, Tiyasha T, Kumar A, Malik T, Jawad AH, Khedher KM, et al.
    J Environ Manage, 2022 Feb 16;309:114711.
    PMID: 35182982 DOI: 10.1016/j.jenvman.2022.114711
    Heavy metals (HMs) such as Lead (Pb) have played a vital role in increasing the sediments of the Australian bay's ecosystem. Several meteorological parameters (i.e., minimum, maximum and average temperature (Tmin, Tmax and TavgoC), rainfall (Rn mm) and their interactions with the other batch HMs, are hypothesized to have high impact for the decision-making strategies to minimize the impacts of Pb. Three feature selection (FS) algorithms namely the Boruta method, genetic algorithm (GA) and extreme gradient boosting (XGBoost) were investigated to select the highly important predictors for Pb concentration in the coastal bay sediments of Australia. These FS algorithms were statistically evaluated using principal component analysis (PCA) Biplot along with the correlation metrics describing the statistical characteristics that exist in the input and output parameter space of the models. To ensure a high accuracy attained by the applied predictive artificial intelligence (AI) models i.e., XGBoost, support vector machine (SVM) and random forest (RF), an auto-hyper-parameter tuning process using a Grid-search approach was also implemented. Cu, Ni, Ce, and Fe were selected by all the three applied FS algorithms whereas the Tavg and Rn inputs remained the essential parameters identified by GA and Boruta. The order of the FS outcome was XGBoost > GA > Boruta based on the applied statistical examination and the PCA Biplot results and the order of applied AI predictive models was XGBoost-SVM > GA-SVM > Boruta-SVM, where the SVM model remained at the top performance among the other statistical metrics. Based on the Taylor diagram for model evaluation, the RF model was reflected only marginally different so overall, the proposed integrative AI model provided an evidence a robust and reliable predictive technique used for coastal sediment Pb prediction.
  16. Sinha A, Mishra S, Sharif A, Yarovaya L
    J Environ Manage, 2021 Aug 15;292:112751.
    PMID: 33991831 DOI: 10.1016/j.jenvman.2021.112751
    Striving to achieve the Sustainable Development Goals (SDGs), countries are increasingly embracing a sustainable financing mechanism via green bond financing. Green bonds have attracted the attention of the industrial sector and policymakers, however, the impact of green bond financing on environmental and social sustainability has not been confirmed. There is no empirical evidence on how this financial product can contribute to achieving the goals set out in Agenda 2030. In this study, we empirically analyze the impact of green bond financing on environmental and social sustainability by considering the S&P 500 Global Green Bond Index and S&P 500 Environmental and Social Responsibility Index, from October 1, 2010 to 31st July 2020 using a combination of Quantile-on-Quantile Regression and Wavelet Multiscale Decomposition approaches. Our results reveal that green financing mechanisms might have gradual negative transformational impacts on environmental and social responsibility. Furthermore, we attempt to design a policy framework to address the relevant SDG objectives.
  17. Yang S, Tan ML, Song Q, He J, Yao N, Li X, et al.
    J Environ Manage, 2023 Mar 15;330:117244.
    PMID: 36621311 DOI: 10.1016/j.jenvman.2023.117244
    Global climate change has led to an increase in both the frequency and magnitude of extreme events around the world, the risk of which is especially imminent in tropical regions. Developing hydrological models with better capabilities to simulate streamflow, especially peak flow, is urgently needed to facilitate water resource planning and management as well as climate change mitigation efforts in the tropics. In view of the need, this paper explores the feasibility of improving streamflow simulation performance in the tropical Kelantan River Basin (KRB) of Peninsular Malaysia through coupling a conceptual process-based hydrological model - Soil and Water Assessment Tool (SWAT) with a deep learning model - Bidirectional Long Short-Term Memory (Bi-LSTM) in two ways. All SWAT parameters were set as their default values in one hybrid model (SWAT-D-LSTM), whereas three most sensitive SWAT parameters were calibrated in the other hybrid model (SWAT-T-LSTM). Comparison of daily streamflow simulation results have shown that SWAT-T-LSTM consistently performs better than SWAT-D-LSTM as well as the stand-alone SWAT and Bi-LSTM model throughout the simulation period. Particularly, SWAT-T-LSTM performs considerably better than the other three models in simulating daily peak flow. Based on the latest projection results of five GCMs from the Sixth Phase of the Coupled Model Intercomparison Project (CMIP6) under three emission scenarios (SSP1-2.6, SSP2-4.5, SSP5-8.5), the best-performed SWAT-T-LSTM was run to assess the potential impacts of climate change on streamflow in the KRB. Ensemble assessment results have concluded that both average and extreme streamflow is much likely to increase considerably in the already wet northeast monsoon season from November to January, which has surely raised the alarm for more frequent flood occurrence in the KRB.
  18. Hantoko D, Li X, Pariatamby A, Yoshikawa K, Horttanainen M, Yan M
    J Environ Manage, 2021 May 15;286:112140.
    PMID: 33652254 DOI: 10.1016/j.jenvman.2021.112140
    The COVID-19 pandemic has imposed a global emergency and also has raised issues with waste management practices. This study emphasized the challenges of increased waste disposal during the COVID-19 crisis and its response practices. Data obtained from the scientific research papers, publications from the governments and multilateral organizations, and media reports were used to quantify the effect of the pandemic towards waste generation. A huge increase in the amount of used personal protective equipments (facemasks, gloves, and other protective stuffs) and wide distribution of infectious wastes from hospitals, health care facilities, and quarantined households was found. The amount of food and plastic waste also increased during the pandemic. These factors caused waste treatment facilities to be overwhelmed, forcing emergency treatment and disposals (e.g., co-disposal in a municipal solid waste incinerator, cement kilns, industrial furnaces, and deep burial) to ramp up processing capacity. This paper discussed the ways the operation of those facilities must be improved to cope with the challenge of handling medical waste, as well as working around the restrictions imposed due to COVID-19. The study also highlights the need for short, mid, and longer-term responses towards waste management during the pandemic. Furthermore, the practices discussed in this paper may provide an option for alternative approaches and development of sustainable strategies for mitigating similar pandemics in the future.
  19. Loow YL, Wu TY
    J Environ Manage, 2018 Jun 15;216:192-203.
    PMID: 28545947 DOI: 10.1016/j.jenvman.2017.04.084
    Among the chemical pretreatments available for pretreating biomass, the inorganic salt is considered to be a relatively new but simple reagent that offers comparable pentose (C5) sugar recoveries as the conventional dilute acid hydrolysis. This study investigated the effects of different concentrations (1.5-6.0% (v/v)) of H2O2 or Na2S2O8 in facilitating CuSO4·5H2O pretreatment for improving pentose sugar recovery from oil palm fronds. The best result was observed when 0.2 mol/L of CuSO4·5H2O was integrated with 4.5% (v/v) of Na2S2O8 to recover 8.2 and 0.9 g/L of monomeric xylose and arabinose, respectively in the liquid fraction. On the other hand, an addition of 1.5% (v/v) of H2O2 yielded approximately 74% lesser total pentose sugars as compared to using 4.5% (v/v) Na2S2O8. By using CuSO4·5H2O alone (control), only 0.8 and 1.0 g/L xylose and arabinose, respectively could be achieved. The results mirrored the importance of using chemical additives together with the inorganic salt pretreatment of oil palm fronds. Thus, an addition of 4.5% (v/v) of Na2S2O8 during CuSO4·5H2O pretreatment of oil palm fronds at 120 °C and 30 min was able to attain a total pentose sugar yield up to ∼40%.
  20. New EK, Tnah SK, Voon KS, Yong KJ, Procentese A, Yee Shak KP, et al.
    J Environ Manage, 2022 Apr 01;307:114385.
    PMID: 35104699 DOI: 10.1016/j.jenvman.2021.114385
    The high dependence on crude oil for energy utilization leads to a necessity of finding alternative sustainable resources. Solvents are often employed in valorizing the biomass into bioproducts and other value-added chemicals during treatment stages. Unfortunately, despite the effectiveness of conventional solvents, hindrances such as expensive solvents, unfavourable environmental ramifications, and complicated downstream separation systems often occur. Therefore, the scientific community has been actively investigating more cost-effective, environmentally friendly alternatives and possess the excellent dissolving capability for biomass processing. Generally, 'green' solvents are attractive due to their low toxicity, economic value, and biodegradability. Nonetheless, green solvents are not without disadvantages due to their complicated product recovery, recyclability, and high operational cost. This review summarizes and evaluates the recent contributions, including potential advantages, challenges, and drawbacks of green solvents, namely ionic liquids, deep eutectic solvents, water, biomass-derived solvents and carbon dioxide in transforming the lignocellulosic biomass into high-value products. Moreover, research opportunities for future developments and potential upscale implementation of green solvents are also critically discussed.
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