Clean technologies and policies for sustainable development in Asia

Barrier properties of cellulose nanofiber film as an external layer of particleboard Abstract The use of formaldehyde-based adhesives in the wood-based composite industry represents a healthcare concern due to its toxic volatile compounds. For this reason, this work presents the use of a formaldehyde barrier layer based on cellulose nanofibers (CNF) obtained from Manila hemp (Musa textilis) fibers. The elaborated CNF films were firstly evaluated in their mechanical properties, gas transmittance, and surface free energy. Commercially available particleboards were produced with urea–formaldehyde resin and then covered in their external faces by CNF films, and the results were compared to those of an industrial-type laminate. These multilayered composites were evaluated in their morphology, surface free energy, and emission of free formaldehyde. Results showed that the addition of CNF layers reduced significantly the emission of formaldehyde (26% less). The bio-based nature of cellulose nanofibers provides an environmentally friendly barrier to prevent the emissions of volatile organic compounds from industrially available particleboards. Graphic abstract

Environmental sustainability practices among palm oil millers Abstract Considering the global palm oil production, it can be identified as the second largest vegetable oil. Palm oil is a natural resource that is favorable for the Malaysian climate. In 2017, Malaysia had a total of 454 palm oil mills with a production capacity of approximately 112 million tonnes of fresh fruit bunches. A sustainable environment denotes high income, value addition and zero waste. Nonetheless, palm oil mills are being associated with the discharge of untreated effluent water stream pollution, solid wastes, air pollution, etc. The important objective of this study is to measure the level of sustainable environmental practices parameters and awareness of millers. The primary data were collected through questionnaire survey and interviews from 71 millers in Malaysia. This study used confirmatory factor analysis to describe the relationships between the environmental parameters for measuring environment sustainability. This study found that most of the millers employ positive practices for environmental sustainability, and the highest environment parameter is disposal of solid wastes. However, this study can be implemented in Malaysian palm oil mills for identifying the lowest parameters. This study suggested to the industries that the new national sustainable policies for palm oil mills, especially for small and medium players, may enhance the environmental parameters.

Wastewater treatment by microbial fuel cell coupled with peroxicoagulation process Abstract A microbial fuel cell is a rapidly growing, eco-friendly and green technology. As per this technology, the microorganisms are employed to convert the chemical energy stored in the biodegradable portion of organic matter into direct electric current by simultaneously treating the wastewater. In this study, dual-chambered H-type mediator-less and membrane-less microbial fuel cell was operated and was optimized using synthetic wastewater as a substrate. The influence of various factors such as cathodic electron acceptors, electrode configuration, electrode spacing on chemical oxygen demand removal and current output were investigated. The maximum current of 1.72 mA was obtained using synthetic wastewater with potassium permanganate as effective catholyte, electrode spacing of 2 cm from the salt bridge and surface area of 98 cm2. This study also investigated the effect of substrate in the optimized MFC by applying different real wastewaters (municipal wastewater, dairy wastewater, cassava wastewater) and found a superior performance by dairy wastewater with maximum current output of 5.23 mA and chemical oxygen demand removal of 94%. Electron microscopic observations revealed the development of biofilm on the electrode surface, which was responsible for biocatalytic activity in the microbial fuel cell during the operation. The current generated using microbial fuel cell was supplied to peroxicoagulation process and was used for the removal of rhodamine B dye. Decolorization of 98% achieved by the novel microbial fuel cell-coupled peroxicoagulation system. The novel microbial fuel cell-coupled peroxicoagulation is an energy-efficient as well as cost-effective technique. Graphic abstract

Carbon Emission Pinch Analysis: an application to the transportation sector in Iskandar Malaysia for 2025 Abstract The energy sector has grown significantly over the years, causing an increase in carbon emission that has led to serious global warming problems. Consequently, electric vehicles (EVs) have become a favourable solution in the transportation sector due to their green technology attributes. This paper aims to apply the Carbon Emission Pinch Analysis (CEPA) method to the transportation sector in Iskandar Malaysia. The modified CEPA method is applied by constructing a composite curve for transportation modes and the total carbon emission was plotted in order to study the minimum electricity requirement that needs to be generated to implement the use of EVs. Road and rail transportation were considered in the transport composite curve based on the current policies available and to achieve the new carbon emission target by the year 2025. The alternatives available to reduce carbon emission in Iskandar Malaysia include increasing public transport modal share; fuel switching from petrol and diesel to natural gas and biofuels; and increasing transport efficiency via plug-in hybrid and EVs. Four scenarios were established and evaluated based on economic and environmental aspects. As a result, Scenario 4 which considered all policies available (transport management, fuel switching and fuel efficiency) have showed the most promising fuel mix for future transportation demands. An estimated total amount of 0.25 TJ of electricity is needed for EV implementation with a total estimated cost of RM 1.3 billion. The total carbon emission for this scenario is 1101.96 kt-CO2. This research can benefit the Government, town planners, or policy makers, for preliminary energy planning.

Utilization of paper waste as growing media for potted ornamental plants Abstract The paper industry generates significant quantities of waste. The recycling of paper waste (PW) for peat replacement in growing media for ornamental plants cultivation was studied. Five ratios of PW–peat (0%, 10%, 30%, 50% or 100% v/v) were evaluated for marigold (Calendula officinalis L.), petunia (Petunia × hybrita L.) and matthiola (Matthiola incana L.) plants. Addition of PW increased the substrate pH and mineral content but decreased the air-filled porosity. In marigold, the use of 100% PW reduced plant height, plant diameter, fresh weight for both leaves and flowers and the total number of flowers produced compared to the control (100% peat). In matthiola, 100% PW reduced plant height, whereas the addition of PW even at 10% decreased plant diameter and fresh weight (biomass) but increased dry matter content. Petunia plants grown in 100% PW exhibited lower growth (plant height and diameter), whereas adding ≥ 50% of PW decreased plant fresh weight. The total number of flower buds and open flowers increased (more than twofold) on plants grown in 30% PW compared to the control substrate, indicating flower earliness. Plant leaf chlorophyll content (Chl a, Chl b, total Chl) decreased as the PW ratio increased. Total phenolics and antioxidant capacity as well as plant damage index and enzymes scavenging activities varied among species. Mineral content fluctuated among species with decreases of N and P in plants grown in PW mixtures while matthiola showed phytotoxicity symptoms. The present study suggests that peat can be substituted by up to 30% of PW for marigold and petunia for potting culture, but not for matthiola, as the physicochemical properties of the substrate need further improvement. Graphical abstract

Synthesis of new materials based on metallurgical slags as a contribution to the circular economy Abstract This work is aimed at developing knowledge about the possibilities of a circular economy arising from the processing of metallurgical slag, which in a number of indicators is close to natural formations. The possibility of manufacturing ceramic catalyst carriers from natural raw materials and industrial waste (metallurgical slags) using powder metallurgy is considered. Properties of metallurgical slags are studied by X-ray diffraction analysis, methods of simultaneous thermal analysis (thermogravimetry/differential thermal analysis), optical microscopy and scanning electron microscopy. Studies have revealed the similarity of the structure and properties of natural raw materials and studied metallurgical slag. It was established that the studied metallurgical slags could be used as an additional component to the zeolite–bentonite base to create a ceramic carrier for the catalyst. Graphic abstract The scheme of manufacture of catalyst carriers from natural raw materials and metallurgical slag.

Planning of cement plants for environmentally friendly production: a fuzzy-weighted stochastic multi-objective model Abstract This study focuses on locating and planning cement plants for environmentally friendly cement production and distribution by achieving environment-oriented and economic objectives. This study introduces a new stochastic goal-programming model with fuzzy-weighted goals. Dust and gaseous emissions are inevitable despite improvements in the chemistry, technology, and process of cement production. A triangular fuzzy pairwise comparison based on expert knowledge indicated that distance between cement plants and residential areas has higher importance than other considered goals. The model was demonstrated by applying it to a real dataset and solved using the branch and bound method. As planning, four optimal plant sites were identified to accept the raw materials of three mines and supply nine demands. The mathematical model can be easily updated and applied in all cases where cement plants are planned to locate the plants, assign raw materials to the plants, and assign cement from the plants to demands. Graphic abstract

Response to the planned public transport system in Ho Chi Minh City: analysis of latent classes Abstract A public transport (PT) system that is a low-carbon transport option is vital for sustainable urban development. However, introducing this type of system in developing cities may be a challenge given residents’ common practice of using private vehicles, especially motorcycles, for transportation. Taking Ho Chi Minh City as an example, this study aims to enhance understanding of preferences for PT. A dataset of 591 motorcycle users about their responses to the planned PT system was analyzed, considering their heterogeneity. The usage frequencies of PT were treated as an indicator of preference. The potential customers were classified into latent classes based on the assumption that there are differences in the factors that influence specific groups. A latent class choice model including two components of class assignment and utility functions was estimated to explain the preferences. Two latent classes were identified: the “collectivistic” class (69.5% of sample) and the “individualistic” class (30.5% of sample). The correlation between preferences for the current bus system and the new PT was captured within each class. The positive roles of social interaction and agreement with PT projects were observed in the “collectivistic” class, while the positive role of distance to work and negative role of dissatisfaction with service were found in the “individualistic” class. Comfort significantly impacted both classes, but the “collectivistic” class responded in a more positive way. The results suggest that differential marketing strategies should be developed to encourage users with different characteristics to make the change to PT. Graphical abstract

An integrated full cost model based on extended exergy accounting toward sustainability assessment of industrial production processes Abstract Existing methods for the sustainability assessment of industrial production processes have considered the values of natural resource use and ecosystem services. However, these methods mainly focus on monetary measures of natural capital cost and ignore some other costs, including human health effects, biodiversity loss and indirect exergy consumption in labor employment. The integrated ecological cumulative exergy consumption accounting method was proposed to improve the existing extended exergy model and provide a comprehensive perspective of the full cost of production including natural resources, human resources and environmental cost. The improved model is illustrated by its application for the steel-making process in China. Of the total cost of the steel-making process, the human resources cost (investment) accounts for only 9.7%. Contrary to the traditional cost evaluation, the result of this case study shows that classical economic assessment cannot reflect an overall ecological sustainable level of the steel-making process. The integrated method framework can be used to assess sustainability in a different spatial scale. Graphic abstract