Plastics are a wide range of synthetic or semi-synthetic materials, mainly consisting of polymers. The use of plastics has increased to over 300 million metric tonnes in recent years, and by 2050, it is expected to grow to 800 million. Presently, a mere 10% of plastic waste is recycled, with approximately 75% ended up in landfills. Inappropriate disposal of plastic waste into the environment poses a threat to human lives and marine species. Therefore, this review article highlights potential routes for converting plastic/microplastic waste into valuable resources to promote a greener and more sustainable environment. The literature review revealed that plastics/microplastics (P/MP) could be recycled or upcycled into various products or materials via several innovative processes. For example, P/MP are recycled and utilized as anodes in lithium-ion (Li-ion) and sodium-ion (Na-ion) batteries. The anode in Na-ion batteries comprising PP carbon powder exhibits a high reversible capacity of ∼340 mAh/g at 0.01 A/g current state. In contrast, integrating Fe3O4 and PE into a Li-ion battery yielded an excellent capacity of 1123 mAh/g at 0.5 A/g current state. Additionally, recycled Nylon displayed high physical and mechanical properties necessary for excellent application as 3D printing material. Induction heating is considered a revolutionary pyrolysis technique with improved yield, efficiency, and lower energy utilization. Overall, P/MPs are highlighted as abundant resources for the sustainable production of valuable products and materials such as batteries, nanomaterials, graphene, and membranes for future applications.
This study attempts to identify the optimum social marketing mix for marketing energy conservation behaviour to students in Malaysian universities. A total of 2000 students from 5 major Malaysian universities were invited to provide their preferred social marketing mix. A choice-based conjoint analysis identified a mix of five social marketing attributes to promote energy conservation behaviour; the mix is comprised of the attributes of Product, Price, Place, Promotion, and Post-purchase Maintenance. Each attribute of the mix is associated with a list of strategies. The Product and Post-purchase Maintenance attributes were identified by students as the highest priority attributes in the social marketing mix for energy conservation behaviour marketing, with shares of 27.12% and 27.02%, respectively. The least preferred attribute in the mix is Promotion, with a share of 11.59%. This study proposes an optimal social marketing mix to university management when making decisions about marketing energy conservation behaviour to students, who are the primary energy consumers in the campus. Additionally, this study will assist university management to efficiently allocate scarce resources in fulfilling its social responsibility and to overcome marketing shortcomings by selecting the right marketing mix.
After twenty-four years of government efforts, the latest national recycling rate in Malaysia rose from 5% in 1993 to approximately 24.6% in 2017. However, the practice of solid waste recycling in developing countries is still challenging compared to developing countries. Especially in Malaysia, a multi-ethnic country where people with different ethics have different living lifestyles. Still, Malaysia faces rapidly increasing solid waste and management costs, lacks appropriate data on solid waste management and recycling, lacks awareness of the 3R's (reduce, reuse and recycle) culture and lacks policies to promote 3R's culture. In addition, prior to the enforcement of ACT 672, information and networks between stakeholders have been limited for more than 20 years. Some scholars believe that the success of recycling practices is mainly influenced by community recycling behaviours. Therefore, in order to improve and evaluate the effectiveness of current national solid waste recycling management systems, research and assessment of community recycling behaviours are essential. This paper aims to evaluate the factors that attract communities to implement recycling in their daily lives and to obtain data through quantitative survey methods. Face-to-face questionnaires are conducted through purposive sampling and collected data is further analysed by PASW statistical tools. The comparison between recyclers and non-recyclers are presented in terms of frequency, means scores and radar chart. The results indicate that policy makers involved in the planning, organisation, and implementation of community recycling programs have to focus on strategies that engage community members and adopt recycling practices to improve environmental impact by changing their attitudes. Based on the results of means scores, the type of age, occupation and place of life must be taken into consideration in order to organize future recycling campaigns or awareness programs. In conclusion, the information will help policymakers make better solid waste recycling management to meet the needs of the public.
Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs.
Production of cellulases and xylanase by a novel Trichoderma asperellum UC1 (GenBank accession no. MF774876) under solid state fermentation (SSF) of raw oil palm frond leaves (OPFL) was optimized. Under optimum fermentation parameters (30 °C, 60-80% moisture content, 2.5 × 106 spores/g inoculum size) maximum CMCase, FPase, β-glucosidase and xylanase activity were recorded at 136.16 IU/g, 26.03 U/g, 130.09 IU/g and 255.01 U/g, respectively. Cellulases and xylanase were produced between a broad pH range of pH 6.0-12.0. The enzyme complex that comprised of four endo-β-1,4-xylanases and endoglucanases, alongside exoglucanase and β-glucosidase showed thermophilic and acidophilic characteristics at 50-60 °C and pH 3.0-4.0, respectively. Glucose (16.87 mg/g) and fructose (18.09 mg/g) were among the dominant sugar products from the in situ hydrolysis of OPFL, aside from cellobiose (105.92 mg/g) and xylose (1.08 mg/g). Thermal and pH stability tests revealed that enzymes CMCase, FPase, β-glucosidase and xylanase retained 50% residual activities for up to 15.18, 4.06, 17.47 and 15.16 h of incubation at 60 °C, as well as 64.59, 25.14, 68.59 and 19.20 h at pH 4.0, respectively. Based on the findings, it appeared that the unique polymeric structure of raw OPFL favored cellulases and xylanase productions.
Scientific research has characterized the effects of dredging, an underwater excavation process for navigational purposes or material extraction, and has shown its association with a number of chemical, physical and biological impacts. Due to this, much environmental management has been applied in the dredging industry in order to manage its detrimental effects. However, developing nations may have different approaches towards their dredging environmental management to compare to their companions with higher economic strength. Moreover, scientific evidence to make an informed decision is often lacking, hence affecting the number of research executed at these nations, limiting their efforts to preserve the environment. This paper reviews the dredging environmental impacts and its two important factors, dredging technology and sediment characteristic, that determine the magnitude of impacts through literature review, and discusses the need for a more integrated dredging environmental management to be developed for developing nations.
Marine plastic pollution (MPP) is an urgent environmental and socio-economic problem. MPP amounts to 300 million tons annually, originates largely from land-based sources and severely impacts marine ecosystem, harms livelihoods and causes costs for businesses and governments. Plastics permeate the whole width and depth of seas and oceans, near well-developed coastal zones and equally in remotest corners. This undermines economic and social value of the oceans, particularly in terms of fisheries productivity and tourism. The G20 members, responsible for about two-thirds of global plastic waste, recognize the problem and undertake preventive measures - individually and collectively. Yet, are there efficient, effective and sufficient given the urgency of MPP and the contribution of G20 countries. This article highlights existing policies and identifies further policy options using a custom framework for MPP policy that merges Circular Economy (CE) and life-cycle perspectives.
A sequencing batch reactor (SBR) with a working volume of 8 L and an exchange ratio of 25% was used to enrich biomass for the treatment of the anaerobically treated low pH palm oil mill effluent (POME). The influent concentration was stepwise increased from 5000 ± 500 mg COD/L to 11,500 ± 500 mg COD/L. The performance of the reactor was monitored at different organic loading rates (OLRs). It was found that approximately 90% of the COD content of the POME wastewater was successfully removed regardless of the OLR applied to the SBR. Cycle studies of the SBR show that the oxygen uptake by the biomass while there is no COD reduction may be due to the oxidation of the storage product by the biomass. Further, the growth kinetic parameters of the biomass were determined in batch experiments using respirometer. The maximum specific growth rate (μmax) was estimated to be 1.143 day(-1) while the half saturation constant (Ks) with respect to COD was determined to be 0.429 g COD/L. The decay coefficient (bD) and biomass yield (Y) were found to be 0.131 day(-1) and 0.272 mg biomass/mg COD consumed, respectively.
The aim of this research is to explore the association between financial development, research and development (R&D) expenditures, globalization, institutional quality, and energy consumption in India by using the quarterly data of 1995-2018. Quantile Autoregressive Distributed Lag (QARDL) approach is employed to examine the relationship. An application of the QARDL approach suggests that the R&D, financial development, globalization, and institutional quality significantly influence energy utilization in India. R&D and institutional quality have a negative effect on energy utilization which shows that due to the increase in the quality of institutions and R&D in the country, energy utilization is likely to decrease. However, globalization and financial performance have a positive influence on energy which depicts that due to the increase in financial performance and globalization in India the energy consumption is likely to increase. According to the outcomes of this research, India should make a policy to ease the penalties of energy utilization by monitoring resource transfer by means of globalization and by implementing energy conversation procedures through the advancement of the financial sector.
This study analyzes and compares the results of leachate composition at the semi-aerobic Pulau Burung Landfill Site (PBLS) (unaerated pond and intermittently aerated pond) and the anaerobic Kulim Sanitary Landfill in the northern region of Malaysia. The raw samples were collected and analyzed for twenty parameters. The average values of the parameters such as phenols (1.2, 6.7, and 2.6 mg/L), total nitrogen (448, 1200, and 300 mg/L N-TN), ammonia-N (542, 1568, and 538 mg/L NH(3)-N), nitrite (91, 49, and 52 mg/L NO(2)(-)-N), total phosphorus (21, 17, and 19 mg/L), BOD(5) (83, 243, and 326 mg/L), COD (935, 2345, and 1892 mg/L), BOD(5)/COD (0.096,0.1124,0.205%), pH (8.20, 8.28, and 7.76), turbidity (1546, 180, and 1936 Formazin attenuation units (FAU)), and color (3334, 3347, and 4041 Pt Co) for leachate at the semi-aerobic PBLS (unaerated and intermittently aerated) and the anaerobic Kulim Sanitary Landfill were recorded, respectively. The obtained results were compared with previously published data and data from the Malaysia Environmental Quality Act 1974. The results indicated that Pulau Burung leachate was more stabilized compared with Kulim leachate. Furthermore, the aeration process in PBLS has a considerable effect on reducing the concentration of several pollutants. The studied leachate requires treatment to minimize the pollutants to an acceptable level prior to discharge into water courses.
This article offers a trend of inventions and implementations of photocatalysis process, desalination technologies and solar disinfection techniques adapted particularly for treatment of industrial and domestic wastewater. Photocatalysis treatment of wastewater using solar energy is a promising renewable solution to reduce stresses on global water crisis. Rendering to the United Nation Environment Programme, 1/3 of world population live in water-stressed countries, while by 2025 about 2/3 of world population will face water scarcity. Major pollutants exhibited from numerous sources are critically discussed with focus on potential environmental impacts & hazards. Treatment of wastewater by photocatalysis technique, solar thermal electrochemical process, solar desalination of brackish water and solar advanced oxidation process have been presented and systematically analysed with challenges. Both heterogenous and homogenous photocatalysis techniques employed for wastewater treatment are critically reviewed. For treating domestic wastewater, solar desalination technologies adopted for purifying brackish water into potable water is presented along with key challenges and remedies. Advanced oxidation process using solar energy for degradation of organic pollutant is an important technique to be reviewed due to their effectiveness in wastewater treatment process. Present article focused on three key issues i.e. major pollutants, wastewater treatment techniques and environmental benefits of using solar power for removal of pollutants. The review also provides close ideas on further research needs and major concerns. Drawbacks associated with conventional wastewater treatment options and direct solar energy-based wastewater treatment with energy storage systems to make it convenient during day and night both listed. Although, energy storage systems increase the overall cost of the wastewater treatment plant it also increases the overall efficiency of the system on environmental cost. Cost-efficient wastewater treatment methods using solar power would significantly ensure effective water source utilization, thereby contributing towards sustainable development goals.
The recalcitrant landfill leachate was anaerobically digested at various mixing ratios with labile synthetic wastewater to evaluate the degradation properties of recalcitrant wastewater. The proportion of leachate to the digestion system was increased in three equal steps, starting from 0% to 100%, and later decreased back to 0% with the same steps. The chemical oxygen demand (COD) for organic carbon and other components were calculated by analyzing the COD and dissolved organic carbon (DOC), and the removal efficiencies of COD carbon and COD others were evaluated separately. The degradation properties of COD carbon and COD others shifted owing to changing of substrate degradability, and the removal efficiencies of COD carbon and COD others were improved after supplying 100% recalcitrant wastewater. The UV absorptive property and total organic carbon (TOC) of each molecular size using high performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with UVA and TOC detectors were also investigated, and the degradability of different molecular sizes was determined. Although the SEC system detected extracellular polymeric substances (EPS), which are produced by microbes in stressful environments, during early stages of the experiment, EPS were not detected after feeding 100% recalcitrant wastewater. These results suggest that the microbes had acclimatized to the recalcitrant wastewater degradation. The high removal rates of both COD carbon and COD others were sustained when the proportion of labile wastewater in the substrate was 33%, indicating that the effective removal of recalcitrant COD might be controlled by changing the substrate's degradability.
Trichoderma asperellum (Ta) was first cultured in synthetic medium (Potato Dextrose Broth, PDB) of various concentrations (100, 75, 50, 25%). The biomass was harvested and inoculated into dye solutions (crystal violet, CV; methyl violet, MV; malachite green, MG; and cotton blue, CB). Reduced concentrations (20, 50, 75%) affected growth rate but their decolourization efficacies remained unaffected. This was attributed to similar numbers and types of functional groups (hydroxyl, amine, ester-lipid, alkane groups) found on the surface of fungal biomass, as revealed by the Fourier transformed infrared spectroscopy (FTIR) analysis. Their production of NADH-reductase for degradation, and their biosorption activities were also unaffected. In general, Ta cultured in reduced concentrations (20, 50, 75%) retained the ability to perform biosorption and biodegradation, similar to cultures from control (100% PDB). This suggested that reduced nutrient levels (as a cost-feasible strategy) could be used to cultivate biomass of Ta for dye removal activities.
The isolate Coriolopsis sp. (1c3) was cultured on muslin cloth to induce formation of filamentous biofilm. The biofilm and the free-mycelium forms (control) were then used to treat two triphenylmethane dyes; Cotton Blue (CB) and Crystal Violet (CV). The biofilm comprised primarily of a compact mass of mycelium while sparse mycelium network was detected in free-mycelium forms. Results revealed significant decolourization activities by filamentous biofilm of 1c3 for CB (79.6%) and CV (85.1%), compared to free-mycelium forms (72.6 and 58.3%, for CB and CV, respectively). Biodegradation occurred in both biofilm and free-mycelium forms. FTIR spectra revealed that biofilm formation (stacking of mycelium), did not have severe implications to the number and types of functional groups available for dye biosorption. The findings here suggested that formation of biofilm in 1c3 was induced effectively on muslin cloth, leading to enhanced decolourization activities. This technology is simple, feasible and can be adopted and further improved to obtain biofilm to enhance their dye removal efficiency in aqueous solutions.
The provision of appropriate waste management is not only an indicator of development but also of broader sustainability. This is particularly relevant to expanding cities in developing countries faced with rising waste generation and associated environmental health problems. Despite these urgent issues, city authorities often lack the evidence required to make well-informed decisions. This study evaluates the carbon and economic performance of low-carbon measures in the waste sector at a city level, within the context of a developing country. Palembang in Indonesia is used as a case of a medium-sized city in a newly industrialized country, with relevance to other similar cities in the developing world. Evidence suggests that the waste sector can achieve substantial carbon emission reductions, and become a carbon sink, in a cost effective way. Hence there is an economic case for a low carbon development path for Palembang, and possibly for other cities in developing and developed countries facing similar challenges.
This study analyzes the regional implications of China's 2017 import ban on plastic waste by examining U.S. census data. A statistically significant decrease in total U.S. plastic waste exports was found, dropping from about 1.4 million tons to 0.6 million tons in the post-ban period. California remained the top exporter, throughout both pre- and post-ban periods, while South Carolina exhibited the highest per capita exports. Malaysia emerged as the largest importer of U.S. plastic waste, followed by Vietnam, Indonesia, and Thailand. The ban also led to a change in the composition of the exported plastic waste. Ethylene polymers increased from 32.6% of total exports in the pre-ban period to 46.9% in the post-ban period. Other plastics (vinyl chloride polymers, styrene polymers, and for plastics not elsewhere specified or included) decreased from 67.4% of total exports in the pre-ban period to 53.1% in the post-ban period. Moreover, we found that exporting plastic waste has significant environmental and human health impacts. For example, the Global Warming Potential (GWP) decreased from 20 million tons CO2-eq in the scenario where 100% of plastics are exported, or 25 million tons exported from the U.S. since 2002, to -11.1 million tons CO2-eq in the scenario where 100% of plastics are treated domestically. Transportation exacerbates these impacts for exported waste scenarios, increasing to 5.4 million tons CO2-eq when plastics are exported by ship while decreasing to 0.9 million tons CO2-eq for domestic treatment. Although exporting plastic waste is initially cost-effective, our study highlights that investing in domestic waste management can yield significant long-term benefits, considering the environmental and public health impacts. Therefore, it is crucial to prioritize context-specific solutions to address the challenges of the evolving global plastic waste landscape.
The protected coral reefs off the coast of Malaysia receive numerous tourists, while also being as fishing grounds. These joint environmental pressures raise the need for additional costly conservation measures. It is natural to consider the potential for expanding the 'user pays' principle, already implemented in the form of various user fees. This study explores the potential for price discrimination among scuba divers at Sipadan in Malaysia. The study applies a choice experiment to estimate scuba divers willingness to pay higher user fees for avoiding decreases of or getting improvements in environmental and recreational aspects of the diving experience. We investigate how sensitivity to fee size and hence willingness to pay vary with suitable selected characteristics of divers. We find potentials for a third degree price discrimination strategy exploiting higher willingness to pay among foreign divers (45%), male divers (16%) and people who has visited Sipadan several times (25%). Thus, revised pricing structures could significantly increase funds for the preservation of Sipadan.
Fibrous silica-titania (FST) catalysts were synthesized by microemulsion followed by silica seed-crystal crystallization methods under various molar ratios of toluene to water (T/W). The catalysts were characterized by XRD, UV-DRS, FESEM, TEM, AFM, N2 adsorption-desorption, FTIR, and ESR. The results revealed that altering the T/W ratio affected the growth of the silica and titania and led to different size, fiber density, silica-titania structure, and number of hydroxyl groups, as well as oxygen vacancies in the FSTs, which altered their behavior toward subsequent application. Photodegradation of ibuprofen (IBP) are in the following order: FST(6:1) (90%) > FST(5:1) (84%) > FST(7:1) (79%) > commercial TiO2 (67%). A kinetics study using Langmuir-Hinshelwood model illustrated that the photodegradation followed the pseudo-first-order and adsorption was the rate-limiting step. Optimization by response surface methodology (RSM) showed that the pH, initial concentration, and catalyst dosage were the remarkable parameters in photodegradation of IBP. The FST (6:1) maintained its photocatalytic activities for up to five cycles reaction without serious catalyst deactivation, and was also able to degrade other endocrine-disrupting chemicals, indicating its potential use for the treatment of those chemicals in wastewater.
Eco-industrial parks promise to reduce environmental and social impacts and improve the economic performance of industrial parks. However, the transition from industrial parks to eco-industrial parks is still not well understood. This study contributes to developing valid hierarchical eco-industrial park transition attribute sets with qualitative information, as prior studies lack an exploration of the attributes in the transition of eco-industrial parks in Hungary. In nature, eco-industrial park transition attributes have causal and hierarchical interrelationships and are described with qualitative information. The assessment involves an analysis of the industrial symbiosis principles by using linguistic preferences. However, multiple attributes are involved in the assessment; therefore, this study proposes the Delphi method to develop a valid attribute set and applies fuzzy set theory to translate qualitative information into crisp values. The fuzzy decision-making trial evaluation laboratory method is used to visualize the attributes' causal interrelationships under uncertainties. The results indicate that the policy and regulatory framework leads to collaboration among firms in the eco-industrial park transition model. In practice, price reforms, management commitment, strategic planning, cognitive barriers and the integration of external information are the practical criteria for improvement. Theoretical and practical implications are also discussed.
International trade of plastic waste promotes the global plastic circular economy and improves resource efficiency, but exacerbates the ubiquitous plastic pollution. Understanding the drivers behind the evolution of the global plastic waste trade network (GPWTN) is pivotal for developing new international instruments to end plastic pollution and fostering clean solid-waste trade. Employing social network analysis (SNA) and quadratic assignment procedure (QAP) model, this study structures the GPWTN using bilateral trade data, revealing shifts from highly centralized to cross-layered networks and relevant drivers. It is suggested that Malaysia and Turkey has become the new key recipients of the GPWTN, replacing China, accompanied by the launch of new environmental regulations in some countries. Transportation cost is the most critical factor for the formation of the GPWTN, followed by gaps in resource demand, bio-based resource availability, and transportation accessibility. Trading partners in closer proximity, especially those with contiguous borders, are more likely to trade in waste plastics, while coastal countries play an important role in these partnerships. Economies with more abundant biomaterials, higher incomes, and greater environmental burdens are more likely to be exporters, while economies with scarcer resources and more compelling demands are more likely to import plastic waste. Countries involved in the trade in plastic waste, as either importers or exporters, receive varying degrees of economic benefits but bear potential environmental impacts. Therefore, global plastic pollution control and trade prosperity necessitates necessitate coordinated endeavors from nations and intergovernmental bodies for a mutually advantageous denouement.