Water pollution is a critical management issue, with many rivers and streams draining urban areas being polluted by the disposal of untreated solid waste and wastewater discharge, storm water and agricultural runoff. This has implications for biodiversity, and many rivers in the developing world are now considered compromised. We investigated benthic macroinvertebrate community structure and composition in relation to physico-chemical conditions of the water column and sediments. The study was conducted in an Austral catchment subject to both urban and agricultural pollutants in two different seasons. We assessed whether sediment characteristics were more important drivers of macroinvertebrate community composition than water column characteristics. We expected clear differences in macroinvertebrate community composition and in the associated community metrics due to distinct flow conditions between the two seasons. A combination of multivariate analyses (canonical correspondence analysis (CCA)) and biological indicator analysis were used to examine these patterns. Chironomidae was the most abundant family (>60%) in the upper mainstem river and stream sites. Stream sites were positively associated with CCA axis 2, being characterised by high turbidity and lower pH, salinity, phosphate concentration, channel width and canopy cover. Canopy cover, channel width, substrate embeddedness, phosphate concentration, pH, salinity and turbidity all had a significant effect on macroinvertebrate community composition. Using CCA variation partitioning, water quality was, however, a better predictor of benthic macroinvertebrate composition than sediment chemical conditions. Furthermore, our results suggest that seasonality had little effect on structuring benthic macroinvertebrate communities in this south-eastern zone of South Africa, despite clear changes in sediment chemistry. This likely reflects the relative lack of major variability in water chemistry compared to sediment chemistry between seasons and the relatively muted variability in precipitation between seasons than the more classic Austral temperate climates.
This study presents a preliminary assessment of biodiesel production from waste sources available in the Kingdom of Saudi Arabia (KSA) for energy generation and solution for waste disposal issues. A case study was developed under three different scenarios: (S1) KSA population only in 2017, (S2) KSA population and pilgrims in 2017, and (S3) KSA population and pilgrims by 2030 using the fat fraction of the municipal solid waste. It was estimated that S1, S2, and S3 scenarios could produce around 1.08, 1.10 and 1.41 million tons of biodiesel with the energy potential of 43423, 43949 and 56493 TJ respectively. Furthermore, annual savings of US $55.89, 56.56 and 72.71 million can be generated from landfill diversion of food waste and added to the country's economy. However, there are challenges in commercialization of waste to biodiesel facilities in KSA, including waste collection and separation, impurities, reactor design and biodiesel quality.
Growing populations, expanding economies, industrialisation, and urbanisation pose a problem for waste management in developing countries. Their waste management methods, on the other hand, are not as efficient as they could be. Most developing countries' current waste management practices do not fully conform to developed countries' best practices for meeting socioeconomic goals. As a result, the importance of waste management in developing countries has grown in recent years. In order to highlight the socioeconomic perspectives of waste management practices, the present study examines the existing literature, policies, information, and records on waste management in developing nations. The findings indicate that essential socioeconomic factors such as finances, population density, per capita income, education level, policies, and technology have a significant impact on waste management, which encompasses waste generation, collection, composition, and disposal/treatment. Nonetheless, waste management has a number of economic benefits, including financial stability, job creation, and community cohesion. This study will inspire further research on the need for developing nations to consider the socioeconomic benefits of proper waste management and to develop a policy plan to achieve these benefits.
This review provides the history and current paradigms of waste management (WM) practices in developing nations during the last five decades. It explores the evolution of the challenges, complexities, and trends during this period. This paper, for the first time, presents an estimation of the amount of municipal solid waste (MSW) generated in developing nations in the last five decades based on the material flow analysis approach. Overall, the amount of MSW in developing countries has increased from about 0.64 billion Mt in 1970 to 2 billion Mt in 2019. This review demonstrates the importance of finding new WM approaches in developing nations in the context of formulating policies, strategies, and highlights the major trends that re-define WM in developing countries. It also aims to present the holistic changes in technology, economic and environmental feasibility aspects to attain an integrated sustainable WM system in developing countries. Specific focus on open-burning, open-dumping, informal recycling, food waste, plastic pollution, and waste collection with reference to Sustainable Development Goals are explained. Drivers for the way forward including circular economy are investigated.
Solid waste management was explored in Asia's last five decades, and the issues and challenges were identified. Waste generation has increased in all nations in the previous 50 years, although more recently, a declining trend has been observed in Japan and Korea. The composition has been predominantly organic, with 45-50% being kitchen waste. Material extraction and productivity to sustain the most populous part of the globe are explained. Waste management technologies have evolved, with more nations slowly transitioning from landfills to using waste-to-energy options. However, landfilling and open dumps are still the major disposal choice in most developing countries in Asia. Thus, the issues of concern include dumpsites management, the informal sector, waste collection, open burning and food waste. Changes (increasing trends) in the recycling technologies and quantum are evident, as seen in several country reports from India, Indonesia, Japan, Malaysia, Singapore, South Korea, Thailand and Vietnam. There are several issues and challenges for recycling, which are explored in the text. Lastly, the drivers that propel the whole scenario of waste management in Asia and the evolution of these drivers over time are discussed. Several recommendations are included to achieve sustainable waste management in Asia.
Research was conducted to determine suitable chemical parameters as indicators of odor from decomposing food wastes. Prepared food scraps were stored in 18 l plastic buckets (2 kg wet weight each) at 20 °C and 8 °C to reproduce high and low temperature conditions. After 1, 3, 7, 10 and 14 days of storage, the odor from the buckets were marked to an intensity scale of 0 (no odor) to 5 (intense) and the corresponding leachate analyzed for volatile fatty acids, ammonia and total organic carbon. A linear relationship between odor intensity and the measured parameter indicates a suitable odor indicator. Odor intensified with longer storage period and warmer surroundings. The study found ammonia and isovaleric acid to be promising odor indicators. For this food waste mixture, offensive odors were emitted if the ammonia and isovaleric acid contents exceeded 360 mg/l and 940 mg/l, respectively.
As the annual production of the solid waste generable in the form of spent coffee bean powder (SCBP) is over 6 million tons, its utilization in the generation of green energy, waste water treatment and as a filler in biocomposites is desirable. The objective of this article is to analyze the possibilities to valorize coffee bean powder as a filler in cellulose matrix. Cellulose matrix was dissolved in the relatively safer aqueous solution mixture (8% LiOH and 15% Urea) precooled to -12.5°C. To the cellulose solution (SCBP) was added in 5-25wt% and the composite films were prepared by regeneration method using ethyl alcohol as a coagulant. Some SCBP was treated with aq. 5% NaOH and the composite films were also prepared using alkali treated SCBP as a filler. The films of composites were uniform with brown in color. The cellulose/SCBP films without and with alkali treated SCBP were characterized by FTIR, XRD, optical and polarized optical microscopy, thermogravimetric analysis (TGA) and tensile tests. The maximum tensile strength of the composite films with alkali treated SCBP varied between (106-149MPa) and increased with SCBP content when compared to the composites with untreated SCBP. The thermal stability of the composite was higher at elevated temperatures when alkali treated SCBP was used. Based on the improved tensile properties and photo resistivity, the cellulose/SCBP composite films with alkali treated SCBP may be considered for packaging and wrapping of flowers and vegetables.
Iron and steel industries are among the contributors of CO2 emission in large volume into the atmosphere, causing detrimental effects to the environment and the ecosystem at large scale. These industries also generate solid wastes in the form of electric arc furnace (EAF) slag during operations which result in about 10-15% slag wastes per ton of steel produced. In this study, the EAF slags from an iron and steel-making factory in Klang, Malaysia was utilized for CO2 sequestration through direct aqueous mineral carbonation. According to the surface area analysis, the fresh EAF slag has a mesoporous structure, its elemental composition shows the presence of 20.91 wt.% of CaO that was used for the sequestration of CO2 through carbonation. The sequestration capacity was found to be 58.36 g CO2/kg of slag at ambient temperature in 3 h, with the liquid/solid (L/S) ratio of 5:1 and using <63μm particle size. Moreover, the shrinking core model (SCM) was used to analyze the solid-fluid reaction in a heterogeneous phase and the CO2 sequestration shows to be controlled by the product layer phase. The EAF slag is demonstrated to have the potential of CO2 sequestration at ambient temperature.
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.
The acceleration of growth in the population in Saudi Arabia and the increase in municipal solid waste generation have caused a problem in Dammam city: an increase in solid waste production. Therefore, solid waste sorting is an important practice of municipal solid waste management. The main objectives in this research are understanding the effect of internal and external factors on household willingness in sorting waste in Dammam city and studying the attempts to construct a theoretical research model by adding market incentives, government facilitators, and awareness into the popular planned behaviour theory to explain residents' waste sorting intentions. The data collection and analysis are based on the questionnaire study, which is based on the questionnaire survey data from 450 households in Dammam. This study revealed that social influence significantly predicts households' willingness to sort and recycle, that is, to promote recycling. Additionally, the variable social influence has a significant but low influence on households' willingness to sort and recycle. The result of the structural equation model shows that perceived behavioural control significantly predicts households' willingness to sort and recycle waste. This finding is consistent with the theoretical expectation. Therefore, this research shows that attitude, social influence, perceived behavioural control, market incentives, government facilitators and awareness positively and significantly affect residents' waste sorting intentions. Additionally, this research corroborates the discrepancy between internal and external variables.
The objective of this study is to explore the similarities and differences in the barriers and motivations between the plastic and resins and food and beverages industries as these two industries are the major contributors of solid waste in Malaysia. Prior studies are lacking with regard to explaining the barriers and motivations in solid waste management from the Malaysian context. This study is focused on 10 firms from the plastics and resins industry and 9 from the food and beverages industry in Malaysia. Through Rasch measurement theory, the results indicate that the barriers of lack of skills and qualifications and lack of closed-loop control and the motivations of cost savings and a business model are performed differently. The findings further confirm that the lack of skills and qualifications is a more difficult barrier to overcome than the lack of closed-loop control, while the motivation factor of a business model is more difficult to achieve than cost savings. In terms of practical contribution, this study provides results that can help policy makers in Malaysia to close the gaps present regarding the adoption of solid waste management practices and to devise appropriate incentives. The study also supports managers of companies in regard to working on the most pressing hindering and promoting factors in the field of solid waste management.
Landfilling is the most widely used disposal method for municipal solid waste around the world. The main disadvantage of this strategy is formation of leachate, among other aspects. Landfill leachate contains highly toxic and bio-refractory substances that are detrimental to the environment and human health. Hence, the risk(s) of discharging potentially harmful landfill leachate into the environment need to be assessed and measured in order to make effective choices about landfill leachate management and treatment. In view of this, the present review aims to investigate (a) how landfill leachate is perceived as an emerging concern, and (b) the stakeholders' mid- to long-term policy priorities for implementing technological and integrative solutions to reduce the harmful effects of landfill leachate. Because traditional methods alone have been reported ineffective, and in response to emerging contaminants and stringent regulations, new effective and integrated leachate treatments have been developed. This study gives a forward-thinking of the accomplishments and challenges in landfill leachate treatment during the last decade. It also provides a comprehensive compilation of the formation and characterization of landfill leachate, the geo-environmental challenges that it raises, as well as the resource recovery and industrial linkage associated with it in order to provide an insight into its sustainable management.
Incense sticks ash is one of the most unexplored by-products generated at religious places and houses obtained after the combustion of incense sticks. Every year, tonnes of incense sticks ash is produced at religious places in India which are disposed of into the rivers and water bodies. The presence of heavy metals and high content of alkali metals challenges a potential threat to the living organism after the disposal in the river. The leaching of heavy metals and alkali metals may lead to water pollution. Besides this, incense sticks also have a high amount of calcium, silica, alumina, and ferrous along with traces of rutile and other oxides either in crystalline or amorphous phases. The incense sticks ash, heavy metals, and alkali metals can be extracted by water, mineral acids, and alkali. Ferrous can be extracted by magnetic separation, while calcium by HCl, alumina by sulfuric acid treatment, and silica by strong hydroxides like NaOH. The recovery of such elements by using acids and bases will eliminate their toxic heavy metals at the same time recovering major value-added minerals from it. Here, in the present research work, the effect on the elemental composition, morphology, crystallinity, and size of incense sticks ash particles was observed by extracting ferrous, followed by extraction of calcium by HCl and alumina by H2SO4 at 90-95 °C for 90 min. The final residue was treated with 4 M NaOH, in order to extract leachable silica at 90 °C for 90 min along with continuous stirring. The transformation of various minerals phases and microstructures of incense sticks ash (ISA) and other residues during ferrous, extraction, calcium, and alumina and silica extraction was studied using Fourier transform infrared (FTIR), dynamic light scattering (DLS), X-ray fluorescence (XRF), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES). DLS was used for analyzing the size during the experiments while FTIR helped in the confirmation of the formation of new products during the treatments. From the various instrumental analyses, it was found that the toxic metals present in the initial incense sticks ash got eliminated. Besides this, the major alkali metals, i.e., Ca and Mg, got reduced during these successive treatments. Initially, there were mainly irregular shaped, micron-sized particles that were dominant in the incense sticks ash particles. Besides this, there were plenty of carbon particles left unburned during combustion. In the final residue, nanosized flowers shaped along with cuboidal micron-sized particles were dominant. present in If, such sequential techniques will be applied by the industries based on recycling of incense sticks ash, then not only the solid waste pollution will be reduced but also numerous value-added minerals like ferrous, silica, alumina calcium oxides and carbonates can be recovered from such waste. The value-added minerals could act as an economical and sustainable source of adsorbent for wastewater treatment in future.
Throughout the years, the construction industry has made an important contribution to the Malaysian economy. Moreover, the Ninth Malaysia Plan (2006–2010) has also played a significant role in the demands of executing major residential housing project developments where it has been observed that construction waste was one of the priority waste streams. Due to the increasing number in the population that is actively involved in economic activities, and the modernization of the country, the types of construction waste that are being produced, and identifying the source such as waste are becoming more complex. Therefore, appropriate actions and approaches are needed to be taken with respect to its effective management in handling the solid waste from construction sites. This paper is intended to review the issues and the challenges enclosed within the supply chain management mechanisms in order for improving construction waste management. Throughout this review, useful information and better understanding concerning the current issues, challenges and the supply chain management mechanisms would be made inclusive in the field to be explored. The findings would also assist in improving the quality and awareness on the construction waste management that is being practiced.
Malaysia is facing an increasing trend in industrial solid waste generation due to industrial development. Thus, there is a paramount need in taking practical actions and measurements to move toward sustainable industrial waste management. The main aim of this study is to assess practicing solid waste minimization by manufacturing firms. Analysis showed that majority of firms (92%) dispose of their wastes rather than utilize other sustainable waste management options. Also, waste minimization methods such as segregation of wastes, on-site recycle and reuse, improved housekeeping, and equipment modification were found to have significant contribution to waste reduction (p
The world has been grappling with the crisis of the COVID-19 pandemic for more than a year. Various sectors have been affected by COVID-19 and its consequences. The waste management system is one of the sectors affected by such unpredictable pandemics. The experience of COVID-19 proved that adaptability to such pandemics and the post-pandemic era had become a necessity in waste management systems and this requires an accurate understanding of the challenges that have been arising. The accurate information and data from most countries severely affected by the pandemic are not still available to identify the key challenges during and post-COVID-19. The documented evidence from literature has been collected, and the attempt has been made to summarize the rising challenges and the lessons learned. This review covers all raised challenges concerning the various aspects of the waste management system from generation to final disposal (i.e., generation, storage, collection, transportation, processing, and burial of waste). The necessities and opportunities are recognized for increasing flexibility and adaptability in waste management systems. The four basic pillars are enumerated to adapt the waste management system to the COVID-19 pandemic and post-COVID-19 conditions. Striving to support and implement a circular economy is one of its basic strategies.
Metal, carbon and conducting polymer nanoparticles are blended with organic phase change materials (PCMs) to enhance the thermal conductivity, heat storage ability, thermal stability and optical property. However, the existing nanoparticle are expensive and need to be handle with high caution during operation as well during disposal owing to its toxicity. Subsequently handling of solid waste and the disposal of organic PCM after longevity usage are of utmost concern and are less exposed. Henceforth, the current research presents a new dimension of exploration by green synthesized nanoparticles from a thorny shrub of an invasive weed named Prosopis Juliflora (PJ) which is a agro based solid waste. Subsequently, the research is indented to decide the concentration of green synthesized nanoparticle for effective heat transfer rate of organic PCM (Tm = 35-40 °C & Hm = 145 J/g). Furthermore, an in-depth understanding on the kinetic and thermodynamic profile of degradation mechanism involved in disposal of PCM after usage via Coats and Redfern technique is exhibited. Engaging a two-step method, we fuse the green synthesized nanomaterial with PCM to obtain nanocomposite PCM. On experimental evaluation, thermal conductivity of the developed nanocomposite (PCM + PJ) increases by 63.8% (0.282 W/m⋅K to 0.462 W/m⋅K) with 0.8 wt% green synthesized nanomaterial owing to the uniform distribution of nanoparticle within PCM matrix thereby contributing to bridging thermal networks. Subsequently, PCM and PCM + PJ nanocomposites are tested using thermogravimetric analyzer at different heating rates (05 °C/min; 10 °C/min; 15 °C/min & 20 °C/min) to analyze the decomposition kinetic reaction. The kinetic and thermodynamic profile of degradation mechanism involved in disposal of PCM and its nanocomposite of PCM + PJ provides insight on thermal parameters to be considered on large scale operation and to understand the complex nature of the chemical reactions. Adopting thirteen different chemical mechanism model under Coats and Redfern method we determine the reaction mechanism; kinetic parameter like activation energy (Ea) & pre-exponential factor (A) and thermodynamic parameter like change in enthalpy (ΔH), change in Gibbs free energy (ΔG) and change in entropy (ΔS). Dispersion of PJ nanomaterial with PCM reduces Ea from 370.82 kJ/mol-1 to 342.54 kJ/mol-1 (7.7% reduction), as the developed nanomaterial is enriched in carbon element and exhibits a catalytic effect for breakdown reaction. Corresponding, value of ΔG for PCM and PCM + PJ sample within heating rates of 05-20 °C/min varies between 168.95 and 41.611 kJ/mol-1. The current research will unbolt new works with focus on exploring the pyrolysis behaviour of phase change materials and its nanocomposite used for energy storage applications. This work also provides insights on the disposal of PCM which is an organic solid waste. The thermo-kinetic profile will help to investigate and predict the optimum heating rate and temperature range for conversion of micro-scale pyrolysis to commercial scale process.
Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin-1, 10°Cmin-1, 15°Cmin-1 and 20°Cmin-1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats-Redfern) and model free methods (Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats-Redfern, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman models were found in the ranges 105-148.48 kJmol-1, 99.41-140.52 kJmol-1, 103.67-149.15 kJmol-1 and 99.93-141.25 kJmol-1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.
Thirteen solid waste samples labeled as scales were collected from a storage area of a crude oil production industry and were analysed for radionuclides concentrations. The radium-226 and radium- 228 concentrations were found to be unexpectedly low, i.e. less than 20 Bqkg. However, six samples were found to contain 7 to 2240 Bq/kg 60 Co. Thus, besides naturally occurring radionuclides, there is a possibility to find artificial radionuclides in solid wastes from crude oil production industry.
Background: Prolonged exposure of heavy metals in the respirable particulate matter (PM10) from municipal solid waste (MSW) landfills may affect children health. Objective: To investigate the association of reported respiratory symptom with heavy metals in PM10, with heavy metals in fingernails among children residing close to MSW landfills. Methods: Two groups of children age 7 to 12 years old were involved in this cross-sectional study. Those residing within 3 km radius from a landfill were the exposed group and those residing more than 3 km radius as the unexposed group. Questionnaires adapted from American Thoracic Society were applied in the survey. Fingernails were used as biomarker. Ten heavy metals elements in PM and fingernail samples were analysed using inductively coupled plasma mass spectrometry (ICP-MS). Results: The cadmium, chromium, copper, manganese, nickel and lead concentrations in PM around the MSW landfills and residential areas exceeded the Canada and USEPA standard permissible limit. Heavy metals in fingernails (p