Sustainable Waste Management Research Articles

Synergising hydrothermal pre-treatment and biological processes for enhancing biohydrogen production from palm oil mill effluent

The high quantity of nutrient-rich palm oil mill effluent (POME) waste in the industry will have a severe negative environmental impact and a high cost of treatment. However, POME waste could be converted into bioenergy via environmentally sustainable processes. Several studies have explored using hydrothermal carbonisation for solid biomass products in biofuel production, but the potential of the liquid phase produced during these processes has received less attention. Therefore, this study aims to assess the potential of biohydrogen production from treated POME as a substrate by hydrothermal process. This study is presented in two phases: the first phase involves substrate pre-treatment using a hydrothermal process to improve biomass properties at different temperatures, and the second phase explores the potential for biohydrogen production from treated POME through dark fermentation. Substrate pre-treatment was conducted at 180, 210, and 240 °C using 100% raw POME. Next, the treated POME was incubated for biohydrogen production at 50 °C for 24hours. A microbial analysis was conducted to determine the most dominant species present in the sample. Our findings show that at 180 °C, the total chemical oxygen demand (COD) removal efficiency was 80%, and acetic acid concentration was 28%. Compared to raw POME, treated POME generated a maximum hydrogen yield and rate (HPR) of 52.19mL H2 g-1 CODrem and 0.59mL H2 mL POME-1 day-1 with a 2.32-fold and 1.59-fold increase, respectively. Meanwhile, Clostridium was a dominant bacterial species identified in the treated POME. These findings demonstrated the feasibility of implementing a hydrothermal process to treat POME and improve its biohydrogen production efficiency. The treated POME from the hydrothermal process is more homogenous and readily consumable by microorganisms used in dark fermentation. Hydrothermal pre-treatment could potentially increase the rate and efficiency of microbial digestion, leading to enhanced hydrogen production. The high COD removal efficiency during the process significantly reduces the environmental impact of POME discharge, and converting POME into a valuable resource through the hydrothermal and dark fermentation process aligns with sustainable waste management practices.

Comparative Study of Waste Management and Sampling Practices in Latvia and Estonia

Abstract The study focuses on waste management and sampling practices carried out in two large Baltic cities: Riga (Latvia) and Tartu (Estonia). Even though waste collection schemes are not at the same centralisation level in the two municipalities, certain similarities can be observed in waste collection, management and sampling processes. Governed by provisions of Council Directive 1999/31/EC of 26 April 1999 on the landfill of waste, general national waste treatment legislation, and the national waste management plans, waste management practices in Latvia and Estonia are moving towards minimalisation of waste landfilling and maximalisation of waste inclusion into various recycling practices (use in waste biodegradation cells, bioreactors, different waste recycling facilities, in developing modern waste management supporting infrastructure, etc.). Therefore, waste management in two countries can be partly characterised as a vital element of emerging circular economy activities aimed at minimising landfill deposition of waste, hence, a more effective and permanent approach to sustainable waste management problems, on the one hand, and maximising the diversified use of waste in different branches of economy, hence, larger economic and social benefits.

Enhancing biogas production from vinasse through optimizing hydraulic retention time and added load using the response surface methodology

Vinasse, a byproduct of ethanol production from sugarcane, is a rich organic matter and poses environmental challenges due to its high pollutant content. Effective biomethane production from vinasse can mitigate its environmental impact by converting organic matter into a useful energy source while reducing its pollutant load. The biomethane production by anaerobic digestion (AD) process of the vinasse byproduct was examined on a laboratory scale. In this regard, several loads from 0.5 to 7 g VS/L were investigated to assess AD performance and methane production. This study investigated how two separate factors, namely the load and hydraulic retention time (HRT), affect both cumulative methane production (CMP) and methane yield (YCH4). This investigation utilized a response surface methodology known as the central composite design (RSM-CCD). Statistical analysis of variance (ANOVA) was employed to evaluate the effectiveness of the model generated. Thus, the model's fit, YCH4 has a maximum R2 value of 0.9759. The results revealed an astounding level of agreement between the experimental data and the proposed model. The RSM results revealed maximum CMP and YCH4 values of 409.82 ml and 178.95 ml/g VS respectively, obtained for optimum load values of 2.17 g VS/L and HRT of 15 h. The results emphasize the environmental and economic significance of AD, providing a sustainable waste management solution that helps reduce greenhouse gas emissions and organic pollution. Additionally, it generates valuable biogas and biofertilizers, presenting economic opportunities through renewable energy production and resource recovery. This approach not only alleviates the environmental burden of vinasse but also enhances the economic viability of ethanol production by creating additional revenue streams.

Review of Plastic Waste Recycling: Advances, Challenges, and Future Perspectives

Plastic waste recycling is pivotal for sustainable waste management, offering solutions to mitigate environmental impacts and conserve resources. This thesis reviews technological advancements, challenges, and future prospects in recycling various plastic types. It begins with an overview of plastic pollution’s global impact and the imperative to manage plastic waste responsibly amidst rising production. Recycling processes are explored, detailing collection, sorting, cleaning, and reshaping methods that extend plastic life cycles while reducing energy consumption and greenhouse gas emissions. The review highlights challenges such as plastic type variability, recycling infrastructure limitations, and market demand discrepancies, affecting recycling effectiveness. Technological advances, including mechanical and chemical recycling innovations, are analyzed for their potential to improve plastic recycling rates. Economic and environmental implications underscore the benefits of effective recycling, contributing to a circular economy and minimizing landfill waste. Future directions advocate for enhanced recycling technologies, standardized labeling, and policy interventions like extended producer responsibility schemes. By addressing these facets, stakeholders can collaboratively advance sustainable plastic waste management globally, fostering a future where environmental stewardship aligns with economic viability.

Value-added Finance Use Animal Waste as Conversion Fertilizer for Vegetable Farming Groups in the West Sinjai Region, Indonesia

Agriculture plays a crucial role globally, and addressing the sustainable management of livestock waste is a growing concern. Converting animal waste into fertiliser not only supports organic farming but also offers a sustainable solution for managing livestock waste. This study aims to evaluate the conversion of fertiliser to animal waste and its potential to generate higher economic value for vegetable farmers in the West Sinjai region. By applying theoretical concepts learned in academic settings to real-world problems, this research aims to enhance knowledge regarding the economic benefits of fertiliser conversion. Additionally, it serves as a valuable reference for future studies on the economic impact of using animal waste as a substitute for chemical fertilisers. The primary goal is to determine the financial benefits and added value of using animal waste in place of chemical fertilisers. This research follows a quantitative descriptive approach, using both primary and secondary data. The population consists of secondary crop farmers in the West Sinjai region, and the sample includes six groups of vegetable farmers in Gunung Perak Village. The results indicate that converting fertiliser to animal waste significantly enhances the economic value for farmers in the West Sinjai region, particularly in Gunung Perak Village. This improvement is due to the cost savings from using animal waste compared to chemical fertilisers per production unit, ultimately leading to higher profits for the farmers.

Sustainable Municipal Solid Waste Management in India by Biomethanation Process

Sustainable Municipal Solid Waste Management in India by Biomethanation Process

Experimental Study of Plastic Bricks Made from Waste Plastics

This study describes the use of municipal plastic waste (MPW) in the construction industry. Plastic is a nonbiodegradable material that takes thousands of years to decompose and causes soil and water pollution. The amount of plastic waste in municipal solid waste (MSW) is increasing rapidly. Usage is estimated to double every decade. Plastic consumption is high and one of the largest plastic wastes is polyethylene (PE). The use of earth-derived clay materials has caused resource depletion and one of these efforts is the efficient use of plastic waste and laterite quarry waste, along with small amounts of asphalt, to meet the growing demand for traditional building materials, which are less absorbent than laterite bricks. The challenge is to develop alternative building materials, such as brick, that have little but sufficient strength. The use of MPW as a building material, especially in brick production, is one of the promising steps towards sustainable resource and waste management. Plastic waste can partially or completely replace one or more raw materials in brick production. Further research based on recent research and a better understanding of the use of waste plastics in bricks is needed to produce high-quality and durable bricks and to achieve an optimal balance in all aspects, especially in terms of cost and functionality.

Deciphering cleaner and sustainable frontiers in scientific cow waste valorization: a review.

The forecasted global population growthis poised to create a greater exigency for livestock-derived food production,leading to a significant wastegeneration from the industrial-scalelivestockoperations, which necessitates to develop sustainable waste management solutions. The heightened demand for livestock and dairy products has driven a surge in cow waste (CW) production. While CW is typically used as organic fertilizer or solid fuel, improper disposal poses potential environmental hazards. Anaerobic digestion and composting transform CW into valuable products, such as biofuels and organic fertilizers, with the potential for electricity and heat generation, biochar production, and advanced friction materials. The CW contains essential inorganic and organic compounds vital for plant functions, including lignin, cellulose, hemicellulose, nitrogen, and minerals such as potassium, sulfur, iron, magnesium, copper, cobalt, and manganese. Additionally, the rich microbial diversity in cow dung drives the production of bioenergy carriers like biomethane and biohydrogen, promoting cost-effective energy generation and environmental sustainability. This review employs bibliometric analysis to explore the latest trends in CW applications, with a particular focus on innovative applications such as cellulose extraction, biochar production, microbial fuel cells, and nanoparticle synthesis. Itfurther evaluates the environmental impacts of these technologies and assesses their potential to advance sustainable and cleaner frontiers in the valorizationof CW.

The Role of EM4 (Effective Microorganisms) in Solid Waste-Powered Microbial Fuel Cells: Investigating Voltage Output and Electrical Conductivity For Bioelectricity Generation

The increasing global demand for renewable energy and sustainable waste management solutions has inspired interest in microbial fuel cells (MFCs) as a dual-purpose technology for bioelectricity generation and waste treatment. This study explores the role of EM4, a consortium of effective microorganisms, in enhancing the voltage output and electrical conductivity of solid waste-powered MFCs. A batch system bioreactor assessed the impact of varying organic waste-to-zeolite ratios on MFC performance. The results demonstrated that a 1:1 ratio of organic waste to zeolite produced the highest electrical conductivity (3160 µS/cm) and the most substantial voltage output (777.5 mV) by day three of the experiment. Statistical analysis, including ANOVA and Kruskal-Wallis tests, revealed significant differences in voltage output across treatments, with a positive correlation between electrical conductivity and voltage production. These findings highlight the potential of integrating EM4 and conductive materials like zeolite to optimize bioelectricity generation in MFCs, contributing to the advancement of sustainable energy technologies.

Understanding the informal waste sector for sustainable waste management using the pressure-state-response framework: a case study in Balikpapan, Indonesia

Understanding the informal waste sector for sustainable waste management using the pressure-state-response framework: a case study in Balikpapan, Indonesia

Sustainable waste management practices in the informal sector: Towards industrial symbiosis

Industrial pollution is considered to be routed in the waste and byproducts of the production process. Traditional pollution control approaches try to eliminate and/or treat the pollutants which are often technically complicated and expensive. In this regard, industrial ecology and industrial symbiosis have emerged as effective strategy to eliminate industrial pollution. This principle requires the generated waste/by-products absorbed in the same or other industrial process cycles and thus the material cycle remains closed. Industrial pollution appears as a big problem in the global south countries, where industrialization is considered as the main thrust of economic development. Usually, in such countries formal pollution control approaches are primarily directed to the formal sectors (such as state owned and legally registered industries), informal sectors are often left behind. Although the role of informal sector is increasingly being recognized for sustainable development, their significance in pollution abatement is a less discussed topic. This article attempts to investigate the informal industrial sector in Dhaka, Bangladesh with empirical evidence. Adopting a qualitative approach with field investigation of the informal industries and detail interviews, this study identified that the informal industries are closely linked in clusters according to the manufacturing process and continue material/byproduct/waster exchange primarily from the need to minimize cost. The studied patterns of waste management practice indicate existence of industrial symbiosis without adequate academic/technical knowledge and designed efforts. This suggests that the informal sector can meaningfully contribute to sustainable development offering insights for the application of similar approaches in the formal sector.

Is Tea Waste A Promising Co-substrate for Optimizing The Cultivation, Growth, and Yield of Charleston Pepper (Capsicum annuum L.)?

To address growing concerns about sustainable agriculture and waste management, this study aimed to explore the viability of tea waste as an eco-friendly alternative substrate for cultivating Charleston peppers (Capsicum annuum), with the goal of optimizing plant growth and yield while reducing soil dependence, lowering cultivation costs, and repurposing agro-industrial waste. Six different substrate combinations were evaluated: 1) Tea waste, 2) Tea waste + Manure, 3) Tea waste + Soil, 4) Manure + Soil, 5) Tea waste + Manure + Soil, and 6) Tea waste + Manure + Soil + Perlite. Data were analyzed using both multivariate and univariate analyses to assess significant differences among treatments. Notably, significant differences in stem diameter were observed among plants grown on different substrates (one-way MANOVA, p <.05). However, plant height and chlorophyll content remained unaffected by substrate type. Although leaf structure exhibited considerable variation across treatments, no significant difference in dry matter content was observed. These results demonstrate that tea waste, especially when combined with other materials, is a promising sustainable substrate for Charleston pepper cultivation, potentially reducing soil dependence and agro-industrial waste.

Role of big data analytics and hyperspectral imaging in waste management for circular economy

The accumulation of waste has a profound impact on the environment, prompting a crucial discussion about effective waste management strategies aligned with Oman Vision 2040’s sustainability goals. The consequences of municipal solid waste generation have multifaceted impacts on the environment, public health, and overall well-being of communities. Addressing these consequences requires a holistic approach that includes the integration of sustainable waste management technologies to foster a circular economy. This paper emphasizes the necessity for a paradigm shift in waste management methodologies, emphasizing the importance of Hyperspectral Imaging and Big Data Analytics into municipal solid waste management processes. This paper explores the synergistic relationship between hyperspectral imaging which is capable of precise material identification, and big data analytics to facilitate comprehensive data analysis. The integration aims to optimize waste segregation, resource recovery, and recycling processes. The utilization of data-driven insights enables predictive modeling and the identification of trends thereby facilitating more efficient and sustainable waste management practices. The harnessing of big data analytics empowers stakeholders to make informed decisions in waste management to achieve long-term environmental, and economic sustainability.

Spatial impulse response analysis and ensemble learning for efficient precision level sensing

In this paper, we propose an innovative method for determining the fill level of containers, such as trash cans, addressing a critical aspect of waste management. The method combines spatial impulse response analysis with machine learning (ML) techniques, offering a unique and effective approach for sound-based classification that can be extended to various domains beyond waste management. By employing a buzzer-generated sine sweep signal, we create a distinctive signature specific to the fill level of the waste container. This signature, once accurately decoded, is then interpreted by a specially developed ensemble learning algorithm. Our approach achieves a classification accuracy of over 90% when implemented locally on a development board, optimizing operational efficiencies and eliminating the need to delegate complex classification tasks to external entities. Using low-cost and energy-efficient hardware components, our method offers a cost-effective approach that contributes to sustainable and efficient waste management practices, providing a reliable and locally deployable solution.

Assessment of Physico-Chemical Properties of Biogas Slurry as an Organic Fertilizer for Sustainable Agriculture

Chemical fertilizers have been extensively used for growing crops and controlling plant diseases, but they pose potential hazards to the environment, soil health, plants, and people. The current world situation highlights the need to implement eco-friendly agricultural practices for sustainable crop production. Using environmentally friendly manure, such as biogas slurry, can help reduce the negative effects of chemical fertilizers. Biogas slurry is an efficient waste material and organic fertilizer, making it an ideal supplement for sustainable crop production and waste management. An experiment was conducted at IARI, New Delhi, to explore the nutrient potential of biogas slurry. The main objective of this study was to assess biogas slurry's physico-chemical characteristics and nutrient contents. Samples of biogas slurry were collected in three replications and analyzed using standard methods for macro and micronutrients. The data revealed that biogas slurry has a pH of 7.2-8.5, EC of 1.06 to 1.12 dS/m, and organic carbon content of 41.7 to 45.8%. In terms of fertility, it contains significant amounts of nitrogen (1.98-2.17%), phosphorus (0.97 to 1.15%), and potassium (1.98 to 2.17%). Additionally, biogas slurry contains micronutrients such as Zn (0.023-0.027 ppm), Cu (0.005-0.009 ppm), Fe (0.32-0.38 ppm), and Mn (0.089-0.094 ppm). Statistical analysis using ANOVA and Post Hoc tests indicated that the mean data values among all three replications do not differ significantly. Therefore, it can be concluded that the nutritive value of biogas slurry is sufficient to reduce the reliance on chemical fertilizers in agriculture. It represents an optimal long-term organic remedy for developing fertile soil, ensuring enduring agricultural productivity, and mitigating the negative environmental impacts associated with waste management.

Fabrication of heterogeneous catalyst for production of biodiesel form municipal sludge

Sewage sludge, a semi-solid byproducts of municipal wastewater treatment processes, offers a sustainable and cost-effective feedstock for biodiesel production through the synthesis of catalytic heterogeneous catalysts. In this study, we developed a novel heterogeneous catalyst by impregnating aluminum nitrate and calcite, obtained from carbon dioxide-sequestering bacteria, onto DigSBiochar (Biochar derived from digested sewage sludge). The produced catalyst was subsequently immobilized with the lipase enzyme isolated from Bacillus sp., creating a bioactive material for the transesterification of lipids in sewage sludge. Comprehensive characterization of the biocatalysts was conducted using Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (FE-SEM). Gas Chromatography-Mass Spectrometry (GC-MS) analysis of the resulting fatty acid methyl esters (FAMEs) demonstrated that the highest yield was achieved with the enzyme immobilized on the activated heterogeneous catalyst using methanol (99 %), followed by the activated heterogeneous catalyst with methanol (96 %), and methanol with Sulfuric acid (82 %). This study underscores the potential of utilizing municipal sewage sludge as a valuable resource for producing efficient heterogeneous catalysts, thereby advancing sustainable waste management practices and promoting renewable energy production.

Production of biogas from various types of spent mushroom substrate under different growth conditions

The mushroom cultivation industry effectively utilizes a diverse range of lignocellulosic waste but generates a significant amount of spent mushroom substrate (SMS) that poses disposal challenges. However, SMS can be used to generate valuable biogas. This study aimed to generate biogas by utilizing different types of spent mushroom substrate (SMS) obtained from three mushroom varieties. These mushroom varieties were cultivated in three types of greenhouses: Photovoltaic Shading greenhouse (PSG), shading greenhouse (SHG), and Control greenhouse (CG). The study found that the total solids (TS) and the amount of SMS used had a significant impact on both the total gas production and the removal of volatile solids (VS). The results demonstrated the feasibility of utilizing SMS as a raw material for biogas production, with variations observed depending on SMS type and greenhouse conditions. It contributes to knowledge in sustainable waste management and renewable energy production from agricultural by-products.

Assimilatory sulphate reduction by acidogenesis: The key to prevent H2S formation during food and green waste composting for sustainable urbanization

Food and green waste composting is a nature-based process for sustainable management of municipal organic waste. Although widely used for these organic wastes, composting is hindered by rapid organic acidification and malodor emission, particularly hydrogen sulphide (H2S). Using genome-resolved metagenomics, this study aimed to decipher the underlying mechanisms of sulphate reduction to H2S by acidogenesis during food and green waste composting. Results showed that both volatile fatty acids (VFAs) and H2S were significantly produced within the first week of composting. Further analysis identified that bacteria (e.g. Lactobacillus) with acid-producing genes (ackA and LDH) were key accomplices to assimilatory sulphate reduction for producing H2S by providing VFAs, especially acetic and lactic acids, as a carbon source. Such sulphate reduction could be directly induced by bacteria (e.g. Bacillus, and Ureibacillus) with intact assimilatory sulphate-reducing genes (cysNC, cysH, and cysJ/I). Nevertheless, individual bacteria (e.g. Paenibacillus and Acetobacter) without any sulphate-reducing genes could collaborate with their partners carrying complemented genes to complete sulphate reduction toward H2S. Furthermore, VFAs production could acidify composting substrates to abiotically aggravate the conversion of sulphur ions (e.g. S2- and HS-) to H2S. Nevertheless, alkaline additives suppressed these mechanisms to prevent both acidogenesis and H2S production, thereby, reducing the global acidification and human toxicity potentials of food and green waste composting.

A comprehensive investigation of the adsorption behaviour and mechanism of industrial waste sintering and bayer red muds for heavy metals.

The issue of heavy metal pollution is a critical global concern that requires urgent solution. However, conventional heavy metal adsorbents are too costly to be applied in large-scale engineering. In this study, adsorption behavior and mechanism of sintering red mud (RM-A) and bayer red mud (RM-B) for heavy metals were investigated to address the disposal of red mud as industrial waste and remediation of heavy metal pollution. Batch adsorption experiments were conducted to explore the adsorption performances of RM-A and RM-B under various conditions. Characterization of RM-A and RM-B before and after adsorption by XRD, FTIR and SEM-EDX was applied to investigate the specific adsorption behavior and mechanism. Adsorption experiments of both RM-A and RM-B fitted pseudo-second-order kinetic model and Langmuir isotherm model, with estimated maximum adsorption capacity of 21.96 and 25.19 mg/g for Cd2+, 21.47 and 26.06 mg/g for Cu2+ and 55.47 and 59.65 mg/g for Pb2+, respectively. Precipitation transformation of calcite was the primary adsorption mechanism for RM-A, whereas ion exchange of cancrinite, surface coordination compounds of hematite and minor precipitation transformation of calcite accounted for the adsorption mechanism for RM-B. Overall, RM-A and RM-B exhibited best adsorption performance for Pb2+, with RM-B showing greater adsorption capacity attributed to its higher specific surface area. This study compared the adsorption properties of RM-A and RM-B for the first time and demonstrated that both red muds can be effectively applied to remove heavy metals, thereby contributing to the sustainable industrial waste management and resourceful reuse.

The Role of Government and Community Collaboration in the Implementation of Waste Management Policies in Palu City

Waste management is a crucial issue for the growing city of Palu. Collaboration between the government and the community is the key to effective and sustainable waste management policy implementation. This study aims to describe the collaborative role between the government and the community in the implementation of waste management policies in Palu City. The method used is descriptive, with data collection through observation, in-depth interviews with relevant parties, and analysis of waste management policy documents. The data obtained was analysed qualitatively to provide an overview of the dynamics of collaboration that occurred. The results showed that the Palu City government has played a role in formulating policies, providing waste management facilities and infrastructure, and building a supportive regulatory framework. The government also initiated waste management programmes such as waste banks and temporary disposal sites (TPS)). On the other hand, the role of the community is seen through active participation in these programmes, as well as involvement in waste reduction and recycling activities in their respective neighbourhoods. Nonetheless, challenges are still faced, including the low level of public awareness, the lack of supporting facilities, and inadequate law enforcement. This study concludes that good collaboration between the government and the community is essential in achieving more effective waste management in Palu City. Strengthening collaboration through education, improving facilities, and consistent law enforcement are needed so that waste management policies can be implemented optimally.