Abstract
The increasing number of people in Indonesia, one of which is the city of Semarang, has led to increased community activities. Increased community activities will affect the increase in the ...amount of waste production. It will also impact the service life of the landfill, so efforts need to be made to extend the service life of the landfill. Efforts can be made to reduce the amount of waste that goes to the landfill, usually by sorting organic and inorganic waste. Reducing the amount of waste can also be done by utilizing waste that has been buried in the landfill (TPA), then processed into alternative fuels or RDF (Refused Derived Fuel). Waste reduction by sorting organic and inorganic waste has been carried out in several places, namely Putri Cempo TPA, Milangsari, and Sukoharjo, with percentage reductions of 79.6%, 35%, and 58%. Meanwhile, the use of waste into fuel or RDF (Refuse Derived Fuel) can also be used as an effort to extend the service life of the landfill because waste that has been buried for a long time has a high calorific value so that it meets the requirements as fuel for the pyrolysis process.
The recycling of source separated polyolefins (POs) (e.g., light weight packaging waste) is already state of the art. Therefore, further plastic materials contained in mixed wastes have become more ...important due to increasing legal pressure. Mixed commercial and municipal solid wastes contain large quantities of POs. These mixed wastes would usually be treated in waste incinerators or processed to refuse-derived fuel for cement plants. Large-scale experiments were conducted to assess the potential of such POs from these waste streams for recycling processes. The potential and applicability of a dry-mechanical and subsequently wet-mechanical (Wet-mechanical) processing with the aim of generating a PO concentrate for chemical recycling purposes was assessed. These investigations’ focus was put on the centrifugal force separator technology as the core element of Wet-mechanical processing. In addition to the input material, all output materials and process water streams were chemically and physically characterized to estimate potential treatment or recycling paths. Results demonstrate that a two-stage purification is necessary to produce POs with sufficient purity out of both wastes. Chlorine and heavy metal levels are simultaneously reduced. The increased quantity of impurities only slightly changes the density of the process waters. Process water analyses show that wastewater treatment is necessary before discharge into a receiving water or sewage treatment plant. The sediment does not fulfil any hazard-relevant properties, and different thermal treatment options are possible.
•A new particle scale transport model for MSW pyrolysis is presented and validated.•Waste is characterized as function of cellulose, hemicellulose, PE, PET and PS.•Composition optimization is based ...on non-isothermal mass loss curves.•Pyrolysis is expressed as a linear combination of pyrolysis of its components.
The solid phase decomposition during pyrolysis of municipal solid waste (MSW) and refuse-derived fuels (RDF) is modelled on particle scale accounting for heat and mass transfer. Waste pyrolysis is expressed as a linear combination of pyrolysis of its components. The novel characterization method used expresses waste composition in terms of three reference species. The selected species are a mixture of cellulose and hemicellulose, a mixture of polystyrene and polyethylene terephthalate, and a mixture of polyethylene and polypropylene. The pyrolysis kinetics models for these components are taken from the literature. The fractions of the components in the mixtures are optimized to fit the model to non-isothermal mass loss curves from selected experimental reports. The particle scale model has been evaluated against experimental transient temperature profiles at the centre of a large waste pellet during pyrolysis. The model is able to predict the main trend, but shows a more fluctuating temperature curve.
An experimental study was undertaken to compare the differences between municipal solid waste (MSW) derived solid recovered fuel (SRF) (complying with CEN standards) and refuse derived fuel (RDF). ...Both fuels were co-combusted with coal in a 50
kW fluidised bed combustor and the metal emissions were compared. Synthetic SRF was prepared in the laboratory by grinding major constituents of MSW such as paper, plastic, textile and wood. RDF was obtained from a local mechanical treatment plant. Heavy metal emissions in flue gas and ash samples from the (coal
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10% SRF) fuel mixture were found to be within the acceptable range and were generally lower than that obtained for coal
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10% RDF fuel mixture. The relative distribution of heavy metals in ash components and the flue gas stream shows the presence of a large fraction (up to 98%) of most of the metals in the ash (except Hg and As). Thermo-gravimetric (TG) analysis of SRF constituents was performed to understand the behaviour of fuel mixtures in the absence and presence of air. The results obtained from the experimental study will enhance the confidence of fuel users towards using MSW-derived SRF as an alternative fuel.
Solid Waste Management (SWM) is a technical subject which requires comprehensive planning, execution, and effective operational monitoring under cost-effective modes compatible with environmentally ...sound technologies. The policymakers made some enormous efforts for the sustainability of this sector as well as setting a benchmark for other municipalities and Waste Management Companies (WMCs) in the country. Provincial Government prioritizes its focus on SWM, i.e., waste collection, transportation, treatment, and final disposal. The waste management sector in Lahore has achieved sustainability in waste collection and haulage components by gaining experience from international outsourcing and, now, sharing its knowledge with other municipalities to strengthen the sector in the country. Lahore has emerged with the highest collection efficiency (84%) in SAARC countries and placed fifth in rank in comparison to 54 low–middle-income countries/cities worldwide. The sectorial interventions in Lahore reveal an aspiration for the sustainability of the SWM sector in Pakistan. However, there is an urgent need to focus and invest in waste-related infrastructure development, i.e., permanent/mobile transfer stations, semi-underground containers for commercial and planned areas, material recovery facilities (MRF), and landfill. Environmental and economic sustainability in this sector can be achieved through public–private partnership (PPP) modality in compost, anaerobic digestion, recycling, and refuse-derived fuel (RDF) as it is a more feasible option to strengthen the industry in the country.
As the volume of textile waste steadily increases, mechanical, chemical and biological technologies for textile waste recovery are evolving. Also, the legal framework of the European Union has stated ...the commitments for promoting the recycling of textile waste in the Member States. So far, however, no decision-making algorithms have been developed for the selection of products recovered from textile waste. Within the present study, a hybrid multi-criteria decision-making algorithm for evaluating textile waste recovered products has been developed applying seven circular economic criteria – ‘Circular economy approach of the technology’, ‘Added-value potential of final product’, ‘Share of textile waste in total waste feedstock’, ‘Diversity of textile mix suitable for specific technology’, ‘Pre-treatment of waste feedstock’, ‘Recovery potential’ and ‘Maturity of a recovery technology’. The weighting of the criteria was determined by eight waste management experts. The results of the expert-based criteria evaluation show that the most important criteria are ‘Added-value potential of final product’ and ‘Circular economy approach of the technology’. The developed decision-making methodology has been adapted to nine textile waste recovered products – compost, refuse-derived fuel, ethanol, glucose, building insulation material from cement and textile waste mix, building insulation material from denim textile waste, terephthalic acid, recovered cotton and recovered polyester. The multi-criteria, decision-making ranking of the products textile shows that the highest potential for products recovered from textile waste is for glucose and terephthalic acid, while the lowest – for ethanol, compost and refuse-derived fuel.
The products generated from a fixed bed pyrolysis unit of solid waste materials were quantitatively characterized, and their energy potential was determined, in order to evaluate their suitability as ...energy sources. An elemental analyzer, a bomb calorimeter, an X-ray fluorescence spectrometer, a Couette viscometer and a TG-MS (thermogravimetric-mass spectrometry) analyzer were employed for the measurements. Biochars obtained at 450 °C were enriched in carbon; their calorific value was high (20–39 MJ/kg) and exceeded that of raw materials. These biochars can be utilized for energy production, preferably at temperatures below 1000 °C, to avoid slagging/fouling phenomena. The bio-oils of pinecones and forest residue obtained at 450 °C, with a density of 0.93–0.94 kg/m3, a pH of 2.1–3, a dynamic viscosity of 1.5–7 cP and a calorific value of 22–27 MJ/kg, were superior to typical flash pyrolysis oil and could be used in static applications for heat or electricity generation after a de-oxygenation process. The quality of RDF bio-oil was lower. The higher heating value of gases from pinecones and RDF fuels at 450 °C was satisfactory for the energy requirements of the process (13.6–13.8 MJ/m3); however, that of forest residue gas was moderately low.
The role of Mechanical–Biological Treatment (MBT) is still of the utmost importance in the management of residual Municipal Solid Waste (MSW). These plants can cover a wide range of objectives, ...combining several types of processes and elements. The aim of this work is to assess and compare, from an environmental point of view, the performance of seven selected MBT plants currently operating in different countries, which represent the main MBT layout and processes. For the scope, a combined Life Cycle Assessment (LCA) and Material Flow Analysis (MFA) approach has been adopted to assess plant-specific efficiencies in materials and energy recovery. Metals recovery was a common and high-efficiency practice in MBT; further recovery of other types of waste was often performed. Each assessed MBT plant achieved environmental benefits: among them, the highest environmental benefit was achieved when the highest amount of waste was recovered (not only with material recycling). Environmental results were strongly affected by the recycling processes and the energy production, with a little contribution from the energy requirement. The impacts achieved by the MBT process were, on average, 14% of the total one. The main condition for a suitable MBT process is a combination of materials recovery for the production of new raw materials, avoiding disposal in landfill, and refuse-derived fuel production for energy recovery. This work can be of help to operators and planners when they are asked to define MBT schemes.
India accounts for six per cent of the world’s primary energy consumption. Rapid urbanization and rapid urban population growth have had a serious impact on energy consumption and subsequent carbon ...emissions. In particular, cities face a complex and interrelated set of challenges across different sectors (building environment, mobility, water and waste management and public services). Re-examining these challenges by integrating smart energy management (SEM) principles is critical for sustainable and low-carbon urban development. In addition, managing energy footprint is one of the most challenging goals for cities, and as existing cities evolve and transform into smart cities, SEM becomes an integral part of the urban transformation. This article comprehensively reviews the different SEM technologies for different sectors (construction, transportation, public services, water and waste), the policies, and the current challenges and opportunities for SEM policy governance in India. Making urban energy smart can manage a city’s energy footprint and have a positive impact on future carbon emissions.
Napier grass is a herbaceous biomass that can be used as biofuel; however, its high ash, potassium, sulfur and chlorine content may cause problems when combusted. Napier grass was submitted to ...vapothermal carbonization (VTC) and hydrothermal carbonization (HTC) processes at 190 and 220 °C to compare their ability to enhance its fuel properties. The different water distribution between phases in the two processes was verified: up to 14.5% of the water vaporized to steam in the VTC ran at 220 °C, while over 99% of the water remained in the liquid state and in contact with the solids during all HTC runs. Both processes improved the calorific value of the Napier grass (up to 20.6% for VTC220 and up to 29.8% for HTC220) due to the higher C content in the chars. Both processes reduced the sulfur content, removing up to 15.3% of it with VTC190 and 28.5% of it with HTC190 compared to that of Napier grass. In contrast, the two processes had different effects on the ash and chlorine content. While HTC removed both ash and Cl from the Napier grass, VTC concentrated it in the chars (ash: 5.6%wt. Napier grass, 3.3%wt. HTC chars, 7.1%wt. VTC; chlorine: 1.08%wt. Napier grass, 0.19%wt. HTC chars, 1.24%wt. VTC). Only the HTC process leached high percentages of Cl (up to 80%), S (up to 70%), sodium (Na, up to 80%) and potassium (K, up to 90%) into the process water. This may prevent fouling and slagging problems when burning HTC char. The biofuel qualities of the raw Napier grass, VTC, and HTC chars were evaluated using two standards: the international standard for solid biofuels, EN ISO 17225, and the Korean regulation for biomass solid recovered fuels (Bio-SRF). Napier grass and VTC chars presented problems regarding Cl content thresholds for both EN ISO 17225 and Bio-SRF. Both VTC and HTC chars along with the Napier grass fulfilled the requirements for heavy metals (Pb, Ni, Cr, and Cd) except for copper. The choice of process in practical applications will depend on the goal; HTC improves fuel quality and VTC has higher high solid, carbon and energy yields.
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