Assessment of Government Incentives for Energy from Waste in Colombia

Municipal solid waste management instruments that influence the use of the refuse as fuel in developing countries: A critical review

Landfills are the destination of most of the refuse generated whereas composting, material recycling, and Waste-to-Energy (WtE) technologies are not commonly employed in developing countries. However, the destination for energy purposes could be supplied with this refuse, improving the viability of energy use. Thus, this article raises some questions to identify aspects that could encourage its use as refuse-derived fuel (RDF) in these countries. Among them, does environmental education affect the municipal solid waste (MSW) source separation with emphasis on a destination? Can selective collection and extended producer responsibility (EPR) affect the MSW for energy recovery? Is there competition between the recycling market and the energy market for RDF? A systematic review of the literature was conducted to gather data and provide answers to such questions. This enabled to observe that EPR, selective collect expansion and source separation influence the quantity and quality of waste sent for energy use. Both internal and external factors impact on source separation. Additionally, there is evidence to support that despite several studies showing their technical, economic, environmental and social viability, the methods of energy usage of the refuse still need to improve their deployment in developing countries. In addition to identifying the main research gaps to be filled in future studies, the article also identified the instruments of MSW management that are to be applied in developing countries to divert recyclable and organic waste from landfill.

Techno-economic analysis of electricity generation from household sewage sludge in different regions of Nigeria

Waste management has been a chronic environmental challenge in Nigeria, coupled with declining economic performance due to energy crises. This study was designed to estimate electricity potential of sewage sludge to meet the 2030 Renewable Energy target. However, there was a need to fill the gap in data related to wastewater management in Nigeria. The wastewater and sludge generated from households were evaluated based on data on population, access to water, and coverage of sewer networks. Consequently, the technical and economic feasibility of electricity generation was assessed using Anaerobic Digestion (AD)1 and Incineration (INC)2 scenarios. The core results found that North Central had the highest potential for wastewater generation (142.8-403.6 billion litres/yr) and collection (8.3-37.5 billion litres/yr) over 20 years. However, the South East had the highest average sewer collection rate of 9.08 %. The AD technology was the most technically viable, with a maximum generation of 6.8 GWh/yr in the North Central. In comparison, the INC outperformed AD in most of the financial viability indicators considered viz-a-viz: Life Cycle Cost (LCC),3 Net Present Value (NPV),4 Pay Back Period (PBP),5 Internal Rate of Return (IRR),6 Levelized Cost of Energy (LCOE).7 The AD had a higher NPV of 16.3-69.58 million USD and a shorter PBP of about 4 years. The INC had a lower LCC of 0.1-0.34 million USD, LCOE of 0.046-0.094 USD/kWh, and a higher IRR of 19.3-25 %. Additionally, the sensitivity of NPV and INC to changes in economic factors would be noteworthy for investors and policymakers. Ultimately, the choice of technology should reflect the fiscal goal and priorities of a project.

Experimental investigation and multi-performance optimization of the leachate recirculation based sustainable landfills using Taguchi approach and an integrated MCDM method

Landfill leachates contain harmful substances viz. chemicals, heavy metals, and pathogens, that pose a threat to human health and the environment. Unattended leachate can also cause ground water contamination, soil pollution and air pollution. This study focuses on management of leachate, by recirculating the rich, nutrient-filled fluid back into the landfills, turning it to a bioreactor, thereby maximising the performance parameters of landfills favourable for electricity production by the waste to energy plants. This study demonstrates a sustainable alternative method for utilising the fluid, rather than treating it using an extremely expensive treatment process. Further, it also experimentally investigates the effect of varying levels of five input parameters of the landfill including waste particle size, waste addition, inorganic content in waste, leachate recirculation rate, and landfill age, each at five levels, on the multiple performance of the landfill using Taguchi's L25 standard orthogonal array. Experimental results are analysed using an integrated MCDM approach i.e. MEREC-PIV method and statistical techniques such as analysis of mean (ANOM) and analysis of variance (ANOVA). The results indicate that the optimal setting of the input parameters is waste particle size at 9 ppm, waste addition at 80 Ktoe, inorganic content in waste at 2%, leachate recirculation rate at 250 l/day and landfill age at 3 years. Further, inorganic content waste is found to be the most significant parameter for the multiple performance of the landfill. This study presents a novel approach to produce input parameters for power plants which may enhance their profitability and sustainability.

Multi-Criteria Selection of Waste-to-Energy Technologies for Slum/Informal Settlements Using the PROMETHEE Technique: A Case Study of the Greater Karu Urban Area in Nigeria

Slum/informal settlements are an integral part of a city, with a population projected to reach 3 billion by 2030. It is also expected that the rate of waste generation will more than triple by 2050 in the cities of low-income countries of sub-Saharan Africa. At this rate, the risk to the environment and health of inhabitants are enormous, because the current waste management practices are not guided by legislation on proper use and disposal. This paper proposes the conversion of waste to energy as a solution to this problem. The aim of this study is to apply the PROMETHEE technique with a combination weighting method to obtain the most appropriate waste-to-energy technology for the slum/informal settlements of the Greater Karu Urban area in Nigeria. The findings reveal that the gasification technology outperformed the other technologies, and the affordability of electricity supply from this technology was determined by a general survey conducted on the slum/informal settlements.

Waste to energy spatial suitability analysis using hybrid multi-criteria machine learning approach

Municipal solid waste is typically managed in developing countries through various disposal methods, such as sanitary landfills or dumpsites. Alternatively, waste to energy (WTE) systems have been recently adopted to provide sustainable waste management and diversify the energy mix. The abundance of remotely sensed datasets and derivatives, along with the rapid development of artificial intelligence, can offer an effective solution for WTE site selection. In this study, an analytical hierarchy process (AHP)-based framework supported by multiple machine learning algorithms (gradient boosted tree (GBT), decision tree (DT), and support vector machines (SVMs)) was established to explore the optimum location for WTE facilities. Various social, legal, environmental, economic, morphological, and land cover parameters were considered under 11 thematic geospatial raster layers. The proposed framework was applied to the 1.5-million-capita city of Sharjah, United Arab Emirates. A novel approach was developed to incorporate Gaussian dispersion modeling for the expected air pollution emissions from a WTE facility. The results showed that the accuracy performance sequence of the algorithms was 94.6, 93.9, and 91.8% for GBT, DT, and SVM, respectively. It was found that the distance from existing landfills had the most critical impact on the optimum location of the WTE facility, followed by the distance from coastline and elevation. The AHP consistency check revealed an acceptable overall criteria consistency index and the ratio of 0.0344 and 0.019, respectively. The results showed that 16.6% of Sharjah was considered extremely highly suitable areas. This research supports decision-makers in developing local guidelines for siting WTE facilities and determining the most suitable locations for such projects.

A Techno-Economic Evaluation of Municipal Solid Waste (MSW) Conversion to Energy in Indonesia

Municipal solid waste (MSW) processing is still problematic in Indonesia. From the hierarchy of waste management, it is clear that energy recovery from waste could be an option after prevention and the 5R (rethink, refuse, reduce, reuse, recycle) processes. The Presidential Regulation No 35/2018 mandated the acceleration of waste-to-energy (WtE) plant adoption in Indonesia. The present study aimed to demonstrate a techno-economic evaluation of a commercial WtE plant in Indonesia by processing 1000 tons of waste/day to produce ca. 19.7 MW of electricity. The WtE electricity price is set at USD 13.35 cent/kWh, which is already higher than the average household price at USD 9.76 cent/kWh. The capital investment is estimated at USD 102.2 million. The annual operational cost is estimated at USD 12.1 million and the annual revenue at USD 41.6 million. At this value, the internal rate of return (IRR) for the WtE plant is 25.32% with a payout time (PoT) of 3.47 years. In addition, this study also takes into account electricity price sales, tipping fee, and pretreatment cost of waste. The result of a sensitivity analysis showed that the electricity price was the most sensitive factor. This study reveals that it is important to maintain a regulated electricity price to ensure the sustainability of the WtE plant in Indonesia.

Identification of critical factors in construction and demolition waste recycling by the grey-DEMATEL approach: a Chinese perspective

The extensive waste produced in construction and demolition activities affects the ecological environment, impeding green development in countries worldwide, including China. China has paid increasing attention to managing construction and demolition waste (CDW). However, most of the existing research only qualitatively studies the factors affecting the recycling of CDW and does not reveal the critical factors. Therefore, based on stakeholder theory and the grey-DEMATEL method, this paper aims to identify and quantitatively analyze the critical factors in CDW recycling from the perspective of China. This paper drew the following conclusions: (1) Stakeholders in China's CDW recycling mainly include the government, CDW production units, and CDW recycling units. (2) Public policy, government subsidies, media promotion, human resources, cost, environmental awareness, technological innovation, and supply chain management are the eight dimensions with 13 factors that constitute CDW recycling in China. (3) For the total relations between factors affecting the recycling of CDW in China, the most influential factor is specific legislation and regulations. The factor with the highest degree of prominence is environmental awareness. The factor with the largest net cause value is the rationality of disposal and landfill charges. The factor with the largest net effect value is experienced construction workers. (4) The critical factors in China's CDW recycling include specific legislation and regulations, mandatory degree of normative standards, environmental awareness, the supply of raw materials for CDW recycling units, and the sale of remanufactured products. Finally, this paper identifies the following management implications: (1) the government should prioritize the task of improving specific legislation and regulations, with a focus on a mandatory degree of normative standards. (2) CDW production units should put the task of improving environmental awareness high on their agenda, with a focus on the supply of raw materials for recycling units. (3) CDW recycling units should prioritize the issue of the sale of remanufactured products. This paper also provides a theoretical basis for revealing the critical factors of CDW recycling in other countries or regions.

Enhancing waste management strategies in Latin America under a holistic environmental assessment perspective: A review for policy support

Waste remains a serious environmental and human health hazard in developing nations, including those in Latin America and the Caribbean (LA&C). Despite important breakthroughs in waste management in LA&C, the region still faces many challenges that require special attention, such as the existence of uncontrolled open dumpsters (33%) or the low recovery rates of waste fractions (below 4%). Moreover, the adoption of sophisticated waste management technologies, such as incineration or anaerobic digestion, is still lagging. This review paper provides environmentally-sound and relevant policy support for municipal solid waste management stakeholders through a critical review of the current situation of the waste management sector in LA&C from an environmental perspective. Thereafter, Life Cycle Assessment (LCA) bibliography linked to waste management, namely collection, sorting, recycling and landfilling applications and technologies worldwide, is used in order to understand potential alternative waste management strategies in LA&C, as well as the potential environmental benefits that could be attained. Finally, based on the holistic review and analysis, the adoption of more sophisticated technologies in landfill sites (e.g. landfill gas flaring), waste-to-energy, as well as higher recycling rates, would enhance waste management in the region and mitigate environmental impacts. A holistic view to support policy formulations, including climate action, for the adoption of integrated waste management strategies in LA&C is imperative.

New Policy and Implementation of Municipal Solid Waste Classification in Shanghai, China

To promote sustainable development, the Chinese government launched a new municipal solid waste (MSW) classification strategy in 2017. Shanghai was selected as one of the first pilot cities for MSW classification. The Shanghai municipal government first established the new MSW classification policy in 2017. The Shanghai Municipal Solid Waste Management Regulation was published in 2019 and came into effect on 1 July 2019. This short communication reports on Shanghai's new MSW classification policy and its implementation. The main content and measures adopted by Shanghai's government to ensure the effective implementation of the new MSW classification policy are introduced. Besides, a SWOT (i.e., strengths, weaknesses, opportunities, and threats) analysis on the present policy and measures is conducted, and based on the results, some discussions and suggestions regarding the implementation of MSW classification in Shanghai and the whole of China are presented.

Mitigation of CO2e Emissions from the Municipal Solid Waste Sector in the Kingdom of Bahrain

Mitigating climate change to limit the global temperature increase (relative to pre-industrial temperatures) to 2 °C is receiving considerable attention around the world. Here, historical and future carbon dioxide equivalent (CO2e) emissions from municipal solid waste (MSW) in Bahrain were calculated using the revised Intergovernmental Panel on Climate Change (IPCC) 1996 and IPCC 2006 methods. The extent to which waste-to-energy (WtE) technologies can contribute to climate change mitigation was assessed by performing a multicriteria analysis. The results indicated that CO2e emissions from MSW in Bahrain have been increasing since the Askar landfill was constructed in 1986. Emission recalculations indicated that CO2e emissions from MSW contribute 6.2% of total emissions in Bahrain rather than the 11.6% reported in the second national communication. Methane emissions from MSW in 2030 are predicted to be 22–63 Gg. The WtE technologies anaerobic digestion and landfill gas recovery gave the best and gasification the worst multicriteria analysis model results. A database of WtE plants around the world should be compiled to allow decisions around the world to be based on best practices. The potential for maximizing energy recovery and decreasing costs needs to be investigated to allow WtE plants to compete better with renewable and nonrenewable energy sources.

An Investigation of the Feasibility of the Organic Municipal Solid Waste Processing by Coking

In the context of transition to a circular economy, one of the strategic priorities is the development of technological innovations aimed at waste processing. In this study, the foundations have been developed for a low-temperature, environmentally safe method for efficient processing of organic municipal solid waste, which may be further applied for processing both municipal and industrial waste organics in order to obtain liquid products. The maximum yield of liquid products is ensured when conducting the coking of a mixture of organic waste with long residuum in the temperature range of 400–420 °C, with a heating rate of 5–70 °C/min, and with an optimal heating time to the coking temperature of 80 min. Recommendations on the use of the waste recycling products are given. The proposed process is consistent with the principles of circular economy and does not require external energy costs because the energy needed for the process is generated by burning the gas produced during the waste coking. The process does not produce emissions into the environment and, in combination with standard refining processes, can be used to obtain commercial petroleum products.

Financial feasibility of waste to energy strategies in the United Arab Emirates

The present research explores the financial feasibility of alternative waste management strategies, based on waste to energy, in the United Arab Emirates. The integrated strategies assessed in this study were primarily based on anaerobic digestion (AD) or incineration. The economics of both strategies were evaluated based on various revenue and cost streams, as well as multiple financial parameters over a 20-year period. Carbon credits were estimated based on the projected carbon emission reductions from each strategy. Realistic public participation and recovery rates for waste separation and recycling were applied. It was found that the incineration strategy is profitable with a net present value of 181 million USD, compared to -127 million USD for the AD strategy. The incineration strategy was more financially favorable in terms of the payback period, internal rate of return and profitability index, mainly due to the larger amount of processed waste. On the other hand, the AD was substantially affected by the landfilling cost of the produced digestate as well as the low participation rate in the proposed food waste separation program. The levelized cost of electricity for incineration and AD was 0.096 and 0.101 USD/kWh, respectively. The incineration and AD strategies were found to breakeven at a minimum of 52.4 and 31.2 million tons of processed waste, respectively. Certain legislative and social modifications made the AD strategy financially feasible. The sensitivity analysis showed that the net present values of both strategies were strongly affected by the variations in capital investments, landfilling costs, and electricity tariff.

Municipal Waste Management Strategy Review and Waste-to-Energy Potentials in New Zealand

Municipal waste management and Waste-to-Energy (WtE) potentials in New Zealand are discussed. The existing main waste management strategy of New Zealand is to reduce, reuse and recycle waste. Most of the remaining waste is currently disposed of in landfills. WtE options were explored in this study as a more sustainable waste treatment alternative in the country, while making use of the annual 30.8 petajoule of available waste energy in New Zealand. Four WtE technology options were discussed and compared, namely incineration, anaerobic digestion, gasification and pyrolysis. The aspects in comparison were air pollution, cost, side products, capacity, commercial maturity, energy efficiency and type of waste treated. Special emphasis was given to environment-friendliness and cost. From the comparison, it was found that anaerobic digestion seems to be the most attractive solution for the country as it is environment-friendly, economical and the concept is consistent with New Zealand’s existing waste management strategy. The major limitations of anaerobic digestion are its low energy production efficiency and its limited waste treatment capacity. Hence, an effective national waste reduction and recycling strategy is crucial for the success of this waste management option.