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Energy Procedía 61 (2014) 704 - 708
The 6th International Conference on Applied Energy - ICAE2014
Economical and environmental impact of waste-to-energy (WTE) alternatives for waste incineration, landfill and
anaerobic digestion
Sieting Tanab' Haslenda Hashima*, Chewtin Leea, Mohd Rozainee Taiba, Jinyue
aFaculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia b School of Sustainable Development of Society and Technology, Malardalen University, SE-72123 Vasteras, Sweden _c School of Chemical Science and Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Sweden_
Abstract
This paper aims to evaluate the economical and environmental impact of waste incineration, landfill gas recovery system (LFGRS), and anaerobic digestion (AD) for municipal solid waste (MSW) management in Malaysia and subsequently assess the potential of each technology for energy uses and carbon reduction. An existing landfill, Taman Beringin, in Malaysia is selected as the case study, which is one of the largest national sites for waste management. The results present that incineration is the most economical profitable and climate-friendly WTE alternative as compared to an conventional landfill. With the production of 1430 MWh/d of heat and 480 MWh/d of electricity from 1000 t/d of MSW input, waste incineration is able to reach 287% of profit increment or 450 TUSD/d and 2250 tCÜ2/d of carbon avoidance by fossil fuel replacement as compared to baseline.
© 2014TheAuthors.PublishedbyElsevierLtd.Thisis an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/3.0/).
Peer-review under responsibility of the Organizing Committee of ICAE2014
Keywords: Anaerobic digestion (AD); Iincineration; Landfill gas recovery system (LFGRS); Municipal solid waste (MSW); Waste-to-energy (WTE)
1. Introduction
Rapid economic and tremendous population growths have caused municipal solid waste (MSW) to proliferate in Malaysia with significant change of waste consumption pattern and waste characteristic. The MSW is typically disposed in a bin or container within the house premise and collected by the respective regional private concessionaires. The wastes are firstly sending to transfer stations for compaction before being sent to the wastes disposal sites. The predominant treatment methods for MSW
* Corresponding author. Tel.: +60-7-5535478; fax: +60-7-5588166. E-mail address: haslenda@cheme.utm.my.
1876-6102 © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/3.0/).
Peer-review under responsibility of the Organizing Committee of ICAE2014
doi: 10.1016/j.egypro.2014.11.947
are landfills or the open dumpsites (93.5%), only 5.5% of MSW is recycled and 1.0% is composted [1]. The over dependency on landfilling had cause emission of methane gas (CH4), a more potent greenhouse gas (GHG) than carbon dioxide (CO2), through anaerobic decomposition of solid waste. GHG emission in waste sector had achieved a 54% of increment from year 1990 to 2008. Meanwhile, comparing the sub-sector within the waste sector, the main release of GHG comes from waste landfill site which released up to 90% the total emission from waste sector in Malaysia [2]. Waste-to-Energy (WtE) is recognised as a promising alternative to overcoming waste generation problem and a potential renewable energy (RE) source. Energy can be recovered from biodegradable and non-biodegradable matter through thermal and biochemical conversions [3]. The utilisation of MSW as a RE could overcome waste disposal issues, generate power for fossil fuel displacement and mitigate GHG emissions from waste treatment by converting CH4 to CO2. This option has therefore been considered an important and crucial factor to successful waste management. Some large-scale alternatives for WtE have been implemented in developed countries such as Japan, Germany, Sweden, The Netherlands, Denmark, and the United Kingdom. However, WtE is still under development in Malaysia [4]. The government is, therefore, interested in engaging WTE technologies to replace the dependency of traditional landfill and reduce the GHG emission, including landfill with biogas recovery system (LFGRS), waste incineration, and anaerobic digestion (AD). Feasibility analyses of WtE in Malaysia have been explored by local researchers over the past decade [5-9] however none of the studies compared the impact change in term of economical and environmental aspect from the existing baseline. Therefore, the objectives of this study is to evaluate the impact change from the baseline study represents by existing landfill as oppose to advance MSW technologies by compare the economic potential and carbon footprint of MSW disposal included LFGRS, incineration and AD for Taman Beringin landfill, Malaysia case study.
2. Methodology
The waste treatment alternatives considered in this study are: 1) LFGRS; 2) waste incineration; and 3) AD. The three waste treatment alternatives are selected as these are the most common WTE alternatives which considered by the Malaysia Government. The economic profitability includes transportation cost, carbon credit through carbon avoidance, and additional profit from selling of by-product. Meanwhile, the GHG calculation based on the Intergovernmental Panel on Climate Change (IPCC) Guideline [10] includes the GHG emission during energy conversion process, transportation of MSW to the waste treatment plant and carbon avoidance by fossil fuel replacement to renewable energy.
2.1Case study -Taman Beringin landfill, Malaysia
The Taman Beringin landfill is located in Jinjang Utara, Kuala Lumpur with an area of 16 ha, as showed in Fig 1. The landfill was currently serve as a waste transfer station (WTS) to transfer the MSW to the Bukit Tagar sanitary landfill located in the northern parts of Selangor state, 60 km away from Kuala Lumpur. [11]. Currently, the Malaysian government considers to further upgrade the waste management system with WTE technologies included LFGRS, waste incineration, or AD, to mitigate global warming potential while gaining profit from selling off by-product (electricity, heat, and fertilizer). Fig 2 presents the three possible alternatives for Taman Beringin landfill after the implementation of new waste management system.
2.1. System Boundary and parameters
Currently, approximately 2,500 t/d of waste was transferred from Taman Beringin landfill to Bukit Tagar sanitary Landfill. A new integrated MSW has been assessed by the government which includes LFGRS, incinerator or AD. For the new scenario,, about 1000 t/d MSW will undergo thermal treatment process lead to less amount of waste will be transferred to Bukit Tagar LFGRS. It is estimated that only
1,500 t/d of MSW will be sent to the landfill together with 10% ash from the incineration. Table 1 presents the data for the MSW management in Taman Beringin landfill.
Fig 1 Location of Taman Beringin landfill
Fig. 2 Flow diagram for current and future scenario of Taman Beringin landfill.
Table 1. Parameter for the solid waste management in Taman Beringin landfill
Parameter Base case Scenario
Taman Beringin lamdfill A. Bukit Tagar LFGRS B. Incineration C. Anaerobic digestion
Waste generation (t/d) 2500 1500 1000 1000
Average distance from transfer station to hub (km) n/a 60 60 60
Transportation trip/day 116 70 5 5
Tipping fee/waste collection fee (USD/t) 60 60 n/a n/a
Carbon Credit (USD/t CO2) 15.38
Transportation cost (USD/t-km) 9
Fertilizer price (USD/t) 153.37
Electricity price (USD/Mwh) 380
District heating price(USD/Mwh) 50
Ash production from incineration (t/t MSW) n/a 0.1 n/a
Electricity production (MWh/ t MSW) 0.374 0.48 n/a
Heat production (MWh/t MSW) n/a 1.43 n/a
Biogas production (m3/t MSW) 47.7 n/a 203.6
fertilizer production (t/tMSW) n/a n/a 1.07
Biogas electricity from AD, (MWh/m3) n/a n/a 0.0021
Biogas heat from AD (MWh/m3) n/a n/a 0.0025
CO2 emission from transportation (t CO2/km) 0.114
CO2 emission from processing (t CO2/t MSW) 1.11 0.49 0.253
3. Result and Discussion
The potential thermal energy generation from MSW in the form of electricity, heat and fertilizer for different scenarios of waste management in Taman Beringin landfill is presented in Fig 3. In term of energy production, heat and electricity production from incineration presents the highest potential with 1430MWh/d of heat and 480 MWh/d of electricity from 1000t/d of MSW input. AD generated lower
amount of energy product as compared to waste incineration, this is compensated by high production of fertilizer from AD (1070 t/d). LFGRS shows the lowest potential of energy production compared to incineration and AD. The economical profitability of the waste management in Taman Beringin landfill is illustrated in Fig 4 where the baseline case study shows a negative net profit of -150TUSD/d. Energy production from incineration resulted in the highest net profit (280 TUSD/d) and carbon credits (3.46 TUSD/d). The LFGRS presents a negative net profit (-53.6 TUSD/d), due to its low production. As compared to the baseline, the new integrated WTE treatment in Taman Beringin provides significant profitability. Incineration achieved the highest profit increment of 287% or 450 TUSD/d, followed by AD with 244% of profit increment (366TUSD/d) and LFGRS (-53.6TUSD/d). The carbon emission analysis is present in Fig 5. The baseline scenario released 2775 tCÜ2/d, from the emission of landfill gas. After implementation of new waste management alternatives, LFGRS shows the highest total emission (2143 tCÜ2/d) as compared to incineration (524.2 tCÜ2/d ) and AD (287.2 tCÜ2/d). Ün the other hand, AD found the highest potential of total carbon avoidance (2487.8 tCÜ2/d) as compared to baseline scenario due to its low net emission.
1600.0 1400.0 1200.0 1000.0 SOO.O 600.0 400.0 200.0 0.0
n Electrcity ¡ MWli d ) ■ Heat iMWh/dl □ Fertilizer lt d)
B - Incineration Scenario
Fig 3. Potential production from different scenarios of waste management in Taman Beringin landfill.
Fig 4 Economical profitable analysis for different scenarios in Taman Beringin landfill.
Fig 5 Carbon emission analysis for different scenarios in Taman Beringin landfill.
4. Conclusion
The economical and environmental impacts of LFGRS, incineration, and AD for a case study in Taman Beringin landfill was performed in this study. The finding suggested that incineration is the most economical profitable and environmental feasibility alternative as compared to the baseline study. It concluded that WTE alternatives especially is a potential option to mitigate GHG emission while achieve economic feasible with by-product production.
Acknowledgements
The authors gratefully acknowledge the research grant and financial support provided by the Ministry of Higher Education (MOHE) and University Teknologi Malaysia (UTM), under the GUP research grant number Q.J130000.2544.03H29. The acknowledgment also dedicated to MyPhD Scholarship from Malaysian Ministry of Education and the EU Eramus Mundus-IDEAS Project for providing scholarship to the first author.
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Biography
Dr. Haslenda Hashim is Associate Prof. and research fellow for PROSPECT of UTM. She specialises in process planning/scheduling, modeling and optimization for low carbon society (LCS), renewable electricity generation, waste to wealth, and fugitive emissions. She was a recipient of Korea Women Inventors Special Award in SIIF 2013.
