This was a paper submission for my module on Environmental Economics and Policy at the University of Leeds, under the program, MSc Environment and Development. I enjoyed working on this. Please do not plagiarise.
INTRODUCTION
This paper assesses the sustainability of four landfill waste recovery options for the Kpone landfill site using a multi-criteria analysis approach. Data used in the multi-criteria analysis was based on literature, site reports and technical reports on product options’ performance and suitability. The Kpone engineered landfill was constructed for use in 2013 under a coordinated effort from the Ghana Government’s Ministry of Works and Housing to implement safer means of waste disposal throughout the capital under the Greater Accra Resilient and Integrated Development (GARID) initiative(Salifu, 2019).
Despite the engineered landfill being designed to international standards with leachate treatment systems, methane collection pipes and other standard features, it faced several sustainability challenges undermining its suitability to last for 25 years for which it was originally designed. After eight years, it was decommissioned as reports indicate this was primarily due to the unexpected waste amounts that overwhelmed the capacity of the Kpone engineered landfill. The Kpone landfill was designed to receive fresh domestic and commercial daily waste of 500 tonnes, gradually exceeding 1,000 tonnes in 2013, peaking at 2,500 tonnes daily by 2016(Fagariba and Song, 2016; Stoisser, 2020).
As a result, several challenges developed, including cell merging, low soil coverage, increased fire outbreaks, frequent leachate pond flooding, an increased presence of rodents, coupled with community demonstrations on health concerns escalated management’s decision concerning the landfill site (Ahlijah, 2016; Amfo-Otu and Seyram Abledu, 2018; Fagariba and Song, 2016). Hence in 2019, the authorities determined to decommission the landfill with consideration of various alternatives to landfill gas (LFG) recovery systems (Salifu, 2019).
Background on landfill gas recovery options
This section provides a brief discussion of the four landfill gas recovery options to ensure understanding of what led to the final selection of these four options. In the decommissioning report by GARID concerning the Kpone landfill and the World Bank Greater Accra Development project report, there was an indication for transforming the decommission site into a recreational centre (The World Bank, 2017; Salifu, 2019). Feasibility evaluations attempted to generate a robust means of funding for maintenance, community employment and reduce the environmental impact arising from residual leachates that would still require management. In addition, it was recognized that decommissioning procedures most often include a landfill recovery system as a part of the management procedure (The World Bank, 2017; Salifu, 2019; Hallaton, 2021; Geosyntec, 2021).
During an initial analysis of waste to energy generations in landfill operations, several factors are considered including waste composition and climatic temperatures (Sattler et al., 2016; Boamah et al., 2017; Kusi et al., 2017). In addition, technology specifications suitable for the unique engineered landfill features are to be considered, such as the number of wells, quality of gas produced, moisture content etc.(Rahmaputro et al., 2012; Ofori-Boateng et al., 2013; Sattler et al., 2016). During this period, the selected literature based on previous studies conducted on the Kpone landfill site, four LFG recovery systems were frequently suggested using analytical tools besides the multi-criteria analysis tool.
APPRAISAL TECHNOLOGY
Multi-criteria analysis sits as part of an extensive set of economic and decision-making tools for deciphering which option amongst a set of alternatives are best for policymakers to usually select (DLG, 2009).
Multi-criteria analysis was selected for this report as it has been frequently used to assess the sustainability of waste management systems, projects, and (Taelman et al., 2018). This is largely because multi-criteria analysis enables the computation of several criteria that may include non-monetary valuations (DLG, 2009). In analysing sustainability frameworks employed in the context of waste management, Taelman et al. (2018) highlight the multi-dimensional nature of waste management, and the highly debated ‘meaning’ of sustainability. Hence, several considerations that influence a waste management project span different geographical locations, technologies, legal implications and actors including waste generators, transporters and managers etc., which cannot be accurately represented in a common baseline of monetary valuations with cost-benefit analysis (CBA).
Cost-Benefit Analysis can include Environmental and Social objectives, provided they can be priced in the monetary valuation ‘language’ of CBA. In this way, CBA is limiting as evidence indicates that such a refinement or use of a proxy that forces a common baseline may not fully capture the ‘full value of such objectives (BIOMOT, 2013).
Furthermore, MCA provides structure, through the judgement of the ‘best’ option based on preset objectives, weightings and performance criteria, altogether described as the input, allowing much more control in the hands of the decision-maker as well greater flexibility and accountability (Beria et al., 2012).
- Decision context: Stakeholders include the Tema Metropolitan Assembly (TMA), who are described as owners of the landfill site, Wastelandfills Ghana Limited, contracted managers of the landfill sites by the TMA, informal workers and scavengers of the landfill site, representatives of GARID and Kpone Community Members (AMEC, 2010; Salifu, 2019).
Based on the assessment of the decommissioning GARID report and stakeholders’ considerations, this report aims to select an appropriate landfill gas recovery method that is economically, technically, socially and environmentally feasible to avoid maintenance challenges that result in premature decommissioning of the landfill site.
2. Options/Alternatives: Considering the available research literature and data, the following alternative options are included in this MCA:
a. Conventional Combined Heat and Power (CHP) Microturbine Landfill gas Recovery
b. Conventional Engine Landfill gas recovery
c. Bioreactor CHP Microturbine Landfill gas recovery
d. Bioreactor Engine Landfill gas recovery
3. Identify the objectives and criteria: To satisfy the priorities of all the stakeholders previously identified in the decision context. Four main objectives have been identified. The first objective, “reducing greenhouse gas emissions and overall environmental impact”, can be classified under environmental impact. The second objective, “financial revenue for maintenance and income for surrounding communities”, addresses the economic concerns of all stakeholders. The third objective, “introducing a maintained or increased contribution to the health and welfare of nearby inhabitants and workers,” acknowledges the social dimension of this study. The fourth objective, “assessing each option’s capacity and operations,” is classified under technical.
The set criteria under each objective are detailed in Table 1.
4. Scoring Index: Table 2 highlights the overall design of the MCDA performance matrix and the set criteria under the four objectives. This landfill gas recovery system was designed for 44 years, from 2016 to 2060.
Methane emissions: Data from three studies on the Kpone landfill emissions were studied(Rahmaputro et al., 2012; Sattler et al., 2016; Salifu, 2019) and compared to a report that proposed the use of emissions from the site considering the four landfill gas recovery systems above(Jangikhatoonabad, 2015). From this, methane emissions were reduced according to each landfill gas recovery system type in the unit of a billion standard cubic feet over the projected period.
Thermal emissions: Clear calculations for the four options were difficult to ascertain; hence estimates were made and matched to baseline options associated with the features of the selected engines and microturbines (United States Department of Energy, 2022; US EPA, 2022). The criteria were assigned a scoring system of 1 to 4 to indicate which ranking had fewer thermal emissions (1) and which had the highest (4).
Leachate Usage: According to Jangikhatoonabad (2015), bioreactor systems make use of leachate within the landfill, whilst conventional recovery systems do not. Previously, leachate that is not used or well-managed have contributed to significant environmental impact leading to contamination of soil and water bodies (Graphic Online, 2020; Obiri-Nyarko et al., 2021).
Construction cost, Payback year, Capital Cost, Annual O&M Cost, Number of households provided electricity, Average Electricity generation and Average methane utilized: Analysis of the estimates were directly from the feasibility study to install and operate landfill gas recovery options in Kpone as the analysis indicated suitable options and their associated costs as well electricity generation potential for each technology option(Jangikhatoonabad, 2015; Sattler et al., 2016). With the average cost of electricity from the landfill gas estimated to be sold to consumers at USD 0.039/kWh, the payback could be concluded(Ofori-Boateng et al., 2013).
Jobs: Estimates were reached using the LFG cost web provided by the US EPA (2022). This was compared to a literature study that indicated employment associated with electricity generation per megawatt is 185 employees for an engineered landfill (Ofori-Boateng et al., 2013). However, this literature did not state the number of years employees would be engaged or associated ripple effects as the LFG cost web does.
Requires waste tillage: In the option selected for LFG, the technology used plays a role. For example, bioreactors require more gas in their pipelines daily. Hence management procedure is to employ waste tillage at the decommissioned site (Sattler et al., 2016).
5. Weighting: It is significant to note that each identified stakeholder regards or weighs each differently for the set objectives. Hence, considering stakeholders’ input through secondary data such as reports, news articles, weighting as assigned to the various objectives and criteria using local scaling and swing scaling (DLG, 2009).
For objective, the environment was ranked 100 due to emerging challenges of leachate contamination from the Kpone landfill site as well as Ghana’s interest as a nation to adhere to the climate protocol agreement (Government of Ghana, 2021). Under environment, methane emissions were ranked 100, with leachate usage and thermal emissions carrying scores of 90 and 80, respectively. Methane emissions rank high due to their compounded effect on global warming. As well, leachate usage is appealing to TMA and landfill managers as it would mean reduced occurrences of flooding, which often lead to contamination of surrounding water bodies. Thermal emissions are ranked third but with a high score because of the awareness that heat may kill, especially in a highly industrialized setting such as Tema (CEIC, 2015).
Economic was ranked 90 due to Ghana’s challenges in funding its sanitation challenges associated with low income and high expenditure from taxes. Hence, costly projects have a history of being scrapped. Hence the expenses and funding arrangements such as Capital year (100), annual cost (90), payback year (80) and construction cost (60) are significant (The World Bank, 2017).
Social was ranked 85 as electricity generation for households (100) and jobs (75) are politically motivated to gain favour within densely populated areas such as Tema(SEDI, 2021).
Lastly, the technical objective was scored 80, with methane utilization scoring 100. Average electricity generated scoring 90 and waste tillage scoring 60. The reason for these scores is Ghana’s indication in expanding its income to include financing from carbon markets and generating income from the sale of methane capture and processing (Asante et al., 2015)
RESULTS AND DISCUSSION
6. Overall value: A composite analysis of the four alternatives revealed Bioreactor Engine as the most sustainable option. By weight, the ‘environment’ objective influenced this alternative most, followed by its technical offerings, social benefits and economic objective. The details can be seen in Figure 4.
7. Examine Results: In the criteria breakdown, we see households (a ‘social’ objective) carrying the greatest weighting for bioreactor engine. After the ‘number of households to be provided electricity’, ‘methane emissions removed’ and ‘leachate usage’ hold the next ‘greatest’ weight respectively. As objectives under environment, this would explain why the environment was perceived to have significant weighting as this includes a weighting of 0.063 from thermal emission ranking. The next suitable option is also a bioreactor option with a microturbine These two top options seem to tally with a feasibility study evaluation of LandGem, IPCC and UTA-CLEEN models for conventional and bioreactor operations (Jangikhatoonabad, 2015).
8. Sensitivity analysis: By conducting a sensitivity analysis of the weightings of the objectives and criteria, we can garner more detail about the effect of prioritizing certain interests of stakeholders over others. For example, if Bioreactor Engineer is the best option in the environment, at what point does that change? From Figure 5 below, we can determine when the overall weighting of the environment is significantly increased from 0.28 to 0.62. Bioreactor CHP with a Microturbine would be the best option as thermal emissions would be considered significant as well, causing a shift in selection priorities.
If a top concern of the Ghana government is speedy loan repayment to its international creditors(Ghana News Agency, 2022), the payback year is adjusted to have greater weighting than the capital cost to demonstrate its prioritization. In this scenario, Bioreactor CHP with Microturbine would be best as its payback year is two years. However, its initial capital cost, the highest among the four options, may deter the government despite its high technical efficiency.
Moreover, the final report emphasized the need for robust maintenance systems in managing the decommissioned landfill as it identified the premature closure of the landfill site could have been avoided in such regard. However, landfill managers attributed more maintenance to cash flow and debt repayment systems. Hence, prioritizing finances would cause conventional alternatives to be preferred(Ahlijah, 2016).
Due to frequent community demonstrations (Stoisser, 2020), an engagement from waste pickers and Kpone community representatives highlighted the need for health concerns, jobs and distributed community benefits from the decommissioned landfill site. Bioreactor CHP with a Microturbine would be the best option where the secondary and tertiary needs of community members of be addressed in job provision and electricity provision for community members from the landfill to be prioritized.
CONCLUSIONS
In conclusion, the landfill gas recovery options hold significant benefits for all stakeholders involved. However, a careful balance to ensure sustained use of the decommissioned landfill must be prioritized to avoid what leads to its early closure. In such a case, financing and economical options may be prioritized to ensure the selected landfill gas recovery system is profitable and economically feasible. In such case, conventional options may be preferred. However, bioreactor alternatives have proven that with high technical efficiency, increased social benefits and minimal environmental impact, it can be a better option, possibly providing more income from higher electricity generation, albeit later on.
REFERENCES
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WORD COUNT: 2,497/2500
Grade: 74/100
Instructor’s comments:
The introduction provides useful background to the study. It would have been useful to contextualise this work within the context of the literature. Did you come across similar studies? Why would it be relevant to conduct a MCA in this context? This would have helped to motivate your work further and beyond the specific context of the study. The methodology is explained in very good detail. It is very clear how the study was performed and what data was used. Something that could have complemented the performance matrix is a column indicating the data sources used. In addition, it isn’t fully clear how each of the objectives were weighted. The sensitivity analysis isn’t referred in the methods but it would have been useful to include a brief note on it here. The results are clearly presented and interpreted. The sensitivity analysis is thoroughly done. The report would have benefitted from a more in-depth discussion of the results. This would have meant to add some reflections on the implications of these findings, how they compare to other existing studies (if any) and what would they mean in terms of existing gaps in the literature / practice. Some reflections on the limitations would have been useful too. On the whole this is a well conducted study. It shows a good engagement with the literature and the method. It could be strengthen by including a more in-depth discussion.