● Maldives’ unique natural and socioeconomic status cause waste management challenges.
● Context-specific solutions needed for sustainable waste management in Maldives.
● Waste management practices differ greatly between Male’ city and outer islands.
● Waste incineration in Male’ will double Maldives’ renewable energy supply.
● Decentralized anaerobic digestion proposed for outer islands to recover energy.
Effective waste management is a major challenge for Small Island Developing States (SIDS) like Maldives due to limited land availability. Maldives exemplifies these issues as one of the most geographically dispersed countries, with a population unevenly distributed across numerous islands varying greatly in size and population density. This study provides an in-depth analysis of the unique waste management practices across different regions of Maldives in relation to its natural and socioeconomic context. Data shows Maldives has one of the highest population density and per capita waste generation among SIDS, despite its small land area and medium GDP per capita. Large disparities exist between the densely populated capital Male’ with only 5.8 km2 area generating 63% of waste and the ~194 scattered outer islands with ad hoc waste management practices. Given Male’s dense population and high calorific waste, incineration could generate up to ~30 GW/a energy and even increase Maldives’ renewable energy supply by 200%. In contrast, decentralized anaerobic digestion presents an optimal solution for outer islands to reduce waste volume while providing over 40%–100% energy supply for daily cooking in local families. This timely study delivers valuable insights into designing context-specific waste-to-energy systems and integrated waste policies tailored to Maldives’ distinct regions. The framework presented can also guide other SIDS facing similar challenges as Maldives in establishing sustainable, ecologically sound waste management strategies.
Initiated a 300000 t/a WtE plant but abandoned due to protest, two small WtE plants operating
Bundhoo et al. (2016); Neehaul et al. (2020)
Seychelles
AIMS
High GDP, Low PD
Multiple biogas plants on animal farms
An incinerator treating oil and hospital waste; expects to set up a MSW WtE plant
Martin (2010); REEEP (2012); Bonnelame (2022)
Singapore
AIMS
High GDP, High PD
A few biogas plants for household waste treatment
Four WtE plants treating over 4000000 t/a of MSW, expect to build a new integrated WtE facility in 2027
Mohee et al. (2015); NEA (2019)
Belize
Caribbean
Low GDP, Low PD
Small-scale animal manure digestion
Not available
Ortega (2009)
Guyana
Caribbean
Low GDP, Low PD
~30 anaerobic digesters in farms
Not available
Rooplall (2017)
Suriname
Caribbean
Low GDP, Low PD
Not available
Two small-scale incinerators treating hospital waste
Zuilen (2006)
Cuba
Caribbean
Low GDP, Low PD
~700 small digestors for organic waste treatment, 450 new in build
Not available
Karagiannidis (2012); González Lorente et al. (2020)
Dominican Republic
Caribbean
Low GDP, Low PD
~20 anaerobic digesters in pig and chicken farms
Not available
Flores (2016)
Grenada
Caribbean
Low GDP, Low PD
Not available
Not available
Grenada (2017)
Haiti
Caribbean
Low GDP, Low PD
A few anaerobic digestors for agricultural waste treatment, small, cheap biodigesters built at home level
Not available
Toussaint & Wilkie (2011)
Jamaica
Caribbean
Low GDP, Low PD
~120 digestors for treating garden and kitchen waste
Not available
Karagiannidis (2012)
Saint Lucia
Caribbean
Low GDP, Low PD
Up to 9% of the total energy generated from biogas
Not available
Holder et al. (2020)
Saint Vincent and the Grenadines
Caribbean
Low GDP, Low PD
Up to 8% of the total energy generated from biogas
Not available
Holder et al. (2020)
Bahamas
Caribbean
High GDP, Low PD
A 2 m3/week anaerobic digestor
Not available
Holder et al. (2020)
Antigua and Barbuda
Caribbean
High GDP, Low PD
Plan to develop a bioreactor system to produce electricity
Not available
Holder et al. (2020); Silva-Martínez et al. (2020)
British Virgin Islands
Caribbean
High GDP, Low PD
Not available
Incineration is the main waste disposal method
Mcdevitt (2008)
Barbados
Caribbean
High GDP, High PD
Up to 18% of the total energy generated from biogas
Not available
Holder et al. (2020)
Fiji
Pacific
Low GDP, Low PD
Nine biogas plants; a new national WtE initiative for AD implementation
Not available
Holder et al. (2020)
Papua New Guinea
Pacific
Low GDP, Low PD
A pilot-scale anaerobic digestor treating farm waste
Not available
Jenangi (1998)
Samoa
Pacific
Low GDP, Low PD
Abandoned a few biogas plants
Abandoned an incineration plant
Isaka et al. (2013)
Tuvalu
Pacific
Low GDP, Low PD
A biogas plant treating pig and human sewage
Not available
Rosillo-Calle & Woods (2003)
Federated States of Micronesia
Pacific
Low GDP, High PD
Not available
An incinerator treating medical waste
Joseph & Prasad (2020); Jackson (2021)
Tab.2
Yard
Food
Other organics
Wood
Dirt, ash, stone, sand
Metal
Paper
Plastic
Textile
Cardboard
Glass
Rubber, leather
Hazardous, pets
Total
Total mass (t/a)
84260
aPercentage (%)
50.85
22.22
4.64
1.74
7.6
2.84
1.87
2.5
1.75
1.55
1.37
0.77
0.31
aMass (t/a)
42846
18723
3910
1466
6404
2393
1576
2107
1475
1306
1154
649
261
aMass (t/a)
117
51
11
4
18
7
4
6
4
4
3
2
1
Total waste (t/a)
231
bLHV MMBtu/t
6
5.2
5
10
0
0
6.7
23
13.8
16.5
0
14.4
0
LHV MMBtu/a
704.3
266.7
53.6
40.2
0
0
28.9
132.7
55.8
59.0
0.0
25.6
0
Ave LHV (kJ/kg)
6246
Total LHV MMBtu
257077
97357
19548
14661
0
0
10557
48450
20349
21549
0
9343
0
Energy capacity GW/a
29.2
Tab.3
1
R Alvarez, G Lidén. (2008). The effect of temperature variation on biomethanation at high altitude. Bioresource Technology, 99(15): 7278–7284 https://doi.org/10.1016/j.biortech.2007.12.055
2
R Alvarez, G Lidén. (2009). Low temperature anaerobic digestion of mixtures of llama, cow and sheep manure for improved methane production. Biomass and Bioenergy, 33(3): 527–533 https://doi.org/10.1016/j.biombioe.2008.08.012
S M Ashekuzzaman, T G Poulsen. (2011). Optimizing feed composition for improved methane yield during anaerobic digestion of cow manure based waste mixtures. Bioresource Technology, 102(3): 2213–2218 https://doi.org/10.1016/j.biortech.2010.09.118
5
C J Banks, M Chesshire, A Stringfellow. (2008). A pilot-scale comparison of mesophilic and thermophilic digestion of source segregated domestic food waste. Water Science and Technology, 58(7): 1475–1481 https://doi.org/10.2166/wst.2008.513
6
F Bernard, T Ben Khelil, V Pichon, L Tissot (2010). The Maldives: 2009 Carbon Audit. Maldives: Be Citizen and Ministy of Housing and Environment (MHE)
7
B Bonnelame (2022). Seychelles expects to set up a waste-to-energy plant in 2 years. Seychelles News Agency, Available online at the website of seychellesnewsagency.com (accessed September 26, 2022)
8
Z M A Bundhoo, S Mauthoor, R Mohee (2016). Potential of biogas production from biomass and waste materials in the Small Island Developing State of Mauritius. Renewable & Sustainable Energy Reviews, 56(Suppl. C): 1087–1100 https://doi.org/10.1016/j.rser.2015.12.026
9
E Cook, C Velis (2021). Global review on safer end of engineered life. London: Royal Academy of Engineering
10
H M El-Mashad, R Zhang. (2010). Biogas production from co-digestion of dairy manure and food waste. Bioresource Technology, 101(11): 4021–4028 https://doi.org/10.1016/j.biortech.2010.01.027
11
EPA (2010). Guidelines for transportation of waste: land and sea. Maldives: Environment Protection Agency
I Ferrer, M Garfí, E Uggetti, L Ferrer-Martí, A Calderon, E Velo. (2011). Biogas production in low-cost household digesters at the Peruvian Andes. Biomass and Bioenergy, 35(5): 1668–1674 https://doi.org/10.1016/j.biombioe.2010.12.036
14
W Flores (2016). Guide Towards a Sustainable Energy Future for the Americas. Tlalpan: Inter-American Network of Academies of Sciences (IANAS)
15
L I Fuldauer, M C Ives, D Adshead, S Thacker, J W Hall. (2019). Participatory planning of the future of waste management in small island developing states to deliver on the Sustainable Development Goals. Journal of Cleaner Production, 223: 147–162 https://doi.org/10.1016/j.jclepro.2019.02.269
16
M Garfí, L Ferrer-Martí, I Perez, X Flotats, I Ferrer. (2011). Codigestion of cow and guinea pig manure in low-cost tubular digesters at high altitude. Ecological Engineering, 37(12): 2066–2070 https://doi.org/10.1016/j.ecoleng.2011.08.018
17
M Garfí, J Martí-Herrero, A Garwood, I Ferrer. (2016). Household anaerobic digesters for biogas production in Latin America: a review. Renewable & Sustainable Energy Reviews, 60(Suppl C): 599–614 https://doi.org/10.1016/j.rser.2016.01.071
18
Lorente Á González, López M Hernández, Álvarez F J Martín, Jiménez J Mendoza. (2020). Differences in electricity generation from renewable sources from similar environmental conditions: the cases of Spain and Cuba. Sustainability, 12(12): 5190–5208 https://doi.org/10.3390/su12125190
19
W D Grenada (2017). Biogas made in jail. Available online at the website of dw.com (accessed September 26, 2022)
20
M A Habib, M M Ahmed, M Aziz, M R A Beg, M E Hoque. (2021). Municipal solid waste management and waste-to-energy potential from Rajshahi City corporation in Bangladesh. Applied Sciences, 11(9): 3744–3763 https://doi.org/10.3390/app11093744
21
N Holder, M Mota‐Meira, J Born, S L Sutrina. (2020). A compilation of the penetration of anaerobic digestion technology in 16 small island developing states in the Caribbean region. Biofuels, Bioproducts & Biorefining, 14(2): 493–502 https://doi.org/10.1002/bbb.2076
22
D Hoornweg, P Bhada-Tata (2012). What a Waste: a Gobal Review of Solid Waste Management. Washington, DC: the World Bank
23
A Hussain, M Filiatrault, S R Guiot (2017). Acidogenic digestion of food waste in a thermophilic leach bed reactor: effect of pH and leachate recirculation rate on hydrolysis and volatile fatty acid production. Bioresource technology, 245(Part A): 1–9
24
IFC (2011). Maldives: Solid Waste. Washington, DC: International Finance Corporation (IFC), World Bank Group
25
IRENA (2021). Renewable Energy Statistics 2021. Abu Dhabi: The International Renewable Energy Agency.
26
M Isaka, L Mofor, H Wade (2013). Pacific lighthouses: renewable energy opportunities and challenges in the pacific island region–Vanuatu. Masdar City: IRENA (International Renewable Energy Agency)
27
L (2021) Jackson. Kosrae State-Solid Waste Mangement Strategy 2018–2027. Palikir: Department of Environment, Climate Change & Emergency Management (DECEM)
28
L (1998) Jenangi. Producing methane gas from effluent. Adelaide: Adelaide University
29
L P Joseph, R Prasad. (2020). Assessing the sustainable municipal solid waste (MSW) to electricity generation potentials in selected Pacific Small Island Developing States (PSIDS). Journal of Cleaner Production, 248: 119222 https://doi.org/10.1016/j.jclepro.2019.119222
30
A Karagiannidis (2012). Waste to energy. Springer
31
S Kaza, L Yao, P Bhada-Tata, F Van Woerden (2018). What a waste 2.0: a global snapshot of solid waste management to 2050. Washington, DC: World Bank Publications
32
I Kelman, J J West. (2009). Climate change and small island developing states: a critical review. Ecological and Environmental Anthropology, 5(1): 1–16
33
A Khalid, M Arshad, M Anjum, T Mahmood, L Dawson. (2011). The anaerobic digestion of solid organic waste. Waste Management, 31(8): 1737–1744 https://doi.org/10.1016/j.wasman.2011.03.021
34
A Kumar, S R Samadder. (2017). A review on technological options of waste to energy for effective management of municipal solid waste. Waste Management, 69: 407–422 https://doi.org/10.1016/j.wasman.2017.08.046
35
S Lansing, J Víquez, H Martínez, R Botero, J Martin. (2008). Quantifying electricity generation and waste transformations in a low-cost, plug-flow anaerobic digestion system. Ecological Engineering, 34(4): 332–348 https://doi.org/10.1016/j.ecoleng.2008.09.002
36
H Y Leong, C K Chang, K S Khoo, K W Chew, S R Chia, J W Lim, J S Chang, P L Show. (2021). Waste biorefinery towards a sustainable circular bioeconomy: a solution to global issues. Biotechnology for Biofuels, 14(87): 1–15 https://doi.org/10.1186/s13068-021-01939-5
37
C Liu, T Nishiyama (2020). CCET guideline series on intermediate municipal solid waste treatment technologies Waste-to-Energy Incineration.
38
X F Lou, J Nair, G Ho. (2012). Field performance of small scale anaerobic digesters treating food waste. Energy for Sustainable Development, 16(4): 509–514 https://doi.org/10.1016/j.esd.2012.06.004
39
L Chand Malav, K K Yadav, N Gupta, S Kumar, G K Sharma, S Krishnan, S Rezania, H Kamyab, Q B Pham, S Yadav. (2020). A review on municipal solid waste as a renewable source for waste-to-energy project in India: current practices, challenges, and future opportunities. Journal of Cleaner Production, 277: 123227 https://doi.org/10.1016/j.jclepro.2020.123227
40
M Martin (2010). National assessment report: Republic of Seychelles (2004–2009). Victoria: Barbados Programme of Action, UN-DESA
41
C (2008) Mcdevitt. Waste management: solid sustainable waste management within the British Virgin Islands. Cape Town: University of Cape Town
42
MEE (2011). State of the Environment. Maldives: Ministry of Environment and Energy
43
MEE (2012). Maldives Scaling-up Renewable Energy Investment Plan. Maldives: Ministy of Environment and Energy
44
MEE (2016). State of the environment. Maldives: Ministry of Environment and Energy
45
MHE (2004). Indentification of Existing Barriers to the Provision of Effective Solid Waste Management Services Within the Maldives and Recommendations for Their Removal. Maldives: Ministry of Home Affairs and Environment
46
MHE (2010). National Economic Environment Development Studies. Maldives: Ministry of Housing and Environment
47
R Mohee, S Mauthoor, Z M A Bundhoo, G Somaroo, N Soobhany, S Gunasee. (2015). Current status of solid waste management in small island developing states: a review. Waste Management, 43(Suppl C): 539–549 https://doi.org/10.1016/j.wasman.2015.06.012
48
J Mosquera, D Chadwick, L Van Kinh (2012). Manure Management Options and Opportunities. Wageningen: Wageningen University and Research Centre
S Nanda, F Berruti. (2021). Municipal solid waste management and landfilling technologies: a review. Environmental Chemistry Letters, 19(2): 1433–1456 https://doi.org/10.1007/s10311-020-01100-y
51
NEA (2019). Zero Waste Master Plan Singapore, Available online at the website of towardszerowaste.gov.sg (accessed September 26, 2022)
52
N Neehaul, P Jeetah, P Deenapanray. (2020). Energy recovery from municipal solid waste in Mauritius: opportunities and challenges. Environmental Development, 33: 100489 https://doi.org/10.1016/j.envdev.2019.100489
53
U N Ngoc, H Schnitzer. (2009). Sustainable solutions for solid waste management in Southeast Asian countries. Waste Management, 29(6): 1982–1995 https://doi.org/10.1016/j.wasman.2008.08.031
54
J O’Connor, B S Mickan, J Rinklebe, H Song, K H Siddique, H Wang, M Kirkham, N S Bolan. (2022). Environmental implications, potential value, and future of food-waste anaerobic digestate management: a review. Journal of Environmental Management, 318: 115519 https://doi.org/10.1016/j.jenvman.2022.115519
55
M Ortega (2009). Installation of a low cost polyethylene biodigester. Geneva: IICA
56
T P T Pham, R Kaushik, G K Parshetti, R Mahmood, R Balasubramanian. (2015). Food waste-to-energy conversion technologies: current status and future directions. Waste Management, 38(Suppl C): 399–408 https://doi.org/10.1016/j.wasman.2014.12.004
57
K K Prajapati, M Yadav, R M Singh, P Parikh, N Pareek, V Vivekanand. (2021). An overview of municipal solid waste management in Jaipur City, India: current status, challenges and recommendations. Renewable & Sustainable Energy Reviews, 152: 111703 https://doi.org/10.1016/j.rser.2021.111703
58
REEEP (2012). REEEP Policy Database Seychelles, Available online at the website of reeep.org (accessed June 14, 2022)
59
S A Robinson. (2020). Climate change adaptation in SIDS: a systematic review of the literature pre and post the IPCC Fifth Assessment Report. Wiley Interdisciplinary Reviews: Climate Change, 11(4): e653 https://doi.org/10.1002/wcc.653
60
R Rooplall (2017). Using farm waste for biogas as alternative source of energy. Guyana Chronicle, Available online at the website of guyanachronicle.com (accessed September 26, 2022)
61
F Rosillo-Calle, J Woods. (2003). Individual Country Biomass Resource Assessment Profiles for Fiji, Kiribati, Samoa, Tonga, Tuvalu & Vanuatu. South Pacific Applied Geoscience Commission (SOPAC) Technical Report, 364: 73–153
62
A V Shekdar. (2009). Sustainable solid waste management: an integrated approach for Asian countries. Waste Management, 29(4): 1438–1448 https://doi.org/10.1016/j.wasman.2008.08.025
63
M Shumais (2010). Waste Management Practices in Dhiffushi, Kaafu Atoll, Maldives. Maldives: Environmental Protection Agency (EPA)
64
R D Silva-Martínez, A Sanches-Pereira, W Ortiz, Galindo M F Gómez, S T Coelho. (2020). The state-of-the-art of organic waste to energy in Latin America and the Caribbean: challenges and opportunities. Renewable Energy, 156: 509–525 https://doi.org/10.1016/j.renene.2020.04.056
65
H Tong, Z Yao, J W Lim, L Mao, J Zhang, T S Ge, Y H Peng, C H Wang, Y W Tong. (2018). Harvest green energy through energy recovery from waste: a technology review and an assessment of Singapore. Renewable & Sustainable Energy Reviews, 98: 163–178 https://doi.org/10.1016/j.rser.2018.09.009
66
R Toussaint, A C Wilkie. (2011). Anaerobic digestion of biowastes: an alternative energy source for Haiti. Energy, 1: 2
67
UNEP (2019). A regional waste management strategy and action plan for zone 6 in Maldives, Maldives: Ministry of Environment (ME)
68
UNSCAP (2021). Maldives National Waste Accounts 2018 & 2019 Final Report. Maldives: National Bureau of Statistics
69
K van Alphen, M P Hekkert, W G J H M Van Sark. (2008). Renewable energy technologies in the Maldives: realizing the potential. Renewable & Sustainable Energy Reviews, 12(1): 162–180 https://doi.org/10.1016/j.rser.2006.07.006
70
S Varjani, H Shahbeig, K Popat, Z Patel, S Vyas, A V Shah, D Barceló, Ngo H Hao, C Sonne, Lam S Shiung. et al.. (2022). Sustainable management of municipal solid waste through waste-to-energy technologies. Bioresource Technology, 355: 127247 https://doi.org/10.1016/j.biortech.2022.127247
71
Bank World (2017). Maldives to Improve Solid Waste Management With World Bank Support. Washigton, DC: World Bank Publications
72
Bank World (2022). World Bank Country and Lending Groups. Washington, DC: World Bank Publications
73
C Zhang, G Xiao, L Peng, H Su, T Tan. (2013a). The anaerobic co-digestion of food waste and cattle manure. Bioresource Technology, 129: 170–176 https://doi.org/10.1016/j.biortech.2012.10.138
74
T Zhang, L Liu, Z Song, G Ren, Y Feng, X Han, G Yang. (2013b). Biogas production by co-digestion of goat manure with three crop residues. PLoS One, 8(6): e66845 https://doi.org/10.1371/journal.pone.0066845
75
L Zuilen (2006). Planning of an integrated solid waste management system in Suriname: a case study in Greater Paramaribo with focus on households. Ghent: Ghent University
