Energy Utilization Assessment of Municipal Sewage Sludge Based on SWOT-FAHP Analysis
2. Materials and Methods
2.1. Treatment and Disposal of MSS in Jiangsu, China
2.2. Composition and Characteristics of MSS
2.3. Treatment and Disposal of MSS
2.3.1. Anaerobic Digestion
3. Legislation of MSS Management in China and Jiangsu, China
4. The Energy Recovery Potential Assessment
4.1. Energy Recovery Potential Assessment of Anaerobic Digestion
4.2. Energy Recovery Potential Assessment of Incineration
4.3. Energy Recovery Potential Assessment of Pyrolysis
4.4. Energy Recovery Potential Assessment of Gasification
5. Comparative Evaluation by SWOT-FAHP Analysis
5.1. SWOT Analysis
- Problem solving: Was the relevant energy utilization method sufficient to treat sewage sludge or is additional treatment required?
- Ecological environment: Were greenhouse gas emissions produced under the background of carbon neutrality, and could a reduction in greenhouse gas emissions be achieved?
- Technological development: Has the method been applied in Jiangsu Province, and at what stage is it currently in (site scale, pilot scale or laboratory scale)?
- Laws and regulations: Were there any corresponding laws and regulations related to this method? Was it a national standard or an industry standard?
5.2. Fuzzy Hierarchy Model and the Introduction of the Trapezoidal Fuzzy Function Method
5.3. Results of SWOT-FAHP Analysis
6. Potential Deployment Barriers to Sludge Pyrolysis
- Sales of pyrolysis products: The market for pyrolysis products needs to be further expanded to effectively utilize pyrolysis products.
- Technical risk issues: If the technology is not applied on a large scale before implementation, the relevant parties would be generally unwilling to bear any unknown risks.
- Financial support issues: It was difficult to obtain project funding due to the lack of operational experience.
- Countermeasures to manage the market problems of pyrolysis products: pygas and bio-oil could be applied for boiler power generation, fuel production, chemical raw materials, etc. Biochar could be employed to produce activated carbon, for soil remediation, in situ adsorption of pollutants in sewage plants, etc.
- Countermeasures to manage large-scale application problems: the government could be the initiator and invest a certain amount of research funds and establish sludge pyrolysis pilots.
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
- Zhang, Q.; Hu, J.; Lee, D.J.; Chang, Y.J. Sludge treatment: Current research trends. Bioresour. Technol. 2017, 243, 1159–1172. [Google Scholar] [CrossRef] [PubMed]
- Cieślik, B.M.; Namieśnik, J.; Konieczka, P. Review of sewage sludge management: Standards, regulations and analytical methods. J. Clean. Prod. 2015, 90, 1–15. [Google Scholar] [CrossRef]
- Husek, M.; Mosko, J.; Pohorely, M. Sewage sludge treatment methods and P-recovery possibilities: Current state-of-the-art. J. Environ. Manag. 2022, 315, 115090. [Google Scholar] [CrossRef] [PubMed]
- Appels, L.; Baeyens, J.; Degrève, J.; Dewil, R. Principles and potential of the anaerobic digestion of waste-activated sludge. Prog. Energy Combust. Sci. 2008, 34, 755–781. [Google Scholar] [CrossRef]
- Breda, C.C.; Soares, M.B.; Tavanti, R.F.R.; Viana, D.G.; da Silva Freddi, O.; Piedade, A.R.; Mahl, D.; Traballi, R.C.; Guerrini, I.A. Successive sewage sludge fertilization: Recycling for sustainable agriculture. Waste Manag. 2020, 109, 38–50. [Google Scholar] [CrossRef]
- Wickham, R.; Xie, S.; Galway, B.; Bustamante, H.; Nghiem, L.D. Anaerobic digestion of soft drink beverage waste and sewage sludge. Bioresour. Technol. 2018, 262, 141–147. [Google Scholar] [CrossRef]
- Li, G.; Hao, Y.; Yang, T.; Wu, J.; Xu, F.; Li, L.; Wang, B.; Li, M.; Zhao, N.; Wang, N.; et al. Air pollutant emissions from sludge-bituminous briquettes as a potential household energy source. Case Stud. Therm. Eng. 2022, 37, 102251. [Google Scholar] [CrossRef]
- Li, G.; Hu, R.; Hao, Y.; Yang, T.; Li, L.; Luo, Z.; Xie, L.; Zhao, N.; Liu, C.; Sun, C.; et al. CO2 and air pollutant emissions from bio-coal briquettes. Environ. Technol. Innov. 2023, 29, 102975. [Google Scholar] [CrossRef]
- Gao, N.; Kamran, K.; Quan, C.; Williams, P.T. Thermochemical conversion of sewage sludge: A critical review. Prog. Energy Combust. Sci. 2020, 79, 100843. [Google Scholar] [CrossRef]
- Seiple, T.E.; Coleman, A.M.; Skaggs, R.L. Municipal wastewater sludge as a sustainable bioresource in the United States. J. Environ. Manag. 2017, 197, 673–680. [Google Scholar] [CrossRef]
- Yadav, M.K.; Gerber, C.; Saint, C.P.; Van den Akker, B.; Short, M.D. Understanding the Removal and Fate of Selected Drugs of Abuse in Sludge and Biosolids from Australian Wastewater Treatment Operations. Engineering 2019, 5, 872–879. [Google Scholar] [CrossRef]
- Suciu, N.A.; Lamastra, L.; Trevisan, M. PAHs content of sewage sludge in Europe and its use as soil fertilizer. Waste Manag. 2015, 41, 119–127. [Google Scholar] [CrossRef] [PubMed]
- Hong, J.; Hong, J.; Otaki, M.; Jolliet, O. Environmental and economic life cycle assessment for sewage sludge treatment processes in Japan. Waste Manag. 2009, 29, 696–703. [Google Scholar] [CrossRef] [PubMed]
- Han, W.; Jin, P.; Chen, D.; Liu, X.; Jin, H.; Wang, R.; Liu, Y. Resource reclamation of municipal sewage sludge based on local conditions: A case study in Xi’an, China. J. Clean. Prod. 2021, 316, 128189. [Google Scholar] [CrossRef]
- Gianico, A.; Braguglia, C.; Gallipoli, A.; Montecchio, D.; Mininni, G. Land Application of Biosolids in Europe: Possibilities, Con-Straints and Future Perspectives. Water 2021, 13, 103. [Google Scholar] [CrossRef]
- Jayaraman, K.; Gökalp, I. Pyrolysis, combustion and gasification characteristics of miscanthus and sewage sludge. Energy Convers. Manag. 2015, 89, 83–91. [Google Scholar] [CrossRef]
- Liu, X.; Chang, F.; Wang, C.; Jin, Z.; Wu, J.; Zuo, J.; Wang, K. Pyrolysis and subsequent direct combustion of pyrolytic gases for sewage sludge treatment in China. Appl. Therm. Eng. 2018, 128, 464–470. [Google Scholar] [CrossRef]
- Choi, Y.-K.; Ko, J.-H.; Kim, J.-S. Gasification of dried sewage sludge using an innovative three-stage gasifier: Clean and H2-rich gas production using condensers as the only secondary tar removal apparatus. Fuel 2018, 216, 810–817. [Google Scholar] [CrossRef]
- Solangi, Y.A.; Tan, Q.; Mirjat, N.H.; Ali, S. Evaluating the strategies for sustainable energy planning in Pakistan: An integrated SWOT-AHP and Fuzzy-TOPSIS approach. J. Clean. Prod. 2019, 236, 117655. [Google Scholar] [CrossRef]
- Samolada, M.C.; Zabaniotou, A.A. Comparative assessment of municipal sewage sludge incineration, gasification and pyrolysis for a sustainable sludge-to-energy management in Greece. Waste Manag. 2014, 34, 411–420. [Google Scholar] [CrossRef]
- Srivastava, P.K.; Kulshreshtha, K.; Mohanty, C.S.; Pushpangadan, P.; Singh, A. Stakeholder-based SWOT analysis for successful municipal solid waste management in Lucknow, India. Waste Manag. 2005, 25, 531–537. [Google Scholar] [CrossRef] [PubMed]
- Chen, G.; Zhang, R.; Guo, X.; Wu, W.; Guo, Q.; Zhang, Y.; Yan, B. Comparative evaluation on municipal sewage sludge utilization processes for sustainable management in Tibet. Sci. Total Environ. 2021, 765, 142676. [Google Scholar] [CrossRef] [PubMed]
- Pušnik, M.; Sučić, B. Integrated and realistic approach to energy planning—A case study of Slovenia. Manag. Environ. Qual. Int. J. 2014, 25, 30–51. [Google Scholar] [CrossRef]
- Kubler, S.; Robert, J.; Derigent, W.; Voisin, A.; Le Traon, Y. A state-of the-art survey & testbed of fuzzy AHP (FAHP) applications. Expert Syst. Appl. 2016, 65, 398–422. [Google Scholar]
- Donatello, S.; Cheeseman, C.R. Recycling and recovery routes for incinerated sewage sludge ash (ISSA): A review. Waste Manag. 2013, 33, 2328–2340. [Google Scholar] [CrossRef] [PubMed]
- 2021 Jiangsu Province National Economic and Social Development Statistical Bulletin. Available online: http://www.js.gov.cn/art/2022/3/31/art_64797_10398993.html (accessed on 5 December 2022).
- Statistical Communiqué of the People’s Republic of China on National Economic and Social Development in 2021. Available online: http://www.gov.cn/xinwen/2022-02/28/content_5676015.htm (accessed on 5 December 2022).
- Fytili, D.; Zabaniotou, A. Utilization of sewage sludge in EU application of old and new methods—A review. Renew. Sustain. Energy Rev. 2008, 12, 116–140. [Google Scholar] [CrossRef]
- Panigrahi, S.; Dubey, B.K. A critical review on operating parameters and strategies to improve the biogas yield from anaerobic digestion of organic fraction of municipal solid waste. Renew. Energy 2019, 143, 779–797. [Google Scholar] [CrossRef]
- Pizzuti, L.; Martins, C.A.; Lacava, P.T. Laminar burning velocity and flammability limits in biogas: A literature review. Renew. Sustain. Energy Rev. 2016, 62, 856–865. [Google Scholar] [CrossRef]
- Syed-Hassan, S.S.A.; Wang, Y.; Hu, S.; Su, S.; Xiang, J. Thermochemical processing of sewage sludge to energy and fuel: Fundamentals, challenges and considerations. Renew. Sustain. Energy Rev. 2017, 80, 888–913. [Google Scholar] [CrossRef]
- Chrispim, M.C.; Scholz, M.; Nolasco, M.A. Biogas recovery for sustainable cities: A critical review of enhancement techniques and key local conditions for implementation. Sustain. Cities Soc. 2021, 72, 103033. [Google Scholar] [CrossRef]
- Cao, Y.; Pawłowski, A. Sewage sludge-to-energy approaches based on anaerobic digestion and pyrolysis: Brief overview and energy efficiency assessment. Renew. Sustain. Energy Rev. 2012, 16, 1657–1665. [Google Scholar] [CrossRef]
- Oladejo, J.; Shi, K.; Luo, X.; Yang, G.; Wu, T. A Review of Sludge-to-Energy Recovery Methods. Energies 2018, 12, 60. [Google Scholar] [CrossRef]
- Wyn, H.K.; Konarova, M.; Beltramini, J.; Perkins, G.; Yermán, L. Self-sustaining smouldering combustion of waste: A review on applications, key parameters and potential resource recovery. Fuel Process. Technol. 2020, 205, 106425. [Google Scholar] [CrossRef]
- Zhang, S.; Wang, F.; Mei, Z.; Lv, L.; Chi, Y. Status and Development of Sludge Incineration in China. Waste Biomass Valorization 2020, 12, 3541–3574. [Google Scholar] [CrossRef]
- Lu, J.W.; Zhang, S.; Hai, J.; Lei, M. Status and perspectives of municipal solid waste incineration in China: A comparison with developed regions. Waste Manag. 2017, 69, 170–186. [Google Scholar] [CrossRef]
- Liang, Y.; Xu, D.; Feng, P.; Hao, B.; Guo, Y.; Wang, S. Municipal sewage sludge incineration and its air pollution control. J. Clean. Prod. 2021, 295, 126456. [Google Scholar] [CrossRef]
- Wei, L.; Wen, L.; Yang, T.; Zhang, N. Nitrogen Transformation during Sewage Sludge Pyrolysis. Energy Fuels 2015, 29, 5088–5094. [Google Scholar] [CrossRef]
- Chen, D.; Yin, L.; Wang, H.; He, P. Pyrolysis technologies for municipal solid waste: A review. Waste Manag. 2014, 34, 2466–2486. [Google Scholar] [CrossRef]
- Djandja, O.S.; Wang, Z.-C.; Wang, F.; Xu, Y.-P.; Duan, P.-G. Pyrolysis of Municipal Sewage Sludge for Biofuel Production: A Review. Ind. Eng. Chem. Res. 2020, 59, 16939–16956. [Google Scholar] [CrossRef]
- Li, G.; Hu, R.; Wang, N.; Yang, T.; Xu, F.; Li, J.; Wu, J.; Huang, Z.; Pan, M.; Lyu, T. Cultivation of microalgae in adjusted wastewater to enhance biofuel production and reduce environmental impact: Pyrolysis performances and life cycle assessment. J. Clean. Prod. 2022, 355, 131768. [Google Scholar] [CrossRef]
- Escalante, J.; Chen, W.H.; Tabatabaei, M.; Hoang, A.T.; Kwon, E.E.; Lin, K.Y.A.; Saravanakumar, A. Pyrolysis of lignocellulosic, algal, plastic, and other biomass wastes for biofuel production and circular bioeconomy: A review of thermogravimetric analysis (TGA) approach. Renew. Sustain. Energy Rev. 2022, 169, 112914. [Google Scholar] [CrossRef]
- Karaca, C.; Sözen, S.; Orhon, D.; Okutan, H. High temperature pyrolysis of sewage sludge as a sustainable process for energy recovery. Waste Manag. 2018, 78, 217–226. [Google Scholar] [CrossRef]
- Miricioiu, M.G.; Zaharioiu, A.; Oancea, M.S.; Bucura, F.; Raboaca, M.; Filote, C.; Ionete, R.E.; Niculescu, V.C.; Constantinescu, M. Sewage Sludge Derived Materials for CO2 Adsorption. Appl. Sci. 2021, 11, 7139. [Google Scholar] [CrossRef]
- Dai, Q.; Liu, Q.; Yılmaz, M.; Zhang, X. Co-pyrolysis of sewage sludge and sodium lignosulfonate: Kinetic study and methylene blue adsorption properties of the biochar. J. Anal. Appl. Pyrolysis 2022, 165, 105586. [Google Scholar] [CrossRef]
- Quan, L.M.; Kamyab, H.; Yuzir, A.; Ashokkumar, V.; Hosseini, S.E.; Balasubramanian, B.; Kirpichnikova, I. Review of the application of gasification and combustion technology and waste-to-energy technologies in sewage sludge treatment. Fuel 2022, 316, 123199. [Google Scholar] [CrossRef]
- Hu, Y.; Lin, J.; Liao, Q.; Sun, S.; Ma, R.; Fang, L.; Liu, X. CO2-assisted catalytic municipal sludge for carbonaceous biofuel via sub- and supercritical water gasification. Energy 2021, 233, 121184. [Google Scholar] [CrossRef]
- Carotenuto, A.; Di Fraia, S.; Massarotti, N.; Sobek, S.; Uddin, M.R.; Vanoli, L.; Predictive, S.W. modeling for energy recovery from sewage sludge gasification. Energy 2023, 263, 125838. [Google Scholar] [CrossRef]
- Spinosa, L.; Ayol, A.; Baudez, J.-C.; Canziani, R.; Jenicek, P.; Leonard, A.; Rulkens, W.; Xu, G.; Van Dijk, L. Sustainable and Innovative Solutions for Sewage Sludge Management. Water 2011, 3, 702–717. [Google Scholar] [CrossRef]
- Ministry of Ecology and Environment the People’s Republic of China. The Law of the People’s Republic of China on the Prevention and Control of Environmental Pollution by Solid Waste. 2020. Available online: https://www.mee.gov.cn/ywgz/fgbz/fl/202004/t20200430_777580.shtml (accessed on 5 December 2022).
- Ministry of Ecology and Environment China. Water Pollution Prevention and Control Action Plan (2015). Available online: http://www.gov.cn/zhengce/content/2015-04/16/content_9613.htm (accessed on 5 December 2022).
- National Development and Reform Commission Ministry of Housing and Urban -Rural Development. Implementation Plan for Supplementing the Weaknesses of Urban Domestic Sewage Treatment Facilities (2020). Available online: http://www.gov.cn/zhengce/zhengceku/2020-08/06/content_5532768.htm (accessed on 5 December 2022).
- National Development and Reform Commission. 14th Five-Year Plan for the Development of Urban Sewage Treatment and Resource Utilization (2021). Available online: https://www.ndrc.gov.cn/xxgk/zcfb/ghwb/202106/t20210611_1283168.html (accessed on 5 December 2022).
- Jiangsu Provincial People’s Government. Three-year plan for the construction of environmental infrastructure in Jiangsu Province. 2019. Available online: http://www.js.gov.cn/art/2019/3/15/art_64752_8287882.html (accessed on 5 December 2022).
- Ministry of Ecology and Environment China. National Hazardous Waste Catalogue. 2020. Available online: https://www.mee.gov.cn/xxgk2018/xxgk/xxgk02/202011/t20201127_810202.html (accessed on 5 December 2022).
- Hao, X.; Chen, Q.; van Loosdrecht, M.C.; Li, J.; Jiang, H. Sustainable disposal of excess sludge: Incineration without anaerobic digestion. Water Res. 2020, 170, 115298. [Google Scholar] [CrossRef]
- Jin, J.; Li, Y.; Zhang, J.; Wu, S.; Cao, Y.; Liang, P.; Zhang, J.; Wong, M.H.; Wang, M.; Shan, S.; et al. Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge. J. Hazard. Mater. 2016, 320, 417–426. [Google Scholar] [CrossRef]
- Singh, V.; Phuleria, H.C.; Chandel, M.K. Estimation of energy recovery potential of sewage sludge in India: Waste to watt approach. J. Clean. Prod. 2020, 276, 122538. [Google Scholar] [CrossRef]
- Buswell, A.M.; Sollo, F.W., Jr. The Mechanism of the Methane Fermentation. J. Am. Chem. Soc. 1948, 70, 1778–1780. [Google Scholar] [CrossRef] [PubMed]
- Chaerul, M.; Febrianto, A.; Tomo, H.S. Peningkatan Kualitas Penghitungan Emisi Gas Rumah Kaca dari Sektor Pengelolaan Sampah dengan Metode IPCC 2006 (Studi Kasus: Kota Cilacap). J. Ilmu Lingkung. 2020, 18, 153–161. [Google Scholar] [CrossRef]
- Hakawati, R.; Smyth, B.M.; McCullough, G.; De Rosa, F.; Rooney, D. What is the most energy efficient route for biogas utilization: Heat, electricity or transport? Appl. Energy 2017, 206, 1076–1087. [Google Scholar] [CrossRef]
- Karagiannidis, A.; Samaras, P.; Kasampalis, T.; Perkoulidis, G.; Ziogas, P.; Zorpas, A. Evaluation of sewage sludge production and utilization in Greece in the frame of integrated energy recovery. Desalination Water Treat. 2012, 33, 185–193. [Google Scholar] [CrossRef]
- Stillwell, A.S.; Hoppock, D.C.; Webber, M.E. Energy Recovery from Wastewater Treatment Plants in the United States: A Case Study of the Energy-Water Nexus. Sustainability 2010, 2, 945–962. [Google Scholar] [CrossRef]
- Zhang, Y.; Li, H. Energy recovery from wastewater treatment plants through sludge anaerobic digestion: Effect of low-organic-content sludge. Environ. Sci. Pollut. Res. 2017, 26, 30544–30553. [Google Scholar] [CrossRef]
- Tchobanoglous, G.; Theisen, H.; Vigil, S.A. Integrated Solid Waste Management: Engineering Principles and Management Issues; McGraw-Hill Science Engineering: New York, NY, USA, 1993. [Google Scholar]
- Li, H.; Feng, K. Life cycle assessment of the environmental impacts and energy efficiency of an integration of sludge anaerobic digestion and pyrolysis. J. Clean. Prod. 2018, 195, 476–485. [Google Scholar] [CrossRef]
- Chang, F.; Wang, C.; Wang, Q.; Jia, J.; Wang, K. Pilot-scale pyrolysis experiment of municipal sludge and operational effectiveness evaluation. Energy Sources Part A Recovery Util. Environ. Eff. 2016, 38, 472–477. [Google Scholar] [CrossRef]
- Ayol, A.; Tezer Yurdakos, O.; Gurgen, A. Investigation of municipal sludge gasification potential: Gasification characteristics of dried sludge in a pilot-scale downdraft fixed bed gasifier. Int. J. Hydrogen Energy 2019, 44, 17397–17410. [Google Scholar] [CrossRef]
- Campoy, M.; Gómez-Barea, A.; Ollero, P.; Nilsson, S. Gasification of wastes in a pilot fluidized bed gasifier. Fuel Process. Technol. 2014, 121, 63–69. [Google Scholar] [CrossRef]
- Yang, Y.; Zhang, Y.; Li, Z.; Zhao, Z.; Quan, X.; Zhao, Z. Adding granular activated carbon into anaerobic sludge digestion to promote methane production and sludge decomposition. J. Clean. Prod. 2017, 149, 1101–1108. [Google Scholar] [CrossRef]
- Luo, J.; Zhang, Q.; Zhao, J.; Wu, Y.; Wu, L.; Li, H.; Tang, M.; Sun, Y.; Guo, W.; Feng, Q.; et al. Potential influences of exogenous pollutants occurred in waste activated sludge on anaerobic digestion: A review. J. Hazard. Mater. 2020, 383, 121176. [Google Scholar] [CrossRef] [PubMed]
- Mao, C.; Feng, Y.; Wang, X.; Ren, G. Review on research achievements of biogas from anaerobic digestion. Renew. Sustain. Energy Rev. 2015, 45, 540–555. [Google Scholar] [CrossRef]
- Morais, J.; Barbosa, R.; Lapa, N.; Mendes, B.; Gulyurtlu, I. Environmental and socio-economic assessment of co-combustion of coal, biomass and non-hazardous wastes in a Power Plant. Resour. Conserv. Recycl. 2011, 55, 1109–1118. [Google Scholar] [CrossRef]
- Chanaka Udayanga, W.D.; Veksha, A.; Giannis, A.; Lisak, G.; Chang, V.W.C.; Lim, T.-T. Fate and distribution of heavy metals during thermal processing of sewage sludge. Fuel 2018, 226, 721–744. [Google Scholar] [CrossRef]
- Deng, W.; Yan, J.; Li, X.; Wang, F.; Chi, Y.; Lu, S. Emission characteristics of dioxins, furans and polycyclic aromatic hydrocarbons during fluidized-bed combustion of sewage sludge. J. Environ. Sci. 2009, 21, 1747–1752. [Google Scholar] [CrossRef]
- Nzihou, A.; Stanmore, B. The fate of heavy metals during combustion and gasification of contaminated biomass-a brief review. J. Hazard. Mater. 2013, 256, 56–66. [Google Scholar] [CrossRef]
- Molino, A.; Chianese, S.; Musmarra, D. Biomass gasification technology: The state of the art overview. J. Energy Chem. 2016, 25, 10–25. [Google Scholar] [CrossRef]
- Choi, Y.-K.; Mun, T.-Y.; Cho, M.-H.; Kim, J.-S. Gasification of dried sewage sludge in a newly developed three-stage gasifier: Effect of each reactor temperature on the producer gas composition and impurity removal. Energy 2016, 114, 121–128. [Google Scholar] [CrossRef]
- Walczuk, M.; Karczmarek, P. Fuzzy Analytic Hierarchy Process Based on Graphical Components. In Proceeding of the 2021 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), Virtual Conference, 11–14 July 2021; pp. 1–7. [Google Scholar]
- NagoorGani, A.; Akram, M.; Vijayalakshmi, P. Certain types of fuzzy sets in a fuzzy graph. Int. J. Mach. Learn. Cybern. 2014, 7, 573–579. [Google Scholar] [CrossRef]
- Adar, E.; Karatop, B.; İnce, M.; Bilgili, M.S. Comparison of methods for sustainable energy management with sewage sludge in Turkey based on SWOT-FAHP analysis. Renew. Sustain. Energy Rev. 2016, 62, 429–440. [Google Scholar] [CrossRef]
|Scheme||Issue||Internal Advantages (S)||Internal Disadvantages (W)||External Opportunities (O)||External Threats (T)|
|Anaerobic digestion||Problem solving||(1) No need to dry or dewater.|
(2) Produces biogas with high energy potential (natural gas, fuel and fertilizer production) .
(3) Low external input energy requirements.
(4) Sludge stabilization and reduction.
|(1) Long reaction time: >14 days .|
(2) Toxicity of exogenous pollutants at high levels .
(3) Biogas requires subsequent treatment before it can be utilized .
(4) High system operation requirements.
|(1) The biogas produced could replace fossil fuels.|
(2) The organic fertilizers could replace nitrogen and phosphate fertilizers.
|(1) Needs large amount of land.|
(2) Competition with other methods.
(3) Affected by the seasons.
|Ecological environment||(1) Emission control system available.||(1) CO2 emissions.||-||-|
|Technological development||(1) Mature technology.|
(2) Could be coordinated with biomass anaerobic digestion.
|(1) High investment costs.|
(2) Low energy conversion efficiency.
(3) Heavy metals, persistent organic pollutants, etc., could not be eliminated and require subsequent treatment.
|(1) Wider applicability than other energy utilization technologies.||(1) The economic environment is unstable.|
|Laws and regulations||-||(1) There are no complete laws or regulation framework.||(1) Environmental awareness is gradually increasing.|
(2) The support of policy.
|Incineration||Problem solving||(1) Sludge is completely reduced and harmless.|
(2) Heat could be recycled for power generation and heating .
(3) Minimizes odor generation.
(4) Ash residue could be used for building materials and the production of phosphoric acid .
|(1) The sludge needs to be dewatered/dried .|
(2) Energy efficiency is low, and mono-incineration had corresponding requirements for the heating value of sludge .
|(1) Government subsidies are available.||(1) Competition with other thermal technologies.|
(2) Higher investment.
|Ecological environment||(1) Emission control system is available.||(1) Production of chloro-compounds.|
(2) Air pollution problems (NOX, N2O, SOX, dioxin and furan emissions) .
(3) Increased demand for gas treatment and strict environmental emission control.
|(1) Environmental problems due to high-risk emissions.|
|Technological development||(1) Mature technology.|
(2) Coordinated incineration could utilize a variety of solid wastes.
|(1) Pretreatment of the sludge required.|
(2) Generally suitable for large sewage plants to ensure economic viability.
(3) Low energy conversion efficiency.
(4) The problem of heavy metal content in ash treatment .
|(1) Technological progress and safety factor improved.||(1) The economic environment was unstable.|
(2) High cost of blended fuels.
|Laws and regulations||(1) Laws and regulations exist and have been adopted.||(1) Sludge incineration requires strict legal control.||(1) Environmental awareness is gradually increasing.||(1) Strengthen legal controls.|
|Gasification||Problem solving||(1) No additional energy required after stable operation.|
(2) Syngas could be used as a feedstock for the production of natural gas, hydrogen and chemical synthesis .
(3) Ash residue could be used for building materials.
|(1) The moisture content of the sludge should be less than 30%.|
(2) The composition and efficiency of the gasification products may vary depending on the operating parameters, and improper handling could produce a large number of by-products such as tar .
|(1) Increased research and investment.||(1) Financing difficulties.|
(2) Competition with other thermal processing processes.
|Ecological environment||(1) Avoids NOX, SOX, dioxin and furan emissions.||(1) Releases large amounts of organic pollutants.||-|
|Technological development||(1) High energy efficiency and carbon balance achieved.|
(2) Could be co-treated with biomass.
|(1) Heavy metal content in ash treatment .|
(2) At present, it has not been promoted and applied.
(3) High investment and operating costs.
(4) The synthesized gas contains tar, coke and hydrogen carbon that may contaminate the device.
|(1) Renewable technology research and development cooperation.||(1) The economic environment was unstable.|
(2) Commercial feasibility is unknown.
|Laws and regulations||-||(1) There are no perfect laws or regulations.||(1) Environmental awareness is gradually increasing.||(1) Lack of environmental standards.|
|Pyrolysis||Problem solving||(1) Bio-oil, pyrolysis gas and biochar have market potential.|
(2) Short processing cycle, large equipment processing capacity and small footprint.
(3) Sludge is completely reduced and harmless .
|(1) Need to be dewatered or dried.|
(2) The composition and efficiency of the pyrolysis product depends on the operating parameters and sludge characteristics .
|(1) Increased research and investment.||-|
|Ecological environment||(1) Reduced greenhouse gas emissions.|
(2) Avoids NOX, SOX, dioxin and furan emissions.
|(1) CO and CO2 emissions.|
|Technological development||(1) High energy efficiency and carbon balance achieved.||(1) It has not been promoted and applied.|
(2) Most of the technologies are proprietary abroad.
|(1) Renewable technology research and development cooperation.||(1) The economic environment is unstable.|
(2) Commercial feasibility needs to be further studied.
|Laws and regulations||(1) There are no perfect laws or regulations.||(1) Environmental awareness is gradually increasing.||(1) Lack of environmental standards.|
|0.5||Equally important||i was equally important to j|
|0.6||Moderately important||i was slightly more important than j|
|0.7||Obviously important||i was obviously more important than j|
|0.8||Strongly important||i was much more important than j|
|0.9||Extremely important||i was extremely important than j|
|0.1, 0.2, 0.3, 0.4||Compare instead||The two elements i and j are compared in reverse, rij = 1−rji|
|Standard||Weight Value||Energy Utilization Methods||Weight|
|Problem solving (a)||0.4945||AD (1)||0.3366|
|Ecological environment (b)||0.2336||Incineration (2)||0.1443|
|Technological developments (c)||0.1665||Gasification (3)||0.1756|
|Laws and regulations (d)||0.1054||Pyrolysis (4)||0.3435|
|Problem Solving (A)||Ecological Environment (B)||Technological Developments (C)||Laws and Regulations (D)||Weight Value|
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Xiang, L.; Li, H.; Wang, Y.; Qu, L.; Xiao, D. Energy Utilization Assessment of Municipal Sewage Sludge Based on SWOT-FAHP Analysis. Water 2023, 15, 260. https://doi.org/10.3390/w15020260
Xiang L, Li H, Wang Y, Qu L, Xiao D. Energy Utilization Assessment of Municipal Sewage Sludge Based on SWOT-FAHP Analysis. Water. 2023; 15(2):260. https://doi.org/10.3390/w15020260Chicago/Turabian Style
Xiang, Lu, He Li, Yizhuo Wang, Linyan Qu, and Dandan Xiao. 2023. "Energy Utilization Assessment of Municipal Sewage Sludge Based on SWOT-FAHP Analysis" Water 15, no. 2: 260. https://doi.org/10.3390/w15020260