Integration of Wastewater Derived Algal Biodiesel in CI Engines: Performance and Emission Analysis with Thermal Barrier Coatings

IJEP 46(5): 406-416 : Vol. 46 Issue. 5 (May 2026)

Full Text

C.S. Abdul Favas1, M. Ramarao1* and S. Prakash2

1. Bharath Institute of Science and Technology (BSIT), Department of Mechanical Engineering, Chennai – 600 073, Tamil Nadu, India
2. Vinayaka Mission’s Research Foundation (Deemed to be University), Department of Mechanical Engineering, Aarupadai Veedu Institute of Technology, Salem – 636 308, Tamil Nadu, India

Abstract

Green algal biomass not only serves as a renewable feedstock for biofuels but also offers a promising approach to reducing water pollution, particularly by removing excess nutrients from wastewater. This study examines the performance of green algae biofuel methyl ester (GABME20), produced from Chlorella vulgaris, in a single-cylinder, four-stroke direct-injection diesel engine with a compression ratio (CR) of 17:1 and thermal barrier coatings. Algal cultivation was carried out using synthetic wastewater enriched with nitrogen and phosphorus, essential nutrients for biomass growth, effectively combining wastewater treatment with biodiesel production. GABME20 was extracted and processed via transesterification and its suitability as a fuel was evaluated through combustion, performance and emission tests. Results showed that increasing the compression ratio improved brake power (BP), heat release rate (HRR) and brake thermal efficiency (BTE), with a maximum BTE increase of 1.72% at CR 18:1 compared to diesel. Regarding emissions, carbon monoxide, hydrocarbon and smoke opacity were reduced by 52%, 35% and 38%, respectively, due to more complete combustion and the oxygenated properties of GABME. However, NOx emissions rose by 17.6% at higher CR because of increased in-cylinder temperature. These results underscore the dual benefits of using algae-based methyl ester GABME—enhancing engine performance through better combustion and promoting environmental sustainability by lowering harmful emissions and utilizing waste-derived biofuel as an alternative to traditional diesel.

Keywords

Green algae biodiesel, Chlorella vulgaris, Compression ratio, Thermal barrier coating, Wastewater derived fuel

References

  1. Eloka-Eboka, A.C., Inambao, F. and Laseinde, O.T. 2018. Determination of thermal and rheological properties of biodiesel fuels from algae and blends.
  2. Chen, Z., Chen, Y., Zhang, H., Qin, H., He, J., Zheng, Z., Zhao, L., Lei, A. and Wang, J. 2022. Evaluation of Euglena gracilis 815 as a new candidate for biodiesel production. Frontiers Bioeng. Biotech.,10: 827513. DOI: 10.3389/fbioe.2022.827513.
  3. Raju, V.D., Nair, J.N., Venu, H., Subramani, L., Soudagar, M.E.M., Mujtaba, M.A., Khan, T.M.Y., Ismail, K.A., Elfasakhany, A., Yusuf, A.A., Mohamed, B.A. and Fattah, I.M.R. 2022. Combined assessment of injection timing and exhaust gas recirculation strategy on the performance, emission and combustion characteristics of algae biodiesel powered diesel engine. Energy Sour., Part A: Recovery, Utilization Env. Effects. 44(4): 8554-8571. DOI: 10.1080/15567036.2022. 2123068.
  4. Zheng, X.F., Liu, C.X., Yan, Y.Y. and Wang, Q. 2014. A review of thermoelectrics research– Recent developments and potentials for sustainable and renewable energy applications. Renewable Sustain. Energy Reviews. 32: 486-503. DOI: 10.1016/j.rser.2013.12.053.
  5. Galande, S.D., Pangavhane, D.R. and Deshmukh, K.B. 2024. The influence of injection pressure and exhaust gas recirculation on a VCR engine fueled by microalgae biodiesel. Heat Transfer. 53(7): 3341-3358. DOI: 10.1002/htj.23075.
  6. Ge, S., Brindhadevi, K., Xia, C., Khalifa, A.S., Elfasakhany, A., Unpaprom, Y., Whangchai, K. 2022. Performance, combustion and emission characteristics of the CI engine fueled with Botryococcus braunii microalgae with addition of TiO2nano-particle. Fuel. 317: 121898. DOI: 10.1016/j.fuel.20 21.121898.
  7. Hariram, V., Sathishbabu, R., Godwin, J.J., Nandagopal, K., Vijayakumar, K., Kumar, S.E. and Priya, K.K. 2025. Enhanced combustion and emission characteristics of diesel-algae biodiesel-hydrogen blends in a single-cylinder diesel engine. Results Eng., 26: 104676. DOI: 10.1016/j. rineng.20 25.104676.
  8. Hegel, P., Martín, L., Popovich, C., Damiani, C., Pancaldi, S., Pereda, S. and Leonardi, P. 2017. Biodiesel production from Neochloris oleoabundans by supercritical technology. Chem. Eng. Processing: Process Intensification. 121: 232-239. DOI: 10.1016/j.cep.2017.08.018.
  9. Inwongwan, S., Duangjan, K., Sensupa, P., Phinyo, K., Ruangrit, K., Pumas, C. and Pekkoh, J. 2025. Ethanol-driven mixotrophic cultivation enhances biomass production and CO2capture in Euglena gracilis for sustainable bioresource utilisation. Algal Res., 90: 104148. DOI: 10.1016/j. algal.2025.104148.
  10. Jhanani, G. K., Salmen, S.H., Al-Obaid, S. and Mathimani, T. 2025. Performance and emission analysis of Scenedesmus dimorphus-based biodiesel with hydrogen as fuel in an unmodified compression ignition engine. Int. J. Hydrogen Energy. 99: 1132-1138. DOI: 10.1016/j.ijhydene. 2024.12.291.
  11. Jung, J.M., Kim, J.Y., Jung, S., Choi, Y.E. and Kwon, E.E. 2021. Quantitative study on lipid productivity of Euglena gracilis and its biodiesel production according to the cultivation conditions. J. Clean. Prod., 291: 125218. DOI: 10.1016/j.jclepro.2020.1252 18.
  12. Karthikeyan, S. and Prathima, A. 2017. Environmental effect of CI engine using microalgae methyl ester with doped nano additives. Transportation Res. Part D: Transport Env., 50: 385-396. DOI: 10.1016/j.trd.2016.11.028.
  13. Kumar, M., Singh, V.K., Ravi, R., Verma, V., Arora, A., Alam, T., Yadav, A.S. and Sharma, A. 2024. Biodiesel production from microalgae oils: A critical review. Proceedings Inst. Mech. Eng., Part E: J. Process Mech. Eng., 240(2). DOI: 10.1177/0954 4089241251775.
  14. Lawal, A., et al. 2015. Pt-based bi-metallic monolith catalysts for partial upgrading of microalgae oil. Stevens Institute of Technology, Hoboken, New Jersey, USA.
  15. No, S.Y. 2020. Application of liquid biofuels to internal combustion engines. Springer Nature. DOI: 10.1007/978-981-13-6737-3.
  16. Ogawa, T., Tamoi, M., Kimura, A., Mine, A., Sakuyama, H., Yoshida, E., Maruta, T., Suzuki, K., Ishikawa, T. and Shigeoka, S. 2015. Enhancement of photosynthetic capacity in Euglena gracilis by expression of cyanobacterial fructose-1,6-sedoheptulose-1,7-bisphosphatase leads to increases in biomass and wax ester production. Biotech. biofuels. 8(1): 80. DOI: 10.1186/s130 68-015-0264-5.
  17. Pandey, A., Larroche, C., Dussap, C.G., Gnansou-nou, E, Khanal, S.K. and Ricke, S. 2019. biofuels: Alternative feedstocks and conversion processes for the production of liquid and gaseous biofuels (2nd edn). Academic press. DOI: 10.1016/C2018-0-00957-3.
  18. Rajendran, A. and Selvam, A.J.S.M.P. 2024. Effects of nozzle geometry, compression ratio and cerium oxide nanoparticles on algae biodiesel performance in a VCR diesel engine with hydrogen addition. Proceedings Inst. Mech. Eng., Part N: J. Nanomater. Nanoeng. Nanosystems. DOI: 10.1177/23977914241304631.
  19. Ramesh, H.S. and Thiyagarajan, P. 2024. Synergistic effect of hydrogen induction on the performance, combustion and emission phenomenon of dual-fuel CI engine with Chlorella vulgaris algae oil and its methyl ester. Int. J. Hydrogen Energy. 72: 1249-1262. DOI: 10.1016/j.ijhydene. 2024.05.430.
  20. Biswas, S. 2020. Algal biofuel: An alternative renewable energy source for cleaner and greener future. M.Sc. Thesis. Visva-Bharati, Birbhum, West Bengal. DOI: 10.13140/RG.2.2.19566.694 46.
  21. Shivashimpi, M.M., Zulapi, G., Futane, M.S., Madi-halli, A.P., Patrot, S. and Patil, O. 2023. Effect of algae biodiesel on performance, combustion and smoke characteristics of CI engine. Int. J. Adv. Res. Sci. Eng., 12(12): 11-23.
  22. Singh, J. and Gu, S. 2010. Commercialization potential of microalgae for biofuels production. Renewable Sustain. Energy Reviews. 14(9): 2596-2610. DOI: 10.1016/j.rser.2010.06.014.
  23. Song, M., Pei, H., Hu, W., Han, F., Ji, Y., Ma, G. and Han, L. 2014. Growth and lipid accumulation properties of microalgal Phaeodactylum tricornutum under different gas liquid ratios. Bioresour. tech., 165: 31-37. DOI: 10.1016/j.biortech.2014.03.070.
  24. ASTM D975. 2023. Standard specification for diesel fuel. ASTM International, USA.
  25. Veeraraghavan, S.M., Kaliyaperumal, G., Dillikan-nan, D. and Poures, M.V.D. 2024. Influence of hydrogen induction on performance and emission characteristics of an agricultural diesel engine fuelled with cultured Scenedesmus obliquus from industrial waste. Process Safety Env. Prot., 187: 1576-1585. DOI: 10.1016/j.psep.2024.05.042.
  26. Vellaiyan, S. 2025. Performance enhancement of a diesel engine using nanoparticle-enriched algae biodiesel-diesel blends with an electrostatic precipitator for nanoparticle emission control. Energy Conversion Manage., 326: 119457. DOI: 10.1016/j.enconman.2024.119457.
  27. ASTM D1298. 2017. Standard test method for density, relative density, or API gravity of crude petroleum and liquid petroleum products by hydrometer method. ASTM International, USA.
  28. ASTM D3588. 2017. Standard practice for calculating heat value, compressibility factor and relative density of gaseous fuels. ASTM International, USA.
  29. ASTM D445. 2024. Standard test method for kinematic viscosity of transparent and opaque liquids (and calculation of dynamic viscosity). ASTM International, USA.
  30. ASTM D2887. 2023. Standard test method for boiling range distribution of petroleum fractions by gas chromatography. ASTM International, USA.
  31. ASTM D613. 2025. Standard test method for cetane number of diesel fuel oil. ASTM International, USA.
  32. ASTM D93. 2020. Standard test methods for flash point by Pensky-Martens closed cup tester. ASTM International, USA.
  33. ASTM D240. 2019. Standard test method for heat of combustion of liquid hydrocarbon fuels by bomb calorimeter. ASTM International, USA.