Life cycle assessment of anaerobic digestion of pig manure coupled with different digestate treatment technologies

Na Duan*, Benyamin Khoshnevisan, Cong Lin, Zhidan Liu, Hongbin Liu

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


The direct use of digestate on farmlands as soil amendment is becoming an uneconomic option for farmers. Moreover, there are serious environmental concerns about its oversupply in regions with intensive biogas plants. Downstream technologies, offering innovative upcycling methods to handle huge amounts of digestate, have absorbed great interest in this context. In this study, three digestate treatment technologies were compared from a life cycle assessment perspective to combine the environmental impacts from pig manure transportation to biogas plants, biogas production, different digestate treatment technologies, and the use of final products. The results showed that scenario including digestate fractionation into solid and liquid, and their use for compost production and microalgae cultivation, respectively, would be a suitable downstream strategy with lower impacts on human health, ecosystem quality, and climate change damage categories, however future improvements still required. The results showed that sealed storage system or fast-continuous downstream processes as well as shorter distances between biogas plants and farms can significantly enhance the environmental performance of coupled anaerobic digestion and microalgae production. The high energy payback also signified that co-digestion of pig manure and microalgae would be energetically favorable in this context. However, having compared the results with a baseline scenario demonstrated that the direct use of digestate on farmlands, under controlled conditions to avoid its over application, is still the most environmentally favorable option, despite being a costly option for farmers. The results achieved in the present study suffered some uncertainties because technologies under consideration are at their infancy stage, thus further research still is required to find the most sustainable solutions.

Original languageEnglish
Article number105522
JournalEnvironment International
Number of pages16
Publication statusPublished - Apr 2020
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by National Key Research and Development Program ( 2018YFD0800803 ), Beijing Science and Technology Pro-gram ( Z161100001316009 ). The authors would like to express their deep appreciation of the financial support provided by International Postdoctoral Exchange Fellowship of China.

Publisher Copyright:
© 2020 The Authors


  • Anaerobic digestion
  • Digestate treatment
  • Flocculation-biological contact oxidation
  • Microalgae


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