Energy recovery from dairy industry waste : a review of methods, challenges, and opportunities
Aryal, Manoj (2025)
2025
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-202601121193
https://urn.fi/URN:NBN:fi:amk-202601121193
Tiivistelmä
This thesis explores the use of dairy processing waste as a source of energy recovery to aid the transition and conversion of Finland to carbon-neutral and circular food systems. The dairy operations produce high-strength wastewater in large volumes, whey, and sludge which in their untreated form are highly hazardous to the environment. The thesis synthesizes the relevant conceptual processes and presents a systematic literature review to evaluate and compare the important energy recovery technologies of anaerobic digestion (AD), two-stage biohydrogen and biomethane production, and hydrothermal liquefaction (HTL) for a medium-sized Finnish dairy plant.
According to the quantitative feasibility analysis, cogeneration with centralized AD is the most balanced in performance. The system generates 654 kWₑ and 736 kWₜ and a nutrient-rich digestate that can be used as biofertilizer with a feed of 550 kg COD/h. It is the most sensible and risk-averse in terms of its commercial maturity (TRL 9), medium CAPEX (approximately 4 M€), and predictable payback period (5-10 years). The alternative technologies, on the other hand, are in pilot or demonstration stages with great uncertainty and expenses.
The thesis finds centralized anaerobic digestion with cogeneration to be the best available technique (BAT) for medium-sized Finnish dairies. It provides a viable, cost-effective, and sustainable alternative means of increasing energy self-reliance and bridging the nutrient nexus, which resonates well with EU and national sustainability objectives.
According to the quantitative feasibility analysis, cogeneration with centralized AD is the most balanced in performance. The system generates 654 kWₑ and 736 kWₜ and a nutrient-rich digestate that can be used as biofertilizer with a feed of 550 kg COD/h. It is the most sensible and risk-averse in terms of its commercial maturity (TRL 9), medium CAPEX (approximately 4 M€), and predictable payback period (5-10 years). The alternative technologies, on the other hand, are in pilot or demonstration stages with great uncertainty and expenses.
The thesis finds centralized anaerobic digestion with cogeneration to be the best available technique (BAT) for medium-sized Finnish dairies. It provides a viable, cost-effective, and sustainable alternative means of increasing energy self-reliance and bridging the nutrient nexus, which resonates well with EU and national sustainability objectives.