Abstract
This study compared four different digestate liquid treatment systems of a theoretical anaerobic digestion plant in order to facilitate the utilization of municipal food waste nutrients in agriculture. The mass, nutrient and energy balances of a theoretical plant digesting 60 kt/y of food waste were used to evaluate the feasibility of the treatments to concentrate nutrients into liquid fertilizer products. The studied technologies for digestate liquid treatment were ammonia stripping, ammonia stripping combined with reverse osmosis (RO), evaporation combined with RO, and stripping combined with both evaporation and RO. As a result, processing of digestate into concentrated fertilizer products consumed less than 10% of the produced energy from food wastes and was also sufficient for the heat-demanding digestate liquid treatments, evaporation and stripping. The digestate liquid treatment systems were considered as nitrogen and potassium concentration methods which were able to concentrate up to 67% of the feedstock nitrogen into transportable fertilizer products with low mass. Of the studied digestate systems evaporation combined with RO was evaluated as the most efficient nutrient recovery technology for the production of transportable fertilizer products due to the high concentration of nutrients and nutrient availability as well as low product mass and energy consumption. Overall, the selection of the treatment technology is dependent on the location of the anaerobic digestion plant relative to the agricultural land and the type of fertilizer products needed.
Original language | English |
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Pages (from-to) | 22–32 |
Number of pages | 11 |
Journal | Journal of Cleaner Production |
Volume | 125 |
DOIs | |
Publication status | Published - Jul 2016 |
Publication type | A1 Journal article-refereed |
Keywords
- Anaerobic digestion
- Digestate liquid treatment
- Evaporation
- Food waste
- Reverse osmosis
- Stripping
Publication forum classification
- Publication forum level 2
ASJC Scopus subject areas
- Industrial and Manufacturing Engineering
- Renewable Energy, Sustainability and the Environment
- General Environmental Science
- Strategy and Management