System analysis of de-watering process for treating biogas digestate

Abstract: Due to increasing production of biogas for transportation and other purposes, generation of biogas digestate is also increased. Biogas digestate is considered as an organic fertilizer which can potentially replace mineral fertilizer used for agricultural purpose as they contain rich soil and plant nutrient. Processing and logistics of the biogas digestate became a challenging opportunity due to presence of higher water content in the raw biogas digestate that is obtained from wet anaerobic digestion process. Many research groups and organizations are involved in designing a sustainable processing mechanism for biogas digestate so that they can be marketable and commercially available as bio-fertilizers. Among various identified processing options, de-watering is an important and mandatory process (solid-liquid separation) involved in full scale biogas digestate processing. This work is focused in systemic assessment of the environmental impacts associated with biogas digestate de-watering process using Life Cycle Impact Assessment (LCIA) methodology. Various operational options are considered for the de-watering process and analyzed accordingly. A comparison from environmental and economical perspective is made within the operational options to find out which one can be efficiently used.