Agronomic assessment of pyrolysed food waste digestate for sandy soil management

Integration of Hydrothermal Carbonisation with Anaerobic Digestion; Opportunities for Valorisation of Digestate

“…As a result, there is a growing need to explore alternative digestate markets and land recycling, with emphasis on digestate enhancement technologies capable of adding value to the whole digestion process. Transforming digestate into carbonaceous solid and liquid fractions using technologies such as pyrolysis [3][4][5][6][7][8][9][10] and hydrothermal carbonisation (HTC) [11][12][13] are now under investigation. The main barriers for industrial uptake of pyrolysis include the requirement for feedstocks to have low moisture content (10% or less) to reduce negative effects of stability, viscosity, pH, and corrosiveness of the pyrolysis liquids [14]; unfavourable energy balances (i.e., high OPEX due to energy consumption for initial feedstock preparation and drying, including high operating temperatures in addition to heat loss and maintenance) [15,16]; controlling the emissions from pyrolysis processes [17]; issues of treatment, upgradability and utilisation of pyrolysis liquids [18,19].…”

Pyrolysis coupled anaerobic digestion process for food waste and recalcitrant residues: Fundamentals, challenges, and considerations

“…Pyrolysis products can produce heat and power, both individually and simultaneously . Char obtained from pyrolysis of ROR has multiple applications, such as for soil improvement, carbon sequestration, and as an adsorbent precursor . The precise distribution of products depends mainly on many various pyrolysis factors such as heating rate, temperature, operating pressure, residence times of the vapors, and the converting biomass/residues and their states of mixing.…”

“…Integration of AD and pyrolysis offers further potentially synergistic combinations which include use of digestate as feedstock for pyrolysis, syngas bio‐methanation, or use of chars as an additive in AD to overcome inhibition problems . Besides, for instance, the digestate from AD could be a suitable feedstock for pyrolysis to enhance biochar production, while the remaining char in the digestate could serve as a soil conditioner if the digestate is utilized as composted …”

“…Biochar has a series of applications such as fuel, for some metallurgical processes, as an attractive substitute for coke derived from fossil fuels, since it contains low concentrations of metals. Char is also an excellent fertilizer: It improves soil texture as a soil conditioner, and it retains and slowly releases nutrients and water while acting as upkeep for beneficial organisms . Giwa et al in their research, employed the utilization of biochar in the AD of FW treatment over long‐run operations to enhance reactor performance at high organic loading rate and biogas improvement.…”

“…Besides, second‐stage pyrolysis decomposition of the ROR and subsequent oil/tar to syngas can find a route of utilization in AD, thus avoiding direct usage of oil/tar that can pose as toxicants to AD microbes. Integrated or combined proposed routes for FW and associated residues treatment during the past few years are scarcely available, except studies on pyrolysis integrated with AD of only FW, biomass, and sludge treatment . There is still a major knowledge gap in the combination of these two technologies.…”