Research Articles (Chemical Engineering)

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Browsing Research Articles (Chemical Engineering) by Subject "Anaerobic digestion (Sewage purification)"

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    Cyanobacterial growth in minimally amended anaerobic digestion effluent and flue-gas
    (MDPI, 2019) Beyl, Talita; Louw, Tobias M.; Pott, Robert W. M.
    ENGLISH ABSTRACT: Anaerobic digestion (AD) is an important industrial process, particularly in a biorefinery approach. The liquid effluent and carbon dioxide in the off-gas, can be used to produce high-value products through the cultivation of cyanobacteria. Growth on AD effluent is often limited due to substrate limitation or inhibitory compounds. This study demonstrates the successful cultivation of Synechococcus on minimally amended AD effluent, supplemented with MgSO4 and diluted with seawater. An 8 L airlift reactor illustrated growth in a pilot scale setup. Higher biomass yields were observed for cyanobacteria grown in diluted AD effluent compared to minimal medium, with 60% total nitrogen removal in the effluent. It was demonstrated that controlling the pH, increasing dissolved salt concentrations and adding MgSO4 to the effluent allowed for the successful cultivation of the cyanobacterium, circumventing the addition of clean water for effluent dilution. This could ultimately increase the feasibility of anaerobic digestion-microalgae integrated biorefineries.
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    Incorporating anaerobic co-digestion of steam exploded or ammonia fiber expansion pretreated sugarcane residues with manure into a sugarcanebased bioenergy-livestock nexus
    (Elsevier, 2019) Mokomelea, Thapelo; Da Costa Sousa, Leonardo; Balan, Venkatesh; Van Rensburg, Eugene; Dale, Bruce E.; Gorgens, Johann F.
    ENGLISH ABSTRACT: The co-digestion of pretreated sugarcane lignocelluloses with dairy cow manure (DCM) as a bioenergy production and waste management strategy, for intensive livestock farms located in sugarcane regions, was investigated. Ammonia fiber expansion (AFEX) increased the nitrogen content and accelerated the biodegradability of sugarcane bagasse (SCB) and cane leaf matter (CLM) through the cleavage of lignin carbohydrate crosslinks, resulting in the highest specific methane yields (292–299 L CH4/kg VSadded), biogas methane content (57–59% v/v) and biodegradation rates, with or without co-digestion with DCM. To obtain comparable methane yields, untreated and steam exploded (StEx) SCB and CLM had to be co-digested with DCM, at mass ratios providing initial C/N ratios in the range of 18 to 35. Co-digestion with DCM improved the nutrient content of the solid digestates, providing digestates that could be used as biofertilizer to replace CLM that is removed from sugarcane fields during green harvesting.