resumo
Anaerobic acidification of eight organic streams (cheese whey, sugarcane molasses, organic fraction of municipal solid wastes (OFMSW), glycerol, soapy slurry, winery wastewater, olive mill effluent, and landfill leachate) was evaluated in batch experiments to determine their acidogenic potential and examine the composition of the produced volatile fatty acids (VFA). Cheese whey, molasses and OFMSW presented the highest acidogenic potentials (0.3 to 0.4 gVFA per g of chemical oxygen demand fed, CODfed) with the predominance of acetic, n-butyric and propionic acids. A further experimental set was applied to cheese whey, by varying food-to-microorganism ratio (F/M) and initial alkalinity. Maximisation of VFA production (up to 0.63 gVFA g(-1)COD(fed)) was obtained for an initial alkalinity of 5 - 7 g L-1 as CaCO3 and F/M ratios of 2 4 gCOD g(-1)VSS. Moreover, it was demonstrated that low F/M ratios combined with high alkalinity supply can shift the VFA profile by increasing the production of propionic and n-valeric acids. The results are useful towards optimal designs for acidogenic processes based on the composition of the VFA produced, since the control of the acidification products is crucial for valorisation in some applications.
palavras-chave
ANAEROBIC-DIGESTION; BIOHYDROGEN PRODUCTION; OPERATING-CONDITIONS; CHEESE WHEY; WATER; SLUDGE; PH; POLYHYDROXYALKANOATES; GLUCOSE
categoria
Biotechnology & Applied Microbiology; Engineering
autores
Silva, FC; Serafim, LS; Nadais, H; Arroja, L; Capela, I
nossos autores
Luísa Seuanes Serafim
Professor Auxiliaragradecimentos
This research was supported by the projects PTDC/AMB-AAC/111316/2009 and PTDC/AMB-AAC/101050/2008 from Fundacao para a Ciencia e a Tecnologia. F.C. Silva acknowledges his Ph.D. grant (SFRH/BD/46845/2008) from Fundacao para a Ciencia e a Tecnologia. L.S. Serafim acknowledges FEDER Funds through the Programa Operacional Factores de Competitividade - COMPETE and national funds through FCT - Fundacao para a Ciencia e a Tecnologia under the project PEST-C/CTM/LA/0011/2011.