Denise Cysneiros

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A two-phase system composed by a leach bed and a methanogenic reactor was modified for the first time to improve volumetric substrate degradation and methane yields from a complex substrate (maize; Zeamays). The system, which was operated for consecutive feed cycles of different durations for 120 days, was highly flexible and its performance improved by(More)
A two step biological process for the conversion of grass biomass to the biodegradable polymer medium chain length polyhydroxyalkanoate (mcl-PHA) was achieved through the use of anaerobic and aerobic microbial processes. Anaerobic digestion (mixed culture) of ensiled grass was achieved with a recirculated leach bed bioreactor resulting in the production of(More)
Continuous Stirred Tank Reactors (CSTRs), operated in batch mode, were used to evaluate the feasibility of psychrophilic (low temperature) digestion of perennial rye grass in a long term experiment (150 days) for the first time. The reactors were operated in parallel at 3 different temperatures, 10, 15 and 37 degrees C. Hydrolysis, acidification and(More)
The importance of cobalt on the anaerobic conversion of methanol under thermophilic conditions was studied in three parallel lab-scale UASB-reactors and in cobalt-limited enriched cultures. Reactors R1, R2, and R3 were fed with methanol in a bicarbonate-buffered medium, supplied with iron and macronutrients: in R1 all metals were supplied (control), R2 was(More)
The feasibility of anaerobic digestion of dairy wastewater at 10°C was investigated in a high height : diameter ratio EGSB reactor. Stable performance was observed at an applied organic loading rate (OLR) of 0.5-2 kg COD m(-3) d(-1) with chemical oxygen demand (COD) removal efficiencies above 85%. When applied OLR increased to values above 2 kg COD m(-3)(More)
In this study, the ability of various sludges to digest a diverse range of cellulose and cellulose-derived substrates was assessed at different temperatures to elucidate the factors affecting hydrolysis. For this purpose, the biogas production was monitored and the specific biogas activity (SBA) of the sludges was employed to compare the performance of(More)
The effect of phase separation and batch duration on the trophic stages of anaerobic digestion was assessed for the first time in leach beds coupled to methanogenic reactors digesting maize (Zea mays). The system was operated for consecutive batches of 7, 14 and 28 days for ∼120 days. Hydrolysis rate was higher the shorter the batch, reaching 8.5(More)
We report, for the first time, extensive biologically mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12°C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of(More)
The application of low-temperature (10 °C) anaerobic digestion (LtAD) for the treatment of complex dairy-based wastewater in an inverted fluidised bed (IFB) reactor was investigated. Inadequate mixing intensity provoked poor hydrolysis of the substrate (mostly protein), which resulted in low chemical oxygen demand (COD) removal efficiency throughout the(More)
The methane potential of a leach bed reactor (LBR) coupled to an anaerobic filter (AF) was assessed using energy maize (Zea mays) as substrate. Four LBRs were used operated as pairs, with and without leachate recirculation, over two feed cycles with retention times of 14 and 28 days. Performance was estimated from the total solids destruction in the LBR,(More)