Comparison of anaerobic degradation processes for bioenergy generation from liquid fraction of pressed solid waste

A novel substrate (obtained from biofraction of municipal solid waste by pressing and called LPW) rich in organic substances was used in three anaerobic degradation processes (biogas, biohydrogen fermentation and microbial fuel cells) to comparatively assess their feasibility for energy recovery. It has turned out that all the processes have successfully degraded that substrate and produced energy carriers (methane and hydrogen) as well as bioelectricity. The maximum energy yields (J g-1 CODremoved day-1) and associated COD removal capacities were 255, 200, 2.8 and 46, 52 and 72 % for biohydrogen, biogas and microbial fuel cell, respectively. The outcomes suggested the prominence of biohydrogen process for simultaneous waste treatment and energy recovery from LPWunder the test conditions ensured. © Springer Science+Business Media Dordrecht 2015

Fermentative hydrogen production by conventionally and unconventionally heat pretreated seed cultures: a comparative assessment

L

Review on the start-up experiences of continuous fermentative hydrogen producing bioreactors

a b s t r a c t The start-up of continuous biohydrogen fermentations is a complex procedure and a key to acceptable hydrogen production performance and successful long-term operation. In this review article, the experiences gained and lessons learned from relevant literature studies dealing with various aspects of H 2 producing bioreactor start-up are comprehensively surveyed. Firstly, the importance of H 2 -forming biosystem start-up including its main steps is outlined. Afterwards, the role of main influencing factors and methods (e.g. strain selection, seed pretreatment and inocula stimulation, switch-over time, bioreactor design, operating conditions) in avoiding the deterioration of starting a reactor is analyzed and presented in detail. Finally, the so far suggested applicable start-up strategies and the corresponding findings are critically discussed pointing out the advantages and disadvantages of each strategy

Potassium acetate solution as a promising option to osmotic distillation for sour cherry (Prunus cerasus L.) juice concentration

Different osmotic agents (OA), such as potassium acetate (CH3COOK), potassium carbonate (K2CO3) and ammonium nitrate (NH4NO3), have been examined as alternatives to the traditionally used calcium chloride (CaCl2) for osmotic distillation concentrating of clarified and pre-concentrated sour cherry (Prunus cerasus L.) juice. Comparison of the process performances based on the permeate fluxes has been carried out. Regarding the permeate flux results, simplified estimation of the overall mass transfer coefficient of the most effective osmotic agent and the reference (CaCl2) solution has been also performed. Furthermore, analytical methods such as total antioxidant activity (TAA) and total polyphenolic content (TPC) using spectrophotometric assays have been also carried out to evaluate the effect of the osmotic distillation on the valuable compounds content of concentrated sour cherry juice. CH3COOK was found to be the most effective, resulted more than 25% higher permeate flux during the sour cherry juice concentration. K2CO3 and NH4NO3 were less effective. The simplified mass transfer estimation showed that the CH3COOK is more effective only at near saturated concentrations compared to the CaCl2. Regarding the TAA and TPC contents, a significant loss was found in case of all OAs during the concentration procedures