No abstract

In the food industry, the brewing sector holds a strategic economic position: in the year 2013, the beer production of the EU-28 was equal to 383,553,000 hL. The brewing process includes chemical and biochemical reactions and solid-liquid separations, involving the generation of various residues and by-products, among which the major two fractions are brewer's spent grain (BSG), and exhausted brewery yeast (BY). Although until today their main use has been for animal feed, in recent years, several studies have investigated the application of anaerobic digestion in order to revalue the brewery wastes.In this work, specific methane production (SMP) and first-order solubilisation (disintegration + hydrolysis) rates (k sol ) for BSG and BY were evaluated. Biomethanation tests were performed in 5-L fed-batch stirred reactors at several substrate/inoculum ratios.

The management of wastewater treatment plants to comply with new strict effluent criteria is a great concern: the activated sludge modeling, when supported by an accurate calibration process, could be an essential tool for this purpose. In the present paper, three WWTPs were characterized in order to support their up-grade. Influent characteristics and activated sludge performances were studied by application of respirometry. Plant operations were simulated by BioWin software (EnviroSim Associates Ltd., Canada). The goodness of the simulation, checked by the calculation of the average relative deviation between measured and simulated data, demonstrated that the model was able to predict the plant performances

Brewer's spent grain (BSG), the residual solid fraction of the final mash process of malting, is a main waste fraction of beer production, recently considered as possible substrate for biovalorization by anaerobic digestion (AD). In this article, the biomethanization of BSG was evaluated by performing biochemical methane potential (BPM) tests. The obtained specific methane production (SMP) was 0.284 LCH4·g-1COD. The process was modelled by implementing the Anaerobic Digestion Model No.1 (ADM1) into AQUASIM software with the focus on the disintegration and hydrolysis step. The calibrated disintegration rate for BSG was equal to 0.823 d-1 and the hydrolysis rate constants varied from 0.124 d-1 for lipids to 1.056 d-1 for proteins. The obtained results showed a good efficiency in treating BSG with anaerobic digestion. The practical conversion degree of the biowaste COD into methane was equal to 81.1%, a high value for a substrate with an elevated solid content. Moreover, the estimated values of disintegration and hydrolysis rates complied with the retention time values generally adopted in an anaerobic digestor

Oxic-settling-anaerobic (OSA) process has been introduced into the treatment line of wastewater in order to upgrade activated sludge processes and to reduce the production of excess sludge. The aim of the present study was to simulate the performance of an OSA pilot plant by implementing the Activated Sludge Model No.2d (ASM2d) into a mathematical modelling software (BioWin). The stepwise calibration, performed both by off-line experiments and software dynamic calibration, was carried out in a heuristic way, adjusting the parameters values that showed a major influence to the effluent and internal concentrations. All the reduction factors introduced into ASM2d to simulate the processes occurring in anoxic and anaerobic conditions were lowered in order to reproduce the concentrations of interest. In addition, the values of parameters of the PAOs (polyphosphate accumulating organisms)-related process (namely qPHA and YPO4) were found lower than those usually adopted. In general, theoretical results were in good agreement with the experimental data obtained from plant’s operation, showing an accurate predictive capacity of the model. Good performance was achieved considering the phosphorus removal related process, while some failures were detected in COD and ammonia simulations.