A model describing a given system should be as simple as possible - but not simpler. The appropriate level of complexity depends both on the type of system and on the intended use of the model. This paper addresses the critical question of which purposes justify increased complexity of biofilm (reactor) models. Additional model features compared to conventional models considered are: (1) the in...

Mathematical models are useful tools to optimize the performance of granular sludge reactors. In these models, typically a uniform granule size is assumed for the whole reactor, even though in reality the granules follow a size distribution and the granule size as such affects the process performance. This study assesses the effect of the granule size distribution on the performance of a granul...

We used in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes concurrently with microscopic examinations and methane measurements to characterize the microbial community of an anaerobic hybrid reactor treating pentachlorophenol (PCP) with a mixture of fatty acids (propionic, butyric, acetic and lactic) and methanol. Archaeal cells detected with probe ARC915 preva...

Calcium and ash accumulation in aerobic granules treating organic wastewater was investigated systematically in this study. It was found that ash content of granular sludge reached 43% at stable state of reactor operation with calcium carbonate precipitation as the main cause. Since granular sludge in the reactor at the steady state was the mixture of granules with different sizes, granules in ...

Two granular sludge sequencing batch reactors (GSBR) with alternating anoxic/aerobic (R1) and anaerobic/aerobic (R2) conditions were operated with a 4-carbon-source synthetic influent. The physical properties of the granular sludge were very good (SVI ≈ 20 mL g−1) and high solid concentrations (up to 35 g L−1) were obtained in the bioreactor operated with a pre-anoxic phase with additional nitr...

A simple experimental set-up was used to study the treatability aspect of phenolic wastewater. Three types of systems: i) activated sludge (A.S), ii) granular activated carbon (A.C) and iii) activated sludge plus activated carbon (A.S + A.C) were experimented under different phenol loadings (100, 200 and 300 mg/l) and different flow rates (21.6 and 43.2 l/d) with initial COD concentration 500 m...

The authors conducted a study on treating synthetic dairy wastewater using aerobic granular sludge (AGS) in laboratory-scale continuous flow reactor (CFR) system. system consisted of an anaerobic reactor, and settling sedimentation tank, with different hydraulic retention times tested over 90-day period. monitored characteristics effluent treatment performance found that the achieved excellent ...

Recombinant strain Xz6-1 was constructed by the protoplast fusion technique with the goal of endowing it with the ability to efficiently degrade pentachlorophenol (PCP). This compound was considered as a representative of possible compounds that can be obtained during the bleaching of pulp for papermaking. The potential of Xz6-1 and Pseudomonas putida to treat PCP synthetic wastewater was explo...

The aim of this work was to investigate the resistance to hydraulic shock loads of flocculent versus granular sludge used in UASB reactors treating sewage with high solids content. Step-wise shock loads were conducted through decreasing HRT to examine the extent of reducing this parameter without significantly changing COD removal efficiency of the reactor. The lowest HRT of 4h resulted in only...