Search results for "Bioreactor"
showing 10 items of 397 documents
Nitrous oxide emissions in a membrane bioreactor treating saline wastewater contaminated by hydrocarbons
2016
The joint effect of wastewater salinity and hydrocarbons on nitrous oxide emission was investigated. The membrane bioreactor pilot plant was operated with two phases: i. biomass acclimation by increasing salinity from 10 gNaCl L−1 to 20 gNaCl L−1 (Phase I); ii. hydrocarbons dosing at 20 mg L−1 with a constant salt concentration of 20 gNaCl L−1 (Phase II). The Phase I revealed a relationship between nitrous oxide emissions and salinity. During the end of the Phase I, the activity of nitrifiers started to recover, indicating a partial acclimatization. During the Phase II, the hydrocarbon shock induced a temporary inhibition of the biomass with the suppression of nitrous oxide emissions. The r…
Nitrate removal microbiology in woodchip bioreactors : a case-study with full-scale bioreactors treating aquaculture effluents
2020
Woodchip bioreactors are viable low-cost nitrate (NO3−) removal applications for treating agricultural and aquaculture discharges. The active microbial biofilms growing on woodchips are conducting nitrogen (N) removal, reducing NO3− while oxidizing the carbon (C) from woodchips. However, bioreactor age, and changes in the operating conditions or in the microbial community might affect the NO3− removal as well as potentially promote nitrous oxide (N2O) production through either incomplete denitrification or dissimilatory NO3− reduction to ammonium (DNRA). Here, we combined stable isotope approach, amplicon sequencing, and captured metagenomics for studying the potential NO3− removal rates, a…
ENVIRONMENTAL FOOTPRINT REDUCTION FOR WASTEWATER TREATMENT BY MULTI-OBJECTIVE OPTIMIZATION AND MODELLING
2020
The current challenge faced by researchers and managers is minimize the environmental footprint of wastewater treatment plants (WWTPs). To accomplish this goal, other than respect legal requirements, WWTPs must provide better responses regarding consumption of energy and resources, greenhouse gas (GHG) emissions, among others. The research hereby presented is based on the application of mathematical modelling with the aim to propose a framework for the minimization of WWTP’s environmental footprint towards optimization techniques. A literature review was held to gain knowledge regarding the main decision support systems (DSS) that are applied to WWTPs since they allow selecting the most app…
Modelling of the air purification from volatile organic compounds in a trickle-bed bioreactor
2016
Badano proces oczyszczania powietrza ze styrenu, substancji zaliczanej do grupy lotnych związków organicznych (LZO), prowadzony w pilotowym bioreaktorze strużkowym (TBB). Ponieważ najważniejszym etapem procesu oczyszczania powietrza z LZO w bioreaktorze strużkowym jest biologiczna reakcja jego rozkładu, zatem, projektując proces, należy przede wszystkim starannie wyselekcjonować mikroorganizmy efektywnie rozkładające usuwane z powietrza zanieczyszczenie, określić warunki najkorzystniejsze dla ich wzrostu oraz wyznaczyć kinetykę reakcji. W wyniku testów porównawczych wyselekcjonowano szczep efektywnie wykorzystujący styren jako jedyne źródło węgla i energii. Był to, pochodzący z kolekcji VTT…
Analysis of Biomass Characteristics in MBR and MB-MBR Systems Fed with Synthetic Wastewater: Influence of a Gradual Salinity Increase
2014
The paper presents the results of a field gathering campaign carried out on two different pilot scale membrane bioreactor (MBR) systems, treating synthetic wastewater subject to a gradual increase of salinity. One was a conventional MBR system, while the other was a moving bed biofilm membrane bioreactor (MB-MBR), which combines suspended biomass and biofilm. Indeed, the presence of suspended carriers inside the bioreactor seems to give benefits due to the collisions between the circulating media and the membrane. The aim of the study was the comparison of two configurations in terms of biomass activity characterization and performance (pollutants removal and hydraulic behaviour). The resul…
Vortex shape in unbaffled stirred vessels: experimental study via digital image analysis
2011
There is a growing interest in using unbaffled stirred tanks for addressing certain processing needs. In this work, digital image analysis coupled with a suitable shadowgraphy-based technique is used to investigate the shape of the free-surface vortex that forms in uncovered unbaffled stirred tanks. The technique is based on back-lighting the vessel and suitably averaging vortex shape over time. Impeller clearance from vessel bottom and tank filling level are varied to investigate their influence on vortex shape. A correlation is finally proposed to fully describe vortex shape also when the vortex encompasses the impeller.
Vacuum air-lift bioreactor for microalgae production
2017
Microalgae production is receiving an increasing interest both by research institutions and commercial companies (Di Caprio et al., 2016). This is due to the growing consciousness of the need to move towards renewable, sustainable feedstoks for commodities production (Wang et al., 2012). However, process development at industrial scale, either based on open or closed photobioreactors, still is in a rather early stage and there is room for further development (Morweiser et al., 2010), especially aimed at reducing process costs. In this work an innovative low-cost technology for microalgae production, currently under development at Palermo University, is described. The main ways through which…
Combined effect of nutrient and flashing light frequency for a biochemical composition shift in Nannochloropsis gaditana grown in a quasi-isoactinic …
2020
Artificial lighting may be an interesting opportunity for the cultivation of microalgae as an alternative to natural sunlight. In particular, light emitting diodes (LEDs) can be employed to tailor the lighting to the microalgal culture in a controlled mode in order to create flashing light. In order to establish the effect of the flashing frequency on growth and biochemical composition of a model microalga, a quasi-isoactinic reactor, in which the light distribution is almost homogeneous, was set up. In this work, it was employed for the cultivation of the heterokont Nannochloropsis gaditana in two growth media with limiting and nonlimiting nutrients. The combined effect of nutrient concent…
Occurrence of Microplastics in Waste Sludge of Wastewater Treatment Plants: Comparison between Membrane Bioreactor (MBR) and Conventional Activated S…
2022
In this study, the presence of microplastics in the sludge of three wastewater treatment plants (WWTPs) was examined. The investigated WWTPs operated based on a conventional activated sludge (CAS) process, with (W1) or without (W2) primary clarification, and a membrane bioreactor process (MBR) (W3). The microplastics (MPs) concentration in the samples of W3 was approximately 81.1 ± 4.2 × 103 particles/kg dry sludge, whereas MPs concentrations in W1 and W2 were 46.0 ± 14.8 × 103 particles/kg dry sludge and 36.0 ± 5.2 × 103 particles/kg dry sludge, respectively. Moreover, MPs mainly consisted of fragments (66–68%) in the CAS plants, whereas the fra…
Możliwości energetycznego wykorzystania biomasy mikroalg
2016
Niniejsze opracowanie przedstawia możliwości zastosowania mikroalg do produkcji biopaliw III generacji - biodiesla, bioetanolu i biowodoru. Opisano parametry - CO2, temperatura, pH, światło i inne - zapewniające optymalne warunki hodowli mikroalg w fotobioreaktorach. Dokonano charakterystyki fotobioreaktorów, pod kątem ich przydatności do hodowli mikroalg na cele energetyczne. Przedstawiono metody termochemicznego i biochemicznego przetwarzania biomasy glonów stosowane do produkcji poszczególnych biopaliw.