Search results for "Bioengineering"
showing 10 items of 1963 documents
Combination of the OSA process with thermal treatment at moderate temperature for excess sludge minimization
2019
Abstract This study investigated the chance to couple the conventional Oxic Settling Anaerobic (OSA) process with a thermic treatment at moderate temperature (35 °C). The maximum excess sludge reduction rate (80%) was achieved when the plant was operated under 3 h of hydraulic retention time (HRT). Compared with the conventional OSA system, the thermic treatment enabled a further improvement in excess sludge minimization of 35%. The observed yield coefficient decreased from 0.25 gTSS gCOD−1 to 0.10 gTSS gCOD−1 when the temperature in the anaerobic reactor was increased to 35 °C, despite the lower HRT (3 h vs 6 h). Moreover, the thermic treatment enabled the decrease of filamentous bacteria,…
Assessment and characterization of the bacterial community structure in advanced activated sludge systems
2019
Abstract The present study is aimed to assess and characterize the structure of bacterial community in advanced activated sludge systems. In particular, activated sludge samples were collected from an Integrated Fixed-film Activated Sludge – Membrane Bioreactor pilot plant under a University of Cape Town configuration with in-series anaerobic (Noair)/anoxic (Anox)/aerobic (Oxy) reactors – and further analyzed. The achieved results – based on Next Generation Sequencing (NGS) of 16S rDNA amplicons – revealed that the bacterial biofilm (bf) communities on plastic carriers of Oxy and Anox reactors had a greater diversity compared to suspended (sp) bacterial flocs of Oxy, Anox and Noair. Indeed,…
Effect of complexing agents on phosphorus release from chemical-enhanced phosphorus removal sludge during anaerobic fermentation
2020
Phosphorus (P) release from sludge containing phosphate precipitates (FePs or AlPs) as well as the anaerobic performance with the addition of complexing agents (citric, tartaric and EDTA) during ambient anaerobic fermentation process were investigated. Results showed that citrate addition was the most effective method to enhance P release from inorganic phosphate by chelation and promote volatile fatty acids (VFAs) production simultaneously during anaerobic fermentation. Equimolar citrate addition with chemical precipitates was the optimal dosage. Microbial analysis revealed that EDTA has the strongest inhibitory effect on microbial activity and community structure, while citrate was more e…
Study on the effects of several operational variables on the enzymatic batch saccharification of orange solid waste
2017
In this work, batch enzyme-aided extraction and enzymatic saccharification of blade-milled orange waste was studied. The operation variables for this process were thoroughly analysed. It was determined that batch runs with initial pH values of 5.0 and 5.2 controlled during the first hour, 50°C and 300-500r.p.m. agitation resulted in the best yields, with a limited total and partial first-order enzyme deactivation (for cellulases and polygalacturonidase, respectively). Orange peel waste (OPW) at 6.7% w/w dry solid, 0.22 filter paper units (FPU)/g DS and proportional activities of other enzymes led to over 40g/L free monosaccharides and global yields to glucose over 80%. When using 10.1% w/w …
Bioplastic recovery from wastewater: A new protocol for polyhydroxyalkanoates (PHA) extraction from mixed microbial cultures
2019
Abstract A new protocol for polyhydroxyalkanoates (PHA) extraction from mixed microbial cultures (MMCs) is proposed. PHA-accumulating capacity of the MMC was selected in a sequencing batch reactor (SBR) fed with a synthetic effluent emulating a fermented oil mill wastewater (OMW). The highest recovery yield and purity (74 ± 8% and 100 ± 5%, respectively) was obtained when using NH4-Laurate for which operating conditions of the extraction process such as temperature, concentration and contact time were optimized. Best conditions for PHA extraction from MMC turned to be: i) a pre-treatment with NaClO at 85 °C with 1 h of contact time, followed by ii) a treatment with lauric acid in a ratio ac…
Applicability of a single‐use bioreactor compared to a glass bioreactor for the fermentation of filamentous fungi and evaluation of the reproducibili…
2021
Abstract The implementation of single‐use technologies offers several major advantages, e.g. prevention of cross‐contamination, especially when spore‐forming microorganisms are present. This study investigated the application of a single‐use bioreactor in batch fermentation of filamentous fungus Penicillium sp. (IBWF 040‐09) from the Institute of Biotechnology and Drug Research (IBWF), which is capable of intracellular production of a protease inhibitor against parasitic proteases as a secondary metabolite. Several modifications to the SU bioreactor were suggested in this study to allow the fermentation in which the fungus forms pellets. Simultaneously, fermentations in conventional glass b…
Simple learning rules to cope with changing environments
2008
10 pages; International audience; We consider an agent that must choose repeatedly among several actions. Each action has a certain probability of giving the agent an energy reward, and costs may be associated with switching between actions. The agent does not know which action has the highest reward probability, and the probabilities change randomly over time. We study two learning rules that have been widely used to model decision-making processes in animals-one deterministic and the other stochastic. In particular, we examine the influence of the rules' 'learning rate' on the agent's energy gain. We compare the performance of each rule with the best performance attainable when the agent …
Use of solid state fermentation to produce Beauveria bassiana for the biological control of european corn borer
1993
The production process of a new bioinsecticide against european corn borer is described. The entomopathogenic fungus, Beauveria bassiana, is cultivated by Solid State Fermentation (SSF). The culture support chosen, clay microgranules, humidified with optimal nutritive solution, is incubated in optimal conditions during 48 hours, then dried for 5 days. The bioinsecticide can be directly used after harvesting, without formulation. This process is original for several reasons : - The granulometry (500 microm) and the bulk density (0.6) of the microgranules are compatible with the mechanical standard application of pesticides on corn. - The bioinsecticide could be produced in a pilot reactor of…
Assessment of landfill leachate biodegradability and treatability by means of allochthonous and autochthonous biomasses
2020
Abstract The biodegradability and treatability of a young (3 years old) municipal landfill leachate was evaluated by means of chemical oxygen demand (COD) fractionation tests, based on respirometric techniques. The tests were performed using two different biomasses: one cultivated from the raw leachate (autochthonous biomass) and the other collected from a conventional municipal wastewater treatment plant after its acclimation to leachate (allochthonous biomass). The long term performances of the two biomasses were also studied. The results demonstrated that the amount of biodegradable COD in the leachate was strictly dependent on the biomass that was used to perform the fractionation tests…
Performance of a membrane-coupled high-rate algal pond for urban wastewater treatment at demonstration scale
2020
[EN] The objective of this study was to evaluate the performance of an outdoor membrane-coupled high-rate algal pond equipped with industrial-scale membranes for treating urban wastewater. Decoupling biomass retention time (BRT) and hydraulic retention time (HRT) by membrane filtration resulted in improved process efficiencies, with higher biomass productivities and nutrient removal rates when operating at low HRTs. At 6 days of BRT, biomass productivity increased from 30 to 66 and to 95 g.m(-3).d(-1) when operating at HRTs of 6, 4 and 2.5 days, respectively. The corresponding nitrogen removal rates were 4, 8 and 11 g N.m(-3).d(-1) and the phosphorous removal rates were 0.5, 1.3 and 1.6 g P…