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BACKGROUND Two lab‐scale experimental systems, a membrane bioreactor (MBR) and a moving bed biofilm reactor‐membrane bioreactor (MBBR‐MBR), both treating real high‐strength, saline wastewater from a table olive processing plant, were operated under identical conditions to comparatively evaluate their performance for three different Hydraulic Retention Times (HRTs) of 88, 96, and 104 h. RESULTS The biological process of both systems, after appropriate biomass acclimatization, was stable and the removal efficiencies were rather high; i.e. regarding Total Organic Carbon (TOC) ≥86.4% and ≥85.6% for the MBR and MMBR‐MBR, respectively, and ≥89.1% regarding Total Polyphenols (TPh) for both systems. Concerning TOC and TPh removal, no statistically significant difference (p<0.05) was observed between the two systems. Reduction of HRT resulted in a slight decrease of mean TOC removal efficiency, but the mean TPh removal was practically unchanged. No membrane chemical cleaning was applied to both systems during the 85‐day long continuous operation. CONCLUSION The comparative assessment showed that both systems (i.e. MBR and MBBR‐MBR) are effective for the advanced biological treatment of TOPW and can achieve quite high removal efficiencies of organic matter and TPh. However, direct effluent reuse for irrigation purposes seems to be hindered by its high salinity. No significant differences were observed in the performance of these systems, apart from the increased aeration (and related energy costs), which is necessary to keep the biofilm carriers floating in the case of the MBBR‐MBR. This article is protected by copyright. All rights reserved.
Sotiris I. Patsios; Konstantinos N. Kontogiannopoulos; Niki Pouliou; Anastasios J. Karabelas. Performance of a membrane bioreactor and a moving bed biofilm reactor–membrane bioreactor treating table olive processing wastewater: a comparative study. Journal of Chemical Technology & Biotechnology 2020, 96, 1030 -1039.
AMA StyleSotiris I. Patsios, Konstantinos N. Kontogiannopoulos, Niki Pouliou, Anastasios J. Karabelas. Performance of a membrane bioreactor and a moving bed biofilm reactor–membrane bioreactor treating table olive processing wastewater: a comparative study. Journal of Chemical Technology & Biotechnology. 2020; 96 (4):1030-1039.
Chicago/Turabian StyleSotiris I. Patsios; Konstantinos N. Kontogiannopoulos; Niki Pouliou; Anastasios J. Karabelas. 2020. "Performance of a membrane bioreactor and a moving bed biofilm reactor–membrane bioreactor treating table olive processing wastewater: a comparative study." Journal of Chemical Technology & Biotechnology 96, no. 4: 1030-1039.
Olive oil production is a significant agricultural activity for the European Union (EU), especially for the countries of Mediterranean basin. Four European countries, namely Spain, Italy, Greece, and Portugal, produce more than 95% of the total EU production of 12.5 million tons. At the same time, olive oil production involves the use of various resources (i.e., energy, water, fertilizers, chemicals, etc.) and it is responsible for a series of environmental impacts in terms of depletion of natural resources, air, water and soil emissions, land and freshwater degradation, and waste/residues generation. These environmental impacts are closely related to the olive oil production practice across the whole olive oil value chain, namely olive cultivation, transportation, olive oil production, and waste management. Moreover, significant differences are accounted in the practices and methods employed during olive oil production between different countries or even within the same country (from one region to another). Scientific tools such as Life Cycle Assessment (LCA) can assist in understanding and evaluating those impacts and identify possible areas for improvement. This study focuses on a comparative in-depth review analysis of the environmental burden of olive oil value chain in two different countries (Greece and Spain), where the olive oil production chains present significant degree of differentiation. The results of the LCA, according to the Eco-Indicator 99 methodology, denote that the environmental impacts are higher for the typical Greek case study for the Human Health and Ecosystem Quality categories, whereas the Spanish case study showed higher normalized impact value for the Resources Depletion category.
Sotiris I. Patsios; Konstantinos N. Kontogiannopoulos; Georgios F. Banias. Environmental impact assessment in agri-production. Bio-Economy and Agri-production 2020, 83 -116.
AMA StyleSotiris I. Patsios, Konstantinos N. Kontogiannopoulos, Georgios F. Banias. Environmental impact assessment in agri-production. Bio-Economy and Agri-production. 2020; ():83-116.
Chicago/Turabian StyleSotiris I. Patsios; Konstantinos N. Kontogiannopoulos; Georgios F. Banias. 2020. "Environmental impact assessment in agri-production." Bio-Economy and Agri-production , no. : 83-116.
Municipal Solid Waste (MSW) management has been a major problem of modern cities for many years. Thus, the development of optimal waste management strategies has been a priority for the European Commission, especially in the transition toward a circular economy. In this paper, an analysis of different MSW treatment methods that can be effectively implemented in the Region of Central Macedonia (RCM) is provided, and their comparison from an environmental point of view is performed. The assessment is based on real data indicated in the recently updated Greek National Waste Management Plan, whereas the different scenarios developed include landfilling without energy recovery, landfilling with energy recovery, recycling and secondary materials recovery, mechanical-biological treatment, bio-waste composting and anaerobic digestion with energy recovery, and incineration with energy recovery. The obtained results illustrate that efficient waste streams sorting is of vital importance for the effective implementation of an integrated waste management system toward the sustainable management of MSW.
Georgios Banias; Maria Batsioula; Charisios Achillas; Sotiris Patsios; Konstantinos Kontogiannopoulos; Dionysis Bochtis; Nicolas Moussiopoulos. A Life Cycle Analysis Approach for the Evaluation of Municipal Solid Waste Management Practices: The Case Study of the Region of Central Macedonia, Greece. Sustainability 2020, 12, 8221 .
AMA StyleGeorgios Banias, Maria Batsioula, Charisios Achillas, Sotiris Patsios, Konstantinos Kontogiannopoulos, Dionysis Bochtis, Nicolas Moussiopoulos. A Life Cycle Analysis Approach for the Evaluation of Municipal Solid Waste Management Practices: The Case Study of the Region of Central Macedonia, Greece. Sustainability. 2020; 12 (19):8221.
Chicago/Turabian StyleGeorgios Banias; Maria Batsioula; Charisios Achillas; Sotiris Patsios; Konstantinos Kontogiannopoulos; Dionysis Bochtis; Nicolas Moussiopoulos. 2020. "A Life Cycle Analysis Approach for the Evaluation of Municipal Solid Waste Management Practices: The Case Study of the Region of Central Macedonia, Greece." Sustainability 12, no. 19: 8221.
A process development study is reported, involving water-based extraction of polyphenols from pomegranate husk and their subsequent membrane concentration. Aiming to optimize extraction, various experimental conditions were investigated, including extraction duration, solid to liquid ratio (2-14 % w/v dry weight), extraction temperature, number of sequential extraction stages (single, double and triple) and type of solvent. It was found that two extraction stages (90 min each) under a solid to water ratio of 3% w/v at 30 °C, were sufficient for obtaining a yield of 85% of total polyphenols from the husk. Subsequently, nanofiltration (NF) was used to concentrate the polyphenols extracts by a volume concentration factor (VCF) of three. Two main process parameters, namely pressure (4-14 bar) and pH (4-8), were examined at constant temperature 30◦C, in batch concentration mode. Results show near optimum NF-membrane performance, with high total polyphenols retention (≥ 98%) at 10 bar pressure and pH 6. Interestingly, the NF-membrane, used for up to 10 filtration batches, exhibited satisfactory flux without intermediate cleaning, suggesting that it could be employed for an extended period. Prospects and challenges are discussed for further process development and practical application.
Emmanouil H. Papaioannou; Soultana T. Mitrouli; Sotiris I. Patsios; Maria Kazakli; Anastasios J. Karabelas. Valorization of pomegranate husk – Integration of extraction with nanofiltration for concentrated polyphenols recovery. Journal of Environmental Chemical Engineering 2020, 8, 103951 .
AMA StyleEmmanouil H. Papaioannou, Soultana T. Mitrouli, Sotiris I. Patsios, Maria Kazakli, Anastasios J. Karabelas. Valorization of pomegranate husk – Integration of extraction with nanofiltration for concentrated polyphenols recovery. Journal of Environmental Chemical Engineering. 2020; 8 (4):103951.
Chicago/Turabian StyleEmmanouil H. Papaioannou; Soultana T. Mitrouli; Sotiris I. Patsios; Maria Kazakli; Anastasios J. Karabelas. 2020. "Valorization of pomegranate husk – Integration of extraction with nanofiltration for concentrated polyphenols recovery." Journal of Environmental Chemical Engineering 8, no. 4: 103951.
Proteins are essential constituents of animal feeds, which comprise mainly vegetable protein (e.g., soybean meal), which is produced and transported globally. The decoupling of protein-production and livestock-growth areas results in protein deficiencies in certain parts of the world, and in significant environmental stress. Alternative, more sustainable protein feeds are necessary to meet the increasing needs, and to decrease the environmental footprint of animal products. Yeast Single Cell Proteins (SCP), produced locally using various agro-industrial by-product streams, have significant potential as alternative animal feed protein. Particularly, Yarrowia lipolytica, an oleaginous, non-pathogenic microorganism has been characterized as a “workhorse” in biotechnological studies, drawing the attention of many researchers. The present review summarizes available resources on critical issues concerning the applicability and commercialization of Yarrowia lipolytica as an environment-friendly protein source for animal feed. It discusses the sustainability of the yeast SCP production process, it presents the recent advances concerning Yarrowia lipolytica cultivation on low-cost agro-industrial by-products, and it stresses the effects on the health and welfare of productive animals due to the inclusion of Yarrowia lipolytica in their diet. The data presented in this study should facilitate relative research advancement and the commercialization of Yarrowia lipolytica’s use as an alternative protein source/supplement for animal feeds.
Sotiris I. Patsios; Anna Dedousi; Evangelia Ν. Sossidou; Antonios Zdragas. Sustainable Animal Feed Protein through the Cultivation of YARROWIA Lipolytica on Agro-Industrial Wastes and by-Products. Sustainability 2020, 12, 1398 .
AMA StyleSotiris I. Patsios, Anna Dedousi, Evangelia Ν. Sossidou, Antonios Zdragas. Sustainable Animal Feed Protein through the Cultivation of YARROWIA Lipolytica on Agro-Industrial Wastes and by-Products. Sustainability. 2020; 12 (4):1398.
Chicago/Turabian StyleSotiris I. Patsios; Anna Dedousi; Evangelia Ν. Sossidou; Antonios Zdragas. 2020. "Sustainable Animal Feed Protein through the Cultivation of YARROWIA Lipolytica on Agro-Industrial Wastes and by-Products." Sustainability 12, no. 4: 1398.
Wastewater from food processing facilities can have high nutrient valorisation potential. Valorising sugar-rich agro-industrial wastewater may have significant impacts on sustainability of wastewater treatment plant (WWTP). The objective of this study is to evaluate the environmental, economic and social impacts of a novel wastewater valorisation technology. This technology is designed to produce single cell protein (SCP) from wastewater of a fruit juice processing facility. To evaluate the comprehensive sustainability impacts on WWTP and overall background economy, a hybrid life cycle assessment model was developed by combining the multi-regional input-output database (Exiobase) with process-based life cycle inventories of conventional and AgroCycle WWTP. The results indicated the upstream impacts of wastewater could have significant influence on sustainability of WWTP with nutrient valorisation. Therefore the ‘zero burden assumption’ should not be adopted for upstream wastewater. For the sustainability performance, valorising nutrients from WWTP with AgroCycle technology can improve the environmental performance of WWTP. However, the positive social-economic impacts were directly associated with WWTP system, not the whole background economy. The production of SCP could reduce the Gross Value Added (GVA) and employment in the ‘oil seeds sector’. In order to improve the social-economic impacts and promote a circular bioeconomy model in the fruit juice sector, further development is required to improve valorisation productivity and create a better value chain for valorised products.
Wenhao Chen; Thomas L. Oldfield; Sotiris I. Patsios; Nicholas M. Holden. Hybrid life cycle assessment of agro-industrial wastewater valorisation. Water Research 2019, 170, 115275 .
AMA StyleWenhao Chen, Thomas L. Oldfield, Sotiris I. Patsios, Nicholas M. Holden. Hybrid life cycle assessment of agro-industrial wastewater valorisation. Water Research. 2019; 170 ():115275.
Chicago/Turabian StyleWenhao Chen; Thomas L. Oldfield; Sotiris I. Patsios; Nicholas M. Holden. 2019. "Hybrid life cycle assessment of agro-industrial wastewater valorisation." Water Research 170, no. : 115275.
Biological treatment of table olive processing wastewater (TOPW) may be problematic due to its high organic and polyphenolic compound content. Biomass acclimatization is a necessary, yet sensitive, stage for efficient TOPW biological treatment. Next-generation sequencing technologies can provide valuable insights into this critical process step. An aerobic membrane bioreactor (MBR) system, initially inoculated with municipal activated sludge, was acclimatized to treat TOPW. Operational stability and bioremediation efficiency were monitored for approx. three months, whereas microbial community dynamics and metabolic adaptation were assessed through metagenomic and metatranscriptomic analysis. A swift change was identified in both the prokaryotic and eukaryotic bio-community after introduction of TOPW in the MBR, and a new diverse bio-community was established. Thauera and Paracoccus spp. are dominant contributors to the metabolic activity of the stable bio-community, which resulted in over 90% and 85% removal efficiency of total organic carbon and total polyphenols, respectively. This is the first study assessing the microbial community dynamics in a well-defined MBR process treating TOPW, offering guidance in the start-up of large-scale applications.
Sotiris I. Patsios; Sofia Michailidou; Konstantinos Pasentsis; Antonios M. Makris; Anagnostis Argiriou; Anastasios J. Karabelas. Analysis of Microbial Community Dynamics during the Acclimatization Period of a Membrane Bioreactor Treating Table Olive Processing Wastewater. Applied Sciences 2019, 9, 3647 .
AMA StyleSotiris I. Patsios, Sofia Michailidou, Konstantinos Pasentsis, Antonios M. Makris, Anagnostis Argiriou, Anastasios J. Karabelas. Analysis of Microbial Community Dynamics during the Acclimatization Period of a Membrane Bioreactor Treating Table Olive Processing Wastewater. Applied Sciences. 2019; 9 (18):3647.
Chicago/Turabian StyleSotiris I. Patsios; Sofia Michailidou; Konstantinos Pasentsis; Antonios M. Makris; Anagnostis Argiriou; Anastasios J. Karabelas. 2019. "Analysis of Microbial Community Dynamics during the Acclimatization Period of a Membrane Bioreactor Treating Table Olive Processing Wastewater." Applied Sciences 9, no. 18: 3647.
Wine waste lees are currently partly exploited for tartaric acid (TA) production, through an environment-offensive process, while concurrently occurring bio-active polyphenolic compounds are wasted. This paper, deals with the development of an integrated, environment friendly process, using mild conditions, for recovering TA with simultaneous exploitation of total polyphenols (TPP) from wine lees. A first process step, described in a previous publication, yields a liquid stream containing approx. 44.2 g L−1 TA and 323.3 mg GAE L−1 TPP. In the present study, various ultrafiltration and nanofiltration membranes are assessed, in bench-scale filtration tests, for their efficiency in separating the two main products (i.e. TA and TPP) from this stream. The most promising process configurations are also tested in a laboratory-scale cross-flow membrane filtration pilot plant and assessed concerning the separation efficiency and the membrane filtration performance, to determine process feasibility at industrial scale. The results show that a nanofiltration membrane with typical pore size approx. 1 kDa exhibits satisfactory separation and low-fouling filtration performance. The permeate, containing the bulk of TA (approx. 42.6 g L−1) could be used for TA recovery, whereas the concentrate, with antioxidant activity (EC50 = 10.0 mg sample mg−1 DPPH.), could be further purified to obtain polyphenolic-rich formulations. © 2017 Society of Chemical Industry
Konstantinos N Kontogiannopoulos; Sotiris I Patsios; Soultana T Mitrouli; Anastasios J Karabelas. Tartaric acid and polyphenols recovery from winery waste lees using membrane separation processes. Journal of Chemical Technology & Biotechnology 2017, 92, 2934 -2943.
AMA StyleKonstantinos N Kontogiannopoulos, Sotiris I Patsios, Soultana T Mitrouli, Anastasios J Karabelas. Tartaric acid and polyphenols recovery from winery waste lees using membrane separation processes. Journal of Chemical Technology & Biotechnology. 2017; 92 (12):2934-2943.
Chicago/Turabian StyleKonstantinos N Kontogiannopoulos; Sotiris I Patsios; Soultana T Mitrouli; Anastasios J Karabelas. 2017. "Tartaric acid and polyphenols recovery from winery waste lees using membrane separation processes." Journal of Chemical Technology & Biotechnology 92, no. 12: 2934-2943.
Konstantinos V. Plakas; Vasilis C. Sarasidis; Sotiris I. Patsios; Dimitra A. Lambropoulou; Anastasios J. Karabelas. Novel pilot scale continuous photocatalytic membrane reactor for removal of organic micropollutants from water. Chemical Engineering Journal 2016, 304, 335 -343.
AMA StyleKonstantinos V. Plakas, Vasilis C. Sarasidis, Sotiris I. Patsios, Dimitra A. Lambropoulou, Anastasios J. Karabelas. Novel pilot scale continuous photocatalytic membrane reactor for removal of organic micropollutants from water. Chemical Engineering Journal. 2016; 304 ():335-343.
Chicago/Turabian StyleKonstantinos V. Plakas; Vasilis C. Sarasidis; Sotiris I. Patsios; Dimitra A. Lambropoulou; Anastasios J. Karabelas. 2016. "Novel pilot scale continuous photocatalytic membrane reactor for removal of organic micropollutants from water." Chemical Engineering Journal 304, no. : 335-343.
A crucial first step in developing a novel cost-effective and environment-friendly process for recovering tartaric acid and bioactive polyphenolic compounds from wine lees involves tartrates dissolution by mild means, aiming to maximize tartaric acid recovery, while minimizing the concentration of undesirable potassium. Such a processing step, using cation exchange resin, has been systematically assessed to obtain a set of near-optimum values of the key variables (i.e. pH, water dosage and cation exchange resin dosage). An experimental design was carried out based on Central Composite Design (CCD) with Response Surface Methodology (RSM) to evaluate the effects of process parameters and their interaction towards the attainment of optimum conditions. All three variables considered were found to be significant; however, the most influential factor for maximum tartaric acid concentration was the volume of added water, whereas for potassium removal the cation exchange resin dosage. A quadratic model was developed that fitted well to the experimental data confirmed by the high R2 values, greater than 0.98. A set of optimum values of the three main variables was determined to be pH = 3.0, water dosage 10 ml/g dry lees and resin dosage 3.5 g/g dry lees. Under these optimum conditions, the predicted tartaric acid and potassium concentration were 43,143 ppm and 178 ppm, respectively, which correspond to 74.9% tartaric acid recovery and 98.8% potassium removal. Furthermore, the corresponding experimental values, from the validation experiment, fitted well to these predictions. This work clearly shows that the recovery of tartaric acid from wine lees can be achieved using cation exchange resin, under mild conditions (ambient temperature) avoiding the waste calcium sulfate sludge of the conventional process.
Konstantinos N. Kontogiannopoulos; Sotiris I. Patsios; Anastasios J. Karabelas. Tartaric acid recovery from winery lees using cation exchange resin: Optimization by Response Surface Methodology. Separation and Purification Technology 2016, 165, 32 -41.
AMA StyleKonstantinos N. Kontogiannopoulos, Sotiris I. Patsios, Anastasios J. Karabelas. Tartaric acid recovery from winery lees using cation exchange resin: Optimization by Response Surface Methodology. Separation and Purification Technology. 2016; 165 ():32-41.
Chicago/Turabian StyleKonstantinos N. Kontogiannopoulos; Sotiris I. Patsios; Anastasios J. Karabelas. 2016. "Tartaric acid recovery from winery lees using cation exchange resin: Optimization by Response Surface Methodology." Separation and Purification Technology 165, no. : 32-41.
Table olive processing wastewater (TOPW) is a seriously polluting and difficult to treat effluent, characterized by widely fluctuating pH and salinity, as well as high concentrations of organic matter and polyphenols. This systematic long-term study in a laboratory-scale pilot demonstrates that membrane bioreactor (MBR) technology is effective in substantially bio-degrading TOPW. After implementation of an appropriate protocol of active biomass acclimatization/proliferation, the MBR pilot was operated for 6 months with real TOPW effluent, under various operating conditions. Total organic carbon (TOC) and total polyphenol (TPh) compounds removal efficiencies were very high with mean values 91.5 and 82.8%, respectively; nutrient (N and P) removal was also satisfactory. The membrane exhibited stable performance at moderate biomass concentration, with a tendency to deteriorate at higher biomass concentration. Fouled membrane permeability could be fully restored by implementing the usual chemical cleaning protocols. Despite the high percentage TOC and TPh removal, the MBR effluent requires final post-treatment to remove a yellowish tint and further reduce its organic content, depending on local discharge standards. The MBR can serve as the basic treatment process in an integrated scheme for TOPW management, which needs additional R&D to further develop and optimize. © 2015 Society of Chemical Industry
Sotiris I. Patsios; Emmanouil H. Papaioannou; Anastasios J. Karabelas. Long-term performance of a membrane bioreactor treating table olive processing wastewater. Journal of Chemical Technology & Biotechnology 2015, 91, 2253 -2262.
AMA StyleSotiris I. Patsios, Emmanouil H. Papaioannou, Anastasios J. Karabelas. Long-term performance of a membrane bioreactor treating table olive processing wastewater. Journal of Chemical Technology & Biotechnology. 2015; 91 (8):2253-2262.
Chicago/Turabian StyleSotiris I. Patsios; Emmanouil H. Papaioannou; Anastasios J. Karabelas. 2015. "Long-term performance of a membrane bioreactor treating table olive processing wastewater." Journal of Chemical Technology & Biotechnology 91, no. 8: 2253-2262.
The rheological properties of membrane biofouling layers developing in Membrane Bioreactors (MBR) have not been measured directly so far, although they are essential for understanding biofouling and for determining conditions to mitigate it. The development of a novel method is reported herein, which permits accurate rheological measurements on membrane biofouling layers, using specimens withdrawn from an operating laboratory-scale MBR. A specially designed test-section (with a pair of flat membrane specimens) allows implementation of realistic operating modes, including automatic periodic back-washing. The membrane specimens, with a biofouling layer representative of a well-controlled MBR operating history, are examined in an advanced parallel-plate rheometer, where special care is taken to prevent ex-situ biofouling layer changes. Measurements performed in oscillatory and steady shearing modes provide valuable information on biofouling layer rheological characteristics, confirming that these layers are typical viscoelastic materials with yield stress exhibiting thixotropic, shear-thinning behavior. Rheological properties of the activated sludge liquor are also assessed. The rheological properties of activated sludge and of biofouling layers display qualitative similarities, although the elastic character of the latter is much more pronounced. The new technique is most useful for studying biofouling layers as a function of the main MBR process parameters. Improvements of the technique for such applications are discussed.
S.I. Patsios; T.B. Goudoulas; E.G. Kastrinakis; S.G. Nychas; A.J. Karabelas. A novel method for rheological characterization of biofouling layers developing in Membrane Bioreactors (MBR). Journal of Membrane Science 2015, 482, 13 -24.
AMA StyleS.I. Patsios, T.B. Goudoulas, E.G. Kastrinakis, S.G. Nychas, A.J. Karabelas. A novel method for rheological characterization of biofouling layers developing in Membrane Bioreactors (MBR). Journal of Membrane Science. 2015; 482 ():13-24.
Chicago/Turabian StyleS.I. Patsios; T.B. Goudoulas; E.G. Kastrinakis; S.G. Nychas; A.J. Karabelas. 2015. "A novel method for rheological characterization of biofouling layers developing in Membrane Bioreactors (MBR)." Journal of Membrane Science 482, no. : 13-24.
Vasilis C. Sarasidis; Konstantinos Plakas; Sotiris I. Patsios; Anastasios J. Karabelas. Investigation of diclofenac degradation in a continuous photo-catalytic membrane reactor. Influence of operating parameters. Chemical Engineering Journal 2014, 239, 299 -311.
AMA StyleVasilis C. Sarasidis, Konstantinos Plakas, Sotiris I. Patsios, Anastasios J. Karabelas. Investigation of diclofenac degradation in a continuous photo-catalytic membrane reactor. Influence of operating parameters. Chemical Engineering Journal. 2014; 239 ():299-311.
Chicago/Turabian StyleVasilis C. Sarasidis; Konstantinos Plakas; Sotiris I. Patsios; Anastasios J. Karabelas. 2014. "Investigation of diclofenac degradation in a continuous photo-catalytic membrane reactor. Influence of operating parameters." Chemical Engineering Journal 239, no. : 299-311.
Residual oil recovery from olive mill solids-containing residues (pomace) necessitates significant reduction of its water content, usually done in direct-contact dryers producing polluting vapors. An environmentally superior alternative involves pomace drying by indirect heating at modest temperatures, vapor condensation and condensate treatment for utilization or safe disposal. To develop such an integrated process, this study focuses on the condensates from pomace drying by indirect-heating at 70–120 °C. These condensates exhibit fairly high concentration of organic substances, significant quantities of phenolic compounds, acidity, and low biodegradability. At the higher temperatures, local overheating of equipment surfaces, especially during the final stage of batch drying, tends to degrade condensate characteristics due to pyrolysis and/or vaporization of organic matter. At relatively low temperatures, condensates exhibit smaller concentration of organic and phenolic compounds, which entail improved biodegradability. Therefore, relatively low temperatures, combined with moderate vacuum, appear to be preferable drying conditions facilitating further condensate treatment.
E.H. Papaioannou; S.I. Patsios; A.J. Karabelas; N.A. Philippopoulos. Characterization of condensates from an indirect olive oil pomace drying process: The effect of drying temperature. Journal of Environmental Chemical Engineering 2013, 1, 831 -837.
AMA StyleE.H. Papaioannou, S.I. Patsios, A.J. Karabelas, N.A. Philippopoulos. Characterization of condensates from an indirect olive oil pomace drying process: The effect of drying temperature. Journal of Environmental Chemical Engineering. 2013; 1 (4):831-837.
Chicago/Turabian StyleE.H. Papaioannou; S.I. Patsios; A.J. Karabelas; N.A. Philippopoulos. 2013. "Characterization of condensates from an indirect olive oil pomace drying process: The effect of drying temperature." Journal of Environmental Chemical Engineering 1, no. 4: 831-837.
Data are reported on photocatalytic mineralization rates of sodium alginate (SA), which is representative of polysaccharides commonly encountered in surface waters and effluents requiring purification. An agitated vessel-type photocatalytic reactor was employed, with suspended TiO2 nanoparticles, to study the effect of UV-A radiant power per unit volume PR (W per L reactor fluid) for which there are insufficient data. Using initial SA concentration ∼30 mg/L, mineralization rates were determined, by monitoring Total Organic Carbon (TOC) reduction, in the range of UV-A PR = 2.15 to 8.57 W L−1 and TiO2 concentrations 0.5 to 1.5 g/L. For this well-mixed heterogeneous photocatalytic environment, the measured fairly high polysaccharide mineralization rates were fitted to a first order kinetic expression. In the parameter range studied, the kinetic constants k (of order 10−2 min−1) were linearly dependent on PR with a slope in the range ∼0.6 × 10−2 to ∼1.0 × 10−2 L/(W min). An optimum catalyst concentration near 1 g/L TiO2 was observed. The experimental techniques developed and the type of kinetic data obtained are considered useful for designing photocatalytic reactors for practical applications. Moreover, it is encouraging that the measured mineralization rates are in accord with those from a continuously operated hybrid photocatalytic membrane reactor of different geometry.
A.J. Karabelas; V.C. Sarasidis; S.I. Patsios. The effect of UV radiant power on the rate of polysaccharide photocatalytic mineralization. Chemical Engineering Journal 2013, 229, 484 -491.
AMA StyleA.J. Karabelas, V.C. Sarasidis, S.I. Patsios. The effect of UV radiant power on the rate of polysaccharide photocatalytic mineralization. Chemical Engineering Journal. 2013; 229 ():484-491.
Chicago/Turabian StyleA.J. Karabelas; V.C. Sarasidis; S.I. Patsios. 2013. "The effect of UV radiant power on the rate of polysaccharide photocatalytic mineralization." Chemical Engineering Journal 229, no. : 484-491.
The successful operation of a hybrid photocatalysis–membrane separation process (in a laboratory-scale pilot system) is demonstrated for degradation of Humic Acids (HAs), which are typical refractory components of Natural Organic Matter (NOM). The Photocatalytic Membrane Reactor (PMR) employing an Ultrafiltration (UF) submerged module was operated in continuous mode with TiO2 catalyst concentration 0.75 g/L and UV-A radiant flux 15.1 J/s, treating feed water with HA concentrations 5.0 and 10.0 mg/L. Experiments carried out within a sufficiently broad pH range (approx. 3.5–7.0) exhibited satisfactory HA mineralization rates and rather high HA mineralization efficiencies; a near optimum pH at approx. 5.5 was identified. The overall process removal efficiency (comprising both HA oxidation and UF membrane rejection) was even higher, as a result of the synergistic effects of photocatalytic oxidation and membrane filtration. The degradation of HA aromatic rings, that diminishes the Disinfection By-Products (DBPs) formation potential, was also very high; the specific UV-A254 removal efficiency was greater than 95% in almost all cases studied. Concerning membrane filtration performance, the periodic backwashing employed, combined with the moderate membrane flux, effectively controlled membrane fouling thus permitting stable continuous operation with no wastewater stream.
S.I. Patsios; V.C. Sarasidis; A.J. Karabelas. A hybrid photocatalysis–ultrafiltration continuous process for humic acids degradation. Separation and Purification Technology 2012, 104, 333 -341.
AMA StyleS.I. Patsios, V.C. Sarasidis, A.J. Karabelas. A hybrid photocatalysis–ultrafiltration continuous process for humic acids degradation. Separation and Purification Technology. 2012; 104 ():333-341.
Chicago/Turabian StyleS.I. Patsios; V.C. Sarasidis; A.J. Karabelas. 2012. "A hybrid photocatalysis–ultrafiltration continuous process for humic acids degradation." Separation and Purification Technology 104, no. : 333-341.
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V.C. Sarasidis; S.I. Patsios; A.J. Karabelas. Humic Acids Degradation by a Hybrid Photocatalysis-Membrane Process: Effect of UV-A Photon dose on Mineralization Kinetics. Procedia Engineering 2012, 44, 290 -292.
AMA StyleV.C. Sarasidis, S.I. Patsios, A.J. Karabelas. Humic Acids Degradation by a Hybrid Photocatalysis-Membrane Process: Effect of UV-A Photon dose on Mineralization Kinetics. Procedia Engineering. 2012; 44 ():290-292.
Chicago/Turabian StyleV.C. Sarasidis; S.I. Patsios; A.J. Karabelas. 2012. "Humic Acids Degradation by a Hybrid Photocatalysis-Membrane Process: Effect of UV-A Photon dose on Mineralization Kinetics." Procedia Engineering 44, no. : 290-292.
A novel system is described, which involves coupling the photo-catalysis process with ultrafiltration, permitting a steady state operation with a fixed quantity of dispersed TiO2 catalytic nano-particles. Results are presented demonstrating the good performance of the system for degradation of a typical polysaccharide (sodium alginate) dissolved in feed-water at relatively small concentration. Using a hollow-fiber UF module submerged in an aerated tank and periodic backwashing, membrane fouling is controlled and TiO2 particles are totally retained by the membranes, thus allowing continuous “once-through” flow operation with no reject stream. Experiments carried out with catalyst concentration in the range 0.25–1.5 g/L and constant UV-A irradiation of 17.7 J/s (in a 9 L capacity system), show fairly high alginate mineralization rates with a maximum TOC removal (∼75%) at TiO2 concentration 0.75 g/L. The three backwash frequencies employed (i.e. 1 min backwashing after 5, 9, or 15 min suction period) result in approximately the same percentage TOC removal; however, the smaller frequencies are desirable as they lead to greater permeate productivity. Based on the present encouraging results, research needs are indicated for overall system improvement and optimization for various applications.
V.C. Sarasidis; Sotiris Patsios; A.J. Karabelas. A hybrid photocatalysis–ultrafiltration continuous process: The case of polysaccharide degradation. Separation and Purification Technology 2011, 80, 73 -80.
AMA StyleV.C. Sarasidis, Sotiris Patsios, A.J. Karabelas. A hybrid photocatalysis–ultrafiltration continuous process: The case of polysaccharide degradation. Separation and Purification Technology. 2011; 80 (1):73-80.
Chicago/Turabian StyleV.C. Sarasidis; Sotiris Patsios; A.J. Karabelas. 2011. "A hybrid photocatalysis–ultrafiltration continuous process: The case of polysaccharide degradation." Separation and Purification Technology 80, no. 1: 73-80.
The scope of this paper is to systematically examine the long-term filtration performance of a laboratory scale MBR pilot, under nine different operating states, for elucidating the role of specific organic fractions of the mixed liquor. It is shown that the Solids Retention Time (SRT) is a major parameter influencing the concentration of both Dissolved Organic Matter (DOM) – mainly comprising Soluble Microbial Products (SMP) – and bound Extracellular Polymeric Substances (bEPS). Increasing SRT results in a noticeable reduction of both total and biodegradable fraction of DOM; at high SRT, the total bEPS concentration slightly increases whereas the bEPS biodegradable fraction decreases. The results underpin a close interrelation between DOM and bEPS, which are apparently under a dynamic equilibrium; biosorption phenomena are suggested as a mechanism significantly influencing this equilibrium. Membrane filtration performance has been examined over a wide range of SRT and HRT values. Temporal profiles of reversible and irreversible filtration resistance have been evaluated in connection with DOM and bEPS concentration data. It appears that low DOM concentration and bEPS content inhibit the self-accelerating phenomena leading to a Trans-membrane Pressure (TMP) jump, thus permitting a longer sustainable filtration operation; possible mechanisms are also suggested. This study provides useful data and ample evidence on the critical effect of DOM and bEPS on membrane fouling, helpful for further investigations and eventually for MBR operation.
S.I. Patsios; A.J. Karabelas. An investigation of the long-term filtration performance of a membrane bioreactor (MBR): The role of specific organic fractions. Journal of Membrane Science 2011, 372, 102 -115.
AMA StyleS.I. Patsios, A.J. Karabelas. An investigation of the long-term filtration performance of a membrane bioreactor (MBR): The role of specific organic fractions. Journal of Membrane Science. 2011; 372 (1-2):102-115.
Chicago/Turabian StyleS.I. Patsios; A.J. Karabelas. 2011. "An investigation of the long-term filtration performance of a membrane bioreactor (MBR): The role of specific organic fractions." Journal of Membrane Science 372, no. 1-2: 102-115.
Sotiris Patsios; Anastasios Karabelas. A review of modeling bioprocesses in membrane bioreactors (MBR) with emphasis on membrane fouling predictions. Desalination and Water Treatment 2010, 21, 189 -201.
AMA StyleSotiris Patsios, Anastasios Karabelas. A review of modeling bioprocesses in membrane bioreactors (MBR) with emphasis on membrane fouling predictions. Desalination and Water Treatment. 2010; 21 (1-3):189-201.
Chicago/Turabian StyleSotiris Patsios; Anastasios Karabelas. 2010. "A review of modeling bioprocesses in membrane bioreactors (MBR) with emphasis on membrane fouling predictions." Desalination and Water Treatment 21, no. 1-3: 189-201.