Optimizing the Extraction Conditions of Hydroxytyrosol from Olive Leaves Using a Modified Spherical Activated Carbon: A New Experimental Design

The purification of hydroxytyrosol from olive leaves extract by modified activated carbon was studied experimentally in a batch system and a column by adsorption and desorption processes. The extraction yield reached 90% of hydroxytyrosol, which is the major compound found in the extract. Despite the abundance of research on extracts of hydroxytyrosol from olive leaves, it seems that the applied methods can be further improved. In this study, several approaches were applied to optimize the extraction conditions of this molecule. Hence, the response surface method and the Box-Behnken design (BBD) were used to evaluate the effect of the temperature, time, and adsorbent dose on the hydroxytyrosol recovery. Moreover, adsorption isotherm, kinetics, and thermodynamic studies were also performed to clarify the nature of the process. The main finding was the obtainment of a maximum adsorption yield of 97.5% at an adsorbent/adsorbate ratio of 1 : 20, after a 6 h cycle and at a temperature of 30°C. Furthermore, adsorption process seemed to fit best with Freundlich model. In addition, the thermodynamic study describes a spontaneous and endothermic process. Desorption assay using ethanol helped to recover 73% of hydroxytyrosol. Furthermore, the HPLC analysis of fractions after column adsorption showed a simple peak of hydroxytyrosol with purity higher than 97% and a flavonoids-rich fraction. These findings would indicate that this separation method for the recovery of phenolic compounds with high antioxidant activity can be a very promising one.This work was supported by the CINEA FP7 Project titled: “EU-MED Cooperation to foster Innovation and Exploitation in the Agro-Food Domain” and the Ministry of Higher Education and Scientific Research, Tunisia

Characterization and Assessment of a Novel Plate and Frame MD Module for Single Pass Wastewater Concentration−FEED Gap Air Gap Membrane Distillation

Membrane distillation (MD) is an up and coming technology for concentration and separation on the verge of reaching commercialization. One of the remaining boundaries is the lack of available full-scale MD modules and systems suitable to meet the requirements of potential industrial applications. In this work a new type of feed gap air gap MD (FGAGMD) plate and frame module is introduced, designed and characterized with tap water and NaCl–H2O solution. The main feature of the new channel configuration is the separation of the heating and cooling channel from the feed channel, enabling a very high recovery ratio in a single pass. Key performance indicators (KPIs) such as flux, gained output ratio (GOR), recovery ratio and thermal efficiency are used to analyze the performance of the novel module concept within this work. A recovery rate of 93% was reached with tap water and between 32–53% with salt solutions ranging between 117 and 214 g NaCl/kg solution with this particular prototype module. Other than recovery ratio, the KPIs of the FGAGMD are similar to those of an air gap membrane distillation (AGMD) channel configuration. From the experimental results, furthermore, a new MD KPI was defined as the ratio of heating and cooling flow to feed flow. This RF ratio can be used for optimization of the module design and efficiency.BMBF, 02WAV1406E, WavE - Verbundprojekt HighCon: Konzentrate aus der Abwasserwiederverwendung, Teilprojekt

Slaughterhouse Wastewater Treatment: A Review on Recycling and Reuse Possibilities

Slaughterhouses produce a large amount of wastewater, therefore, with respect to the increasing water scarcity, slaughterhouse wastewater (SWW) recycling seems to be a desirable goal. The emerging challenges and opportunities for recycling and reuse have been examined here. The selection of a suitable process for SWW recycling is dependent on the characteristics of the wastewater, the available technology, and the legal requirements. SWW recycling is not operated at a large scale up to date, due to local legal sanitary requirements as well as challenges in technical implementation. Since SWW recycling with single-stage technologies is unlikely, combined processes are examined and evaluated within the scope of this publication. The process combination of dissolved air flotation (DAF) followed by membrane bioreactor (MBR) and, finally, reverse osmosis (RO) as a polishing step seems to be particularly promising. In this way, wastewater treatment for process water reuse could be achieved in theory, as well as in comparable laboratory experiments. Furthermore, it was calculated via the methane production potential that the entire energy demand of wastewater treatment could be covered if the organic fraction of the wastewater was used for biogas production.DFG, 414044773, Open Access Publizieren 2021 - 2022 / Technische Universität Berli

Anaerobic Digestion of Olive MillWastewater and Process Derivatives—Biomethane Potential, Operation of a Continuous Fixed Bed Digester, and Germination Index

Olive mill wastewater (OMW) management is an economic and environmental challenge for olive oil-producing countries. The recovery of components with high added value, such as antioxidants, is a highly researched approach that could help refinance performant wastewater treatment systems. Anaerobic (co-)digestion is a suitable process to valorize the energetic and nutritional content of OMW and OMW-derived waste streams from resource recovery processes. Issues of process stability, operation, and yields discourage industrial application. Deepening the understanding of biomethane potential, continuous anaerobic digester operational parameters, and co-substrates is key to large-scale implementation. The biomethane potential of different OMWderived samples and organic solid market waste as co-substrate was 106–350 NL methane per kg volatile solids (VS). The highest yields were obtained with the co-substrate and depolyphenolized OMW mixed with retentate from an ultrafiltration pretreatment. Over 150 days, an anaerobic fixed-bed 300 L digester was operated with different OMW-derived substrates, including OMW with selectively reduced polyphenol concentrations. Different combinations of organic loading rate and hydraulic retention time were set. The biogas yields ranged from 0.97 to 0.99 L of biogas per g of volatile solids (VS) eliminated, with an average methane content in the produced biogas of 64%. Potential inhibition of the process due to high polyphenol concentrations or over-acidification through volatile fatty acids was avoided in the continuous process through process and substrate manipulation.The InnoVa research project (2nd German-African Innovation Promotion Prize: Prof. Sami Sayadi, Prof. Sven Geißen) was funded by the Bundesministerium für Bildung und Forschung, grant number 01DG20005, and managed by the Deutsche Luft-und Raumfahrtzentrum—Projektträger. This research was supported by the Ministry of Higher Education and Scientific Research-Tunisia under a contract program for the Laboratory of Environmental Bioprocesses (LR01CBS2015). We acknowledge support by the German Research Foundation and the Open Access Publication Fund of TU Berlin

Non-Biological Slaughterhouse Wastewater Treatment with Membrane Processes—An Opportunity for Water Recycling

The pressure-driven membrane separation processes ultrafiltration (UF) and reverse osmosis (RO) enable the effective purification of wastewater, in particular in combination, allowing organic and inorganic contaminants to be separated from the wastewater. Consequently, this work investigates the suitability of this technology for slaughterhouse wastewater (SWW) recycling. This was investigated by means of laboratory and bench-scale plant membrane experiments, whereby slaughterhouse wastewater (SWW) pre-treated by flotation was first treated with UF and then further purified with RO. Through the process combination UF + RO in the bench scale experiment, a reduction of the parameters total organic carbon (TOC), chemical oxygen demand (COD) of more than 98% and 97% for the parameter total nitrogen (TN) could be achieved. This means that wastewater reuse without product contact can be guaranteed. For direct process water reuse, only the concentration limit for ammonium could not be reached. In addition, scanning electron microscopy (SEM) images and energy dispersive X-ray spectroscopy (EDX) analyses of the RO membrane were carried out before and after the experiment, which did not indicate any scaling effects

Slaughterhouse Wastewater Treatment: A Review on Recycling and Reuse Possibilities

Slaughterhouses produce a large amount of wastewater, therefore, with respect to the increasing water scarcity, slaughterhouse wastewater (SWW) recycling seems to be a desirable goal. The emerging challenges and opportunities for recycling and reuse have been examined here. The selection of a suitable process for SWW recycling is dependent on the characteristics of the wastewater, the available technology, and the legal requirements. SWW recycling is not operated at a large scale up to date, due to local legal sanitary requirements as well as challenges in technical implementation. Since SWW recycling with single-stage technologies is unlikely, combined processes are examined and evaluated within the scope of this publication. The process combination of dissolved air flotation (DAF) followed by membrane bioreactor (MBR) and, finally, reverse osmosis (RO) as a polishing step seems to be particularly promising. In this way, wastewater treatment for process water reuse could be achieved in theory, as well as in comparable laboratory experiments. Furthermore, it was calculated via the methane production potential that the entire energy demand of wastewater treatment could be covered if the organic fraction of the wastewater was used for biogas production

Characterization and Assessment of a Novel Plate and Frame MD Module for Single Pass Wastewater Concentration–FEED Gap Air Gap Membrane Distillation

Membrane distillation (MD) is an up and coming technology for concentration and separation on the verge of reaching commercialization. One of the remaining boundaries is the lack of available full-scale MD modules and systems suitable to meet the requirements of potential industrial applications. In this work a new type of feed gap air gap MD (FGAGMD) plate and frame module is introduced, designed and characterized with tap water and NaCl–H2O solution. The main feature of the new channel configuration is the separation of the heating and cooling channel from the feed channel, enabling a very high recovery ratio in a single pass. Key performance indicators (KPIs) such as flux, gained output ratio (GOR), recovery ratio and thermal efficiency are used to analyze the performance of the novel module concept within this work. A recovery rate of 93% was reached with tap water and between 32–53% with salt solutions ranging between 117 and 214 g NaCl/kg solution with this particular prototype module. Other than recovery ratio, the KPIs of the FGAGMD are similar to those of an air gap membrane distillation (AGMD) channel configuration. From the experimental results, furthermore, a new MD KPI was defined as the ratio of heating and cooling flow to feed flow. This RF ratio can be used for optimization of the module design and efficiency