Optimization of phosphorus recovery from anaerobic digester effluents in agri-industry

Phosphorus (P) is an essential nutrient to sustain life. P is widely used by agriculture sectors as fertilizer to secure food production and sustain human necessities. Since the major sources of P come from non-replaceable and non-renewable natural phosphate rock reserves, it is expected a depletion of this raw material in the next 80 years. In addition, every year, it is estimated that up to 10 Mt are wasted into the hydrosphere causing serious environmental damage in water bodies (e.g., eutrophication). Alongside climate change and the increased risk of draughts in the near future, it is important to guarantee the quality of those water bodies and secure food and feed production in the agriculture sector. Therefore, to reduce the pressure in water bodies, we should increase the efforts to treat wastewater before release, which in turn can be used as a source for P recovery. Thus, the main objective of the present work was the optimization of P recovery from full-scale Anaerobic Digestion (AD) effluents using precipitation methods with the addition of chemical (e.g., Mg, Ca or Fe salts), as well as exploring alternatives to conventional chemicals, such as seawater, bine (Mg-rich sources), and mussel shells and cork ashes (Ca-rich sources). This work is integrated in BIOECONORTE project - water and nutrients management based on BIOrefinery and circular ECOnomy towards a sustainable agri-food system of the NORTE of Portugal. The addition of chemicals was based on the initial concentration of P in the effluent (brewery and dairy industry), and different molar ratios (salt:P) 1:1, 2:1, 3:1 or 4:1 were applied. P precipitation using FeCl3, at the different Fe:P ratios, showed a P-recovery between 88-100 % and 57-85% in brewery and dairy wastewaters, respectively. With the addition of CaCl2, for the different Ca:P ratios, and adjusting the pH to 10, the P recovery ranged between 58-84% and 92-95% in brewery and dairy wastewaters, respectively. The experiments carried out with mussel shells (only with dairy wastewater, but for the different Ca:P ratios) demonstrated a P-recovery of 12-41%, 89-99%, and 98-99% when using raw shells, calcinated shells, and hydrated-calcinated shells, respectively. The seawater was tested in synthetic wastewater, at a 20% (v/v) ratio, showing a P recovery of 64%. In conclusion, these results demonstrate the viability of the use of alternative salt sources for P precipitation and recovery, contributing to the circular economy of agri-food industry.This study was supported by the BioEcoNorte project (NORTE-01-0145-FEDER-000070) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte and by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020info:eu-repo/semantics/publishedVersio

Science communication in bioengineering and biotechnology: Active and collaborative learning project

In a society increasingly dependent on science and technology, the need to equip our students with the most varied digital and communication skills is crucial. Active and collaborative learning among peers is essential for the acquisition of transversal skills. Communication is one of the main tools that the Engineer uses to reach his target audience. Science Communication in Bioengineering and Biotechnology (CCBioTec) is a project on Innovation and Development of Teaching and Learning supported by Center IDEA-UMinho, a structure that emerges to promote and value Innovation and Development of Teaching and Learning at the University of Minho. CCBioTec is transversal to a set of Learning Units (LU) under the responsibility of the Department of Biological Engineering (DEB), including one LU of each year of the Integrated Masters in Biological Engineering and in Biomedical Engineering. The main goals of CCBioTEc are: to foster the awareness of the DEB educational community on the importance of science communication, as well as to develop science communication skills, through the production of short videos (pitches) displaying the explanation, in a simple and dynamic way, of complex concepts of Bioengineering and Biotechnology related with the curricula of each LU. CCBioTec started in the second semester of 2020/21, and it will go on in the 1st semester of 2021/22. The project was designed to be implemented according to the following steps: 1 - Technical and pedagogical training of teachers; 2 - Technical training of students involved in the project - Week CCBioTEC-2021; 3 - Development of materials for Science Communication in Bioengineering and Biotechnology; 4 - CCBioTec-2021 competition. In CCBioTec, teachers presenting himself as a mediator/facilitator of learning, boosting students development of transversal skills, collaborative work, decision making and the expression of ideas, together with the acquisition of knowledge foreseen in the curricular contents of the LU.(undefined)info:eu-repo/semantics/publishedVersio

A design of experiments to assess phosphorous removal and crystal properties in struvite precipitation of source separated urine using different Mg sources

Supplementary data associated with this article can be found, in the online version, at: http://dx.doi.org/10.1016/j.cej.2016.03.148.Phosphorus recycling and recovery has received special attention due to its non-replaceable and non-renewability. Phosphorus recovery from human urine in the form of struvite crystals is a potential alternative source. In this work, the efficiency of struvite precipitation from source separated human urine and struvite crystals size were analyzed using three different Mg2+ sources (MgCl2, Mg(OH)2 and MgO), individually evaluated using a statistical design of experiments to assess the combined effect of Mg2+:P molar ratio (1:1, 1.5:1 and 2:1) and stirring speed (30, 45 and 60 rpm). Formation of struvite crystals was confirmed by X-ray Diffraction (XRD) and scanning electron microscopy (SEM) with an energy dispersive spectrometer (EDS). Using the optimal conditions determined, MgO as Mg2+ source at 2:1 molar ratio and a stirring speed of 30 rpm, 99% of P was recovered as struvite crystals with a size of 50 to 100 m.This project has received funding from the European Union’s Seventh Programme for research, technological development and demonstration under grant agreement No. 308535. The authors also acknowledge the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462)

Microbial acclimation to concentrated human urine in Bio-electrochemical system

The aim of this study is to promote the gradual acclimation of bioelectroactive microorganisms in BES to concentrated human urine, and to assess different anode potentials and carbon materials in Microbial Electrolysis Cells (MEC). Human urine is highly concentrated in nutrients, representing more than 80% of the total N load and around 45% of the total P load in municipal wastewater. Separation of urine from other wastewater streams is an interesting option to keep these valuable nutrients concentrated, in order to develop a suitable nutrient recovery concept. This work is integrated in the Value from Urine (VFU) concept, where phosphate is recovered from source segregated human urine through struvite precipitation and ammonia is recovered in a Bio-electrochemical System (BES). Enrichment of an anaerobic sludge community in urine-degrading-electroactive microorganisms was promoted in an Microbial Fuel Cell (MFC) operated with increasing concentrations of real human urine (after phosphorous removal, as struvite). This acclimated electroactive biofilm was used to inoculate the anode of MECs, aiming at H2 and ammonia production in the cathode compartment. Different carbon modified anodes and defined anode potentials were assessed in terms of performance and microbial diversity of the developed electroactive biofilms

Bioelectrochemically-assisted recovery of valuable resources from urine

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Source separated urine is highly concentrated in nutrients and biodegradable compounds. This work explores the potential of combining nutrient recovery from urine with simultaneous energy production in bioelectrochemical systems (BES), under the FP7 project "ValueFromUrine". Non-spontaneous phosphorus (P) recovery by struvite precipitation was analysed by adding three different magnesium (Mg) sources (magnesium chloride (MgCl2), magnesium hydroxide (Mg(OH)2) and magnesium oxide (MgO)). A statistical design of experiments was used to evaluate the effect of Mg:P molar ratio (1:1, 1.5:1 and 2:1) combined with stirring speed (30, 45 and 60 rpm) for each Mg source tested. MgO at 2:1 molar ratio and a stirring speed of 30 rpm allowed to achieve the highest P recovery efficiency (99 %) with struvite crystals size of 50 to 100 μm [1]. Urine obtained after P recovery, showed high concentration of biodegradable compounds being subsequently fed as substrate in a microbial fuel cell (MFC). Microbial acclimation to urine was performed in a MFC resulting in an anaerobic community successfully enriched in “urine-degrading” electroactive microorganisms. When compared to the control assay operated without preliminary microbial enrichment (81±9 mA m-2), the acclimation method achieved significantly higher current density (455 mA m-2) (p<0.05). Tissierella and Paenibacillus were the dominant genus identified in the adapted microbial community. Tissierella can convert creatinine to acetate, whereas bacterial species belonging to the Paenibacillus genus are known to function as exoelectrogens. Corynebacterium that comprise urea-hydrolysing bacteria was also detected in the developed biofilms. [...]info:eu-repo/semantics/publishedVersio

Carbon nanomaterials for electrode modification in CH4-producing bioelectrochemical systems

Introduction: Unprecedented environmental phenomena have led to emerging and challenging plans to tackle global threats for the humanity namely intensive use of fossil resources and global warming. CO2 emission to the atmosphere is one of the major driver of global climate change. In this context, the development of alternative technologies for carbon capture and utilization has attracting more and more attention. Electrochemically assisted CO2 conversion in bioelectrochemical systems (BESs) for CH4 production is a new and emerging technology. This innovative approach allows the storage of electrical renewable energy in the form of CH4 that can, when needed, be reconverted, but also the simultaneous CO2 capture contributing to mitigate the climate change and the global warming. However, this technology has limitations mainly related to the electrons transference between the electrode and the biocatalysts. Previous results, obtained within the research group, demonstrated that it is possible to increase the efficiency of the process by improving the electrode surface area which, in turn, improved the microbial attachment. Methodology: This work aimed to investigate the effect of the presence of carbon nanomaterials (carbon nanotubes (CNTs)) at the cathode, on the CH4 production via CO2 reduction. It was hypothesized that the presence of carbon nanomaterials will improve the electrode surface area, thus increasing the electron transfer between the electrode and the biocatalysts. The production of CH4 was analyzed in two BESs, one working with a modified electrode (BES-CNT) and another one that works as a control with a non-modified electrode (BES-CTRL). The potential of CNTs to improve CH4 production was investigated under different electrochemical control modes, potentiostatic and galvanostatic. In addition, the microbial community developed at the biocathode was also investigated. Results: The results demonstrated that for both electrochemical control modes, the production of CH4 was higher in the presence of CNTs compared to the control assay. The study of the microbial community developed at the biocathode under galvanostatic control demonstrated a clear enrichment of methanogens compared to the initial inoculum, however no significant differences were observed between both BES. Conclusions: In conclusion, this work contributed with preliminary insights on the effect of carbon nanomaterials, namely CNTs, to improve the biocathode performance on BESs for CH4 production from CO2.This study was supported by the Portuguese Foundation for Science and Technology(FCT) under the scope of the strategic funding of UIDB/04469/2020 unit.info:eu-repo/semantics/publishedVersio

An innovative bioelectrochemical system for the recovery of phosphorus, ammonia and electricity from urine

Ammonium and phosphate fertilizers are needed in agriculture to ensure a sufficient food production. The recovery of valuable nutrients (ammonium and phosphate) from waste(water) streams will help to overcome future shortages and reduce the need for phosphorous ore imports and energy intensive ammonia production. One person produces on average 1.5 L of urine per day, which contains about 9.1 g N /L and 1 g P /L. Urine contributes about 80% of the N load and 50% of the P load in conventional domestic wastewaters. These high nutrient concentrations in urine make it possible to develop more effective and energy efficient recovery technologies. In the ValueFromUrine project the phosphorus recovery will be performed by struvite precipitation from hydrolyzed urine and the resulting effluent will be used for ammonium recovery and simultaneously electricity generation in Bioelectrochemical systems. Bioelectrochemical systems (ie Microbial Fuel Cells) are engineered systems in which bacteria catalyze the oxidation of organic substrates and transfer electrons to anode and at the cathode oxygen is reduced. The aim of our project is to develop, demonstrate and evaluate an effective energy-efficient system for the recovery of nutrients from urine. Our treatment system will be able to recover >95% of the phosphorous (as struvite) and nitrogen (as struvite and ammonia / ammonium sulphate) while producing energy. These products can substitute salts used by the chemical industry, the artificial fertilizer industry and the agricultural sector which are currently obtained in a non-renewable and unsustainable wa

Cooperative Behaviour of specific tasks in multi-agent systems and robot control using dynamic approach

In order to foster research and development in a multi-agent robotic environment three fundamental improvements on the robots need to be carried out: a) a very reliable and robot control which works at high speeds and a dynamic approach is described in this work; b) Cooperative behaviour is very important since without it there is no ball pass, and that is becoming more and more necessary; c) Upwards kick, since traditional horizontal kickers are already very common. Other improvements were carried out in the robots but due to lack of space in this paper are not described. This paper describes how these three issues were tackled by the MINHO team and shows their next directions

High accuracy navigation in unknown environment using adaptive control

Aiming to reduce cycle time and improving the accuracy on tracking, a modified adaptive control was developed, which adapts autonomously to changing dynamic parameters. The platform used is based on a robot with a vision based sensory system. Goal and obstacles angles are calculated relatively to robot orientation from image processing software. Autonomous robots are programmed to navigate in unknown and unstructured environments where there are multiple obstacles which can readily change their position. This approach underlies in dynamic attractor and repulsive forces. This theory uses differential equations that produce vector fields to control speed and direction of the robot. This new strategy was compared with existing PID method experimentally and it proved to be more effective in terms of behaviour and time-response. Calibration parameters used in PID control are in this case unnecessary. The experiments were carried out in robot Middle Size League football players built for RoboCup. Target pursuit, namely, ball, goal or any absolute position, was tested. Results showed high tracking accuracy and rapid response to moving targets. This dynamic control system enables a good balance between fast movements and smooth behaviour

Microbial community dynamics in diesel waste biodegradation using sequencing batch bioreactor operation mode (SBR)

The dynamic of molecular microbial community during diesel waste biodegradation was investigated. The waste was treated in bioreactors operated in sequencing batch operation mode (SBR) in four cycles of 72 h, using optimized setpoints (pH, initial waste load, C:N ratio, aeration). Optimal conditions allowed the system to reach biodegradation of 53.3, 96.0, 76.2 and 75.0% at the end of cycles one, two three and four, respectively. Oxygen uptake rate (OUR) indicated increases in microbial activity from cycle one to cycle two (124.9 to 252.9 mgO2/L/h) and decreases in cycles three and four (120.4 to 108.8 mgO2/L/h, respectively). Investigations of microbial diversity showed changes in the microbial community members at the end of the cycle one. Significant reductions in the relative ecotoxicity were observed beginning with cycle two, and the reductions extended until the end of process. The SBR operation mode proved to be an efficient method for treating the diesel waste, and the process allowed for relevant reductions in the hydrocarbon content of the waste along with an increase in its environmental quality. Changes in the microbial members are evidence of the synergistic action of the microbiota in the process.Key words: Microbial diversity, denaturing gradient gel electrophoresis, sequencing batch, biodegradation