Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella

[EN] Two outdoor photobioreactors were operated to evaluate the effect of variable ambient temperature on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella. Four experiments were carried out in different seasons, maintaining the temperature-controlled PBR at around 25¿°C (by either heating or cooling), while the temperature in the non-temperature-controlled PBR was allowed to vary with the ambient conditions. Temperatures in the range of 15¿30¿°C had no significant effect on the microalgae cultivation performance. However, when the temperature rose to 30¿35¿°C microalgae viability was significantly reduced. Sudden temperature rises triggered AOB growth in the indigenous microalgae culture, which worsened microalgae performance, especially when AOB activity made the system ammonium-limited. Microalgae activity could be recovered after a short temperature peak over 30¿°C once the temperature dropped, but stopped when the temperature was maintained around 28¿30¿°C for several days.This research work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Projects CTM2014-54980-C2-1-R and CTM2014-54980-C2-2-R) jointly with the European Regional Development Fund (ERDF), both of which are gratefully acknowledged. It also received support from the Spanish Ministry of Education, Culture and Sport via a pre-doctoral FPU fellowship to authors J. González-Camejo (FPU14/05082) and S. Aparicio (FPU/15/02595).Gonzalez-Camejo, J.; Aparicio Antón, SE.; Ruano, M.; Borrás, L.; Barat, R.; Ferrer, J. (2019). Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella. Bioresource Technology. 290:1-10. https://doi.org/10.1016/j.biortech.2019.121788S11029

Selecting the most suitable microalgae species to treat the effluent from an anaerobic membrane bioreactor

[EN] Conventional treatments for nutrient removal in wastewater are shifting to Anaerobic Membrane Bioreactors, which produce a high-quality effluent with minimum sludge production. The effluent resulting contains high nitrogen and phosphorus load that can be eliminated by microalgae culture. The aim of this study is to evaluate the ammonium and phosphorus removal rate of different microalgae species in the effluent of an anaerobic treatment. For that, 4 different microalgae species have been tested (Chlamydomonas reinhardtii, Scenedesmus obliquus, Chlorella vulgaris and Monoraphidium braunii) in batch monoculture and mixed conditions. Results indicate that all species are able to eliminate both P and N in the medium with high removal rates. However a slight interspecies competition may boost these removal rates and productivity values ensuring, the success of the process.This research was supported by the Spanish Ministry of Economy and Competitiveness (MINECO ) [grant numbers CTM2014-54980-C2-1-R and CTM2014-54980-C2-2-R], European Regional Development Fund [ERDF ], and Spanish Ministry of Education, Culture and Sport via pre-doctoral FPU fellowship to the (third) author [grant number FPU14/05082].Paches Giner, MAV.; Martínez-Guijarro, MR.; Gonzalez-Camejo, J.; Seco Torrecillas, A.; Barat, R. (2018). Selecting the most suitable microalgae species to treat the effluent from an anaerobic membrane bioreactor. Environmental Technology. 2018. https://doi.org/10.1080/09593330.2018.1496148S201

Outdoor flat-panel membrane photobioreactor to treat the effluent of an anaerobic membrane bioreactor. Influence of operating, design, and environmental conditions

[EN] As microalgae have the ability to simultaneously remove nutrients from wastewater streams while producing valuable biomass, microalgae-based wastewater treatment is a win-win strategy. Although recent advances have been made in this field in lab conditions, the transition to outdoor conditions on an industrial scale must be further investigated. In this work an outdoor pilot-scale membrane photobioreactor plant was operated for tertiary sewage treatment. The effects of different parameters on microalgae performance were studied including: temperature, light irradiance (solar and artificial irradiance), hydraulic retention time (HRT), biomass retention time (BRT), air sparging system and influent nutrient concentration. In addition the competition between microalgae and ammonium oxidising bacteria for ammonium was also evaluated. Maximum nitrogen and phosphorus removal rates of 12.5 +/- 4.2 mgN.L-1.d(-1) and 1.5 +/- 0.4 mgP.L-1.d(-1), respectively, were achieved at a BRT of 4.5 days and HRT of 2.5 days, while a maximum biomass productivity of 78 +/- 13 mgVSS.L-1.d(-1 )(VSS: volatile suspended solids) was reached. While the results obtained so far are promising, they need to be improved to make the transition to industrial scale operations feasible.This research work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO, CTM2011-28595-C02-01 and CTM2011-28595-C02-02) jointly with the European Regional Development Fund (ERDF), both of which are gratefully acknowledged. It was also supported by the Spanish Ministry of Education, Culture and Sport via a pre-doctoral FPU fellowship to author J. Gonzalez-Camejo (FPU14/05082).Gonzalez-Camejo, J.; Barat, R.; Ruano García, MV.; Seco Torrecillas, A.; Ferrer, J. (2018). Outdoor flat-panel membrane photobioreactor to treat the effluent of an anaerobic membrane bioreactor. Influence of operating, design, and environmental conditions. Water Science & Technology. 78(1):195-206. https://doi.org/10.2166/wst.2018.259S195206781Arbib, Z., Ruiz, J., Álvarez-Díaz, P., Garrido-Pérez, C., Barragan, J., & Perales, J. A. (2013). Long term outdoor operation of a tubular airlift pilot photobioreactor and a high rate algal pond as tertiary treatment of urban wastewater. Ecological Engineering, 52, 143-153. doi:10.1016/j.ecoleng.2012.12.089Arias, D. M., Uggetti, E., García-Galán, M. J., & García, J. (2017). Cultivation and selection of cyanobacteria in a closed photobioreactor used for secondary effluent and digestate treatment. Science of The Total Environment, 587-588, 157-167. doi:10.1016/j.scitotenv.2017.02.097Feng, P., Deng, Z., Hu, Z., & Fan, L. (2011). Lipid accumulation and growth of Chlorella zofingiensis in flat plate photobioreactors outdoors. Bioresource Technology, 102(22), 10577-10584. doi:10.1016/j.biortech.2011.08.109Gao, F., Li, C., Yang, Z.-H., Zeng, G.-M., Feng, L.-J., Liu, J., … Cai, H. (2016). Continuous microalgae cultivation in aquaculture wastewater by a membrane photobioreactor for biomass production and nutrients removal. Ecological Engineering, 92, 55-61. doi:10.1016/j.ecoleng.2016.03.046Giménez, J. B., Robles, A., Carretero, L., Durán, F., Ruano, M. V., Gatti, M. N., … Seco, A. (2011). Experimental study of the anaerobic urban wastewater treatment in a submerged hollow-fibre membrane bioreactor at pilot scale. Bioresource Technology, 102(19), 8799-8806. doi:10.1016/j.biortech.2011.07.014González-Camejo, J., Serna-García, R., Viruela, A., Pachés, M., Durán, F., Robles, A., … Seco, A. (2017). Short and long-term experiments on the effect of sulphide on microalgae cultivation in tertiary sewage treatment. Bioresource Technology, 244, 15-22. doi:10.1016/j.biortech.2017.07.126González-Camejo, J., Barat, R., Pachés, M., Murgui, M., Seco, A., & Ferrer, J. (2017). Wastewater nutrient removal in a mixed microalgae–bacteria culture: effect of light and temperature on the microalgae–bacteria competition. Environmental Technology, 39(4), 503-515. doi:10.1080/09593330.2017.1305001Gouveia, L., Graça, S., Sousa, C., Ambrosano, L., Ribeiro, B., Botrel, E. P., … Silva, C. M. (2016). Microalgae biomass production using wastewater: Treatment and costs. Algal Research, 16, 167-176. doi:10.1016/j.algal.2016.03.010Kim, K., Choi, J., Ji, Y., Park, S., Do, H., Hwang, C., … Holzapfel, W. (2014). Impact of bubble size on growth and CO 2 uptake of Arthrospira ( Spirulina ) platensis KMMCC CY-007. Bioresource Technology, 170, 310-315. doi:10.1016/j.biortech.2014.08.034Leão, P. N., Vasconcelos, M. T. S. D., & Vasconcelos, V. M. (2009). Allelopathy in freshwater cyanobacteria. Critical Reviews in Microbiology, 35(4), 271-282. doi:10.3109/10408410902823705Ledda, C., Idà, A., Allemand, D., Mariani, P., & Adani, F. (2015). Production of wild Chlorella sp. cultivated in digested and membrane-pretreated swine manure derived from a full-scale operation plant. Algal Research, 12, 68-73. doi:10.1016/j.algal.2015.08.010Pachés, M., Romero, I., Hermosilla, Z., & Martinez-Guijarro, R. (2012). PHYMED: An ecological classification system for the Water Framework Directive based on phytoplankton community composition. Ecological Indicators, 19, 15-23. doi:10.1016/j.ecolind.2011.07.003Ruiz-Martinez, A., Serralta, J., Pachés, M., Seco, A., & Ferrer, J. (2014). Mixed microalgae culture for ammonium removal in the absence of phosphorus: Effect of phosphorus supplementation and process modeling. Process Biochemistry, 49(12), 2249-2257. doi:10.1016/j.procbio.2014.09.002Su, Y., Mennerich, A., & Urban, B. (2012). Coupled nutrient removal and biomass production with mixed algal culture: Impact of biotic and abiotic factors. Bioresource Technology, 118, 469-476. doi:10.1016/j.biortech.2012.05.093Tan, X.-B., Zhang, Y.-L., Yang, L.-B., Chu, H.-Q., & Guo, J. (2016). Outdoor cultures of Chlorella pyrenoidosa in the effluent of anaerobically digested activated sludge: The effects of pH and free ammonia. Bioresource Technology, 200, 606-615. doi:10.1016/j.biortech.2015.10.095Viruela, A., Murgui, M., Gómez-Gil, T., Durán, F., Robles, Á., Ruano, M. V., … Seco, A. (2016). Water resource recovery by means of microalgae cultivation in outdoor photobioreactors using the effluent from an anaerobic membrane bioreactor fed with pre-treated sewage. Bioresource Technology, 218, 447-454. doi:10.1016/j.biortech.2016.06.116Whitton, R., Le Mével, A., Pidou, M., Ometto, F., Villa, R., & Jefferson, B. (2016). Influence of microalgal N and P composition on wastewater nutrient remediation. Water Research, 91, 371-378. doi:10.1016/j.watres.2015.12.054Woertz, I., Feffer, A., Lundquist, T., & Nelson, Y. (2009). Algae Grown on Dairy and Municipal Wastewater for Simultaneous Nutrient Removal and Lipid Production for Biofuel Feedstock. Journal of Environmental Engineering, 135(11), 1115-1122. doi:10.1061/(asce)ee.1943-7870.0000129Wu, Y.-H., Zhu, S.-F., Yu, Y., Shi, X.-J., Wu, G.-X., & Hu, H.-Y. (2017). Mixed cultivation as an effective approach to enhance microalgal biomass and triacylglycerol production in domestic secondary effluent. Chemical Engineering Journal, 328, 665-672. doi:10.1016/j.cej.2017.07.088Xu, M., Li, P., Tang, T., & Hu, Z. (2015). Roles of SRT and HRT of an algal membrane bioreactor system with a tanks-in-series configuration for secondary wastewater effluent polishing. Ecological Engineering, 85, 257-264. doi:10.1016/j.ecoleng.2015.09.06

Short and long-term experiments on the effect of sulphide on microalgae cultivation in tertiary sewage treatment

[EN] Microalgae cultivation appears to be a promising technology for treating nutrient-rich effluents from anaerobic membrane bioreactors, as microalgae are able to consume nutrients from sewage without an organic carbon source, although the sulphide formed during the anaerobic treatment does have negative effects on microalgae growth. Short and long-term experiments were carried out on the effects of sulphide on a mixed microalgae culture. The short-term experiments showed that the oxygen production rate (OPR) dropped as sulphide concentration increased: a concentration of 5 mg S L¿1 reduced OPR by 43%, while a concentration of 50 mg S L¿1 came close to completely inhibiting microalgae growth. The long-term experiments revealed that the presence of sulphide in the influent had inhibitory effects at sulphide concentrations above 20 mg S L¿1 in the culture, but not at concentrations below 5 mg S L¿1. These conditions favoured Chlorella growth over that of Scenedesmus.This research work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO, CTM2011-28595-C02-01 and CTM2011-28595-C02-02) jointly with the European Regional Development Fund (ERDF), both of which are gratefully acknowledged. It was also supported by the Spanish Ministry of Education, Culture and Sport via a pre doctoral FPU fellowship to author J. Gonzalez-Camejo (FPU14/05082) and by the Spanish Ministry of Economy and Competitiveness via a pre doctoral FPI fellowship to author R. Serna-Garcia (project CTM2014-54980-C2-1-R)Gonzalez-Camejo, J.; Serna-Garcia, R.; Viruela Navarro, A.; Paches Giner, MAV.; Durán Pinzón, F.; Robles Martínez, Á.; Ruano García, MV.... (2017). Short and long-term experiments on the effect of sulphide on microalgae cultivation in tertiary sewage treatment. Bioresource Technology. 244:15-22. https://doi.org/10.1016/j.biortech.2017.07.126S152224

Maximizing resource recovery from urban wastewater through an innovative facility layout

[EN] This research work proposes an innovative layout for urban wastewater treatment based on anaerobic technology, microalgal cultivation and membrane technology. The proposed Water Resource Recovery Facility (WRRF) system can treat urban wastewater efficiently, complying with legal discharge limits and allowing for resource recovery, i.e. energy, nutrients and reclaimed water. In addition, the proposed layout produces less solid wastes than a conventional wastewater treatment plant (WWTP) and it is possible to recover energy as biogas, not only from the original wastewater sources but also from the biomass generated in the WRRF system

Resource recovery from sulphate-rich sewage through an innovative anaerobic-based water resource recovery facility (WRRF)

[EN] This research work proposes an innovative water resource recovery facility (WRRF) for the recovery of energy, nutrients and reclaimed water from sewage, which represents a promising approach towards enhanced circular economy scenarios. To this aim, anaerobic technology, microalgae cultivation, and membrane technology were combined in a dedicated platform. The proposed platform produces a high-quality solid- and coliform-free effluent that can be directly discharged to receiving water bodies identified as sensitive areas. Specifically, the content of organic matter, nitrogen and phosphorus in the effluent was 45 mg COD.L-1 , 14.9 mg N.L-1 and 0.5 mg P.L-1 , respectively. Harvested solar energy and carbon dioxide biofixation in the form of microalgae biomass allowed remarkable methane yields (399 STP L CH 4.kg(-1) CODinf ) to be achieved, equivalent to theoretical electricity productions of around 0.52 kWh per m 3 of wastewater entering the WRRF. Furthermore, 26.6% of total nitrogen influent load was recovered as ammonium sulphate, while nitrogen and phosphorus were recovered in the biosolids produced (650 +/- 77 mg N.L-1 and 121.0 +/- 7.2 mg P.L-1).This research was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Projects CTM2014-54980-C2-1-R and CTM2014-54980-C2-2-R) jointly with the European Regional Development Fund (ERDF), which are gratefully acknowledged. This research was also supported by the Spanish Ministry of Education, Culture and Sport via two pre-doctoral FPU fellowships (FPU14/05082 and FPU15/02595) and by the Spanish Ministry of Economy and Competitiveness via two pre-doctoral FPI fellowships (BES-2015-071884, BES-2015-073403) and one Juan de la Cierva contract (FJCI-2014-21616). The authors would also like to acknowledge the support received from Generalitat Valenciana via two VALithornd post-doctoral grants (APOSTD/2014/049 and APOSTD/2016/104) and via the fellowships APOTI/2016/059 and CPI-16-155, as well as the financial aid received from the European Climate KIC association for the 'MAB 2.0' Project (APIN0057_ 2015-3.6-230_ P066-05) and Universitat Politecnica de Valencia via a pre-doctoral FPI fellowship to the seventh author.Seco Torrecillas, A.; Aparicio Antón, SE.; Gonzalez-Camejo, J.; Jiménez Benítez, AL.; Mateo-Llosa, O.; Mora-Sánchez, JF.; Noriega-Hevia, G.... (2018). Resource recovery from sulphate-rich sewage through an innovative anaerobic-based water resource recovery facility (WRRF). Water Science & Technology. 78(9):1925-1936. https://doi.org/10.2166/wst.2018.492S19251936789Bair, R. A., Ozcan, O. O., Calabria, J. L., Dick, G. H., & Yeh, D. H. (2015). Feasibility of anaerobic membrane bioreactors (AnMBR) for onsite sanitation and resource recovery (nutrients, energy and water) in urban slums. Water Science and Technology, 72(9), 1543-1551. doi:10.2166/wst.2015.349Barat, R., Serralta, J., Ruano, M. V., Jiménez, E., Ribes, J., Seco, A., & Ferrer, J. (2013). Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants. Water Science and Technology, 67(7), 1481-1489. doi:10.2166/wst.2013.004Batstone, D. J., Hülsen, T., Mehta, C. M., & Keller, J. (2015). Platforms for energy and nutrient recovery from domestic wastewater: A review. Chemosphere, 140, 2-11. doi:10.1016/j.chemosphere.2014.10.021Bilad, M. R., Arafat, H. A., & Vankelecom, I. F. J. (2014). Membrane technology in microalgae cultivation and harvesting: A review. Biotechnology Advances, 32(7), 1283-1300. doi:10.1016/j.biotechadv.2014.07.008Carrington E.-G. 2001 Evaluation of Sludge Treatments for Pathogen Reduction. http://europa.eu.int/comm/environment/pubs/home.htm.Cookney, J., Mcleod, A., Mathioudakis, V., Ncube, P., Soares, A., Jefferson, B., & McAdam, E. J. (2016). Dissolved methane recovery from anaerobic effluents using hollow fibre membrane contactors. Journal of Membrane Science, 502, 141-150. doi:10.1016/j.memsci.2015.12.037De Morais, M. G., & Costa, J. A. V. (2007). Biofixation of carbon dioxide by Spirulina sp. and Scenedesmus obliquus cultivated in a three-stage serial tubular photobioreactor. Journal of Biotechnology, 129(3), 439-445. doi:10.1016/j.jbiotec.2007.01.009Giménez, J. B., Robles, A., Carretero, L., Durán, F., Ruano, M. V., Gatti, M. N., … Seco, A. (2011). Experimental study of the anaerobic urban wastewater treatment in a submerged hollow-fibre membrane bioreactor at pilot scale. Bioresource Technology, 102(19), 8799-8806. doi:10.1016/j.biortech.2011.07.014Giménez, J. B., Martí, N., Ferrer, J., & Seco, A. (2012). Methane recovery efficiency in a submerged anaerobic membrane bioreactor (SAnMBR) treating sulphate-rich urban wastewater: Evaluation of methane losses with the effluent. Bioresource Technology, 118, 67-72. doi:10.1016/j.biortech.2012.05.019Giménez, J. B., Bouzas, A., Carrere, H., Steyer, J.-P., Ferrer, J., & Seco, A. (2018). Assessment of cross-flow filtration as microalgae harvesting technique prior to anaerobic digestion: Evaluation of biomass integrity and energy demand. Bioresource Technology, 269, 188-194. doi:10.1016/j.biortech.2018.08.052González-Camejo, J., Serna-García, R., Viruela, A., Pachés, M., Durán, F., Robles, A., … Seco, A. (2017). Short and long-term experiments on the effect of sulphide on microalgae cultivation in tertiary sewage treatment. Bioresource Technology, 244, 15-22. doi:10.1016/j.biortech.2017.07.126Martí, N., Barat, R., Seco, A., Pastor, L., & Bouzas, A. (2017). Sludge management modeling to enhance P-recovery as struvite in wastewater treatment plants. Journal of Environmental Management, 196, 340-346. doi:10.1016/j.jenvman.2016.12.074Moosbrugger R. , WentzelM. & EkamaG.1992Simple Titration Procedures to Determine H2CO3 Alkalinity and Short-chain Fatty Acids in Aqueous Solutions Containing Known Concentrations of Ammonium, Phosphate and Sulphide Weak Acid/Bases. Water. Res. Commission, Report, No. TT 57/92.Morales, N., Boehler, M., Buettner, S., Liebi, C., & Siegrist, H. (2013). Recovery of N and P from Urine by Struvite Precipitation Followed by Combined Stripping with Digester Sludge Liquid at Full Scale. Water, 5(3), 1262-1278. doi:10.3390/w5031262Pretel, R., Durán, F., Robles, A., Ruano, M. V., Ribes, J., Serralta, J., & Ferrer, J. (2015). Designing an AnMBR-based WWTP for energy recovery from urban wastewater: The role of primary settling and anaerobic digestion. Separation and Purification Technology, 156, 132-139. doi:10.1016/j.seppur.2015.09.047Pretel, R., Robles, A., Ruano, M. V., Seco, A., & Ferrer, J. (2016). Economic and environmental sustainability of submerged anaerobic MBR-based (AnMBR-based) technology as compared to aerobic-based technologies for moderate-/high-loaded urban wastewater treatment. Journal of Environmental Management, 166, 45-54. doi:10.1016/j.jenvman.2015.10.004Sharma, B., Sarkar, A., Singh, P., & Singh, R. P. (2017). Agricultural utilization of biosolids: A review on potential effects on soil and plant grown. Waste Management, 64, 117-132. doi:10.1016/j.wasman.2017.03.002Sialve, B., Bernet, N., & Bernard, O. (2009). Anaerobic digestion of microalgae as a necessary step to make microalgal biodiesel sustainable. Biotechnology Advances, 27(4), 409-416. doi:10.1016/j.biotechadv.2009.03.001Sid, S., Volant, A., Lesage, G., & Heran, M. (2017). Cost minimization in a full-scale conventional wastewater treatment plant: associated costs of biological energy consumption versus sludge production. Water Science and Technology, 76(9), 2473-2481. doi:10.2166/wst.2017.423Viruela, A., Murgui, M., Gómez-Gil, T., Durán, F., Robles, Á., Ruano, M. V., … Seco, A. (2016). Water resource recovery by means of microalgae cultivation in outdoor photobioreactors using the effluent from an anaerobic membrane bioreactor fed with pre-treated sewage. Bioresource Technology, 218, 447-454. doi:10.1016/j.biortech.2016.06.11

Outdoor microalgae-based urban wastewater treatment: recent advances, applications and future perspectives

[EN] Although microalgae-based wastewater treatment has been traditionally carried out in extensive waste stabilization ponds, recent trends focus on the use of microalgae to apply the circular economy principles in the wastewater treatment sector due to the capacity of algae to absorb carbon dioxide while recovering nutrients from sewage. To this aim, the development of new intensive microalgae-based systems with higher efficiency and level of process control is required. Results obtained for these systems at lab scale are generally promising. However, upscaling to outdoor conditions is often uncertain. Some advances have been made in terms of applying open systems at large scale. However, there are still some issues related to land requirements and the economic feasibility and robustness of the process that have to be overcome to widely implement these systems. This article aims at describing the main design and operating factors regarding outdoor microalgae cultivation. It will also explain some microalgae cultivation technologies to treat wastewater, showing their advantages, disadvantages, and the possibility to treat different wastewater streams with microalgae cultures. Future perspectives of this biotechnology will be commented as well.This research work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Projects CTM2014-54980-C2-1-R and CTM2014-54980-C2-2-R) jointly with the European Regional Development Fund (ERDF), both of which are gratefully acknowledged. It was also supported by the Spanish Ministry of Education, Culture, and Sport via a predoctoral FPU fellowship to J. González-Camejo (FPU14/05082).Gonzalez-Camejo, J.; Ferrer, J.; Seco, A.; Barat, R. (2021). Outdoor microalgae-based urban wastewater treatment: recent advances, applications and future perspectives. Wiley Interdisciplinary Reviews Water. 8(3):1-24. https://doi.org/10.1002/wat2.1518S12483European Comission Directive. (1998).Amending Council Directive 91/271/EEC with respect to certain requirements established in Annex I.Official Journal of the European Communities. 98/15/EC: 29–30. (C. 27 Feb).Abinandan, S., & Shanthakumar, S. (2015). Challenges and opportunities in application of microalgae ( Chlorophyta ) for wastewater treatment: A review. Renewable and Sustainable Energy Reviews, 52, 123-132. doi:10.1016/j.rser.2015.07.086Abis, K. L., & Mara, D. D. (2005). Primary facultative ponds in the UK: the effect of operational parameters on performance and algal populations. Water Science and Technology, 51(12), 61-67. doi:10.2166/wst.2005.0427Abu-Ghosh, S., Fixler, D., Dubinsky, Z., & Iluz, D. (2016). Flashing light in microalgae biotechnology. Bioresource Technology, 203, 357-363. doi:10.1016/j.biortech.2015.12.057Acién, F. G., Gómez-Serrano, C., Morales-Amaral, M. M., Fernández-Sevilla, J. M., & Molina-Grima, E. (2016). Wastewater treatment using microalgae: how realistic a contribution might it be to significant urban wastewater treatment? Applied Microbiology and Biotechnology, 100(21), 9013-9022. doi:10.1007/s00253-016-7835-7Fernández, F. G. A., Reis, A., Wijffels, R. H., Barbosa, M., Verdelho, V., & Llamas, B. (2021). The role of microalgae in the bioeconomy. New Biotechnology, 61, 99-107. doi:10.1016/j.nbt.2020.11.011Acién Fernández, F. G., Gómez-Serrano, C., & Fernández-Sevilla, J. M. (2018). Recovery of Nutrients From Wastewaters Using Microalgae. Frontiers in Sustainable Food Systems, 2. doi:10.3389/fsufs.2018.00059AlMomani, F. A., & Örmeci, B. (2016). Performance Of Chlorella Vulgaris, Neochloris Oleoabundans, and mixed indigenous microalgae for treatment of primary effluent, secondary effluent and centrate. Ecological Engineering, 95, 280-289. doi:10.1016/j.ecoleng.2016.06.038Arbib, Z., de Godos, I., Ruiz, J., & Perales, J. A. (2017). Optimization of pilot high rate algal ponds for simultaneous nutrient removal and lipids production. Science of The Total Environment, 589, 66-72. doi:10.1016/j.scitotenv.2017.02.206Arias, D. M., Rueda, E., García-Galán, M. J., Uggetti, E., & García, J. (2019). Selection of cyanobacteria over green algae in a photo-sequencing batch bioreactor fed with wastewater. Science of The Total Environment, 653, 485-495. doi:10.1016/j.scitotenv.2018.10.342Assunção, J., & Malcata, F. X. (2020). Enclosed «non-conventional» photobioreactors for microalga production: A review. Algal Research, 52, 102107. doi:10.1016/j.algal.2020.102107Barbera, E., Sforza, E., Grandi, A., & Bertucco, A. (2020). Uncoupling solid and hydraulic retention time in photobioreactors for microalgae mass production: A model-based analysis. Chemical Engineering Science, 218, 115578. doi:10.1016/j.ces.2020.115578Barceló-Villalobos, M., Fernández-del Olmo, P., Guzmán, J. L., Fernández-Sevilla, J. M., & Acién Fernández, F. G. (2019). Evaluation of photosynthetic light integration by microalgae in a pilot-scale raceway reactor. Bioresource Technology, 280, 404-411. doi:10.1016/j.biortech.2019.02.032Behera, B., Acharya, A., Gargey, I. A., Aly, N., & P, B. (2019). Bioprocess engineering principles of microalgal cultivation for sustainable biofuel production. Bioresource Technology Reports, 5, 297-316. doi:10.1016/j.biteb.2018.08.001Bhattacharya, M., & Goswami, S. (2020). Microalgae – A green multi-product biorefinery for future industrial prospects. Biocatalysis and Agricultural Biotechnology, 25, 101580. doi:10.1016/j.bcab.2020.101580Bosma, R., de Vree, J. H., Slegers, P. M., Janssen, M., Wijffels, R. H., & Barbosa, M. J. (2014). Design and construction of the microalgal pilot facility AlgaePARC. Algal Research, 6, 160-169. doi:10.1016/j.algal.2014.10.006Butler, E., Hung, Y.-T., Suleiman Al Ahmad, M., Yeh, R. Y.-L., Liu, R. L.-H., & Fu, Y.-P. (2015). Oxidation pond for municipal wastewater treatment. 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Ultrafiltration Harvesting of Microalgae Culture Cultivated in a WRRF: Long-Term Performance and Techno-Economic and Carbon Footprint Assessment

[EN] A cross-flow ultrafiltration harvesting system for a pre-concentrated microalgae culture was tested in an innovative anaerobic-based WRRF. The microalgae culture was cultivated in a membrane photobioreactor fed with effluent from an anaerobic membrane bioreactor treating sewage. These harvested microalgae biomasses were then anaerobically co-digested with primary and secondary sludge from the water line. Depending on the needs of this anaerobic co-digestion, the filtration harvesting process was evaluated intermittently over a period of 212 days for different operating conditions, mainly the total amount of microalgae biomass harvested and the desired final total solids concentration (up to 15.9 g center dot L-1 with an average of 9.7 g center dot L-1). Concentration ratios of 15-27 were obtained with average transmembrane fluxes ranging from 5 to 28 L center dot m-2 center dot h-1. Regarding membrane cleaning, both backflushing and chemical cleaning resulted in transmembrane flux recoveries that were, on average, 21% higher than those achieved with backflushing alone. The carbon footprint assessment shows promising results, as the GHG emissions associated with the cross-flow ultrafiltration harvesting process could be less than the emissions savings associated with the energy recovered from biogas production from the anaerobic valorisation of the harvested microalgae.This research work was supported by the Science and Innovation Spanish Ministry (Projects CTM2014-54980-C2-1-R/C2-2-R) and the European Regional Development Fund (ERDF). Generalitat Valenciana supported this study via fellowship APOTI/2016/56 to the first author. The Science and Innovation Spanish Ministry has also supported this study via a pre-doctoral FPU fellowship to the second author (FPU14/05082). The authors would also like to acknowledge the support received from the Universitat Politècnica de València via a pre-doctoral FPI fellowship for the third author, as well as the financial aid received from the European Climate KIC association for the MAB 2.0 Project (APIN0057_2015-3.6-230_P066-05).Mora-Sánchez, JF.; Gonzalez-Camejo, J.; Noriega-Hevia, G.; Seco, A.; Ruano, MV. (2024). Ultrafiltration Harvesting of Microalgae Culture Cultivated in a WRRF: Long-Term Performance and Techno-Economic and Carbon Footprint Assessment. Sustainability. 16(1). https://doi.org/10.3390/su1601036916

On-line monitoring of photosynthetic activity based on pH data to assess microalgae cultivation

[EN] Microalgae performance of outdoor cultivation systems is influenced by environmental and operating dynamics. Monitoring and control systems are needed to maximise biomass productivity and nutrient recovery. The goal of this work was to corroborate that pH data could be used to monitor microalgae performance by means of data from an outdoor membrane photobioreactor (MPBR) plant. In this system, microalgae photosynthetic activity was favoured over other physical and biological processes, so that the pH data dynamics was theoretically related to the microalgae carbon uptake rate (CUR). Shortand long-term continuous operations were tested to corroborate the relationship between the first derivate of pH data dynamics (pH') and microalgae photosynthetic activity. Short-term operations showed a good correlation between gross pH' values and MPBR performance. An indicator of the maximum daily average microalgae activity was assessed by a combination of on-line pH' measurements obtained in the long-term and a microalgae growth kinetic model. Both indicators contributed to the development of advanced real-time monitoring and control systems to optimise microalgae cultivation technology.Authors would like to acknowledge the Ministry of Economy and Competitiveness (Spain) for their support in Projects CTM2014-54980C2-1-R and CTM2014-54980-C2-2-R, together with the European Regional Development Fund. The author J. Gonzalez-Camejo would also like to thank the Ministry of Education, Culture and Sport (Spain) for its support (pre-doctoral fellowship, FPU14/05082).E-supplementary data can be found in on-line version of the manuscript.Gonzalez-Camejo, J.; Robles Martínez, Á.; Seco, A.; Ferrer, J.; Ruano, MV. (2020). On-line monitoring of photosynthetic activity based on pH data to assess microalgae cultivation. Journal of Environmental Management. 276:1-8. https://doi.org/10.1016/j.jenvman.2020.111343S18276Abu‐Ghosh, S., Dubinsky, Z., & Iluz, D. (2020). Acclimation of thermotolerant algae to light and temperature interaction1. Journal of Phycology, 56(3), 662-670. doi:10.1111/jpy.12964Arbib, Z., de Godos, I., Ruiz, J., & Perales, J. A. (2017). Optimization of pilot high rate algal ponds for simultaneous nutrient removal and lipids production. Science of The Total Environment, 589, 66-72. doi:10.1016/j.scitotenv.2017.02.206Barbera, E., Sforza, E., Grandi, A., & Bertucco, A. (2020). Uncoupling solid and hydraulic retention time in photobioreactors for microalgae mass production: A model-based analysis. Chemical Engineering Science, 218, 115578. doi:10.1016/j.ces.2020.115578De Farias Silva, C. E., de Oliveira Cerqueira, R. B., de Lima Neto, C. F., de Andrade, F. P., de Oliveira Carvalho, F., & Tonholo, J. (2020). 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Kinetic modelling of microalgae cultivation for wastewater treatment and carbon dioxide sequestration. Algal Research, 32, 131-141. doi:10.1016/j.algal.2018.03.015Fernández, I., Acién, F. G., Guzmán, J. L., Berenguel, M., & Mendoza, J. L. (2016). Dynamic model of an industrial raceway reactor for microalgae production. Algal Research, 17, 67-78. doi:10.1016/j.algal.2016.04.021Fernández-Sevilla, J. M., Brindley, C., Jiménez-Ruíz, N., & Acién, F. G. (2018). A simple equation to quantify the effect of frequency of light/dark cycles on the photosynthetic response of microalgae under intermittent light. Algal Research, 35, 479-487. doi:10.1016/j.algal.2018.09.026Foladori, P., Petrini, S., & Andreottola, G. (2018). Evolution of real municipal wastewater treatment in photobioreactors and microalgae-bacteria consortia using real-time parameters. Chemical Engineering Journal, 345, 507-516. doi:10.1016/j.cej.2018.03.178González-Camejo, J., Barat, R., Aguado, D., & Ferrer, J. (2020). 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Improving membrane photobioreactor performance by reducing light path: operating conditions and key performance indicators

©IWA Publishing 2020. The definitive peer-reviewed and edited version of this article is published in Water Research, Volume 172, 1 April 2020, 115518 https://doi.org/10.1016/j.watres.2020.115518 and is available at www.iwapublishing.com.[EN] Microalgae cultivation has been receiving increasing interest in wastewater remediation due to their ability to assimilate nutrients present in wastewater streams. In this respect, cultivating microalgae in membrane photobioreactors (MPBRs) allows decoupling the solid retention time (SRT) from the hydraulic retention time (HRT), which enables to increase the nutrient load to the photobioreactors (PBRs) while avoiding the wash out of the microalgae biomass. The reduction of the PBR light path from 25 to 10 cm increased the nitrogen and phosphorus recovery rates, microalgae biomass productivity and photosynthetic efficiency by 150, 103, 194 and 67%, respectively.The areal biomass productivity (aBP) also increased when the light path was reduced, reflecting the better use of light in the 10-cm MPBR plant. The capital and operating operational expenditures (CAPEX and OPEX) of the 10-cm MPBR plant were also reduced by 27 and 49%, respectively. Discharge limits were met when the 10-cm MPBR plant was operated at SRTs of 3-4.5 d and HRTs of 1.25-1.5 d. At these SRT/HRT ranges, the process could be operated without a high fouling propensity with gross permeate flux (J(20)) of 15 LMH and specific gas demand (SGD(p)) between 16 and 20 Nm(air)(3)center dot M-permeate(-3). which highlights the potential of membrane filtration in MPBRs. When the continuous operation of the MPBR plant was evaluated, an optical density of 680 nm (0D680) and soluble chemical oxygen demand (sCOD) were found to be good indicators of microalgae cell and algal organic matter (AOM) concentrations, while dissolved oxygen appeared to be directly related to MPBR performance. Nitrite and nitrate (NOx) concentration and the soluble chemical oxygen demand:volatile suspended solids ratio (sCOD:VSS) were used as indicators of nitrifying bacteria activity and the stress on the culture, respectively. These parameters were inversely related to nitrogen recovery rates and biomass productivity and could thus help to prevent possible culture deterioration.This research work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Projects CTM2014-54980-C2-1-R and CTM2014-54980-C2-2-R) jointly with the European Regional Development Fund (ERDF), both of which are gratefully acknowledged. 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