Continuous 3-year outdoor operation of a flat-panel membrane photobioreactor to treat effluent from an anaerobic membrane bioreactor

A membrane photobioreactor (MPBR) plant was operated continuously for 3 years to evaluate the separate effects of different factors, including: biomass and hydraulic retention times (BRT, HRT), light path (Lp), nitrification rate (NOxR) and nutrient loading rates (NLR, PLR). The overall effect of all these parameters, which influence MPBR performance had not previously been assessed. The multivariate projection approach chosen for this study provided a good description of the collected data and facilitated their visualization and interpretation. Forty variables used to control and assess MPBR performance were evaluated during three years of continuous outdoor operation by means of principal component analysis (PCA) and partial least squares (PLS) analysis. The PCA identified the photobioreactor light path as the factor with the largest influence on data variability. Other important factors were: air flow rate (Fair), nitrogen and phosphorus recovery rates (NRR, PRR), biomass productivity (BP),optical density at 680 nm (OD680), ammonium and phosphorus effluent concentration (NH4, P), HRT, BRT, and nitrogen and phosphorus loading rates (NLR and PLR). The MPBR performance could be adequately estimated by a PLS model based on all the recorded variables, but this estimation worsened appreciably when only the controllable variables (Lp, Fair, HRT and BRT) were used as predictors, which underlines the importance of the non-controlled variables on MPBR performance. The microalgae cultivation process could thus only be partially controlled by the design and operating variables. As effluent nitrate concentration was shown to be the key factor in the nitrification rate, it can be used as an indirect measurement of nitrifying bacteria activity. A high nitrification rate was found to be inadvisable, since it showed an inverse correlation with NRR. In this respect, temperature appeared to be the main ambient/controlling factor in nitrifying bacteria activity

Immobilisation of yeasts on oak chips or cellulose powder for use in bottle-fermented sparkling wine

[EN] Sparkling wine production comprises two successive fermentations performed by Sacharomyces cerevisiae strains. This research aimed to: develop yeast immobilisation processes on two wine-compatible supports; study the effects of yeast type (IOC 18-2007 and 55A) and the immobilisation support type (oak chips and cellulose powder) on the fermentation kinetics, the deposition rate of lees and the volatile composition of the finished sparkling wine; compare the fermentation parameters of the wines inoculated with immobilised or non-immobilised cells. Proper immobilisation of yeast on oak chips and cellulose powder was demonstrated by electron microscopy. Total sugar consumption occurred in under 60 days in all bottles, regardless of the strain used and the way they were inoculated in wine. Deposition of lees was 3-fold faster in the bottles containing immobilised cells than in those with free cells; no addition of adjuvants was necessary. The analysis of the volatile compounds of the finished sparkling wines showed significant differences in the formation of esters, acids, alcohols, aldehydes and lactones according to the yeast and the immobilisation support used. Oak chips were the more appropriate support for yeast immobilisation. No significant differences in the sensorial analysis of the sparkling wines produced by the different strategies were found.This work was supported by the "Programa Valoritxa i Transfereix" 2013 (Ref: UV-CPI13274-159983) of the Universitat de Valencia, Valencia, Spain. This institution has not intervened in the collection, analysis and interpretation of the data, nor in the report writing or the decision to publish the manuscript.Berbegal, C.; Polo, L.; García Esparza, MJ.; Lizama Abad, V.; Ferrer, S.; Pardo, I. (2019). Immobilisation of yeasts on oak chips or cellulose powder for use in bottle-fermented sparkling wine. Food Microbiology. 78:25-37. https://doi.org/10.1016/j.fm.2018.09.016S25377

Dynamic Membranes for Enhancing Resources Recovery from Municipal Wastewater

This paper studied the feasibility of using dynamic membranes (DMs) to treat municipal wastewater (MWW). Effluent from the primary settler of a full-scale wastewater treatment plant was treated using a flat 1 µm pore size open monofilament polyamide woven mesh as supporting material. Two supporting material layers were required to self-form a DM in the short-term (17 days of operation). Different strategies (increasing the filtration flux, increasing the concentration of operating solids and coagulant dosing) were used to enhance the required forming time and pollutant capture efficiency. Higher permeate flux and increased solids were shown to be ineffective while coagulant dosing showed improvements in both the required DM forming time and permeate quality. When coagulant was dosed (10 mg L−1) a DM forming time of 7 days and a permeate quality of total suspended solids, chemical oxygen demand, total nitrogen, total phosphorous and turbidity of 24 mg L−1, 58 mg L−1, 38.1 mg L−1, 1.2 mg L−1 and 22 NTU, respectively, was achieved. Preliminary energy and economic balances determined that energy recoveries from 0.032 to 0.121 kWh per m3 of treated water at a cost between 0.002 to 0.003 per m3 of treated water can be obtained from the particulate material recovered in the DM

Influence of total solids concentration on membrane permeability in a submerged hollow-fibre anaerobic membrane bioreactor

The main aim of this work was to study the influence of the mixed liquor total solids (MLTS) concentration on membrane permeability (K 20) in a submerged anaerobic membrane bioreactor (SAnMBR) pilot plant, which is equipped with industrial hollow-fibre membranes and treats urban wastewater. This pilot plant was operated at 33°C and 70 days of SRT. Two different transmembrane fluxes (13.3 and 10 LMH) were tested with a gas sparging intensity of 0.23 Nm 3 m -2 h -1 (measured as Specific Gas Demand referred to membrane area). A linear dependence of K 20 on MLTS concentration was observed within a range of MLTS concentration from 13 to 32 g L -1 and J 20 of 10 LMH. K 20 was maintained at sustainable values (about 100 LMH bar -1) even at high MLTS concentrations (up to 20 g L -1). In addition, several short-tests were carried out when the membranes were operated at high MLTS concentrations in order to assess the effect of the physical cleaning strategies (relaxation and back-flush) on membrane performance. It was observed that, with the applied gas sparging intensity, the duration of the relaxation stage did not critically affect the membrane performance. On the other hand, the required back-flush frequency was considerably affected by the MLTS concentration. © IWA Publishing 2012.This research work has been supported by the Spanish Research Foundation (CICYT Projects CTM2008-06809-C02-01 and CTM2008-06809-C02-02, and MICINN FPI grant BES-2009-023712) and Generalitat Valenciana (Projects GVA-ACOMP2010/130 and GVA-ACOMP2011/182), which are gratefully acknowledged.Robles Martínez, Á.; Durán Pinzón, F.; Ruano García, MV.; Ribes Bertomeu, J.; Ferrer Polo, J. (2012). Influence of total solids concentration on membrane permeability in a submerged hollow-fibre anaerobic membrane bioreactor. Water Science and Technology. 66(2):377-384. doi:10.2166/wst.2012.196S37738466

Optimising an outdoor membrane photobioreactor for tertiary sewage treatment

The operation of an outdoor membrane photobioreactor plant which treated the effluent of an anaerobic membrane bioreactor was optimised. Biomass retention times of 4.5, 6, and 9 days were tested. At a biomass retention time of 4.5 days, maximum nitrogen recovery rate:light irradiance ratios, photosynthetic efficiencies and carbon biofixations of 51.7 ± 14.3 mg N·mol−1, 4.4 ± 1.6% and 0.50 ± 0.05 kg CO2·m3influent, respectively, were attained. Minimum membrane fouling rates were achieved when operating at the shortest biomass retention time because of the lower solid concentration and the negligible amount of cyanobacteria and protozoa. Hydraulic retention times of 3.5, 2, and 1.5 days were tested at the optimum biomass retention times of 4.5 days under non-nutrient limited conditions, showing no significant differences in the nutrient recovery rates, photosynthetic efficiencies and membrane fouling rates. However, nitrogen recovery rate:light irradiance ratios and photosynthetic efficiency significantly decreased when hydraulic retention time was further shortened to 1 day, probably due to a rise in the substrate turbidity which reduced the light availability in the culture. Optimal carbon biofixations and theoretical energy recoveries from the biomass were obtained at hydraulic retention time of 3.5 days, which accounted for 0.55 ± 0.05 kg CO2·m−3influent and 0.443 ± 0.103 kWh·m−3influent, respectively

Anaerobic membrane bioreactors (AnMBR) treating urban wastewater in mild climates

Feasibility of an AnMBR demonstration plant treating urban wastewater (UWW) at temperatures around 25-30 ºC was assessed during a 350-day experimental period. The plant was fitted with industrial-scale hollow-fiber membranes and fed with the effluent from the pre-treatment of a full-scale municipal WWTP. Biodegradability of the UWW reached values up to 87%, although a portion of the biodegradable COD was consumed by sulfate reducing organisms. Effluent COD remained below effluent discharge limits, achieving COD removals above 90%. System operation resulted in a reduction of sludge production of 36-58% compared to theoretical aerobic sludge productions. The membranes were operated at gross transmembrane fluxes above 20 LMH maintaining low membrane fouling propensities for more than 250 days without chemical cleaning requirements. Thus, the system resulted in net positive energy productions and GHG emissions around zero. The results obtained confirm the feasibility of UWW treatment in AnMBR under mild and warm climates

A semi-industrial AnMBR plant for urban wastewater treatment at ambient temperature: Analysis of the filtration process, energy balance and quantification of GHG emissions

A semi-industrial scale AnMBR urban wastewater treatment plant was operated for 580 days at ambient temperature (ranging from 10-30 ○C) to assess its long-term filtration performance, energy balance and GHG emissions. The applied 20ºC-standardized transmembrane flux (J20) was varied between 15 and 25 LMH and the specific gas demand per m2 of membrane (SGDm) was modified between 0.10 to 0.40 Nm3·m-2·h-1 (corresponding to a specific gas demand per permeate volume (SGDP) between 10 to 20 Nm3·m-3). The filtration strategy allowed successful long-term operations without any chemical cleaning requirements and little fouling for 233 days. The plant operated as a net energy producer for more than 50 % of the experimental period, with an average net energy demand of -0.169±0.341, -0.190±0.376 and -0.205±0.447 kWh·m-3, considering 0 %, 50 % and 70 % of dissolved methane recovery, respectively. Finally, demethanization of AnMBR effluent is needed to achieve an environmentally sustainable operation of the technology. Therefore, the combination of AnMBR with degassing membranes appears as a suitable alternative to conventional wastewater treatment

A semi-industrial scale AnMBR for municipal wastewater treatment at ambient temperature: performance of the biological process

A semi-industrial scale AnMBR plant was operated for more than 600 days to evaluate the long-term operation of this technology at ambient temperature (ranging from 10 to 27 ºC), variable hydraulic retention times (HRT) (from 25 to 41 h) and influent loads (mostly between 15 and 45 kg COD·d−1). The plant was fed with sulfate-rich high-loaded municipal wastewater from the pre-treatment of a full-scale WWTP. The results showed promising AnMBR performance as the core technology for wastewater treatment, obtaining an average 87.2 ± 6.1 % COD removal during long-term operation, with 40 % of the data over 90%. Five periods were considered to evaluate the effect of HRT, influent characteristics, COD/-S ratio and temperature on the biological process. In the selected periods, methane yields varied from 70.2±36.0 to 169.0±95.1 STP L CH4·kg−1 CODinf, depending on the influent sulfate concentration, and wasting sludge production was reduced by between 8 % and 42 % compared to conventional activated sludge systems. The effluent exhibited a significant nutrient recovery potential. Temperature, HRT, SRT and influent COD/-S ratio were corroborated as crucial parameters to consider in maximizing AnMBR performance

Tratamientos biológicos de aguas residuales

El presente libro tiene como objetivo general conocer los fundamentos y la aplicación de las tecnologías disponibles para el tratamiento bilógico de las aguas residuales. Este libro pretende dotar a estudiantes, profesionales o investigadores de los conocimientos y habilidades necesarias para el pre-diseño de diferentes sistemas de tratamiento bilógico de las aguas residuales y de los fangos producidos en el proceso. Para ello, se profundiza en el estudio de los procesos biológicos, cuyo uso generalizado en la depuración de aguas residuales urbanas y gran número de industriales, por una parte, y su gran complejidad, por otra, justifica la importancia de un estudio detallado de los mismos. Asimismo, se tratan aspectos fundamentales referentes a la microbiología de los procesos, la cinética y la estequiometría de las reacciones bioquímicas, tipos de procesos, esquemas de proceso, aplicabilidad, etc. Además, se aborda la problemática de la producción de fangos, así como el diseño de los distintos métodos de tratamiento existentes.Ferrer Polo, J.; Seco Torrecillas, A.; Robles Martínez, Á.; Asensi Dasí, EJ.; Serralta Sevilla, J. (2022). Tratamientos biológicos de aguas residuales. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/181422EDITORIA

Impacts of Early Holocene environmental dynamics on open-air occupation patterns in the Western Mediterranean: insights from El Arenal de la Virgen (Alicante, Spain)

Open-air sites represent a fundamental proxy of the Early Holocene adaptive systems in the Iberian Peninsula. However, its research potential for the study of human–environmental interactions has been minimally explored. In this work, we present the results of an integrated research programme focused on open-area excavations at the Mesolithic site of Arenal de la Virgen (Alicante, Spain). Novel multi-scalar geoarchaeological and archaeo-stratigraphic studies, coupled with featured-based palaeobotanical analysis, were used to design an extensive radiocarbon dating programme and produce different Bayesian chronological models. Our results distinguish two different Mesolithic occupation phases, dating to 9.3–9.1 and 8.6–8.3k cal a bp respectively, consisting of combustion features and lithic scatters. The comparison of occupational dynamics with the nearby palaeoecological records of Salines and Villena indicated that both Mesolithic phases occurred under relatively stable environmental conditions. The second Mesolithic phase, however, ended during the onset of the 8.2k cal a bp climatic event, when sedimentation processes shifted from soil formation to accretion of aeolian sands. We demonstrate that the end of the Mesolithic occupations at Arenal de la Virgen coincides with the cessation of radiocarbon-dated activity in other open-air Postglacial sites in the central Mediterranean region of Iberia.This research is primarily part of a project that has received funding from the European Research Council (ERC) under the Horizon 2020 research and innovation programme (Grant agreement No. 683018) to JFLdP. Additional analyses on the pollen data sets have been produced in the context of the research project HAR2017-88503-P supported by the Spanish Ministry of Science and Innovation. JFLdP is additionally supported by the Plan Gen-T programme (Ref.CIDEGENT-18/040) from the Generalitat Valenciana. JRR is currently supported by a Margarita Salas fellowship (ref. MARSALAS21-22) at the University of Alicante, and AP-D is holder of a María Zambrano fellowship at the University of the Basque Country (UPV/EHU) both funded by the European Union-Next Gene and the Ministry of Universities (Government of Spain)