Algal bacterial processes for the treatment of agroindustrial wastewatwers: a biodegradability screening

The potential of photosynthetic oxygenation for the removal of carbon, nitrogen and phosphorus from 5 agroindustrial wastewaters (at several wastewater dilutions) was investigated in enclosed batch biodegradation tests using a mixed microalgae consortium and activated sludge as model microorganisms. The target wastewaters were obtained from potato processing (PW), fish processing (FW), animal feed production (MW), coffee manufacturing (CW) and yeast production (YW). The maximum final organic carbon (TOC) and nitrogen removal efficiencies were recorded for 2 fold diluted FW (64±2 % and 85±1%, respectively), while the maximum P-PO43- removal was 89±0.01% for undiluted PW. Nitrogen removal via biomass assimilation was the main nitrogen removal mechanism since neither nitrification nor stripping were recorded regardless of the wastewater and dilution evaluated. The biodegradable TOC was the most common limiting component in the wastewaters evaluated. The C/N ratio of the biomass generated was not correlated with the initial C/N ratio of the wastewaterDepartamento de Ingeniería de Sistemas y AutomáticaMáster en Investigación en Ingeniería de Procesos y Sistemas Industriale

Simultaneous biogas upgrading and centrate treatment in an outdoors pilot scale high rate algal pond

Producción CientíficaThe bioconversion of biogas to biomethane coupled to centrate treatment was evaluated in an outdoors pilot scale high rate algal pond interconnected to an external CO2-H2S absorption column (AC) via settled broth recirculation. CO2-removal efficiencies ranged from 50 to 95% depending on the alkalinity of the cultivation broth and environmental conditions, while a complete H2S removal was achieved regardless of the operational conditions. A maximum CH4 concentration of 94% with a limited O2 and N2 stripping was recorded in the upgraded biogas at recycling liquid/biogas ratios in the AC of 1 and 2. Process operation at a constant biomass productivity of 15 g m−2 d−1 and the minimization of effluent generation supported high carbon and nutrient recoveries in the harvested biomass (C = 66 ± 8%, N = 54 ± 18%, P ≈ 100% and S = 16 ± 3%). Finally, a low diversity in the structure of the microalgae population was promoted by the environmental and operational conditions imposed.Ministerio de Economía, Industria y Competitividad (Project CTM2015-70442-R and Red Novedar

Seasonal variation of biogas upgrading coupled with digestate treatment in an outdoors pilot scale algal-bacterial photobioreactor

Producción CientíficaThe yearly variations of the quality of the upgraded biogas and the efficiency of digestate treatment were evaluated in an outdoors pilot scale high rate algal pond (HRAP) interconnected to an external absorption column (AC) via a conical settler. CO2 concentrations in the upgraded biogas ranged from 0.7% in August to 11.9% in December, while a complete H2S removal was achieved regardless of the operational month. CH4 concentrations ranged from 85.2% in December to 97.9% in June, with a limited O2 and N2 stripping in the upgraded biogas mediated by the low recycling liquid/biogas ratio in the AC. Biomass productivity ranged from 0.0 g m−2 d−1 in winter to 22.5 g m−2 d−1 in summer. Finally, microalgae diversity was severely reduced throughout the year likely due to the increasing salinity in the cultivation broth of the HRAP induced by process operation in the absence of effluent.INCOVER - Innovative Eco-Technologies for Resource Recovery from Wastewater (689242

SETAC Europe 28th Annual Meeting

The demand of multicomponent methods for the analysis of compounds of emerging concern (CECs) in environmental matrices is a reality today. However, conventional techniques based on Solid Phase Extraction (SPE) coupled to Liquid Chromatography Mass Spectrometry (LC-MS) are very often only available in high-tech laboratorie

Influence of the seasonal variation of environmental conditions on biogas upgrading in an outdoors pilot scale high rate algal pond

Producción CientíficaThe influence of the daily and seasonal variations of environmental conditions on the quality of the upgraded biogas was evaluated in an outdoors pilot scale high rate algal pond (HRAP) interconnected to an external absorption column (AC) via a conical settler. The high alkalinity in the cultivation broth resulted in a constant biomethane composition during the day regardless of the monitored month, while the high algal-bacterial activity during spring and summer boosted a superior biomethane quality. CO2 concentrations in the upgraded biogas ranged from 0.1% in May to 11.6% in December, while a complete H2S removal was always achieved regardless of the month. A limited N2 and O2 stripping from the scrubbing cultivation broth was recorded in the upgraded biogas at a recycling liquid/biogas ratio in the AC of 1. Finally, CH4 concentration in the upgraded biogas ranged from 85.6% in December to 99.6% in August.2019-12-312019-12-31INCOVER - Innovative Eco-Technologies for Resource Recovery from Wastewater (689242

Feasibility study of biogas upgrading coupled with nutrient removal from anaerobic effluents using microalgae-based processes

Producción CientíficaThe present research was conducted to simultaneously optimize biogas upgrading and carbon and nutrient removal from centrates in a 180-L high-rate algal pond interconnected to an external CO2 absorption unit. Different biogas and centrate supply strategies were assessed to increase biomass lipid content. Results showed 99 % CO2 removal efficiencies from simulated biogas at liquid recirculation rates in the absorption column of 9.9 m3 m−2 h−1, concomitant with nitrogen and phosphorus removal efficiencies of 100 and 82 %, respectively, using a 1:70 diluted centrate at a hydraulic retention time of 7 days. The lipid content of the harvested algal–bacterial biomass remained low (2.9–11.2 %) regardless of the operational conditions, with no particular trend over time. The good settling characteristics of the algal–bacterial flocs resulted in harvesting efficiencies over 95 %, which represents a cost-effective alternative for algal biomass reutilization compared to conventional physical–chemical techniques. Finally, high microalgae biodiversity was found regardless of the operational conditions.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. (Project GR76, VA024U14, and RTA2013-00056-C03-02

Evaluation of the dynamics of microalgae population structure and process performance during piggery wastewater treatment in algalbacterial photobioreactors

Producción CientíficaThe dynamics of microalgae population during piggery wastewater (PWW) treatment in four open photobioreactors operated at 27 days of hydraulic retention time, and inoculated with Chlorella sp. (R1), Acutodesmus obliquus (R2), Oscillatoria sp. (R3) and in the absence of inoculum (R4), were evaluated for 6 months. In addition, the algalbacterial biomass concentration, removal of organic matter, nutrients and heavy metals were also assessed. The results revealed a high diversity and rapid variations in the structure of microalgae populations, Chlorella sp. being dominant in R4 throughout most of the operational period. Steady state average biomass concentration ranged from 2445-2610 mg/L in R1-R3 to 3265 mg/L in R4. No significant differences were recorded in the removal efficiencies (REs) of total organic carbon (86- 87%), inorganic carbon (62-71%), total nitrogen (82-85%) and total phosphorous (90-92%). Finally, Zn-REs accounted for 26% in R3, 37% in R2, and 49% in R1 and R4

Procesos innovadores de tratamiento de aguas residuales en sistemas algas-bacterias: un paso hacia su aplicación a escala real

El tratamiento de las aguas residuales es una necesidad actual obligatoria para la protección del medio ambiente. Las limitaciones de las tecnologías convencionales usadas para tratamiento de aguas residuales implican la necesidad de desarrollar nuevas técnicas. En este contexto, los procesos de interacción microalgas-bacterias aparecen como una opción sostenible y respetuosa con el medio ambiente. Estos procesos se basan en la oxidación de la materia orgánica de las aguas residuales por las bacterias heterótrofas. Estos productos de oxidación son asimilados por las microalgas durante la fotosíntesis para producir el oxígeno que será nuevamente utilizado por las bacterias. Durante esta interacción simbiótica se produce una biomasa algal-bacteriana que puede ser utilizada para producción de biocombustibles y/o biofertilizantes. El objetivo central de esta tesis ha sido determinar las principales limitaciones y potencial de la biotecnología algas-bacterias poder aplicarla a escala industrial. Los resultados obtenidos muestran como esta biotecnología es apta para reemplazar el uso de las convencionales usadas en tratamiento de aguas.Departamento de Ingeniería Química y Tecnología de Medio Ambient

Removal of contaminants of emerging concern from urban wastewater in novel algal-bacterial photobioreactors

Producción CientíficaThis work evaluates the removal of five pharmaceuticals and personal care products, i.e., ibuprofen, naproxen, salicylic acid, triclosan and propylparaben, from urban wastewater under two novel algal-bacterial photobioreactor settings. The first configuration (phase A) consisted of an anoxic-aerobic photobioreactor operating at a hydraulic retention time (HRT) of 2 d at different concentrations of total organic carbon (TOC) (90 mg L−1–200 mg L−1). In the second configuration (phase B) an anaerobic step was introduced before the anoxic tank to set a photosynthetic A2O process. In this phase, the HRT varied between 3 and 4 d and the TOC was kept constant at 200 mg L−1. In addition, the impact of external aeration in the aerobic photobioreactor was assessed. The maximum removals for ibuprofen, naproxen, salicylic acid, triclosan and propylparaben (94 ± 1%, 52 ± 43%, 98 ± 2%, 100 ± 0%, 100 ± 0%, respectively) were recorded during phase B. In phase A, low TOC concentrations triggered higher ibuprofen and naproxen removals likely due to the high contribution of biological oxidation on their removal. In phase B, total or very high removal efficiencies were observed for ibuprofen, propylparaben and triclosan independently on the operating conditions. In contrast, the removal efficiency of naproxen and salicylic acid decreased when the HRT dropped from 4 to 3 d in the absence of external aeration, which suggests that biodegradation played a key role in their removal. In addition, sorption might have contributed to the elimination of triclosan and propylparaben from the wastewater.Junta de Castilla y León (Projects UIC71 / CLU 2017-09 )Ministerio de Ciencia, Innovación y Universidades (projects RED NOVEDAR / CTQ2017-84006-C3-1-R and grant Juan de la Cierva Incorporación JCI-2015-23304

Influence of biogas flow rate on biomass composition during the optimization of biogas upgrading in microalgal-bacterial processes

Producción CientíficaThe influence of biogas flow rate (0, 0.3, 0.6, and 1.2 m3 m–2 h–1) on the elemental and macromolecular composition of the algal-bacterial biomass produced from biogas upgrading in a 180 L photobioreactor interconnected to a 2.5 L external bubbled absorption column was investigated using diluted anaerobically digested vinasse as cultivation medium. The influence of the external liquid recirculation/biogas ratio (0.5 < L/G < 67) on the removal of CO2 and H2S, and on the concentrations of O2 and N2 in the upgraded biogas, was also evaluated. A L/G ratio of 10 was considered optimum to support CO2 and H2S removals of 80% and 100%, respectively, at all biogas flow rates tested. Biomass productivity increased at increasing biogas flow rate, with a maximum of 12 ± 1 g m–2 d–1 at 1.2 m3 m–2 h–1, while the C, N, and P biomass content remained constant at 49 ± 2%, 9 ± 0%, and 1 ± 0%, respectively, over the 175 days of experimentation. The high carbohydrate contents (60–76%), inversely correlated to biogas flow rates, would allow the production of ≈100 L of ethanol per 1000 m3 of biogas upgraded under a biorefinery process approach.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. Project VA024U14 and GR76)INIA (Project RTA2013-00056-C03-02