Importance of ecological interactions during wastewater treatment using High Rate Algal Ponds under different temperate climates

Galès, Amandine; Bonnafous, Anaïs; Carré, Claude; Jauzein, Vincent; Lanouguère, Elodie; Floc’h, Emilie Le; Pinoit, Joanna; Poullain, C.; Roques, Cécile; Sialve, Bruno; Simier, Monique; Steyer, Jean-Philippe; Fouilland, Éric

doi:10.1016/j.algal.2019.101508

Cited by 46 publications

(43 citation statements)

References 31 publications

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“…AOB compete with microalgae for ammonium uptake, transforming it into nitrite, while nitrite oxidising bacteria (NOB) carry out the second step of nitrification, oxidising nitrite to nitrate. If NOB activity is similar or higher than that of AOB, nitrite therefore does not accumulate and the concentration of NO 3 appears as a good indicator 30 of nitrifying bacteria activity (Galès et al, 2019). It should be noted that despite microalgae being able to absorb nitrate to grow, its consumption rate is significantly lower than that of ammonium (González-Camejo et al, 2019c).…”

Section: Nitrificationmentioning

confidence: 99%

“…The competition between microalgae-nitrifying bacteria for ammonium uptake has been identified as a highly relevant factor in the performance of a mixed microalgae culture (Galès et al, 2019;González-Camejo et al, 2019c), so that determining the most important parameters in nitrifying bacteria activity would help to maintain bacteria growth at a minimum and favour microalgae growth.…”

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confidence: 99%

“…sCOD concentration was also expected to show higher influence on MPBR performance as it can be used as an indirect measure of extracellular organic matter (EOM) content.However, the results of the fitted PLS model gave little weight to these variables(Figure 6b), possibly due to the production of these organic compounds being increased either to microalgae activity(Lau et al, 2019), or when algae are under stress(Lee et al, 2018). In addition, the proliferation of competing organisms such as heterotrophs (which hinder microalgae activity) reduces the sCOD in the culture(Galès et al, 2019).The variance in this parameter could thus be influenced by both high and low microalgae and heterotrophic bacteria activity and their correlation pattern could have changed throughout the 3-year operating period, reducing their importance in the overall model. Unexpectedly, NO 2 showed a relatively small influence on the PLS model, since nitrite was found to inhibit microalgae growth (González-Camejo et al, 2019b).…”

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confidence: 99%

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

et al. 2020

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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), nutrient loading rates (NLR, PLR) and others. 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 visualisation 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: nitrogen and phosphorus recovery rates (NRR, PRR), biomass productivity (BP), optical density of 680 nm (OD680), ammonium and phosphorus effluent concentration (NH 4 , P), HRT, BRT, air flow rate (F air) 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 2 worsened appreciably when only the controlled variables (Lp, F air , 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. A high nitrification rate was found to be inadvisable, since it showed an inverse correlation with NRR. In this respect, temperature and microalgae biomass concentration appeared to be the main factors to mitigate nitrifying bacteria activity.

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Section: Nitrificationmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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

et al. 2020

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“…The generated biomass was predominantly members of the genus Scenedesmus as found in other studies, with wastewater as culture medium, in which Chlorella and Scenedesmus are prominent. [43][44][45] Using compressed CO 2 as a supplemental inorganic carbon source for the growth of microalgae, a higher maximum cell density with a lower cultivation time was observed, as shown in Fig. 2.…”

Section: Microalgae Growthmentioning

confidence: 87%

Evaluation of microalgae growth in a mixed‐type photobioreactor system for the phycoremediation of wastewater

Pacheco

Hoeltz

Bjerk

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND Remediation of wastewater using microalgae is an alternative way of reducing environmental impacts associated with wastewater treatment while simultaneously generating biomass that can be converted into biofuels. In this study, the phycoremediation of a secondary urban effluent by native microalgae was investigated using a photobioreactor designed to receive carbon dioxide (CO2). The experiments were carried out with and without CO2 addition, and the physicochemical parameters of the effluent were monitored. The biomass yield was determined as the dry weight, and both the lipid and fatty acid profiles were obtained by gas chromatography with mass spectrometry detection. RESULTS With respect to biomass production, lipid content and phycoremediation of the secondary urban effluent, the best results were observed in the experiments using CO2. In these experiments, reductions of biological oxygen demand (54.34%), total phosphorus (92.4%), ammoniacal nitrogen (97.1%) and total Kjeldahl nitrogen (92.8%) were observed. The CO2 addition also enhanced microalgae growth, as the maximum cell density (MCD) was 54.26% higher after a shorter period of time compared to the MCD obtained without CO2 addition. The biomass yields were 0.5324 ± 0.007 g L−1 and 0.821 ± 0.014 g L−1 without and with CO2 addition, respectively. The lipid yields per unit of biomass for the CO2 supplemented cultures were not statistically different from cultures that were not supplemented with CO2, and the same was observed for fatty acid composition. CONCLUSION The use of the mixed‐type photobioreactor has been shown to be a potential alternative method for biomass production and wastewater phycoremediation. © 2019 Society of Chemical Industry

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“…However, the data was disperse (i.e. low R 2 values), probably due to the high variability of these ambient conditions throughout the day (Galès et al, 2019) and seasonal variations. Sunlight and temperatures are thus key parameters and should be continuously monitored to correctly assess MPBR performance.…”

Section: Key Performance Indicatorsmentioning

confidence: 99%

Improving membrane photobioreactor performance by reducing light path: operating conditions and key performance indicators

et al. 2020

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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 2 process could be operated without a high fouling propensity with gross permeate flux (J20) of 15 LMH and specific gas demand (SGDp) between 16 and 20 Nm 3 airꞏm-3 permeate, 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 (OD680) 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.

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Importance of ecological interactions during wastewater treatment using High Rate Algal Ponds under different temperate climates

Abstract: Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.

Cited by 46 publications

References 31 publications

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

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

Evaluation of microalgae growth in a mixed‐type photobioreactor system for the phycoremediation of wastewater

Improving membrane photobioreactor performance by reducing light path: operating conditions and key performance indicators

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