Digestate color and light intensity affect nutrient removal and competition phenomena in a microalgal-bacterial ecosystem

Marcilhac, Cyril; Sialve, Bruno; Pourcher, Anne‐Marie; Ziebal, Christine; Bernet, Nicolas; Béline, Fabrice

doi:10.1016/j.watres.2014.07.012

Cited by 130 publications

(57 citation statements)

References 29 publications

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“…Using centrate the removal capacity increases in both reactors, up to 32 and 14 mg N L − 1 day − 1 at 30% centrate in the culture medium for tubular and raceway reactors respectively, in opposite to that expected from biomass productivity decrease. These data are higher of those reported by other authors; Cabanelas et al [32] obtained a maximal removal capacity of 9.8 mg N L −1 day −1 using Chlorella vulgaris to treat centrate whereas a nitrogen removal capacity of 8.5 mg N L −1 day −1 was reported for Chlorella cultures using ten-fold diluted centrate; this value increased to 22.7 mg N L −1 day −1 under optimal conditions [33]. A similar trend was reported for pig manure, with nitrogen removal capacity ranging from 0.5 to 12 mg N L −1 day −1 [34].…”

Section: Resultscontrasting

confidence: 52%

Utilization of centrate from wastewater treatment for the outdoor production of Nannochloropsis gaditana biomass at pilot-scale

et al. 2015

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In this work, the outdoor pilot-scale production of marine microalga Nannochloropsis gaditana using centrate from the anaerobic digestion of municipal wastewater was evaluated. For this, outdoor semi-continuous cultures were performed in both tubular and raceway reactors mixing seawater with different centrate percentages (15%, 20% and 30%) as culture medium. It was demonstrated that N. gaditana can be produced using centrate as the only nutrient source but at percentages below 30%. At this level inhibition was caused by an excess of ammonium in both photobioreactors, as confirmed by chlorophyll fluorescence and average irradiance data, thus reducing productivity. At 15% and 20% centrate percentages, biomass productivity was equal to that measured when using Algal culture medium, of 0.48 and 0.10 g L −1 day −1 for tubular and raceway reactors respectively. During the experiments nitrogen depuration decreased from 85% to 63% in tubular reactors with the increase of centrate percentage in the culture medium and the decrease in biomass productivity, while in raceway reactors an opposite behavior was observed due to ammonia stripping from the cultures. Phosphorus depuration from the culture medium was 85% whatever the system used and the centrate percentage in the culture medium indicating a phosphorus limitation into the cultures. By supplying additional phosphorus, to achieve an N:P ratio of 5, it was possible to enhance productivity and increase nitrogen depuration in both systems. The use of centrate is confirmed as a useful method for reducing microalgae production costs and for increasing process sustainability. Consequently, it is demonstrated that for the production of microalgae biomass, centrate from wastewater treatment plants can be used as the exclusive nutrient source, achieving high productivities and nutrient removal rates if using suitable strains and if the system is operated adequately.

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Section: Resultscontrasting

confidence: 52%

Utilization of centrate from wastewater treatment for the outdoor production of Nannochloropsis gaditana biomass at pilot-scale

et al. 2015

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“…Using C. vulgaris, a maximal removal capacity of 9.8 mg N ·l − 1 ·day − 1 and 3.0 mg P ·l − 1 ·day − 1 was reported using centrate [3]. On the other hand, nitrogen removal of 8.5 mg N l −1 ·day −1 was reported for Chlorella cultures using ten-fold diluted centrate; this value increasing to 22.7 mg N l −1 ·day −1 under optimal conditions [18]. A similar trend was reported for pig manure, with nitrogen removal ranging from 0.5 to 12 mg N l −1 ·day −1 [32].…”

Section: Discussionmentioning

confidence: 94%

Utilization of centrate for the production of the marine microalgae Nannochloropsis gaditana

et al. 2015

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In this paper, the production of the microalga Nannochloropsis gaditana using centrate from the anaerobic digestion of treated urban wastewater is studied. For this, semicontinuous cultures were performed indoors at laboratory scale, under controlled conditions, supplying seawater with different centrate percentages from a real wastewater treatment plant as the culture medium. It was demonstrated that N. gaditana can be produced using solely centrate as the nutrient source but only at percentages below 50%. Above this level, inhibition is caused by an excess of ammonia, thus reducing productivity. In the 30-50% centrate range, biomass productivity was 0.4 g·l −1 ·day −1 , equal to that measured when using Algal culture medium. Moreover, the biochemical composition of the biomass was also equal to that measured when using Algal culture medium, with the protein content in the 30-40% d.wt. range; whereas the lipid content ranged from 20 to 25% d.wt. Under these conditions, phosphorus depuration from the culture medium was in the 80-90% range while nitrogen depuration was only between 20 and 40%, indicating an excess of nitrogen in the centrate with respect to phosphorus. In spite of this phosphorus limitation, in the optimal centrate range (30-50% in the culture medium), the cells performed under optimal conditions, removing up to 35 mg N ·l −1 ·day −1 and 5.7 mg P ·l −1 ·day −1 , with quantum yield values measuring 1.0-1.3 g·E −1 . By supplying additional phosphorus, it was possible to enhance productivity and increase nitrate and phosphorus depuration to over 80%. The use of centrate is confirmed as a useful method for reducing microalgae production costs while also increasing process sustainability, especially when using biomass for bioenergy applications.

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“…can be found in wastewater, any of which can be toxic to microalgae . The system's performance can also be significantly influenced by the presence of suspended solids and the colour of the water (Marcilhac et al, 2014).…”

Section: Wastewater Compositionmentioning

confidence: 99%

Wastewater treatment using microalgae: how realistic a contribution might it be to significant urban wastewater treatment?

Acién

Gómez-Serrano

Morales-Amaral

et al. 2016

Appl Microbiol Biotechnol

267

139

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Microalgae have been proposed as an option for wastewater treatment since the 1960's but still this technology has not been expanded to an industrial scale. In this paper, the major factors limiting the performance of these systems are analysed. The composition of the wastewater is highly relevant, and especially the presence of pollutants such as heavy metals and emerging compounds. Biological and engineering aspects are also critical and have to be improved to at least approximate the performance of conventional systems, not just in terms of capacity and efficiency but also in terms of robustness. Finally, the harvesting of the biomass and its processing into valuable products poses a challenge; yet at the same time, an opportunity exists to increase economic profitability. Land requirement is a major bottleneck that can be ameliorated by improving the system's photosynthetic efficiency. Land requirement has a significant impact on the economic balance but the profits from the biomass produced can enhance these systems' reliability, especially in small cities.3

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Digestate color and light intensity affect nutrient removal and competition phenomena in a microalgal-bacterial ecosystem

Cited by 130 publications

References 29 publications

Utilization of centrate from wastewater treatment for the outdoor production of Nannochloropsis gaditana biomass at pilot-scale

Utilization of centrate from wastewater treatment for the outdoor production of Nannochloropsis gaditana biomass at pilot-scale

Utilization of centrate for the production of the marine microalgae Nannochloropsis gaditana

Wastewater treatment using microalgae: how realistic a contribution might it be to significant urban wastewater treatment?

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