Enclosed tubular and open algal–bacterial biofilm photobioreactors for carbon and nutrient removal from domestic wastewater

Posadas, Esther; García‐Encina, Pedro A.; Domı́nguez, A.; Díaz, Ignacio; Bécares, Eloy; Blanco, Saúl; Muñoz, Raúl

doi:10.1016/j.ecoleng.2014.03.007

Cited by 78 publications

(32 citation statements)

References 33 publications

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“…On the other hand, starch content was low in all microalgae tested, which determined the nature of the enzymes used during the enzymatic hydrolysis (targeting cellulose and hemicellulose). The C, N and P content of the microalgae biomass grown in domestic wastewater (A1, A2 and C) was in agreement with values typically reported in literature (Posadas et al, 2014), and confirmed the balanced microalgae growth in domestic wastewater. The high ash content recorded in A1 and A2 (~ 40 %) was likely due to the high evaporation losses in the thin layer outdoor photobioreactor, compared to the low ash content measured in the biomass obtained from the enclosed anoxic-aerobic photobioreactor.…”

Section: Methodssupporting

confidence: 77%

Saccharification of microalgae biomass obtained from wastewater treatment by enzymatic hydrolysis. Effect of alkaline-peroxide pretreatment

Juarez

Lorenzo-Hernando

Muñoz

et al. 2016

Bioresource Technology

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An enzymatic method for the carbohydrate hydrolysis of different microalgae biomass cultivated in domestic (DWB) † and pig manure (PMWB) wastewaters, at different storage conditions (fresh, freeze-dried and reconstituted), was evaluated. The DWB provided sugars yields between 40 and 63%, although low xylose yields (< 23.5%).Approximately 2% of this biomass was converted to byproducts as succinic, acetic and formic acids. For PMWB, a high fraction of the sugars (up to 87%) was extracted, but mainly converted into acetic, butyric and formic acids, which was attributed to the bacterial action. In addition, the performance of an alkaline-peroxide pretreatment, conducted for 1 hour, 50ºC and H 2 O 2 concentrations from 1 to 7.5% (w/w), was essayed. The hydrolysis of pretreated microalgae supported a wide range of sugars extraction for DWB (55-90%), and 100% for PMWB. Nevertheless, a large fraction of these sugars (~30% for DWB and 100% for PMWB) was transformed to byproducts. HighlightsTested biomass showed different behaviours depending on the algae/bacteria ratio.Enzymatic hydrolysis of DWB yielded high glucose and low xylose extraction.Sugars from PMWB were completely released by enzymatic hydrolysis but oxidized.Acetic, formic and succinic acids were the main byproducts from released sugars.Pretreatment enhanced enzymatic hydrolysis performance for almost all biomass tested. † Abbreviations: DWB, domestic wastewater biomass; PMWB, pig manure microalgae biomass; HRT, hydraulic retention time; SRT, sludge retention time; CO 2 , carbon dioxide; CH 4 , methane. Keywords: Enzymatic hydrolysis; Glucose; Xylose; Wastewater; Alkaline-peroxide pretreatment IntroductionWorld human population and industrial activity have exponentially increased during last decades, with a concomitant raise in global energy demand. This growth has been traditionally based on fossil fuels, whose side effects have turned this dependence environmentally unsustainable (Chisti, 2007). New renewable fuel sources and biorefinery approaches for designing cost-effective and "green" processes are expected to create more efficient and sustainable economies (Daroch et al., 2013). During the past decade, microalgae have experimented a continuous and positive development due to their wide range of practical applications: wastewater treatment, nitrogen and phosphorous recovery, biogas upgrading, production of biofuels, biofertilizers, animal and fish feed, etc. Despite Oswald and co-workers were pioneers in introducing the microalgae biorefinery concept in the 60's, the combination and optimization of processes for the valorisation of microalgae biomass obtained from wastewaters treatment remains a challenge nowadays (Acién et al, 2014).Microalgae biomass is mainly composed of proteins (6% -52%), lipids (5% -23%) and carbohydrates (7% -23%) (Tijani et al., 2015). This content may vary within microalgae strains and is highly dependent on cultivation conditions, especially under nutrients-deprivation scenarios. Among them, carbohydrates are one of th...

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Section: Methodssupporting

confidence: 77%

Saccharification of microalgae biomass obtained from wastewater treatment by enzymatic hydrolysis. Effect of alkaline-peroxide pretreatment

Juarez

Lorenzo-Hernando

Muñoz

et al. 2016

Bioresource Technology

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“…A recently performed in-depth analysis on microalgae based on wastewater composition confirmed these figures (Fouilland et al, 2014). Surprisingly, the cultures are generally dominated by a single strain, making up to 90% of the total microalgae population, although more complex populations can also be found (Morales-Amaral et al, 2015a;Park et al, 2011;Posadas et al, 2014).…”

Section: Biological Aspectsmentioning

confidence: 56%

“…Moreover, because it makes no sense to sterilize wastewater prior to treatment, the final population mostly varies as a function of the environmental and operational conditions (although specific strains can be inoculated), especially the composition of wastewater being processed (Posadas et al, 2014). With respect to the microalgae, information is scarce regarding the variation in population as a function of culture conditions.…”

Section: Biological Aspectsmentioning

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

237

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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“…light intensity [18,26,35,70], CO 2 concentrations [26,29,71], etc., affects biomass accumulation, and on quantifying and manipulating biomass lipid concentrations [24][25][26][27]72,73]. Additionally, much research has been done from a fundamental understanding of algae biofilms in nature [57,63,64,74,75], and in using biofilms to treat wastewater of contaminants [5,6,[30][31][32][33][34][35][36][37][38]. The section below draws on these studies, and on the extensive amount of literature on planktonic algae growth, to determine how to potentially maximize productivity of algae biofilm growth systems.…”

Section: Algae Biofilm Biomass and Lipid Productionmentioning

confidence: 98%

“…There has also recently been a significant amount of algae biofilm research on novel reactor designs studying biomass and lipid production rates [14,[17][18]20,21,[24][25][26][27][28][29]. Other studies on algae biofilms have related not specifically to biofuel and bioproduct production, but rather, on using them to treat wastewaters of nitrogen and phosphorus using algal turf scrubbers and novel biofilm growth systems [5][6][30][31][32][33][34][35][36][37][38]. Additionally, there are many studies on algae biofilms from a fundamental perspective i.e.…”

mentioning

confidence: 97%

Factors affecting algae biofilm growth and lipid production: A review

Schnurr

Allen

2015

Renewable and Sustainable Energy Reviews

195

120

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Enclosed tubular and open algal–bacterial biofilm photobioreactors for carbon and nutrient removal from domestic wastewater

Cited by 78 publications

References 33 publications

Saccharification of microalgae biomass obtained from wastewater treatment by enzymatic hydrolysis. Effect of alkaline-peroxide pretreatment

Saccharification of microalgae biomass obtained from wastewater treatment by enzymatic hydrolysis. Effect of alkaline-peroxide pretreatment

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

Factors affecting algae biofilm growth and lipid production: A review

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