Innovative hybrid system for wastewater treatment: High-rate algal ponds for effluent treatment and biofilm reactor for biomass production and harvesting

Assis, Letícia Rodrigues de; Calijuri, Maria Lúcia; Assemany, Paula Peixoto; Silva, Thiago Abrantes; Teixeira, Jamily Santos

doi:10.1016/j.jenvman.2020.111183

Cited by 38 publications

(8 citation statements)

References 36 publications

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“…Few studies have focused on the growth stages of biofilms of solid carbon source carriers, which are crucial to understanding the impact of biofilms on wastewater treatment [ 14 , 28 , 32 , 33 , 34 ]. Figure 5 shows the growth trend of bacterial biofilms on carrier-PLA-cavity and naked-carrier.…”

Section: Resultsmentioning

confidence: 99%

Innovative Coating–Etching Method of Biocarrier Fabrication for Treating Wastewater with a Low C/N Ratio

Zhang

Lei

et al. 2022

Polymers

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A novel method was used to fabricate the bio-carrier with both a high specific surface area and good compatibility. The results of monitoring the growth of biofilms at a low C/N ratio (0.83) showed that resulting carrier-PLA-cavity offered certain advantages for biofilm growth by providing an appropriate microenvironment for bacterial growth in wastewater treatment. The biofilm on carrier-PLA-cavity grew and updated faster than the naked-carrier. The biomass and thickness of biofilms growing on carrier-PLA-cavity were 10 kg/m3 and 500 μm, respectively. From the wastewater tests, 90% of the total nitrogen was removed via simultaneous nitrification and denitrification (SND) by the biofilm biomass attached to carrier-PLA-cavity, compared to 68% for the naked-carrier. The COD removal efficiency values of the carrier-PLA-cavity and naked-carrier were 94% and 86%, respectively. The microbial community analysis of carrier biofilms showed that Halomonas was the most abundant genus, and heterotrophic nitrification and denitrification were responsible for nitrogen removal in both reactors. Notably, this method does not require any complicated equipment or structural design. This novel method might be a promising strategy for fabricating biocarriers for treating wastewater with a low C/N ratio.

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Section: Resultsmentioning

confidence: 99%

Innovative Coating–Etching Method of Biocarrier Fabrication for Treating Wastewater with a Low C/N Ratio

Zhang

Lei

et al. 2022

Polymers

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“…Although the culture was maintained under autotrophic conditions, a heterotrophic bacterial fraction was expected to have persisted, as has been described previously for other wastewater-derived phototrophic cultures (e.g. [ 9 ]). Microalgal members were recognized by chlorophyll autofluorescence and appeared red, while non-phototrophic bacteria were distinguished via SYTO 9 nucleic acid stain and appeared green ( Fig 3 ).…”

Section: Resultsmentioning

confidence: 99%

“…These photoautotrophs are capable of rapid CO 2 uptake and fixation via their photosynthetic metabolism, generating the energy-rich sugars needed to fuel cellular activities. Like plants, microalgae readily assimilate inorganic nitrogen and phosphorus, meaning there is potential to utilize wastewater as a cheap and abundant algal growth medium [8][9][10][11]. As an added benefit, algal biomass has inherent commercial value, and can be used for example as a bio-fertilizer [12].…”

Section: Introductionmentioning

confidence: 99%

Interaction between CO2-consuming autotrophy and CO2-producing heterotrophy in non-axenic phototrophic biofilms

Ronan

Kroukamp²,

Liss³

et al. 2021

PLoS ONE

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As the effects of climate change become increasingly evident, the need for effective CO2 management is clear. Microalgae are well-suited for CO2 sequestration, given their ability to rapidly uptake and fix CO2. They also readily assimilate inorganic nutrients and produce a biomass with inherent commercial value, leading to a paradigm in which CO2-sequestration, enhanced wastewater treatment, and biomass generation could be effectively combined. Natural non-axenic phototrophic cultures comprising both autotrophic and heterotrophic fractions are particularly attractive in this endeavour, given their increased robustness and innate O2-CO2 exchange. In this study, the interplay between CO2-consuming autotrophy and CO2-producing heterotrophy in a non-axenic phototrophic biofilm was examined. When the biofilm was cultivated under autotrophic conditions (i.e. no organic carbon), it grew autotrophically and exhibited CO2 uptake. After amending its growth medium with organic carbon (0.25 g/L glucose and 0.28 g/L sodium acetate), the biofilm rapidly toggled from net-autotrophic to net-heterotrophic growth, reaching a CO2 production rate of 60 μmol/h after 31 hours. When the organic carbon sources were provided at a lower concentration (0.125 g/L glucose and 0.14 g/L sodium acetate), the biofilm exhibited distinct, longitudinally discrete regions of heterotrophic and autotrophic metabolism in the proximal and distal halves of the biofilm respectively, within 4 hours of carbon amendment. Interestingly, this upstream and downstream partitioning of heterotrophic and autotrophic metabolism appeared to be reversible, as the position of these regions began to flip once the direction of medium flow (and hence nutrient availability) was reversed. The insight generated here can inform new and important research questions and contribute to efforts aimed at scaling and industrializing algal growth systems, where the ability to understand, predict, and optimize biofilm growth and activity is critical.

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“…Researchers from Brazil have worked with hybrid HRAP systems, consisting of the combination of HRAP with a biofilm unit [217,218]. In hybrid HRAP systems, additional carbon source supplementation (CO2) was not necessary since biofilm provided better conditions for atmospheric CO2 capture [217].…”

Section: Biomass Retention Technologiesmentioning

confidence: 99%

“…In addition, hybrid systems followed by a settling tank provided a biomass production 2.6 greater than that of a conventional HRAP followed by a settling tank. Moreover, biomass harvesting in the hybrid system was facilitated [218]. Recently, attached biofilms in carriers have been explored for MBC [59,60,112].…”

Section: Biomass Retention Technologiesmentioning

confidence: 99%

A half-century of research on microalgae-bacteria for wastewater treatment

et al. 2022

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Innovative hybrid system for wastewater treatment: High-rate algal ponds for effluent treatment and biofilm reactor for biomass production and harvesting

Cited by 38 publications

References 36 publications

Innovative Coating–Etching Method of Biocarrier Fabrication for Treating Wastewater with a Low C/N Ratio

Innovative Coating–Etching Method of Biocarrier Fabrication for Treating Wastewater with a Low C/N Ratio

Interaction between CO2-consuming autotrophy and CO2-producing heterotrophy in non-axenic phototrophic biofilms

A half-century of research on microalgae-bacteria for wastewater treatment

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