Bio-clogging mitigation in vertical subsurface flow constructed wetlands using rhamnolipids-citric acid compound

Cao, Yuan; Li, Yue; Tong, Daniel; Sha, Mengqiao; Lv, Dongqing; Wang, Sen; Kong, Fanyu

doi:10.1016/j.cej.2021.131278

“…In the related field of constructed wetlands for wastewater treatment, researchers' suggestions for addressing bioclogging that have merit for woodchip bioreactors include: selecting filter media with coarse fractions (Suliman et al, 2006) packed optimally (Song et al, 2015), oxygenating the media by periodic draining ("resting") (Nivala et al, 2012), treating the influent (Guofen et al, 2010;Ping, et al, 2018;Cao et al, 2021), or disrupting bacterial quorum sensing (Shi et al, 2017). In addition to intermittent operation, Nivala et al (2012) suggest inclusion of multiple inlet manifolds in bed design.…”

Section: Discussionmentioning

confidence: 99%

Carbon supplementation and bioaugmentation to improve denitrifying woodchip bioreactor performance under cold conditions

Feyereisen

¹

,

Wang

²

,

Wang

³

et al. 2022

Preprint

0

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Cold temperatures limit nitrate-N load reductions of woodchip bioreactors in higher-latitude climates. This two-year, on-farm (Willmar, Minnesota, USA) study was conducted to determine whether field-scale nitrate-N removal of woodchip bioreactors can be improved by the addition of cold-adapted, locally isolated bacterial denitrifying strains (bioaugmentation) or dosing with a carbon (C) source (biostimulation). In Spring 2017, biostimulation removed 66% of the nitrate-N load, compared to 21% and 18% for bioaugmentation and control, respectively. The biostimulation nitrate-N removal rate (NRR) was also significantly greater, 15.0 g N m-1 d-1, versus 5.8 and 4.4 g N m-1 d-1, for bioaugmentation and control, respectively. Bioclogging of the biostimulation beds limited dosing for the remainder of the experiment; NRR was greater for biostimulation in Fall 2017, but in Spring 2018 there were no differences among treatments. Carbon dosing did not increase outflow dissolved organic C concentration. The abundance of one of the inoculated strains, Cellulomonas sp. strain WB94, increased over time, while another, Microvirgula aerodenitrificans strain BE2.4, increased briefly, returning to background levels after 42 days. Eleven days after inoculation in Spring 2017, outflow nitrate-N concentrations of bioaugmentation were sporadically reduced compared to the control for two weeks but were insignificant over the study period. The study suggests that biostimulation and bioaugmentation are promising technologies to enhance nitrate removal during cold conditions. A means of controlling bioclogging is needed for biostimulation, and improved means of inoculation and maintaining abundance of introduced strains is needed for bioaugmentation. In conclusion, biostimulation showed greater potential than bioaugmentation for increasing nitrate removal in a woodchip bioreactor, whereas both methods need improvement before implementation at the field scale.

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“…In the related field of constructed wetlands for wastewater treatment, researchers' suggestions for addressing bioclogging that have merit for woodchip bioreactors include: selecting filter media with coarse fractions (Suliman et al, 2006) packed optimally (Song et al, 2015), oxygenating the media by periodic draining ("resting") (Nivala et al, 2012), treating the influent (Guofen et al, 2010;Ping, et al, 2018;Cao et al, 2021), or disrupting bacterial quorum sensing (Shi et al, 2017). In addition to intermittent operation, Nivala et al (2012) suggest inclusion of multiple inlet manifolds in bed design.…”

Section: Discussionmentioning

confidence: 99%

Carbon supplementation and bioaugmentation to improve denitrifying woodchip bioreactor performance under cold conditions

Feyereisen

¹

,

Wang

²

,

Wang

³

et al. 2022

Preprint

0

View full text Add to dashboard Cite

Cold temperatures limit nitrate-N load reductions of woodchip bioreactors in higher-latitude climates. This two-year, on-farm (Willmar, Minnesota, USA) study was conducted to determine whether field-scale nitrate-N removal of woodchip bioreactors can be improved by the addition of cold-adapted, locally isolated bacterial denitrifying strains (bioaugmentation) or dosing with a carbon (C) source (biostimulation). In Spring 2017, biostimulation removed 66% of the nitrate-N load, compared to 21% and 18% for bioaugmentation and control, respectively. The biostimulation nitrate-N removal rate (NRR) was also significantly greater, 15.0 g N m-1 d-1, versus 5.8 and 4.4 g N m-1 d-1, for bioaugmentation and control, respectively. Bioclogging of the biostimulation beds limited dosing for the remainder of the experiment; NRR was greater for biostimulation in Fall 2017, but in Spring 2018 there were no differences among treatments. Carbon dosing did not increase outflow dissolved organic C concentration. The abundance of one of the inoculated strains, Cellulomonas sp. strain WB94, increased over time, while another, Microvirgula aerodenitrificans strain BE2.4, increased briefly, returning to background levels after 42 days. Eleven days after inoculation in Spring 2017, outflow nitrate-N concentrations of bioaugmentation were sporadically reduced compared to the control for two weeks but were insignificant over the study period. The study suggests that biostimulation and bioaugmentation are promising technologies to enhance nitrate removal during cold conditions. A means of controlling bioclogging is needed for biostimulation, and improved means of inoculation and maintaining abundance of introduced strains is needed for bioaugmentation. In conclusion, biostimulation showed greater potential than bioaugmentation for increasing nitrate removal in a woodchip bioreactor, whereas both methods need improvement before implementation at the field scale.

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“…Recently, several innovative dosing strategies were presented, such as addition of B. subtilis (Ping et al 2021), enzymes (Tang et al 2018), biosurfactants (Du et al 2016) and rhamnolipids-citric acid compound (Cao et al 2021), which have good solubilizing effect and environmental friendliness.…”

Section: Introductionmentioning

confidence: 99%

Bioclogging alleviation for constructed wetland based on the interaction among biofilm growth and hydrodynamics

Tang

¹

,

Chen

²

,

Zhang

³

et al. 2022

Environ Sci Pollut Res

1

0

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Bioclogging is the most crucial operation problem of the constructed wetlands, which reduce its removal e ciency and life span. A strategy through properly increasing hydraulic loading is proposed in this study to alleviate the bioclogging for CWs. The two-dimensional porous media ow cell (2D PMFC) test indicated that a quadratic correlation was found between local bio lms growth rate and the near-wall Reynolds number (r > 0.765, p < 0.05). The bio lm growth rate declined with the ow rate when Re exceeded 6. It was also found that the higher owrate (6 mL/min) lead to the homogeneous bio lm and velocity distribution in the PFMC. The column test indicated that the highest hydraulic loading (9.2 cm/h) produced the smallest decrease in hydraulic conductivity, which was 80 times more than that of low hydraulic load (3.0 cm/h) at the end (40 days) of experiment. Moreover, the relatively homogenized distribution of bio lm was found along the column with the highest hydraulic loading, which con rmed that the proper increase in hydraulic loading can alleviate bioclogging.

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Bio-clogging mitigation in vertical subsurface flow constructed wetlands using rhamnolipids-citric acid compound

Cited by 34 publications

References 56 publications

Carbon supplementation and bioaugmentation to improve denitrifying woodchip bioreactor performance under cold conditions

Carbon supplementation and bioaugmentation to improve denitrifying woodchip bioreactor performance under cold conditions

Carbon supplementation and bioaugmentation to improve denitrifying woodchip bioreactor performance under cold conditions

Bioclogging alleviation for constructed wetland based on the interaction among biofilm growth and hydrodynamics

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