Effect of backwashing on perchlorate removal in fixed bed biofilm reactors

Choi, Young Chul; Li, Xu; Raskin, Lutgarde; Morgenroth, Eberhard

doi:10.1016/j.watres.2007.01.025

Cited by 24 publications

(10 citation statements)

References 30 publications

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“…The impact of backwashing on biomass in drinking water biofilters has yielded considerable attention. A number of previous studies indicated that backwashing could affect the amount of attached biomass (Gibert et al 2013;Kasuga et al 2007;Lahav et al 2001;Miltner et al 1995;Nakhla and Farooq 2003), which could impact the performance of drinking water biofilters (Choi et al 2007;Hozalski and Bouwer 2001). For an example, Liu et al (2012a) revealed that the removal of dissolved organic carbon (DOC) and DON decreased via the running time after backwashing.…”

Section: Introductionmentioning

confidence: 99%

Operational performance, biomass and microbial community structure: impacts of backwashing on drinking water biofilter

Liao

Chen

Zhang

et al. 2014

Environ Sci Pollut Res

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Biofiltration has been widely used to reduce organic matter and control the formation of disinfection by-products in drinking water. Backwashing might affect the biofilters' performance and the attached microbiota on filter medium. In this study, the impacts of backwashing on the removal of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and N-nitrosamine precursors by a pilot-scale biological activated carbon (BAC) filtration system were investigated. The impacts of backwashing on biomass and microbial community structure of BAC biofilm were also investigated. Phospholipid fatty acid (PLFA) analysis showed that backwashing reduced nearly half of the attached biomass on granular activated carbon (GAC) particles, followed by a recovery to the pre-backwashing biomass concentration in 2 days after backwashing. Backwashing was found to transitionally improve the removal of DOC, DON and N-nitrosamine precursors. MiSeq sequencing analysis revealed that backwashing had a strong impact on the bacterial diversity and community structure of BAC biofilm, but they could gradually recover with the operating time after backwashing. Phylum Proteobacteria was the largest bacterial group in BAC biofilm. Microorganisms from genera Bradyrhizobium, Hyphomicrobium, Microcystis and Sphingobium might contribute to the effective removal of nitrogenous organic compounds by drinking water biofilter. This work could add some new insights towards the operation of drinking water biofilters and the biological removal of organic matter.

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Section: Introductionmentioning

confidence: 99%

Operational performance, biomass and microbial community structure: impacts of backwashing on drinking water biofilter

Liao

Chen

Zhang

et al. 2014

Environ Sci Pollut Res

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“…(2007). The inner diameter of the bioreactor was 2·54 cm; each section was packed to a height of 2·54 cm (total fixed‐bed depth of 10·16 cm) with 2‐mm glass beads that were etched with hydrofluoric acid as described previously (Choi et al. 2007).…”

Section: Methodsmentioning

confidence: 99%

Quantification of genes and gene transcripts for microbial perchlorate reduction in fixed-bed bioreactors

Long

Bae

et al. 2012

Journal of Applied Microbiology

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Aims: Optimization of full‐scale, biological perchlorate treatment processes for drinking water would benefit from knowledge of the location and quantity of perchlorate‐reducing bacteria (PRB) and expression of perchlorate‐related genes in bioreactors. The aim of this study was to quantify perchlorate removal and perchlorate‐related genes (pcrA and cld) and their transcripts in bioreactors and to determine whether these genes or transcripts could serve as useful biomarkers for perchlorate treatment processes. Methods and Results: Quantitative PCR (qPCR) assays targeting pcrA and cld were applied to two pilot‐scale, fixed‐bed bioreactors treating perchlorate‐contaminated groundwater. pcrA and cld genes per microgram of DNA were two‐ to threefold higher and three‐ to fourfold higher, respectively, in the bioreactor showing superior perchlorate‐removal performance. In a laboratory‐scale bioreactor, quantities of pcrA and cld genes and transcripts were compared under two distinct performance conditions (c. 60 and 20% perchlorate removal) for a 5‐min empty bed contact time. cld genes per microgram of DNA were approximately threefold higher and cld transcripts per microgram of RNA were approximately sixfold higher under the higher perchlorate‐removal condition. No differences in pcrA genes or transcripts per microgram of DNA or RNA, respectively, were detected between the c. 60 and 20% perchlorate‐removal conditions, possibly because these assays did not accurately quantify pcrA genes and transcripts in the mixed culture present. Conclusions: Quantities of cld genes and transcripts per microgram of DNA and RNA, respectively, were found to be higher when perchlorate removal was higher. However, quantities of pcrA and cld genes or transcripts were not found to directly correlate with perchlorate‐removal rates. Significance and Impact of the Study: To our knowledge, this study represents the first application of qPCR assays to quantify perchlorate‐related genes and transcripts in continuous‐flow bioreactors. The results indicate that cld gene and transcript quantities can provide insights regarding the quantity, location and gene expression of PRB in bioreactors.

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“…5) [13]. This result indicates that the BAF bed with longer contact time led to a greater reduction in organic carbon and shorter filtration cycle time [14], while shorter contact time led to lower organic reduction because high water flow velocity can remove loosely attached large microbial aggregates [15]. This suggested that optimal operating condition of BAF bed were a filtration velocity of <3 m/d with regard to filtrate quality parameters and filtration cycle time.…”

Section: Performance Of High-rate Fibre Filter and Baf Pretreatment Smentioning

confidence: 97%

Configuration of an efficient seawater pretreatment system for simultaneous organic and particulate matters removal

Hyun

2011

Desalination and Water Treatment

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To cite this article: Kil-Soo Hyun (2011) Configuration of an efficient seawater pretreatment system for simultaneous organic and particulate matters removal, Desalination and Water Treatment, 33:1-3, 295-299, ab s t r ac tIn this study, the high-rate fibre filter (HRF) using the fibre media and the biological aerated filter (BAF) followed by granular media filter (GMF) using anthracite and granular activated carbon (GAC) was evaluated as an effective pre-treatment for simultaneous organic and particulate matter removal. As a result, the HRF bed was more effective in reducing particulate matters, while the BAF bed was effective in reducing conventional pollutants as well as particulate matters. The performance results of combined HRF/BAF/GMF system in terms of pollutants and headloss achieved 12-35% higher reduction and about 1.7 times slower development than those of the combined HRF/ GMF system. The performance of combined HRF/BAF system (FV 30/3 m/h) followed by GAC filter (FV 5 m/h) showed an excellent removal results of >80% for organics and nutrients and >90% for particulate matters, which typically cause membrane biofouling and colloidal fouling. This reveals that combined HRF/BAF/GMF system is an effective pretreatment system to control and reduce the extent of membrane fouling compared to conventional coagulation-granular filtration.

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Effect of backwashing on perchlorate removal in fixed bed biofilm reactors

Cited by 24 publications

References 30 publications

Operational performance, biomass and microbial community structure: impacts of backwashing on drinking water biofilter

Operational performance, biomass and microbial community structure: impacts of backwashing on drinking water biofilter

Quantification of genes and gene transcripts for microbial perchlorate reduction in fixed-bed bioreactors

Configuration of an efficient seawater pretreatment system for simultaneous organic and particulate matters removal

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