Investigating the efficiency of constructed wetlands in the removal of heavy metals and enteric pathogens from wastewater

Odinga, Christine; Swalaha, Feroz Mahomed; Otieno, Fred; Ranjith, Kumar R.; Bux, Faizal

doi:10.1080/21622515.2013.865086

Cited by 31 publications

(13 citation statements)

References 69 publications

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“…Table 4 shows removal of pathogens by each treatment wetland and Phase. The VSSF TWs provide some disinfection, and the objective of this section is showing the contribution regarding pathogen indicators performance of each of treatment lines [ 23 , 50 ]. VF-N had more than 50% of data as compared to VF-M when total coliforms and E. coli were analyzed at below 1 × 10 3 (1000) MPN/100 mL for each phase.…”

Section: Resultsmentioning

confidence: 99%

“…VSSF TWs contribute to disinfection, with removals of between one and three log-units of fecal coliforms or Escherichia coli ( E. coli ) [ 11 , 22 ]. In TWs filtration, entrapment, and sedimentation are cited as important processes in the removal of relatively large amounts of pathogens [ 23 ]. Furthermore, Headly et al [ 22 ] indicate that the combination of sand media, loading, and vegetation requires less depth to achieve a given effluent E. coli concentration.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Bed Depth Reduction, Media Change, and Partial Saturation as Combined Strategies to Modify in Vertical Treatment Wetlands

Vera-Puerto

Valdés

Correa

et al. 2021

IJERPH

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The aim of this work was to evaluate the performance of vertical subsurface flow treatment wetlands (VSSF TWs) for treating rural domestic wastewater when strategies such as bed depth reduction and media change are used in combination with bottom saturation. Two treatment wetland systems were implemented: normal (VF-N), with a bed depth of 1.0 m, and modified (VF-M), with a bed depth of 0.5 m and a bottom layer of natural zeolite. Schoenoplectus californicus was used as experimental plant. These two treatment systems were operated at a hydraulic loading rate of 120 mm/d in two phases. Phase I did not use bottom saturation, while Phase II involved a bottom saturation of the zeolite layer of the VF-M system. The results show that bed depth reduction did not have a significant effect (p > 0.05) in terms of organic matter, solids, and ammonium removal. Conversely, it had a significant influence (p < 0.05) on phosphate as well as a negative effect on pathogen removal. This influence could be explained by initial media capacity for phosphorus removal and filtration importance in the case of pathogens. Partial saturation only had a positive influence on total nitrogen removal. The addition of a bottom layer of natural zeolite showed no positive effect on nutrient removal. The plant showed adaptation and positive development in both VF-N and VF-M. The water balance showed that water loss was not influenced by bed depth reduction. Therefore, according to the previous results, a combination of the proposal modifications to VSSF TWs can be introduced for treating rural domestic wastewater.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of Bed Depth Reduction, Media Change, and Partial Saturation as Combined Strategies to Modify in Vertical Treatment Wetlands

Vera-Puerto

Valdés

Correa

et al. 2021

IJERPH

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“…For this reason, rooted plant species have found a wider application. Rooted hydrophytes (e.g., Phragmites spp., Thypha spp., Cyperus alternifolius , and others) and flood-tolerant species (e.g., Chrysopogon zizanioides ) have been employed with excellent results for the construction of surface- and subsurface-flow wetlands (reviewed by [60,61]), as well as floating bed systems [62,63]. In constructed wetlands, the composition of growth beds plays a pivotal role.…”

Section: Phytoremediationmentioning

confidence: 99%

Heavy Metal Pollutions: State of the Art and Innovation in Phytoremediation

DalCorso

Fasani

Manara

et al. 2019

IJMS

335

108

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Mineral nutrition of plants greatly depends on both environmental conditions, particularly of soils, and the genetic background of the plant itself. Being sessile, plants adopted a range of strategies for sensing and responding to nutrient availability to optimize development and growth, as well as to protect their metabolisms from heavy metal toxicity. Such mechanisms, together with the soil environment, meaning the soil microorganisms and their interaction with plant roots, have been extensively studied with the goal of exploiting them to reclaim polluted lands; this approach, defined phytoremediation, will be the subject of this review. The main aspects and innovations in this field are considered, in particular with respect to the selection of efficient plant genotypes, the application of improved cultural strategies, and the symbiotic interaction with soil microorganisms, to manage heavy metal polluted soils.

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“…The works of Otter et al [51], Zurita et al [58], and Adrados et al [59] have reported that VSSF TWs provide removals ranging from one and four log units of pathogens (FC), which is similar to those achieved in the present study. Pathogen removal in VSSF TWs can be explained by removal mechanisms, including natural die-off because of starvation, predation, sedimentation, filtration, entrapment, and adsorption, but filtration would be the main pathway [60]. The similarity in pathogen removal in both climate conditions in the VSSF TWs suggests filtration as the main removal mechanism because all VSSF TWs had the same total bed depth (1.0 m), and no effect of climate condition was found.…”

Section: Effluent Concentrations and Removal Efficiencymentioning

confidence: 97%

Performance Comparison of Vertical Flow Treatment Wetlands Planted with the Ornamental Plant Zantedeschia aethiopica Operated under Arid and Mediterranean Climate Conditions

Vera-Puerto

Escobar

Rebolledo

et al. 2021

Water

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This work compares the performance of vertical subsurface flow treatment wetlands (VSSF TWs) for wastewater treatment, planted with Zantedeschia aethiopica (Za), here operated simultaneously under two different climate conditions, arid and Mediterranean. The experimental setup was divided into two treatment lines for each climate condition: three VSSF TWs planted with Schoenplectus californicus (Sc) (VSSF-S), as the control, and three VSSF TWs planted with Zantedeschia aethiopica (Za) (VSSF-Z), as the experimental unit. The four treatment systems were operated at a hydraulic loading rate of 120 mm/d during spring and summer seasons, in two locations, Iquique (Atacama Desert, Chile) and Talca (Central Valley, Chile). The water quality in effluents, plant development, and water balance were used as performance measures. In terms of the water quality, the influents’ characteristics were similar in both climates and classified as “diluted”. For the effluents, in both climate conditions, average COD and TSS effluent concentrations were below 50 mg/L and 15 mg/L, respectively. In both climate conditions, average TN and TP effluent concentrations were below 40 mg/L and 2 mg/L, respectively. Furthermore, only total nitrogen (TN) and total phosphorus (TP) in effluents to VSSF-Z had a significant effect (p < 0.05) in relation to the climate condition. Regarding plant development, Za showed a lower height growth in both climate conditions, with arid consistently 0.3 m and Mediterranean decreasing from 0.6 m to 0.2 m. However, the physiological conditions of the leaves (measured by chlorophyll content) were not affected during operation time in both climates. Water balance showed that it was not influenced by the climate conditions or plant, with water loss differences below 5%. Therefore, taking into account the water quality and water balance results, Zantedeschia aethiopica can be used in VSSF TWs in a way similar to traditional plants under arid and Mediterranean climates. However, its use has to be carefully considered because lower height could affect the esthetics for its implementation in the VSSF TWs.

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Investigating the efficiency of constructed wetlands in the removal of heavy metals and enteric pathogens from wastewater

Cited by 31 publications

References 69 publications

Evaluation of Bed Depth Reduction, Media Change, and Partial Saturation as Combined Strategies to Modify in Vertical Treatment Wetlands

Evaluation of Bed Depth Reduction, Media Change, and Partial Saturation as Combined Strategies to Modify in Vertical Treatment Wetlands

Heavy Metal Pollutions: State of the Art and Innovation in Phytoremediation

Performance Comparison of Vertical Flow Treatment Wetlands Planted with the Ornamental Plant Zantedeschia aethiopica Operated under Arid and Mediterranean Climate Conditions

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