Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System

George Kirumba; George Thumbi; John Mwangi; John Mbugua

doi:doi:10.11648/j.ijepp.20221005.12

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Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System

George Kirumba, George Thumbi, John Mwangi, John Mbugua

Published in International Journal of Environmental Protection and Policy (Volume 10, Issue 5)

Received: 20 September 2022 Accepted: 19 October 2022 Published: 29 October 2022

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Abstract

Floating Treatment Wetlands (FTW) is a novel technology in wastewater treatment where emergent macrophytes are supported by a floating mat on the water surface. A small-scale two-stage FTW was designed and commissioned in April 2019 to treat sewage influent of the Kibendera Waste Stabilization Ponds (WSP), Ruiru, Kenya. The study evaluated the system’s sewage treatment efficiency over a 6-month period (May-October 2019). The system operating under a constant inflow rate of 1.75m³/day was operated under aerobic (1^st stage) and anoxic conditions (2^nd stage). Highest mean monthly influent concentrations of 61.8mg/L, 544mg/L, 681mg/L, 72mg/L, 22.5mg/L and 0.12 mg/L were recorded for Total Phosphorus (TP), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Ammonia, Nitrate and Nitrite respectively. Sedimentation, nitrification-denitrification, aerobic bacterial breakdown of organic matter, nutrients uptake by plants, entrapment of suspended solids by plant roots and adsorption onto filter media were responsible for wastewater treatment. Optimum treatment efficiencies of 69.9%, 84.3%, 94%, 80.1%, 91% and 80.3% for TP, COD, TSS, ammonia, nitrate and nitrite were recorded in August 2019. During this period, effluent TSS (27mg/L), ammonia (8mg/L), nitrate (0.6mg/L) and nitrite (0.012mg/L) concentrations conformed to NEMA’s effluent guideline values. However, COD and TP concentrations of 85 mg/L and 11.6 mg/L respectively observed over the period failed to meet the local effluent standards. The study recommends further studies to investigate the adsorption capacities of other locally available materials for use as filter media to enhance organic matter and phosphorus removal. Based on the significant results reported, large-scale implementation of the technology in the WSP would realize a higher quality effluent.

Published in	International Journal of Environmental Protection and Policy (Volume 10, Issue 5)
DOI	10.11648/j.ijepp.20221005.12
Page(s)	122-129
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2022. Published by Science Publishing Group

Keywords

Floating Wetlands, Sewage Treatment Efficiency, Filter Media, Nitrification-Denitrification, Adsorption

References

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APA Style

George Kirumba, George Thumbi, John Mwangi, John Mbugua. (2022). Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System. International Journal of Environmental Protection and Policy, 10(5), 122-129. https://doi.org/10.11648/j.ijepp.20221005.12

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ACS Style

George Kirumba; George Thumbi; John Mwangi; John Mbugua. Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System. Int. J. Environ. Prot. Policy 2022, 10(5), 122-129. doi: 10.11648/j.ijepp.20221005.12

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AMA Style

George Kirumba, George Thumbi, John Mwangi, John Mbugua. Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System. Int J Environ Prot Policy. 2022;10(5):122-129. doi: 10.11648/j.ijepp.20221005.12

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@article{10.11648/j.ijepp.20221005.12,
  author = {George Kirumba and George Thumbi and John Mwangi and John Mbugua},
  title = {Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System},
  journal = {International Journal of Environmental Protection and Policy},
  volume = {10},
  number = {5},
  pages = {122-129},
  doi = {10.11648/j.ijepp.20221005.12},
  url = {https://doi.org/10.11648/j.ijepp.20221005.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijepp.20221005.12},
  abstract = {Floating Treatment Wetlands (FTW) is a novel technology in wastewater treatment where emergent macrophytes are supported by a floating mat on the water surface. A small-scale two-stage FTW was designed and commissioned in April 2019 to treat sewage influent of the Kibendera Waste Stabilization Ponds (WSP), Ruiru, Kenya. The study evaluated the system’s sewage treatment efficiency over a 6-month period (May-October 2019). The system operating under a constant inflow rate of 1.75m3/day was operated under aerobic (1st stage) and anoxic conditions (2nd stage). Highest mean monthly influent concentrations of 61.8mg/L, 544mg/L, 681mg/L, 72mg/L, 22.5mg/L and 0.12 mg/L were recorded for Total Phosphorus (TP), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Ammonia, Nitrate and Nitrite respectively. Sedimentation, nitrification-denitrification, aerobic bacterial breakdown of organic matter, nutrients uptake by plants, entrapment of suspended solids by plant roots and adsorption onto filter media were responsible for wastewater treatment. Optimum treatment efficiencies of 69.9%, 84.3%, 94%, 80.1%, 91% and 80.3% for TP, COD, TSS, ammonia, nitrate and nitrite were recorded in August 2019. During this period, effluent TSS (27mg/L), ammonia (8mg/L), nitrate (0.6mg/L) and nitrite (0.012mg/L) concentrations conformed to NEMA’s effluent guideline values. However, COD and TP concentrations of 85 mg/L and 11.6 mg/L respectively observed over the period failed to meet the local effluent standards. The study recommends further studies to investigate the adsorption capacities of other locally available materials for use as filter media to enhance organic matter and phosphorus removal. Based on the significant results reported, large-scale implementation of the technology in the WSP would realize a higher quality effluent.},
 year = {2022}
}

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TY  - JOUR
T1  - Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System
AU  - George Kirumba
AU  - George Thumbi
AU  - John Mwangi
AU  - John Mbugua
Y1  - 2022/10/29
PY  - 2022
N1  - https://doi.org/10.11648/j.ijepp.20221005.12
DO  - 10.11648/j.ijepp.20221005.12
T2  - International Journal of Environmental Protection and Policy
JF  - International Journal of Environmental Protection and Policy
JO  - International Journal of Environmental Protection and Policy
SP  - 122
EP  - 129
PB  - Science Publishing Group
SN  - 2330-7536
UR  - https://doi.org/10.11648/j.ijepp.20221005.12
AB  - Floating Treatment Wetlands (FTW) is a novel technology in wastewater treatment where emergent macrophytes are supported by a floating mat on the water surface. A small-scale two-stage FTW was designed and commissioned in April 2019 to treat sewage influent of the Kibendera Waste Stabilization Ponds (WSP), Ruiru, Kenya. The study evaluated the system’s sewage treatment efficiency over a 6-month period (May-October 2019). The system operating under a constant inflow rate of 1.75m3/day was operated under aerobic (1st stage) and anoxic conditions (2nd stage). Highest mean monthly influent concentrations of 61.8mg/L, 544mg/L, 681mg/L, 72mg/L, 22.5mg/L and 0.12 mg/L were recorded for Total Phosphorus (TP), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Ammonia, Nitrate and Nitrite respectively. Sedimentation, nitrification-denitrification, aerobic bacterial breakdown of organic matter, nutrients uptake by plants, entrapment of suspended solids by plant roots and adsorption onto filter media were responsible for wastewater treatment. Optimum treatment efficiencies of 69.9%, 84.3%, 94%, 80.1%, 91% and 80.3% for TP, COD, TSS, ammonia, nitrate and nitrite were recorded in August 2019. During this period, effluent TSS (27mg/L), ammonia (8mg/L), nitrate (0.6mg/L) and nitrite (0.012mg/L) concentrations conformed to NEMA’s effluent guideline values. However, COD and TP concentrations of 85 mg/L and 11.6 mg/L respectively observed over the period failed to meet the local effluent standards. The study recommends further studies to investigate the adsorption capacities of other locally available materials for use as filter media to enhance organic matter and phosphorus removal. Based on the significant results reported, large-scale implementation of the technology in the WSP would realize a higher quality effluent.
VL  - 10
IS  - 5
ER  -

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Author Information

George Kirumba

School of Chemical and Biological Systems Engineering, Technical University of Kenya, Nairobi, Kenya
George Thumbi

School of Civil and Resource Engineering, Technical University of Kenya, Nairobi, Kenya
John Mwangi

School of Civil, Environmental and Geospatial Engineering, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
John Mbugua

School of Chemistry and Material Science, Technical University of Kenya, Nairobi, Kenya

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APA Style

George Kirumba, George Thumbi, John Mwangi, John Mbugua. (2022). Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System. International Journal of Environmental Protection and Policy, 10(5), 122-129. https://doi.org/10.11648/j.ijepp.20221005.12

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ACS Style

George Kirumba; George Thumbi; John Mwangi; John Mbugua. Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System. Int. J. Environ. Prot. Policy 2022, 10(5), 122-129. doi: 10.11648/j.ijepp.20221005.12

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AMA Style

George Kirumba, George Thumbi, John Mwangi, John Mbugua. Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System. Int J Environ Prot Policy. 2022;10(5):122-129. doi: 10.11648/j.ijepp.20221005.12

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@article{10.11648/j.ijepp.20221005.12,
  author = {George Kirumba and George Thumbi and John Mwangi and John Mbugua},
  title = {Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System},
  journal = {International Journal of Environmental Protection and Policy},
  volume = {10},
  number = {5},
  pages = {122-129},
  doi = {10.11648/j.ijepp.20221005.12},
  url = {https://doi.org/10.11648/j.ijepp.20221005.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijepp.20221005.12},
  abstract = {Floating Treatment Wetlands (FTW) is a novel technology in wastewater treatment where emergent macrophytes are supported by a floating mat on the water surface. A small-scale two-stage FTW was designed and commissioned in April 2019 to treat sewage influent of the Kibendera Waste Stabilization Ponds (WSP), Ruiru, Kenya. The study evaluated the system’s sewage treatment efficiency over a 6-month period (May-October 2019). The system operating under a constant inflow rate of 1.75m3/day was operated under aerobic (1st stage) and anoxic conditions (2nd stage). Highest mean monthly influent concentrations of 61.8mg/L, 544mg/L, 681mg/L, 72mg/L, 22.5mg/L and 0.12 mg/L were recorded for Total Phosphorus (TP), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Ammonia, Nitrate and Nitrite respectively. Sedimentation, nitrification-denitrification, aerobic bacterial breakdown of organic matter, nutrients uptake by plants, entrapment of suspended solids by plant roots and adsorption onto filter media were responsible for wastewater treatment. Optimum treatment efficiencies of 69.9%, 84.3%, 94%, 80.1%, 91% and 80.3% for TP, COD, TSS, ammonia, nitrate and nitrite were recorded in August 2019. During this period, effluent TSS (27mg/L), ammonia (8mg/L), nitrate (0.6mg/L) and nitrite (0.012mg/L) concentrations conformed to NEMA’s effluent guideline values. However, COD and TP concentrations of 85 mg/L and 11.6 mg/L respectively observed over the period failed to meet the local effluent standards. The study recommends further studies to investigate the adsorption capacities of other locally available materials for use as filter media to enhance organic matter and phosphorus removal. Based on the significant results reported, large-scale implementation of the technology in the WSP would realize a higher quality effluent.},
 year = {2022}
}

Copy | Download

TY  - JOUR
T1  - Evaluation of Sewage Treatment Efficiency of a Two-Stage Floating-Wetland System
AU  - George Kirumba
AU  - George Thumbi
AU  - John Mwangi
AU  - John Mbugua
Y1  - 2022/10/29
PY  - 2022
N1  - https://doi.org/10.11648/j.ijepp.20221005.12
DO  - 10.11648/j.ijepp.20221005.12
T2  - International Journal of Environmental Protection and Policy
JF  - International Journal of Environmental Protection and Policy
JO  - International Journal of Environmental Protection and Policy
SP  - 122
EP  - 129
PB  - Science Publishing Group
SN  - 2330-7536
UR  - https://doi.org/10.11648/j.ijepp.20221005.12
AB  - Floating Treatment Wetlands (FTW) is a novel technology in wastewater treatment where emergent macrophytes are supported by a floating mat on the water surface. A small-scale two-stage FTW was designed and commissioned in April 2019 to treat sewage influent of the Kibendera Waste Stabilization Ponds (WSP), Ruiru, Kenya. The study evaluated the system’s sewage treatment efficiency over a 6-month period (May-October 2019). The system operating under a constant inflow rate of 1.75m3/day was operated under aerobic (1st stage) and anoxic conditions (2nd stage). Highest mean monthly influent concentrations of 61.8mg/L, 544mg/L, 681mg/L, 72mg/L, 22.5mg/L and 0.12 mg/L were recorded for Total Phosphorus (TP), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Ammonia, Nitrate and Nitrite respectively. Sedimentation, nitrification-denitrification, aerobic bacterial breakdown of organic matter, nutrients uptake by plants, entrapment of suspended solids by plant roots and adsorption onto filter media were responsible for wastewater treatment. Optimum treatment efficiencies of 69.9%, 84.3%, 94%, 80.1%, 91% and 80.3% for TP, COD, TSS, ammonia, nitrate and nitrite were recorded in August 2019. During this period, effluent TSS (27mg/L), ammonia (8mg/L), nitrate (0.6mg/L) and nitrite (0.012mg/L) concentrations conformed to NEMA’s effluent guideline values. However, COD and TP concentrations of 85 mg/L and 11.6 mg/L respectively observed over the period failed to meet the local effluent standards. The study recommends further studies to investigate the adsorption capacities of other locally available materials for use as filter media to enhance organic matter and phosphorus removal. Based on the significant results reported, large-scale implementation of the technology in the WSP would realize a higher quality effluent.
VL  - 10
IS  - 5
ER  -

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