Impact of ozonation in removing organic micro-pollutants in primary and secondary municipal wastewater: effect of process parameters

Achisa C. Mecha, Maurice S. Onyango, Aoyi Ochieng, Maggy N. B. Momba

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The study investigates the influence of process parameters on the effectiveness of ozonation in the removal of organic micro-pollutants from wastewater. Primary and secondary municipal wastewater containing phenol was treated. The effect of operating parameters such as initial pH, ozone dosage, and initial contaminant concentration was studied. An increase in contaminant decomposition with pH (3–11) was observed. The contaminant removal efficiencies increased with an increase in ozone dose rate (5.5–36.17 mg L−1 min−1). Furthermore, the ultraviolet absorbance (UV 254 nm) of the wastewater decreased during ozonation indicating the breakdown of complex organic compounds into low molecular weight organics. Along the reaction, the pH of wastewater decreased from 11 to around 8.5 due to the formation of intermediate acidic species. Moreover, the biodegradability of wastewaters, measured as biological and chemical oxygen demand (BOD5/COD), increased from 0.22 to 0.53. High ozone utilization efficiencies of up to 95% were attained thereby increasing the process efficiency; and they were dependent on the ozone dosage and pH of solution. Ozonation of secondary wastewater attained the South African water standards in terms of COD required for wastewater discharge and dissolved organic carbon in drinking water and increased significantly the biodegradability of primary wastewater.
Original languageEnglish
Pages (from-to)756-765
JournalWater Science and Technology
Volume74
Issue number3
DOIs
Publication statusPublished - 2016

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Ozonization
Wastewater
wastewater
Ozone
ozone
Biodegradability
Impurities
pollutant
effect
micropollutant
parameter
ozonation
Chemical oxygen demand
biochemical oxygen demand
Organic carbon
absorbance
Organic compounds
Potable water
chemical oxygen demand
Phenols

Cite this

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title = "Impact of ozonation in removing organic micro-pollutants in primary and secondary municipal wastewater: effect of process parameters",
abstract = "The study investigates the influence of process parameters on the effectiveness of ozonation in the removal of organic micro-pollutants from wastewater. Primary and secondary municipal wastewater containing phenol was treated. The effect of operating parameters such as initial pH, ozone dosage, and initial contaminant concentration was studied. An increase in contaminant decomposition with pH (3–11) was observed. The contaminant removal efficiencies increased with an increase in ozone dose rate (5.5–36.17 mg L−1 min−1). Furthermore, the ultraviolet absorbance (UV 254 nm) of the wastewater decreased during ozonation indicating the breakdown of complex organic compounds into low molecular weight organics. Along the reaction, the pH of wastewater decreased from 11 to around 8.5 due to the formation of intermediate acidic species. Moreover, the biodegradability of wastewaters, measured as biological and chemical oxygen demand (BOD5/COD), increased from 0.22 to 0.53. High ozone utilization efficiencies of up to 95{\%} were attained thereby increasing the process efficiency; and they were dependent on the ozone dosage and pH of solution. Ozonation of secondary wastewater attained the South African water standards in terms of COD required for wastewater discharge and dissolved organic carbon in drinking water and increased significantly the biodegradability of primary wastewater.",
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Impact of ozonation in removing organic micro-pollutants in primary and secondary municipal wastewater: effect of process parameters. / Mecha, Achisa C.; Onyango, Maurice S.; Ochieng, Aoyi; Momba, Maggy N. B.

In: Water Science and Technology, Vol. 74, No. 3, 2016, p. 756-765.

Research output: Contribution to journalArticle

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T1 - Impact of ozonation in removing organic micro-pollutants in primary and secondary municipal wastewater: effect of process parameters

AU - Mecha, Achisa C.

AU - Onyango, Maurice S.

AU - Ochieng, Aoyi

AU - Momba, Maggy N. B.

PY - 2016

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AB - The study investigates the influence of process parameters on the effectiveness of ozonation in the removal of organic micro-pollutants from wastewater. Primary and secondary municipal wastewater containing phenol was treated. The effect of operating parameters such as initial pH, ozone dosage, and initial contaminant concentration was studied. An increase in contaminant decomposition with pH (3–11) was observed. The contaminant removal efficiencies increased with an increase in ozone dose rate (5.5–36.17 mg L−1 min−1). Furthermore, the ultraviolet absorbance (UV 254 nm) of the wastewater decreased during ozonation indicating the breakdown of complex organic compounds into low molecular weight organics. Along the reaction, the pH of wastewater decreased from 11 to around 8.5 due to the formation of intermediate acidic species. Moreover, the biodegradability of wastewaters, measured as biological and chemical oxygen demand (BOD5/COD), increased from 0.22 to 0.53. High ozone utilization efficiencies of up to 95% were attained thereby increasing the process efficiency; and they were dependent on the ozone dosage and pH of solution. Ozonation of secondary wastewater attained the South African water standards in terms of COD required for wastewater discharge and dissolved organic carbon in drinking water and increased significantly the biodegradability of primary wastewater.

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