The effect of turbidity levels and Moringa oleifera concentration on the effectiveness of coagulation in water treatment

Laboratory experiments were carried out to assess the water purification and antimicrobial properties of Moringa oleifera (MO). Hence different concentrations (25 to 300 mg/L) were prepared from a salt (1 M NaCl) extract of MO fine powder and applied to natural surface water whose turbidity levels r...

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Bibliographic Details
Published in:Water science and technology 2009-01, Vol.59 (8), p.1551-1558
Main Authors: Nkurunziza, T, Nduwayezu, J B, Banadda, E N, Nhapi, I
Format: Article
Language:English
Subjects:
Coagulation
Color removal
Colour
Drinking water
E coli
Escherichia coli
Flocculation
Fresh Water - chemistry
Fresh Water - microbiology
Hardness
Hydrogen-Ion Concentration
Iron
Manganese
Moringa oleifera
Moringa oleifera - chemistry
Nephelometry and Turbidimetry
Parameters
pH effects
Plant Extracts - chemistry
Powder
Purification
Removal
Seeds - chemistry
Sodium chloride
Surface water
Turbidity
Water hardness
Water purification
Water Purification - methods
Water Purification - standards
Water treatment
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Summary:Laboratory experiments were carried out to assess the water purification and antimicrobial properties of Moringa oleifera (MO). Hence different concentrations (25 to 300 mg/L) were prepared from a salt (1 M NaCl) extract of MO fine powder and applied to natural surface water whose turbidity levels ranged from 50 to 450 NTU. The parameters determined before and after coagulation were turbidity, pH, colour, hardness, iron, manganese and Escherichia coli. The experiments showed that turbidity removal is influenced by the initial turbidity since the lowest turbidity removal of 83.2% was observed at 50 NTU, whilst the highest of 99.8% was obtained at 450 NTU. Colour removal followed the same trend as the turbidity. The pH exhibited slight variations through the coagulation. The hardness removal was very low (0 to 15%). However, high removals were achieved for iron (90.4% to 100%) and manganese (93.1% to 100%). The highest E. coli removal achieved was 96.0%. Its removal was associated with the turbidity removal. The optimum MO dosages were 150 mg/L (50 NTU and 150 NTU) and 125 mg/L for the rest of the initial turbidity values. Furthermore all the parameters determined satisfied the WHO guidelines for drinking water except for E. coli.
ISSN:0273-1223
1996-9732
DOI:10.2166/wst.2009.155