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

Abstract

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.

Optimizing the solar water disinfection (SODIS) method by decreasing turbidity with NaCl

“…The use of coagulation-flocculation in water treatment in developing countries has been tested and proven to be effective; however, the availability of these chemicals and relatively high cost place this treatment method beyond the means of many people (World Health Organization 2002). The use of Moringa Oleifera has shown to be effective at reducing turbidity as well as improving microbial quality in water (Nkurunziza et al 2009;Pritchard et al 2009;Ferreira et al 2011); however, it is not available in all regions of concern and the process requires extraction of the lectin from the seed.…”

Microbiological Botulinum Toxins Removing From Drinking Water Sources by Treatment of Coagulation Process

“…So, detection of bacterial group in a large number implies that the contaminated drinking water may be responsible for increasing number of water borne diseases in the country. It is evident from the study that water quality further deteriorated at the consumer level [14].…”

Application of Hybrid Process of Coagulation/Flocculation and Membrane Filtration to Water Treatment

“…The parameters analyzed in the experiments -color, turbidity, pH, and removal of Giardia and Cryptosporidium -were evaluated in triplicate for each combination of the factors "A" and "B". The results were analyzed by ANOVA using the F test and phase contrast (Nkurunziza et al, 2009) to obtain the optimum concentration of each coagulant for each water sample with initial turbidity of 50 to 450 NTU, to be later used in the combined process of coagulation/flocculation/membrane filtration. The software Statistica, version 8.0/2010, was used for the statistical analysis, and p values of less than 0.05 were considered significant.…”

“…This increase in turbidity and color in water treated with moringa was also observed in other studies, especially when the water had relatively low initial turbidity and color (Ramos, 2005). Nkurunziza et al (2009), using a 3% solution of moringa seeds, prepared with saline water, to treat water from the rivers in the province of Rwanda, obtained removal efficiency of 83.2% in samples with turbidity of 50 NTU and higher values (99.8%) in water with turbidity of 450 NTU. The optimum concentrations found in this study were 150 mg/L for 50 NTU and 125 mg/L for other turbidity levels tested by the researchers.…”