Abstract:
The bio-coagulants extracted from moringa stenopetala seed, aloe Vera leaves and cactus
leaves by using 1MNaCl were examined for the removal of turbidity and microbial
contaminants in drinking water. The three factors coagulant type, coagulant dose, and pH
were investigated in the treated drinking water of Physico-chemical and microbial properties
at the room temperature. The local plants of moringa stenopetala seed, aloe Vera leaves skin,
and cactus leaves were utilized for extracting bio-coagulants of MS-SC, AV-SC & Ca-SC
respectively. The characterization of the bio coagulants shows a 43.95%, 13.9% &10.94%
protein content of moringa stenopetala seed, aloe Vera leaves and cactus leaves respectively.
However, the Nano drop measurement of protein concentration of bio-coagulants was 2.534
mg/ml of MS-SC, 3.434 mg/ml of AV-SC, and 1.647 mg/ml of Ca-SC. Those bio coagulants
have a high tendency to form large floc and settled the attached particle from the water body.
This is due to the cationic positive charge of protein from bio coagulants interaction with
destabilized negative charge particles of water. Six Jar test equipment was utilized to explore
the coagulation activities of the Bio coagulants. The jar test was performed at three different
mixing modes for 1min of rapid mixing (120rpm) followed by 19 min of slow blending (40
rpm) for flocculation followed by 15 min settling at room temperature. The Physico-chemical
and microbial properties of the treated water such as pH, turbidity, alkalinity, conductivity
TDS, and microbial quality (total coliform and E. coli.) were performed. It was found that
Moringa stenopetala (MS-SC) and Aloe Vera plants (AV-SC) have better turbidity removal
efficiency than cactus plants (Ca-SC). The turbidity removal efficiency of MS-SC, AV-SC,
and Ca-SC bio coagulants were 67 - 98.83%, 59.61 - 98.74 %, and 27.4-69.83 %
respectively. It is noted that the highest alkalinity percent reduction was found at a dose of
50 mg/l and pH of 7.5 for AV-SC. Complete removal of E. coli was achieved with MS-SC bio
coagulant at a pH of 7.5 and dose of 150 mg/l. The main factors of Coagulant type,
Coagulant dose and the interaction between (coagulant type and pH) were significantly (see
in the annex table 7.5) ([F (2, 53)] =22.774; p > 0.05), ([F (2, 53) = 80.591; P > 0.05) and
([F (4, 53) = 3.081; P > 0.05)) affect the turbidity removal efficiency respectively. The result
obtained in this research suggests, that using Bio coagulants as a water treatment could be a
promising strategy for the reduction of turbidity and microbial community to a safe level.
Keywords: Bio-coagulant; Total coliform; E. coli, turbidity, drinking water