The use of synthetic coagulants is not regarded as suitable due to health and economic
considerations. Studies were carried out in laboratory scale on deionised water containing synthetic turbidity
of kaolinite. Experiments were carried out in four turbidity ranges: 10, 50, 500, 1000 (NTU) and the pH range 5-8.
The efficiency of moringa oleifera seed extract and polyaluminum chloride was examined with jar test. Extract
of moringa oleifera seed could respectively remove turbidities of 98, 97, 89 and 55 percent in optimum
concentration 10-30 (mg/l) and the optimum pH of 6-8. Poly aluminum chloride could remove 99, 98, 95 and
89 percent of the above mentioned turbidity ranges in optimum concentration of 20-30 (mg/l) with the optimum
pH of 8. The aim of this study was to compare the efficiency of two coagulants polyaluminum chloride and
“moringa oleifera”, which is a natural coagulant. The results of this study showed that the extract of moringa
oleifera seed had a minimal effect on pH and a higher efficiency in removing high turbidities in comparison with
low turbidities. Reduction of pH decreased the efficiency of polyaluminum chloride in turbidity removal. Studies
showed that the dominant mechanism turbidity removal by moringa oleifera seed extract was adsorption and
charge neutralization and intera particular bridging.