Keywords : Coagulation
The Use of Okra as a Coagulant and Coagulant Aids in the Removal of Heavy Metals of Solid Waste Leachates
Engineering and Technology Journal,
2012, Volume 30, Issue 20, Pages 3524-3535
Coagulation-Flocculation processes play an important role in the treatment of water
and wastewater. Aluminum sulfate (alum) and polyelectrolyte (polymer) are the
common chemical coagulants which are used in this process. The produced leachate in
waste disposal places is considered to be one of the highly contaminated resources
from the physical, chemical, and biological point of view.
In Sulaimaniah, Tanjaro was found to be one of those solid waste landfill areas.
Okra is used for the treatment of raw leachate samples that obtained directly from
Sulaimaniah – Iraq solid waste sanitary landfill area. Fresh solid waste samples of the
leachates were taken and tested for their heavy metals concentrations contents. It was
found that the leachate contains a high amount of heavy metals of cadmium,
chromium, copper, nickel, and zinc. By using conventional coagulants of alum,
polymer and natural indigenous okra (as a primary coagulant or in combination with
the other two primary coagulants) and by the jar testing, the best concentrations and pH
values of the coagulants were determined. Analyzing the results, it was found that the
optimal pH values were 6.65, 9.00 and 7.00 for alum, polymer and okra, respectively.
In addition, the best dose of alum was1400 mg/L in which a removal of heavy metals
yielded 45-80 %, while the best dose of polymer was 500 mg/L in which a removal of
70-95% was achieved. For okra, the best dose was 500 mg/L in which a removal of
heavy metals yielded 20-100%. It was found that okra has an efficient coagulation
power with respect to alum and polymer in removing heavy metals elements in solid