Document Type : Research Paper


1 Chemical Engineering Dept, university of technology - iraq

2 Petroleum Technology Dept.,University of Technology - Iraq


This research aimed to study the removal efficiency of oil
pollutant from industrial wastewater by dissolved-air flotation (DAF)
with and without chemical coagulants. The sample test of wastewater is
discharged from Daura Refinery. The performance of dissolved air
flotation for example saturation pressure and recycle ratio were studied.
The industrial wastewater treated by DAF is carried out with two types
of chemical coagulants: Alum and Polyacrylamid. The treatment method
of wastewater by DAF with and without chemical coagulants and their
effect on the removal efficiency of oil, results were obtained at different
parameters such as saturation pressure (2,5-5.5atm) and recycle ratio
(20-50). It has been found the oil removal efficiency (R %) increases with
increase in recycle ratio (R.R) and saturation pressure (P). The
maximum oil removal efficiency in DAF unit without coagulants is found
to be equal to 60%, while with polyacrylamide coagulants is equal to 94,
90 %, while with alum coagulants is equal to 89, 82 % and with
combination of alum+ polyacrylamide coagulants is equal to 98.96,
95.5 % for initial oil concentration (Co) 50, 200 ppm respectively. The
experimental results were indicated the removal efficiency of oil by using
polyacrylamide as alone is more effective than adding alum but
combination of them, resulted improvement in removal efficiency. The
experimental results of DAF process with coagulants are expressed in
develop general empirical correlation by chemical cad in computer


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