In this work a practical comparison has been done between the conventional
coagulation and flocculation method and Ballast flocculation as a primary settling
procedure that was used to treat sewage water in Al-Zaafraniya apartment complex.
The results show that the conventional method using alum as coagulant 75 mg/L,
gives removal efficiencies of Total suspended solid TSS 50-60%, BOD 30-40%
and total phosphorus TP 40% at total time of 60 minutes. While the Ballast
flocculation method using alum 75 mg/L , polyelectrolyte 1.5 mg/L and sand 10
mg/l (70μm) gives removal efficiencies of TSS 50-70%, BOD 30-40% and TP
68% at total time less than 22 minutes.
From the above, a conclusion can be noticed that the Ballast flocculation
method means reduction in equipment size and footprint area more over efficiency
in total phosphorus removal.