Applicability of Al/P (Aluminium/Phosphorus) Ratio in SeDAF Process for Enhanced Phosphorus Removal

Abstract

Objectives : To prevent eutrophication and algal blooms, Ministry of Environment in Korea has reinforced the effluent standards of wastewater treatment facilities. In the last 20 years, various advanced wastewater treatment processes have been introduced nationwide. The sedimentation･dissolved air flotation (SeDAF) process has been developed for efficient enhanced phosphorus removal in the previous researches. In the study, several factors were reviewed to examine the operation characteristics of the SeDAF process. In particular, the applicability of aluminium/phosphorus (Al/P) and aluminium/turbidity (Al/T) ratios were investigated intensively.Methods : To derive the appropriate operating conditions for the SeDAF process, several sets of lab-scale tests were carried out. For each operating condition, Al/P (Al/T-P), Al/PO₄3--P, and Al/T (Al/Turbidity) ratios were analyzed, compared and reviewed respectively.Results and Discussion : Al/P ratio was revealed as the most prominent factor in terms of stability and feasibility of operation, and Al/P values of the SeDAF process could achieve lower values than those of other processes in the previous researches.Conclusions : It could be expected that the coagulant dosage decision using Al/P ratio has many advantages to reduce coagulant dosage and to decrease the amount of sludge production in the SeDAF process.