ABSTRACT
Coke-plant effluents contain free and combined (fixed) ammonia. The free ammonia may be stripped out by application of steam, but to strip combined ammonia, an alkalization of the wastewater, usually by the addition of lime, is required. The fate of ammonia nitrogen in the treatment of coke-plant effluents is presented in Table I. Poor performance of stripping facilities is caused by several factors such as fluctuation of wastewater flow to the still, insufficient alkalization, insufficient steam flows, and others. To obtain satisfactory performance of ammonia stripping, proper design and operation of stripping facilities is required. To achieve an advanced performance, in addition to the above requirements, an improved process control is needed. Fate of Ammonia Nitrogen in Treatment of Coke-Plant Effluents [<xref ref-type="bibr" rid="ref70_1 ref70_2">1</xref>–<xref ref-type="bibr" rid="ref70_3">3</xref>]
Concentration (mg/L)
Raw Wastewater
3,000
After Stripping of Free Ammonia
1,500
After Stripping of Free and Fixed Ammonia Poor Performance
300
Satisfactory Performance
100
Advanced Performance
30
After Biological Dephenolization
70–150
After Biological Nitrification
>1
