1996 Volume 82 Issue 5 Pages 447-452
An experimental study was carried out to apply the biological denitrification method for cokeoven wastewater (ammonia liquor) treatment.
An ammonia liquor contains not only high concentrated phenol, ammonia but also cyanide, thiocyanate and hydrogen sulfide. Therefore the biological denitrification for the liquor has been considered to be very difficult.
But the nitrificated liquor return system makes it possible to remove almost ammonia in the liquor. The nitrification-denitrification process of ammonia liquor was proceeded on the course of nitrites (NO2) form.
When the nitrites concentration was kept under 50mg/1, in this system the activated-sludge was very stable. Consequently nitrification and denitrification rate became very fast under the condition of the high total nitrogen (T-N) load (kg-N/kgMLSS·day).
(nitrification rate:8.9mg-N/gMLSS·Hr, denitrification rate:5.8mg-N/gMLSS·Hr)
The nitrification liquor return system required that almost all ammonia in the liquor must be removed through process in order to stabilize the process.
At the same time, chemicals (an organic carbon ex. Methyl alcohol and a alkali salt ex. Na2CO3) were required.
