Abstract: The A2/O technology is adopted by Baicheng Zhongtai Coking Co.，Ltd. to treat coking
wastewater，with solid sodium carbonate being used as the pH regulation agent. However，the solid
nature of sodium carbonate can result in issues such as lag in adjustments leading to surpassing
of standard pH levels as well as considerable manual effort during the process. Experiments have
found that using a 30% solution of NaOH instead of solid Na2CO3 to adjust the pH of wastewater can
effectively solve the drawbacks of the original process，achieve excellent regulation effects，and save
approximately 400 000 yuan in wastewater treatment cost each ye ar.

Key words: Coking wastewater, pH regulation, NaOH solution, Sludge activity