In the present study, gas phase dielectric barrier discharge (GPDBD) was used for pretreatment of coking
wastewater with the objective of improving its biodegradability. The effects of some operational parameters
including initial concentration, pH value of coking wastewater and air flow rate in GPDBD reactor on
the COD removal were investigated. The removal efficiency of main compounds (total phenol, PAHs and
NH3–N) and biodegradability (BOD5/COD) of coking wastewater were evaluated. The results show that
the removal of COD by GPDBD fitted well with the second-order kinetics. The raw pH of coking wastewater
was beneficial for COD removal. The optimal air flow rate was observed as 2 L min1
. Approximately
100% of total phenol and PAHs (benzoquinone, naphthalenol, dimethyl phthalate, etc.) removal was
achieved at a reaction time of 120 min, and the removal efficiency of NH3–N reached 21%. The
BOD5/COD ratio increased from 0.14 to 0.52 within 100 min of discharge treatment, suggesting the
biodegradability of the coking wastewater was significantly improved. The GPDBD system is an effective
pretreatment method for enhancing the biodegradability of coking wastewater.