In this study, the NH4-N, organic nitrogen, color and COD removal were investigated in raw wastewaters (WW1, WW2, WW3) of a textile industry that performs cotton and polyester dyeing and printing processes. For this purpose, ozonation at neutral pH (pH 7.5) and at high pH (pH 10), powder activated carbon adsorption at pH 7 and air stripping process at high pH (pH 10) were used. The maximum removal efficiency for WW1, WW2 and WW3 in terms of NH4-N was obtained by ozonation (99%) at high pH and by adsorption (96%). However, the maximum removal efficiency for NH4-N obtained by the air stripping process was determined as 56%. Due to the difficulty of chemical hydrolysis of the organic nitrogen, the removal efficiency by ozonation and air stripping process was low.
As a result, ozonation of the raw wastewater at high pH values can be regarded as the most suitable method due to the high pH value of the industrial raw wastewater and higher removal efficiency and easy application according to other processes applied.