*2.1. Raw Wastewater*

CW parameters used in the experiments are shown in Table 1. Low values of parameters indicating the content of organic compounds (total organic carbon, TOC and chemical oxygen demand, COD), and the almost complete absence of suspended solids (TSS) and nitrogen compounds (total Kjeldahl nitrogen, TNK), indicated the effective operation of the preliminary treatment (C/DAF) at the production plant. The very high value of the electrolytic conductivity indicated significant wastewater salinity that cannot be derived from only aluminum coagulants used in wastewater treatment in the factory or reagents for pH correction. Despite the high five day biochemical oxygen demand (BOD5) value and theoretically high potential susceptibility to biological treatment (described as BOD5/COD ratio, 0.382), even a small amount of raw cosmetic wastewater has a negative effect on biological wastewater treatment plants, hence the need for further treatment.


**Table 1.** Cosmetic wastewater parameters.
