Combined methods of highly polluted pharmaceutical wastewater treatment-a case study of high recovery

Our study details the investigation of real pharmaceutical wastewater (PhWW) treatment. A combination of the Fenton process, sand filtration, ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) was tested. The sample of PhWW was highly polluted, containing high chemical oxygen demand (COD, 25,000 mg·L⁻¹), total organic carbon (TOC, 4,940 mg·L⁻¹), conductivity (κ, 40,000 mg·L⁻¹), and total N (4,054 mg·L⁻¹) values. The pretreatment (Fenton, sand filter, UF) decreased the above parameters for 62%, 56%, 10%, and 88%, respectively. An additional membrane treatment was required since the values obtained in the pretreatment were above maximum contaminant levels (MCLS). The next membrane step with the loose NF membrane (HL) COD, TOC, conductivity, and total N additionally decreased for 87%, 71%, 24%, and 32%, respectively. Tight NF (NF90, NF270) and RO (XLE) membranes were used in the final step and, according to the obtained parameters, membrane permeate streams could be discharged into the sewer without any risk to the ecosystem. Finally, and the most importantly, the combined methods of the pharmaceutical wastewater treatment resulted in high recovery of more than 90%.