https://doi.org/10.15255/KUI.2014.014
Published: Kem. Ind. 64 (5-6) (2015) 229−236
Paper reference number: KUI-14/2014
Paper type: Original scientific paper
Download paper:  PDF

Bioremediation Kinetics of Pharmaceutical Industrial Effluent

M. Šabić Runjavec, M. Vuković Domanovac, Z. Findrik Blažević and E. Meštrović

Abstract

In recent years, concerns about the occurrence and fate of pharmaceuticals that could be present in water and wastewater has gained increasing attention. With the public’s enhanced awareness of eco-safety, environmentally benign methods based on microorganisms have become more accepted methods of removing pollutants from aquatic systems. This study investigates bioremediation of pharmaceutical wastewater from pharmaceutical company Pliva Hrvatska d.o.o., using activated sludge and bioaugmented activated sludge with isolated mixed bacterial culture. The experiments were conducted in a batch reactor in submerged conditions, at initial concentration of organic matter in pharmaceutical wastewater, expressed as COD, 5.01 g dm^–3 and different initial concentrations of activated sludge, which ranged from 1.16 to 3.54 g dm^–3. During the experiments, the COD, pH, concentrations of dissolved oxygen and biomass were monitored. Microscopic analyses were performed to monitor the quality of activated sludge. Before starting with the bioremediation in the batch reactor, toxicity of the pharmaceutical wastewater was determined by toxicity test using bacteria Vibrio fischeri. The obtained results showed that the effective concentration of the pharmaceutical wastewater was EC50 = 17 % and toxicity impact index was TII50 = 5.9, meaning that the untreated pharmaceutical industrial effluent must not be discharged into the environment before treatment. The results of the pharmaceutical wastewater bioremediation process in the batch reactor are presented in Table 1. The ratio γXv ⁄ γX maintained high values throughout all experiments and ranged from 0.90 and 0.95, suggesting that the concentrations of biomass remained unchanged during the experiments. The important kinetic parameters required for performance of the biological removal process, namely μmax, Ks, Ki, Y and kd were calculated from batch experiments (Table 2). Figs. 1 and 2 show the experimental results of changes in concentrations of substrate γS0 = 5.01 g dm^–3 for different initial concentrations of activated sludge in comparison to Endo- -Haldane model. Changes in concentrations of activated sludge during four days of experiments P1 and P2 are presented in Figs. 4 and 5, respectively. These results suggest that the bioremediation process is well described by the selected model. Process efficiency of pharmaceutical wastewater treatment was approximately 64.8 % (Fig. 3), while in experiment P2 with bioaugmented activated sludge (Fig. 2), the same efficiency was obtained 24 hours earlier than in experiment P1 (Fig.1). Microscopic examination of the activated sludge (Fig. 6) showed that bioaugmentation has no effect on formation of the flocs, but increases efficiency of the bioremediation in a way that the pharmaceutical wastewater treatment is faster and more efficient with bioaugmented activated sludge (Table 3, Fig. 2).

This work is licensed under a Creative Commons Attribution 4.0 International License

Keywords

kinetics, bioremediation, bioaugmentation, wastewater, pharmaceuticals