Treatment of pharmaceutical wastewater containing β-lactam ring

Abstract

Pharmaceutical industry is one of the major industries in Bangladesh which has its own strong manufacturing capabilities to produce and export pharmaceuticals products. Along with its products, it also generates wastewater which is a concern from environmental point of view. Pharmaceutical wastewater is generally characterized by high toxicity and BOD5 and COD content, making it a potential threat to the environment and public health. Antibiotics in pharmaceutical wastewater are of particular concern, as they can induce bacterial resistance, even at low concentrations. Antibiotics generally have low biodegradability since they are biocidal substances and the degradation of these substances cannot be accomplished in the natural environment or biological treatment plants. The antibiotics containing liquid waste of pharmaceutical industries usually contain high amount of β-Lactam ring. The present study was undertaken to find out an effective decontamination process and also to evaluate the performance of Effluent Treatment Plant (ETP) in treating pharmaceutical wastewater containing β-Lactam ring so that it can comply with the national environmental standard. The main objective of the research was to provide a solution for the effective decontamination of β-Lactam residues in pharmaceutical wastewater using varying chemicals and reaction time and thus improving the efficiency of effluent treatment plant. For decontamination, a trial was made in the present study to use organic CH3COOH with NaOH in order to reduce the effects on microorganism in treating β-Lactam ring containing wastewater by biological treatment process along with the commonly used inorganic HCl with NaOH. The study result showed that both the combination of chemicals were effective in decontaminating β-Lactam ring for a 3-hr reaction time and no reformation of β-Lactam ring after neutralization by HCl or CH3COOH was observed in the study by HPLC analysis. Regarding the effect of two acids on microorganism in biological treatment process, study result showed that the microbial count remained the same in Aeration tank for both the cases. However, the amount of CH3COOH acid required in decontamination was higher than that of HCl, and from economic consideration, use of HCl is preferred to CH3COOH, since cost of CH3COOH is also higher (around 98%) than that of HCl.

The performance of different units of a Biological (Activated Sludge Process) CETP has also been studied in the present study after discharging decontaminated wastewater in CETP, as the concentration of decontaminated wastewater is higher than the allowable wastewater discharge limit set by ECR, 1997. From this research, it was observed that the contaminant in antibiotic containing wastewater was significantly reduced (reduction of BOD5 62%, COD 68%, TSS 98% and TDS 28%) in Combined Tank with the mixing of relatively high volume and low concentration of wastewater from Solid Dosage Unit. Therefore, the dominant treatment in CETP is the Dilution process. Apart from dilution, removal of BOD5 (66%) and COD (46%) mostly occurred in Aeration Unit of CETP. Having relatively less initial concentration of contaminants in Combined tank, the effluent discharged from the final point of CETP complies with the ECR, 1997 Standard limit regarding pH, TDS, TSS, BOD5 and COD values, except DO concentration. It was observed from the laboratory analysis that COD, BOD5, TDS, TSS and Turbidity of wastewater in Clarifier, DO Increase Tank and Filtration unit, has not been removed much compared to removal in Aeration unit. Therefore, regarding the performance of decontamination and CETP in the studied industry, it can be said that the β-Lactam ring is successfully decontaminated for both combination of chemicals (NaOH and CH3COOH, NaOH and HCl) with 3-hr retention time and no reformation of β-Lactam in CETP for decontaminated cephalosporin wastewater and Combined Tank, Aeration Tank were found effective in CETP, other units such as Clarifier and Filtration unit was found ineffective in treating the industry's wastewater.