The increasing use of antibiotics and the presence of pharmaceutical residues in wastewater is becoming a serious environmental problem. Studies show that most of consumed antibiotics are not metabolized in the body. Conventional wastewater treatment plants are not able to completely remove them so they are constantly excreted into the environment. In addition to humans, an important source of antibiotics in effluents are also veterinary medicine, pharmaceutical industry, hospitals and research facilities. Antibiotics are found in low concentrations in the environment because of their continuous discharge they are a potential threat on aquatic organisms as well as humans.
Within the master's thesis, two advanced oxidation processes and their combination for the removal of antibiotics from wastewater are presented. We studied ozonation, hydrodynamic cavitation and their combination. The processes were performed at different ozone flows and different concentrations of amoxicillin. The efficiency of the processes was monitored with determination of total organic carbon (TOC) and chemical oxygen demand (COD). Biodegradability of antibiotic was evaluated with respirometry of activated sludge.
The results showed that ozonation itself is the most efficient process, as we achieved the highest decomposition efficiencies in terms of TOC 26 % and COD 62 %. Hydrodynamic cavitation did not achieve the preferred effect as the efficiencies were the lowest, according to the TOC < 1% and COD 20 %. The combination of both processes, however, gave the same results as the ozonation process itself. Respirometry of activated sludge proved that the untreated antibiotic is not biodegradable even after cavitation. Only the process of ozonation and the combination of ozonation and cavitation at least partially degraded the antibiotic, and increased its biodegradability.
|
