Antibiotic Removal Rates Research Articles

Fate of organic pollutants in a pilot-scale membrane bioreactor-nanofiltration membrane system at high water yield in antibiotic wastewater treatment

A double membrane system combining a membrane bioreactor (MBR) with a nanofiltration (NF) membrane at the pilot scale was tested to treat real antibiotic wastewater at a pharmaceutical company in Wuxi (China). The water yield of the pilot system reached over 92 ± 5.6% through recycling the NF concentrate to the MBR tank. Results showed that the pilot scale system operated in good conditions throughout the entire experiment period and obtained excellent water quality in which the concentrations of chemical oxygen demand and total organic carbon were stable at 35 and 5.7 mg/L, respectively. The antibiotic removal rates of both spiramycin (SPM) and new spiramycin in wastewater were over 95%. Organics analysis results showed that the main organics in the biological effluent were proteins, soluble microbial by-product-like, fulvic acid-like and humic-like substances. These organics could be perfectly rejected by the NF membrane. Most of the organics could be removed through recycling NF concentrate to the MBR tank and only a small part was discharged with NF concentrate and permeate.

Photodegradation of the Antibiotic Penicillin G in the Aqueous Solution using UV-A Radiation

Background and purpose: Highly consumption of antibiotics and their entrance into the environment has increased concerns all over the world. These compounds enter to the environment through an incomplete metabolism and a considerable amount of them cannot be removed using usual waste filtration systems. Therefore, the present study aimed to investigate the feasibility of using ultraviolet radiation (UV-A) to remove penicillin G (PENG) from aqueous phase and determining its removal efficiency. Materials and Methods: The experiments were carried out in the batch mode. The samples were assessed in a 2-liter reactor. In order to investigate the effect of UV-A radiation on the removal rate of antibiotic penicillin G (PENG), the following parameters were studied. Three concentration levels of PENG antibiotic (10,25, and 45 mg/l) were exposed to UV-A at three pH levels (3,7,11) and were evaluated at four reaction times (30,60,90, and 120 min). Antibiotic penicillin G (PENG) was determined using HPLC instrument (Waters YL9100,USA) and results analyzed using factorial design software. Results: The finding demonstrated that antibiotic removal rate increased by decreasing pH and decreasing the initial concentration of antibiotic and increasing contact time. The maximum rate of penicillin G removal occurred in acidic pH (pH=3) is as much as 38%. All of the variables in the process have been statistically significant effect (p<0.001). Conclusion: Results showed that by reducing the pH, increasing contact time and reducing the antibiotic concentration, the removal rate increases. In conclusion, photodegradation process using UV-A may enhance the rate of penicillin G degradation in polluted water and could be used as a complementary step for other chemical and biological processes to remove penicillin G from the aqueous solution. Therefore, UV-A process in conjugate with the other processes is an appropriate method for reducing antibiotic penicillin G in polluted water resources. (*Dehghani M. Ahmadi M. Nasseri S. Photodegradation of the Antibiotic Penicillin G in the Aqueous SolutionUsing UV-A Radiation. IJHS 2013;1(3):43-50) http://jhs.mazums.ac.ir

Different removal behaviours of multiple trace antibiotics in municipal wastewater chlorination

The chlorination behaviours of 12 antibiotics belonging to six classes at environmentally relevant concentrations were systematically examined under typical conditions relevant to municipal wastewater chlorination. Cefotaxime, cefalexin, ampicillin and tetracycline were completely removed under all three initial free chlorine dosages (5 mg/L, 10 mg/L, and 15 mg/L). The removal efficiencies of sulphamethoxazole, sulphadiazine, roxithromycin, anhydro-erythromycin, ofloxacin, and trimethoprim were closely correlated to the residual free chlorine concentration, and no further significant mass removal was observed after the residual free chlorine concentration decreased to less than ∼0.75 mg/L. Ammonia plays a critical role during chlorination because of its competition with antibiotics for free chlorine to form combined chlorine, which reacts slowly with these antibiotics. Except for norfloxacin and ciprofloxacin, the removal behaviours of the 10 other target antibiotics under ammonia nitrogen concentrations ranging from 2 to 15 mg/L were characterised by a rapid initial removal rate upon contact with free chlorine during the first 5 s–1 min (depending on the specific antibiotic and ammonia nitrogen concentration) and then a much slower removal rate. Free chlorine was responsible for the reaction with antibiotics during the rapid stage (first 5 s–1 min), whereas combined chlorine reacted with antibiotics in the subsequent slow stage. Combined chlorine can remove norfloxacin and ciprofloxacin at a relatively faster rate. The presence of suspended solids at 30 mg/L slightly decreased the antibiotic removal rate. The kinetic rate constants decreased by 2.1–13.9%, while the half-lives increased by 2.0–15.0% compared to those of a 0 mg/L suspended solid for the target antibiotics.

Effect of hemoperfusion of clearance of gentamicin, cephalothin, and clindamycon from plasma of normal dogs.

Nine normal dogs were divided into three groups of three. Group 1 was given an overdose of gentamicin; group 2, cephalothin; and group 3, clindamycin. Group 1 had hemoperfusion with Amberlite XE-336, and groups 2 and 3 with Amberlite XAD-4 resin adsorbents, for 6 hr with a blood flow rate of 300 ml/min. The plasma clearance and removal rates of antibiotics by the hemoperfusion columns were high. The clearance rate of gentamicin from plasma (mean +/- standard deviation) ranged from 59 +/- 30 to 199 +/- 6 ml/min, of cephalothin from 66 +/- 14 to 157 +/- 8 ml/min, and of clindamycin from 55 +/- 9 to 125 +/- 16 ml/min. Of the total dose of antibiotic administered, the hemoperfusion columns removed 67% from theplasma in group 1, 41% in group 2, and 18% in group 3. The fact that antibiotics may be rapidly removed from the blood during hemoperfusion should be considered in calculation of the therapeutic dose of antibiotic required for patients who receive this preocedure. Also, hemoperfusion can effectively and rapidly remove certain antibiotics from the blood of patients who have had a potentially toxic overdose.