The influence of selected pharmaceuticals on biogas production from laboratory and real anaerobic sludge.

The presented study summarizes laboratory tests results to define the inhibition effect of selected pharmaceuticals on biogas production under anaerobic digestion conditions. Two sets of inhibition tests were realized: (i) with real anaerobic sludge (from municipal wastewater treatment plant (WWTP) where sludge is present and includes a wide spectrum of pharmaceuticals over a long period) and (ii) with laboratory sludge (sludge without pharmaceuticals). Methanogenic tests lasting 20 days were performed with three analgesics (diclofenac, ibuprofen, and tramadol), two antibiotics (amoxicillin and ciprofloxacin), ß-blocker (atenolol), three psychoactive compounds (carbamazepine, caffeine, and cotinine), and a mixture of these compounds. All tests were performed with two concentrations of pharmaceuticals (10 µg/L and 500 µg/L). Results of the methanogenic tests showed the different behaviors of the investigated sludges in the presence of individual pharmaceuticals. Stimulation of anaerobic digestion was mostly detected for laboratory (unadapted) sludge (e.g., the addition of ibuprofen at a concentration of 500 µg/L increased biogas production by 61%). On the other hand, pharmaceuticals inhibited biogas production for real sludge (e.g., the addition of ciprofloxacin 500 µg/L decreased biogas production by 52%).

Estimation of amount of selected pharmaceuticals sorbed onto digested sludge from wastewater treatment plant Bratislava-Petrzalka.

Antibiotics and antidepressants are among the most successful drugs used for human therapy. Their concentration in influent on WWTP is relative high and there can be removed by biodegradation or sorption. The aim of this study was to define the amounts of sorbed pharmaceuticals on digested sludge from WWTP Bratislava - Petrzalka. The amounts of sorbed pharmaceuticals were calculated from knowing partition coefficients for selected pharmaceuticals and from analytically measured pharmaceutical´s concentrations in sludge liquor. From this calculation were estimated the one-year sorbed amount of pharmaceutical onto sludge from wastewater treatment plant Petrzalka (26,066g/y for ciprofloxacin, 756g/y for azithromycin, 647g/y for clarithromycin, 445g/y for venlafaxine and 148g/y for citalopram).

Occurrence of illicit drugs and selected pharmaceuticals in Slovak municipal wastewater.

We analyzed illicit drugs and their metabolites and pharmaceuticals in wastewater from 15 selected wastewater treatment plants (WWTPs) in Slovakia. Our results indicate that methamphetamine is one of the most commonly used illegal drugs in all the regions of Slovakia monitored in this study. Compared with the international results, the Slovak cities of Dunajská Streda (479 mg/day/1000inh) and Trnava (354 mg/day/1000inh) are among the cities with the largest numbers of methamphetamine users in Europe. These results indicate an increase in the incidence of drugs in big cities and in the satellite cities (Trnava and Dunajská Streda) near Bratislava. These results also confirm the police statistics about production and use of illicit drugs in Slovakia. The highest specific loads of cocaine were found in Bratislava (112 mg/day/1000inh), followed by Petrzalka (74 mg/day/1000inh). Compared with other European cities, Bratislava and the other Slovak cities in this study have a relatively low number of COC consumers. The ecstasy load in wastewater from larger cities also significantly increased over the weekend and during music festivals. The highest 2-year mean concentrations of THC-COOH, a cannabis biomarker, were observed in the sewage from BA-Petrzalka and BA-Central (191 and 171 ng/L, respectively). A first complex monitoring of pharmaceuticals in all therapeutic groups was also realized in selected Slovak WWTPs. Occurrence of wide spectrum of pharmaceuticals with very high concentrations as well as consumptions were observed mainly in small Slovak cities. Considering all 120 monitored pharmaceuticals, Valsartan had the highest concentrations: 6000 ng/L, on average.

Utilization of Fenton-like reaction for antibiotics and resistant bacteria elimination in different parts of WWTP.

Utilization of relatively low-cost modification of Fenton reaction for the elimination of selected antibiotics and resistant coliforms in different part of wastewater treatment plant (WWTP) was studied. The concentration of antibiotics and occurrence of resistant gems in different stages of WWTP in the capital city of Slovakia - Bratislava was analyzed by LC-MS/MS technique. Consequently, Fenton-like reaction was applied for the elimination of chemical and biological contaminants. Comparative study with classical Fenton reaction was also done. Very high concentrations of clarithromycin, ciprofloxacin and azithromycin in influent water were found. Coliform bacteria were predominantly resistant to ampicillin, ciprofloxacin and gentamicin. After the mechanical stage, the concentration of antibiotics in water was significantly decreased because of the sorption during this step. Biological step degraded 12 types of antibiotics. Analyses of effluent water showed very bad elimination of azithromycin (919ng/L) and clarithromycin (684ng/L). Contrary, ciprofloxacin was removed with very high efficiency (95%). The number of resistant bacteria was also significantly decreased in effluent water. In the case of Escherichia coli only ampicillin and gentamicin resistance bacteria were detected. Our results show that antibiotics as well as resistant bacteria were eliminated by the modification of classical Fenton reaction with high efficiency. The modification of the Fenton reaction can decrease the process wages, environmental impact. Moreover, the degradation process was easily controlled, monitored and tuned.