Detailed characterization, antibiotic resistance and seasonal variation of hospital wastewater.

This study investigates the presence of the different classes of micro-pollutants such as pharmaceutical active compounds (PhACs) (20 antibiotics, 8 analgesics and anti-inflammatories, 5 cytostatic agents, 7 ß-blockers, 4 lipid regulators, 13 psychiatrics, 1 antidiabetic, 1 receptor antagonist, 1 local anaesthetic, 1 antihypertensive and their 5 metabolites), hormones (8 compounds), X-ray contrast agents (6 compounds), benzotriazoles (3 compounds) and pesticides (6 compounds), and antibiotic resistance in hospital wastewater (HWW) of a medical faculty in Istanbul, Turkey. In addition, the seasonal variations of the selected PhACs and X-ray contrast agents and antibiotic resistance were evaluated for 2 years in a total of eight samples. In the PhACs, sulfamethoxazole and its metabolite (4 N-acethyl-sulfamethoxazole) in the antibiotic group and paracetamol in the analgesic and anti-inflammatory group were found at 100% of frequency and the highest concentrations as 35, 43 and 210 µg/L, respectively. The mean concentrations of psychiatric compounds were found less than 0.25 µg/L except carbamazepine (1.36 µg/L). Bisphenol A in hormone group had the highest concentration up to 14 µg/L. In the hormone group compounds, 17-α-Ethinylestradiol and 17-ß-Estradiol were detected at lower mean concentrations of 0.2 and 0.05 µg/L, respectively. 1H-benzotriazole had the highest concentration with the mean concentration of 24.8 µg/L in benzotriazole group compounds. The compounds in X-ray contrast agents group were noted as compounds detected at the highest concentration in HWW up to 3000 µg/L. Antibiotic resistance against azithromycin, clindamycin and trimethoprim-sulfamethoxazole antibiotics was observed around 50% in the winter period. The seasonal variation was detected for the most of the investigated PhACs, especially in antibiotic group which was in line with those significant differences in antibiotic resistance rates in the studied antibiotics between winter and summer seasons.

An integrated electrocoagulation-nanofiltration process for carwash wastewater reuse.

In the present work, advanced treatment of carwash wastewater with an integrated electrocoagulation-nanofiltration (EC-NF) process to reuse the treated wastewater as rinsing water was investigated. The wastewater was pretreated by EC process under various operating parameters such as temperature (25 °C, 35 °C, 45 °C), stirring speed (150 rpm, 250 rpm, 350 rpm), and electrode connection mode (MP-P, MP-S, BP-S) using Fe electrode. The best results were achieved at 25 °C, 250 rpm and MP-P connection mode for EC, considering both pollutant removals and energy consumptions. EC sludge was characterized scanning electron microscopy-energy dispersive index (ESEM-EDX) analysis. The pretreated carwash wastewater using EC process was further treated by NF process using NF 270 and Desal 5DL membranes. Desal 5 DL membrane provided the highest treatment performance for chloride (92%), conductivity (80%) and total hardness (90%) parameters for EC-NF process. Resistance in series model was used for a deeper discussion of the reasons for flux decline. In addition, Fourier transform infrared (FTIR) spectroscopy and contact angle measurements were conducted for membrane fouling characterization. The foulants mainly accumulated on the membrane surface forming a cake layer and lower extent of membrane fouling was occurred for both membranes. As a result, this study showed that the water quality for reuse in carwashing process could be achieved with an integrated EC-NF process.

Occurence and Prioritization of Pharmaceutical Active Compounds in Domestic/Municipal Wastewater Treatment Plants.

In this study, pharmaceutically active compounds (PhACs) were analyzed in the influent and effluent of a domestic wastewater treatment plant in Turkey and a municipal wastewater treatment plant in Germany and the toxicity of these wastewaters were estimated using a toxic unit (TU) approach. A total of 21 and 32 PhACs were detected in the domestic wastewater and the municipal wastewater, respectively. The TUs estimated for PhACs in municipal wastewater were higher than the TUs estimated for PhACs present in domestic wastewater. The levels of the anti-anxiety drug, oxazepam were estimated to be in the high risk category (HQ > 10) in both wastewaters. In bench-scale tests with ozonation, the removals of four PhACs in the municipal wastewater were investigated. At a dose of 2 mg/L ozone, 97%-98% of diclofenac and carbamazepine were removed. The lowest removal rate at 71% was observed for metoprolol.

Performance and microbial shift during acidification of a real pharmaceutical wastewater by using an anaerobic sequencing batch reactor (AnSBR).

In this study, a lab-scale anaerobic sequencing batch reactor (AnSBR) was used for the acidification of a pharmaceutical wastewater sourced from etodolac chemical synthesis tanks. The effects of the organic loading rate (OLR), and etodolac and sulfate concentrations on the acidification rate and microbial community in AnSBR were investigated at 35 °C with a hydraulic retention time (HRT) of 37 h, a pH of 5, and OLRs up to 5.2 kgCOD/m3·day. The AnSBR accomplished a 60% acidification ratio and 50-60% etodolac removal at OLRs up to 2.6 kgCOD/m3·day. However, at OLR = 3.9 kgCOD/m3·day, acidification was not achieved due to sulfite inhibition; pre-ozonation was applied to overcome this sulfite inhibition. Although etodolac and COD removals were improved, the wastewater was not successfully acidified. Real-time polymerase chain reaction (Q-PCR) and fluorescent in situ hybridization (FISH) analyses revealed that acidification was inhibited by the dominance of sulfate reducing bacteria (SRB) over acidification bacteria in the AnSBR. However, increasing the OLR to 5.2 kgCOD/m3·day led to toxicity stress in the SRB due to increased sulfite concentrations. Sulfate load fundamentally affected acidification process and microbial community composition. The presence of etodolac with concentration up to 56 mg/L did not have a significant effect on VFA production and the microbial community.

Removal of Organic Matter and Etodolac from Pharmaceutical Industry Wastewater by PAC Adsorption.

The removal of organic matter and etodolac (an anti-inflammatory pharmaceutical) from a real process wastewater by using powdered activated carbon (PAC) adsorption before and after Fenton oxidation has been studied. The wastewater sample is collected from the final stage of chemical synthesis of a pharmaceutical (etodolac). Fenton oxidation resulted with decrease in chemical oxygen demand (84% removal) and etodolac concentration was reduced to 0.7 mg L-1. Optimum adsorption equilibrium conditions were found as t = 16 hours, and m = 10 g L-1. The Freundlich model showed the best fit for the adsorption of both wastewater with R2 values of 0.89 and 0.99. Lower pseudo-second-order rate constant (k2) (0.067 < 2.62) obtained from the adsorption of raw wastewater with higher organic matter concentration confirms the chemisorption of the adsorbates onto the PAC. Pore surface mass diffusion with R2 value of 0.92 was found as rate-controlling step for adsorption process with Fenton pre-treated wastewater.

Electrochemical treatment of carwash wastewater using Fe and Al electrode: Techno-economic analysis and sludge characterization.

The present study was conducted to investigate the electrochemical treatment of carwash wastewater using electrocoagulation (EC) process with Fe and Al electrodes. The effects of operating conditions such as initial pH (2-10), current density (0.1-5 mA/cm2) and operating time (5-50 min) on chemical oxygen demand (COD), oil-grease, chloride removal efficiencies as well as total operating costs were studied. The optimum conditions that achieve higher removal efficiencies were found as pH: 8, current density: 3 mA/cm2, operating time: 30 min for Fe electrode and pH: 6, current density: 1 mA/cm2, operating time: 30 min for Al electrode. The removal efficiencies for COD, oil-grease and chloride were obtained as 88%, 90% and 50% for Fe and 88%, 68% and 33% for Al electrodes under the optimum conditions. The total operating costs at the optimum conditions were calculated as 0.6 $/m3 and 0.3 $/m3 for Fe and Al electrodes, respectively. The sludge samples generated after EC process were characterized with Fourier transform infrared (FTIR) spectroscopy and zeta potential measurements for both electrodes. The analyses showed the presence of hydroxides and oxyhydroxides in the sludge samples and the surface of the sludge samples was negatively charged in the wide range of pH. As a conclusion, this study revealed that EC process using Fe electrode should be a feasible technology for higher COD and oil-grease removals from carwash wastewaters.

Characterization and toxicity of hospital wastewaters in Turkey.

The aim of the study was to present first preliminary characterization of Turkish hospital wastewaters, their environmental risk, and a method for toxicity assessment. The hospital wastewater samples were collected from two of the largest medical faculty hospitals and a training and research hospital in Istanbul, Turkey. The samples from the selected hospitals were taken as grab samples on March 2014. Overall, 55 substances including pharmaceuticals and their metabolites, pesticides, and corrosion inhibitors were analyzed in all hospital wastewaters. Analysis of toxicity and the antibiotic resistance bacteria were investigated in addition to the chemical analysis in the wastewater of one hospital. Hazard quotients (HQs) and toxic units (TUs) were calculated as basis of the environmental risk assessment. Fourteen pharmaceuticals in hospital wastewater (HWW) were classified as "high risk" with HQ > 10. HQHWW values higher than 100 were determined for five antibiotics and one analgesic, namely, ofloxacin, clarithromycin, ciprofloxacin, sulfapyridine, trimethoprim, and diclofenac. Ofloxacin with an HQHWW of 9090 was observed to be the most hazardous compound. HQ and TU values of the wastewater treatment plant (WWTP) effluent dropped significantly due to dilution in the sewer. Further elimination by biological degradation or adsorption was observed only in some cases. However, the decreased HQWWTPeffluent values do not the change environmental load significantly. Therefore, advanced treatment processes should be applied to remove the persistent compounds. In combination with the results on antibiotic resistance, we would prefer on-site treatment of hospital wastewater. Toxicological assessment was performed using cytotoxic and mutagenic screening tests. The results of the Ames assay showed that the native hospital wastewaters had strongly mutagenic activity with a ≤10-fold increase relative to negative controls. The mutagenic potentials of the samples were generally concentration and metabolic activation dependent. Multiple antibiotic resistances were demonstrated with the tested isolates to ciprofloxacin, trimethoprim, and ceftazidime. This study demonstrates that the hospital wastewaters in Istanbul exhibit strong environmental and toxicological risks, as well as high multiple drug resistance to commonly used antibiotics.

Improving the performance of an aerobic membrane bioreactor (MBR) treating pharmaceutical wastewater with powdered activated carbon (PAC) addition.

In this study, the effects of organic loading rate (OLR) and the addition of powdered activated carbon (PAC) on the performance and membrane fouling of MBR were conducted to treat real pharmaceutical process wastewater. Over 145 days of operation, the MBR system was operated at OLRs ranging from 1 to 2 kg COD m(-3) day(-1) without sludge wasting. The addition of PAC provided an improvement in the flux, despite an increase in the OLR:PAC ratio. The results demonstrated that the hybrid PAC-MBR system maintained a reduced amount of membrane fouling and steadily increased the removal performance of etodolac. PAC addition reduced the deposition of extracellular polymeric substance and organic matter on the membrane surface and resulted an increase in COD removal even at higher OLRs with low PAC addition. Membrane fouling mechanisms were investigated using combined adsorption fouling models. Modified fouling index values and normalized mass transfer coefficient values indicated that predominant fouling mechanism was cake adsorption.

Column studies for the adsorption of cationic surfactant onto an organic polymer resin and a granular activated carbon.

Adsorption beds containing granular activated carbon and organic polymer resin are used widely to remove organic pollutants from wastewaters and water streams. Adsorption polymers are becoming alternatives to activated carbon for removal of surfactants by adsorption techniques. This study investigated the adsorption characteristics of cetyl trimethylammonium bromide (CTAB) as a cationic surfactant for selected concentrations below and above critical micelle concentration (CMC). A series of column tests were performed to determine the breakthrough curves by using two different adsorbents: (1) Hydraffin CC 8 x 30 as a commercial granular activated carbon (GAC) and (2) Lewatit VPOC 1064 MD PH as a commercial organic polymer resin. In the experiments, the volumetric flow rate was maintained at 10.5 mL/min (approximately 2 m3/ m2 x h). Loading of adsorbents was continued until breakthrough was 10% of the feed concentration. The breakthrough took place at 488 bed volume (BV) below CMC (C0 = 40 mg/L) and 39 BV above CMC (C0 = 400 mg/ L) onto GAC. The organic polymer resin, however, showed a higher adsorption capacity than GAC (1412 BV below CMC and 287 BV above CMC). From the Logit method, the value of adsorption rate coefficient (K) and adsorption capacity coefficient (N) were obtained.