Hospital Wastewater Treatment Plant Research Articles

Assessment of Pharmaceuticals, Personal Care Products, and Hormones in Wastewater Treatment Plants Receiving Inflows from Health Facilities in North West Province, South Africa.

The presence of 17 pharmaceutical and personal care products (PPCPs) belonging to various therapeutic categories was investigated in two hospital wastewater treatment plants (WWTPs) in North West Province, South Africa. The compounds were extracted from wastewater samples by solid-phase extraction and analysed by liquid chromatography-tandem mass spectrometry. The results showed that ofloxacin, chloramphenicol, and bezafibrate were generally below the limit of quantification (LOQ) in the analysed samples. Acetaminophen and ibuprofen were the dominant pharmaceuticals in the influent streams with corresponding concentrations ranging from 21 to 119 μg/L and 0.3 to 63 μg/L, respectively. Both WWTPs were shown to have the capability to remove some of the target PPCPs, including acetaminophen (76-98%), tetracycline (15-93%), ibuprofen (44-99%), and triclocarban (13-98%). The monitoring of the target PPCPs in both influent and effluent samples of the investigated WWTPs revealed that the discharge of inadequately treated effluents could be contributing to the possible increase in the concentrations of these contaminants in the receiving environmental compartments. Further studies must be focused on the broader characterisation of these matrices in order to assess the potential ecological impacts of this waste disposal practice.

Evaluation of psychiatric hospital wastewater toxicity: what is its impact on aquatic organisms?

The primary source of pharmaceuticals to the aquatic environment is the discharge of wastewater effluents. Pharmaceuticals are a large and diverse group of compounds. Among them, psychotropic substances are particularly interesting to study due to their specific known mode of action. The present study was performed to investigate the effects of wastewater effluents from a psychiatric hospital wastewater treatment plant (WWTP) on several aquatic organisms. All the analyzed pharmaceuticals (10 compounds) were detected in WWTP effluents as well as in the receiving river. Although the environmental concentrations were generally at trace levels (ngL-1 to μgL-1), induce toxic effects were observed. This study showed the effects of the WWTP effluents on the oogenesis and/or embryogenesis of amphipod crustacean Gammarus fossarum, Japanese fish medaka Oryzias latipes, mollusk Radix peregra, and planarian Schmidtea polychroa. A decrease of the number of oocytes and produced embryos was observed for G. fossarum and S. polychroa. Similarly, the hatching rate of R. peregra was affected by effluents. In the receiving river, the macroinvertebrate community was affected by the wastewater effluents discharge.

Occurrence and distribution of carbamazepine, nicotine, estrogenic compounds, and their transformation products in wastewater from various treatment plants and the aquatic environment

The concentrations and fates of carbamazepine and metabolites (CBMs), nicotine and metabolites (NCTs), estrogenic compounds and metabolites (Es) in various water samples were investigated. Different concentrations were found for water from different sources. The concentrations of these pharmaceuticals and personal care products and their metabolites in human waste treatment plant (HTP) influents (0.08–173 μg L−1) were higher than in the other influent samples and the lowest levels were observed in hospital wastewater treatment plant influents (0.03–7.33 μg L−1). The concentrations were higher in HTP effluents (0.01–11.2 μg L−1) than in the other effluent samples and lowest in sewage treatment plant effluents (0.003–1.26 μg L−1). The NCTs were the most frequently detected pharmaceuticals and personal care products (concentration range 0.05–89.6 μg L−1) in the wastewater treatment plant influents, but the CBMs were found at the highest concentrations (0.003–6.88 μg L−1). 10, 11-Dihydro-10, 11-dihydroxycarbamazepine was the most abundant of the CBMs in the wastewater treatment plants and water samples. Trans-3′-hydroxycotinine was dominant in the HTP and hospital wastewater treatment plant influents, whereas the parent NCT was dominant in the sewage treatment plant influents and in all the effluent and other water samples. Estriol was the dominant estrogenic compound in the HTP and hospital wastewater treatment plant influents. Estriol and estrone were found in many of the HTP influents, but estrone was dominant in the effluent and other water samples. The total removal efficiencies for the CBMs, NCTs, and estrogenic compounds for the treatment plants were −101% to 56%, 2.9%–99%, and >98%, respectively.

Perfil de resistência aos antibióticos e prevalência dos genes qacEΔ1 e sul1 em Pseudomonas aeruginosa de efluente hospitalar

Introduction: Hospital effluents may pose great environmental risk due to the presence of pathogenic microorganisms, drugs and chemical components. Pseudomonas aeruginosa is an opportunistic pathogen frequently found in hospital environment. Objective: To evaluate the resistome of P. aeruginosa from the hospital wastewater treatment plant (HWTP) in a hospital complex of Rio de Janeiro city. Method: Twenty isolates from the five stages of the HWTP were identified as P. aeruginosa by 16S rRNA gene sequencing analysis. Susceptibility to antibiotics was determined according to CLSI and qacEΔ1 and sul1 genes were detected by PCR. Sulphonamide residues were investigated by high performance liquid chromatography coupled to sequential mass spectrometry. Results: The sulfamethoxazole has been demonstrated at a level below 50 ng L-1. Sulfonamide resistance (80%) has been demonstrated followed by quinolone class (50%) and 13 susceptibility patterns to antimicrobials. The qacEΔ1-sul1 genes were detected in 100% of isolates suggesting the presence of class 1 integrons in the whole HWTP. Conclusions: The results signalized limitations of HWTP and propagation of resistance genes in all stages of the HWTP. These data also contribute to the environmental sanitary surveillance in the design of prevention actions against negative impact on the public health.

Occurrence, distribution, and potential sources of antibiotics pollution in the water-sediment of the northern coastline of the Persian Gulf, Iran

Occurrence and frequency of six most prescribed antibiotics (tetracycline, norfloxacin, azithromycin, anhydro erythromycin, cephalexin, and amoxicillin) were assessed in three wastewater treatment plants (WWTPs), and in water and sediments of the Persian Gulf at Bushehr coastline, Iran. The antibiotics concentration in the influent and effluent of septic tank (the hospital WWTP), activated sludge (the hospital WWTP), and stabilization pond (municipal WWTP) ranged between 7.89 and 149.63, 13.49–198.47, 6.55–16.37 ng/L, respectively. Conventional treatment resulted in incomplete removal of most of the studied antibiotics. Furthermore, the activated sludge was more effective in terms of antibiotic elimination compared to the stabilization pond or septic tank. The mean concentration of antibiotics ranged 1.21–51.50 ng/L in seawater and 1.40–25.32 ng/g in sediments during summer and winter. Norfloxacin was the dominant detected antibiotic in seawater, sediments, and influent of two hospital WWTPs. Seasonal comparisons showed significant differences for erythromycin and amoxicillin concentrations in seawater. Spatial variation indicated the role of physicochemical properties on distribution of antibiotics in seawater and sediments. The results emphasize the need to pay attention to antibiotic contamination in water and sediments of the Persian Gulf.

Comprehensive analysis of antagonistic endocrine activity during ozone treatment of hospital wastewater

To reduce the discharge of micropollutants, advanced wastewater treatment methods were investigated in the last years. Estrogenic effects were found to be reduced by ozonation. These activities are usually measured using genetically modified cell-based tests. As these bioassays are representing a sum parameter, also inhibitory effects such as antagonistic effects need to be further investigated as they are potentially reducing the detected activities. Therefore, a direct comparison of chemical target analysis and biological equivalent concentrations measured by bioassays is often difficult. To investigate the fate of antagonistic activities and their role in mixtures with agonistic activities, two hospital wastewater treatment plants were studied after different treatment steps. Thereby highly enriched samples were analyzed by a combination of bioassays with chemical target and non-target analyses. In order to achieve an in-depth characterization of the antagonistic activities a fractionation of the enriched samples was performed. To identify relevant compounds an effect directed identification approach was used by combining high-resolution mass spectrometry and bioassays. The results showed a high reduction for estrogene and androgene activities. However, a constant antagonistic activity after membrane bioreactor and ozone treatment was observed. A reduction of the antagonistic activity was observed after passing an activated carbon filter. The fractionation approach showed a specific finger-print of each sample of the different treatment steps. Hereby we could show that the composition of agonistic and antagonistic active compounds is changing after each treatment step while the overall measured activity stays the same. Using fractionation and the combination of bioassays the number of relevant features detected by chemical non-target screening could be reduced by >85%. As a result the phosphorous flame retardant TCEP could be identified as anti-estrogene active. Future research should be done to identify more antagonistic active compounds and potentially active transformation products after ozone treatment.

Electrochemical oxidation of key pharmaceuticals using a boron doped diamond electrode

Abstract This study assesses the degradation by electrochemical oxidation via boron doped diamond (BDD) electrodes of the selected pharmaceutical compounds iopromide (IOP), sulfamethoxazole (SMX), 17-alpha-ethinylestradiol (EE2) and diclofenac (DCF) in simulated wastewater and real hospital effluent wastewater. The influence of the flow rate in the electrochemical cell, applied current, initial compound concentration and wastewater matrix (simulated (SWW) versus real effluent (RWW) wastewater) was evaluated. A kinetic evaluation confirmed that the degradation can be described via pseudo first-order reaction kinetics for all experimental conditions tested. It was shown that SMX, EE2 and DCF degraded readily in SWW and RWW. The degradation of IOP was significantly slower, which is in agreement with previously reported slow degradation kinetics using typical advanced oxidation processes. Activation energies for the degradation reactions were calculated. The flow rate in the electrochemical cell had only a moderate effect on the degradation rate of EE2 and DCF. The applied current, however, had a major effect. The BDD electrochemical oxidation was shown to be an effective technique for removing pharmaceutical components from the effluent of a biological hospital wastewater treatment plant. However, the slower degradation of transformation products should be taken into account, when a full mineralization of the pharmaceuticals is pursued.

The occurrence, fate, and distribution of natural and synthetic hormones in different types of wastewater treatment plants in Iran

Abstract Over the past few years, the presence of steroid estrogens in the environment has become a major concern. In this study, the concentrations of estrone (E1), 17β-estradiol (E2), and 17α-ethinyl estradiol (EE2) were measured in some wastewater treatment plants (WWTPs) in Iran. These samples were collected from the municipal, rural, livestock, commercial, and hospital WWTPs, extracted by dispersive liquid–liquid micro extraction (DLLME) technique, derivatized, and detected by GC/MS. In these treatment plants, various processes including conventional activated sludge (CAS), aerated lagoon (AL), moving bed biofilm reactor (MBBR), and activated sludge with wetland (AS + WL) are used. The highest concentration of hormones was observed in the influents and effluents of livestock, municipal, commercial, and hospital WWTPs, respectively. The maximum elimination rate was obtained in MBBR followed by AS + WL, CAS and AL. The biodegradation and adsorption rates along with adsorption coefficients of log k d and log k oc were measured for all target compounds.

Two-year survey of specific hospital wastewater treatment and its impact on pharmaceutical discharges.

It is well known that pharmaceuticals are not completely removed by conventional activated sludge wastewater treatment plants. Hospital effluents are of major concern, as they present high concentrations of pharmaceutically active compounds. Despite this, these specific effluents are usually co-treated with domestic wastewaters. Separate treatment has been recommended. However, there is a lack of information concerning the efficiency of separate hospital wastewater treatment by activated sludge, especially on the removal of pharmaceuticals. In this context, this article presents the results of a 2-year monitoring of conventional parameters, surfactants, gadolinium, and 13 pharmaceuticals on the specific study site SIPIBEL. This site allows the characterization of urban and hospital wastewaters and their separate treatment using the same process. Flow proportional sampling, solid-phase extraction, and liquid chromatography coupled with tandem mass spectrometry were used in order to obtain accurate data and limits of quantification consistent with ultra-trace detection. Thanks to these consolidated data, an in-depth characterization of urban and hospital wastewaters was realized, as well as a comparison of treatment efficiency between both effluents. Higher concentrations of organic carbon, AOX, phosphates, gadolinium, paracetamol, ketoprofen, and antibiotics were observed in hospital wastewaters compared to urban wastewaters. Globally higher removals were observed in the hospital wastewater treatment plant, and some parameters were shown to be of high importance regarding removal efficiencies: hydraulic retention time, redox conditions, and ambient temperature. Eleven pharmaceuticals were still quantified at relevant concentrations in hospital and urban wastewaters after treatment (e.g., up to 1μg/L for sulfamethoxazole). However, as the urban flow was about 37 times higher than the hospital flow, the hospital contribution appeared relatively low compared to domestic discharges. Thanks to the SIPIBEL site, data obtained from this 2-year program are useful to evaluate the relevance of separate hospital wastewater treatment.

Antibiotic Resistance and Antibiotic Resistance Genes in Escherichia coli Isolates from Hospital Wastewater in Vietnam.

The environmental spread of antibiotic-resistant bacteria has been recognised as a growing public health threat for which hospitals play a significant role. The aims of this study were to investigate the prevalence of antibiotic resistance and antibiotic resistance genes (ARGs) in Escherichia coli isolates from hospital wastewater in Vietnam. Wastewater samples before and after treatment were collected using continuous sampling every month over a year. Standard disk diffusion and E-test were used for antibiotic susceptibility testing. Extended-spectrum beta-lactamase (ESBL) production was tested using combined disk diffusion. ARGs were detected by polymerase chain reactions. Resistance to at least one antibiotic was detected in 83% of isolates; multidrug resistance was found in 32%. The highest resistance prevalence was found for co-trimoxazole (70%) and the lowest for imipenem (1%). Forty-three percent of isolates were ESBL-producing, with the blaTEM gene being more common than blaCTX-M. Co-harbouring of the blaCTX-M, blaTEM and qepA genes was found in 46% of isolates resistant to ciprofloxacin. The large presence of antibiotic-resistant E. coli isolates combined with ARGs in hospital wastewater, even post-treatment, poses a threat to public health. It highlights the need to develop effective processes for hospital wastewater treatment plants to eliminate antibiotic resistant bacteria and ARGs.

Determination of 4-nonylphenol and 4- tert -octylphenol compounds in various types of wastewater and their removal rates in different treatment processes in nine wastewater treatment plants of Iran

Abstract Alkylphenols (APs), considered as xenoestrogenic compounds, mainly exist as 4-nonylphenol (4-NP) and 4- tert -octylphenol (4- t -OP) in environments. The high stability and accumulation of APs in aquatic systems have caused endocrine disruption. In this study we measured APs in the wastewater influent and effluent samples, from the urban, rural, livestock, commercial and hospital wastewater treatment plants (WWTPs) in Iran. Dispersive liquid–liquid microextraction (DLLME) combined with gas chromatography–mass spectrometry (GC–MS) was used for the extraction and determination of 4-NP and 4- t -OP. In these treatment plants, various processes such as activated sludge, aerated lagoon, moving bed biofilm reactor and activated sludge along with wetland were applied. The highest concentration of 4-NP and 4- t -OP was observed in commercial and livestock sewages. The activated sludge along with wetland and then the MBBR process showed the highest removal rates of pollutants. The rates of biodegradability and accumulation in sludge were determined and also the specific adsorption coefficient K d and the organic carbon–water partition coefficient k OC of the sludge for APs were calculated.

Assessment of airborne bacteria and noroviruses in air emission from a new highly-advanced hospital wastewater treatment plant

Exposure to bioaerosols can pose a health risk to workers at wastewater treatment plants (WWTPs) and to habitants of their surroundings. The main objective of this study was to examine the presence of harmful microorganisms in the air emission from a new type of hospital WWTP employing advanced wastewater treatment technologies. Air particle measurements and sampling of inhalable bacteria, endotoxin and noroviruses (NoVs) were performed indoor at the WWTP and outside at the WWTP ventilation air exhaust, downwind of the air exhaust, and upwind of the WWTP. No significant differences were seen in particle and endotoxin concentrations between locations. Bacterial concentrations were comparable or significantly lower in the exhaust air than inside the WWTP and in the upwind reference. Bacterial isolates were identified using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. In total, 35 different bacterial genera and 64 bacterial species were identified in the air samples. Significantly higher genus and species richness was found with an Andersen Cascade Impactor compared with filter-based sampling. No pathogenic bacteria were found in the exhaust air. Streptomyces was the only bacterium found in the air both inside the WWTP and at the air emission, but not in the upwind reference. NoV genomes were detected in the air inside the WWTP and at the air exhaust, albeit in low concentrations. As only traces of NoV genomes could be detected in the exhaust air they are unlikely to pose a health risk to surroundings. Hence, we assess the risk of airborne exposure to pathogenic bacteria and NoVs from the WWTP air emission to surroundings to be negligible. However, as a slightly higher NoV concentration was detected inside the WWTP, we cannot exclude the possibility that exposure to airborne NoVs can pose a health risk to susceptible to workers inside the WWTP, although the risk may be low.

Determination of Ketorolac in the Effluent from a Hospital Treating Plant and Kinetics Study of Its Photolytic Degradation

In this work, two specific, sensitive, and rapid analytical methods were developed. One of them was for the determination of ketorolac in a hospital wastewater treatment plant where there is no interference with other organic substances; the other one was for the determination of the degradation kinetics in aqueous medium. Ketorolac was extracted from wastewater samples through solid-phase extraction (SPE) cartridges, then it was identified and quantified by high-performance liquid chromatography (HPLC). Ketorolac was detected in concentrations between 0.1376 and 0.2667 μg/L. Photolytic degradation was performed on aqueous solutions of ketorolac tromethamine reference substance, at a concentration of 50 μg/mL. Samples were in direct contact with ultraviolet light in a dark chamber, equipped with two mercury lamps (254 nm) at a radiation source of 15 W. The results of the photolytic degradation were adjusted to a first-order model, obtaining a half-life of 4.8 hrs.

Removal of bacterial cells, antibiotic resistance genes and integrase genes by on-site hospital wastewater treatment plants: surveillance of treated hospital effluent quality

This study aims to evaluate the removal efficiency of microbial contaminants by wastewater treatment plants (WWTPs) operated on-site of two hospitals.

Prevalence and Removal Efficiency of Enterococcal Species and Vancomycin-resistant Enterococci of a Hospital Wastewater Treatment Plant

Simultaneous presence of various antibiotics and bacteria in hospital wastewaters creates a suitable environment, in which the bacteria, such as enterococci become resistant to the antibiotics. The aim of this study was to evaluate the performance of different units of the hospital wastewater treatment plant (HWTP) to remove Enterococcus spp and Vancomycin-resistant Enterococcus (VRE). The study was performed on the 27 samples collected from HWTP in Hamedan, Iran during December 2014 to August 2015. Enterococcus spp and VRE were identified by biochemical tests and then the isolates were confirmed by PCR. Finally, the antibiotic susceptibility test was performed using disk diffusion methods. Of the 27 samples examined, 315 a total of enterococcal isolates were obtained. Of the 315 isolates of enterococci investigated, 162 (51.42%) were identified as E. faecium, 87 (27.61%) as E. hirae, 35 (11.11%) as E. faecalis, 11 (3.5%) as E. gallinarum, 7 (2.22%) as E. casseliflavus, 4 (1.26%) E. avium, and 9 (2.85%) isolates VR E. faecium.The results of antibiotic susceptibility testing showed that of the total 315 isolates, 146 (46.34%) were resistance to tetracycline, 9 (2.85%) were resistance to vancomycin and Teicoplanin. Lower antibiotic resistance was seen with Nitrofurantoin 2 (1.26%). This study indicates a high prevalence of multidrug resistance among E. faecium isolated from HWTP, thus, it could be considered as a threat to the health and safety of wastewater workers and even public health.

Prevalence and Removal Efficiency of Enterococcal Species and Vancomycin-resistant Enterococci of a Hospital Wastewater Treatment Plant

Prevalence and Removal Efficiency of Enterococcal Species and Vancomycin-resistant Enterococci of a Hospital Wastewater Treatment Plant

Bacterial Communities and Antibiotic Resistance Communities in a Full-Scale Hospital Wastewater Treatment Plant by High-Throughput Pyrosequencing

The community of whole microbes and antibiotic resistance bacteria (ARB) in hospital wastewater treatment plants (WWTP) receiving domestic wastewater (DWW) and hospital wastewater (HWW) was investigated. Samples from an influent of a secondary clarifier, at each treatment train, were characterized for the whole microbial community and ARB on the antibiotic resistance database, based on high-throughput pyrosequencing. The pyrosequencing analysis revealed that the abundance of Bacteroidetes in the DWW sample was higher (~1.6 times) than in the HWW sample, whereas the abundance of Proteobacteria in the HWW sample was greater than in the DWW sample. At the top twenty of the genus level, distinct genera were observed—Saprospiraceae in the DWW and Zoogloea in the HWW. Apart from the top twenty genera, minor genera showed various antibiotic resistance types based on the antibiotic resistance gene database.

Determination of antipsychotic drugs in hospital and wastewater treatment plant samples by gas chromatography/tandem mass spectrometry.

The development and performance evaluation of a method for the simultaneous determination of six antipsychotic drugs in hospital effluents and wastewater treatment plants (WWTP) samples are herein presented. The method involves an off-line mixed mode (reversed-phase and strong cation exchange) solid phase extraction (SPE) with gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS). The present methodology was validated following internationally accepted criteria, and the studied parameters included selectivity, linearity, limits of detection (LOD) and quantitation (LLOQ), instrumental limits, precision and accuracy, stability and recovery. The procedure was linear for concentrations ranging from 0.1 to 10μg/L (0.02 to 2μg/L for haloperidol), with determination coefficients higher than 0.99 for all analytes. Intra- and inter-day precision was lower than 15% for all analytes at the studied concentrations, while accuracy remained between a ±15% interval. Recoveries ranged from 31% to 83%. Low LODs were achieved, between 2 and 10ng/L, allowing a reliable identification of all analytes at trace levels, using only 50mL as sample volume. All studied parameters complied with the defined criteria and the method was successfully applied to gather preliminary results of the determination of antipsychotics on hospital effluents and on influent and effluent of WWTPs, opening perspectives for the study of their fate in the aquatic environment.

Study of Operational and Maintenance Problems and Parameters of Extended Aeration Activated Sludge Process in Golestan Hospital Wastewater Treatment Plant, Ahvaz, and Their Solutions

Background:Hospital wastewater is among hazardous wastewater due to its composition of pathogens and toxic chemicals. Discharge of untreated hospital wastewater to environment is hazardous for human and environment. Aims of this study were to identify Operational and Maintenance problems of Extended Aeration Activated sludge process in Golestan Hospital wastewater treatment plant (WTP), Ahwaz, Iran, and to find their solutions. n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n Materials and Methods:Sampling period was 6 months of 2015. BOD5, COD, and TSS parameters analysed in the hospital WTP effluent. In addition, VLR, Qr/Q, MLSS, F/M, SVI, HRT, and tc parameters measured in aeration tank, then operational and maintenance parameters calculated. n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n Results:Results shown that average of operation & maintenance parameters were: F/M = 0.35, HRT = 6 hour, Qr/Q = 64.28 , VLR = 1.1 Kg BOD/m3.d, MLSS = 2819.36 mg/l, SVI = 144.89 ml/g, tc = 10.93 days. n n n n n n n n n n n n n n n n n n n n n n n n n n n Conclusion:Results of operational and maintenance parameters shown that biological process behavior of the hospital WTP was Extended Aeration Activated Sludge in past years, but converted to conventional activated sludge process due to increase in hospital beds of clinical and out patients departments , which increased water consumption lead to increase wastewater flow rate. High flow rate lead to increase hydraulic load and diluting organic matter load, so hydraulic retention time and sludge age decreased.

Multidrug resistant Pseudomonas aeruginosa survey in a stream receiving effluents from ineffective wastewater hospital plants.

BackgroundMulti-drug resistant forms of Pseudomonas aeruginosa (MDRPA) are a major source of nosocomial infections and when discharged into streams and rivers from hospital wastewater treatment plants (HWWTP) they are known to be able to persist for extended periods. In the city of Manaus (Western Brazilian Amazon), the effluent of three HWWTPs feed into the urban Mindu stream which crosses the city from its rainforest source before draining into the Rio Negro. The stream is routinely used by Manaus residents for bathing and cleaning (of clothes as well as domestic utensils) and, during periods of flooding, can contaminate wells used for drinking water.Results16S rRNA metagenomic sequence analysis of 293 cloned PCR fragments, detected an abundance of Pseudomonas aeruginosa (P. aeruginosa) at the stream’s Rio Negro drainage site, but failed to detect it at the stream’s source. An array of antimicrobial resistance profiles and resistance to all 14 tested antimicrobials was detected among P. aeruginosa cultures prepared from wastewater samples taken from water entering and being discharged from a Manaus HWWTP. Just one P. aeruginosa antimicrobial resistance profile, however, was detected from cultures made from Mindu stream isolates. Comparisons made between P. aeruginosa isolates’ genomic DNA restriction enzyme digest fingerprints, failed to determine if any of the P. aeruginosa found in the Mindu stream were of HWWTP origin, but suggested that Mindu stream P. aeruginosa are from diverse origins. Culturing experiments also showed that P. aeruginosa biofilm formation and the extent of biofilm formation produced were both significantly higher in multi drug resistant forms of P. aeruginosa.ConclusionsOur results show that a diverse range of MDRPA are being discharged in an urban stream from a HWWTP in Manaus and that P. aeruginosa strains with ampicillin and amikacin can persist well within it.