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| 2. |
- Jarnheimer, Per-åke, et al.
(author)
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Fluoroquinolone Antibiotics in a Hospital Sewage Line; Occurrence, Distribution and Impact on Bacterial Resistance
- 2004
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In: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 36:10, s. 752-5
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Journal article (peer-reviewed)abstract
- In hospital sewage lines, human faecal bacteria are exposed to antibiotics, posing a risk for selection of antibiotic resistant microorganisms. We constructed a system for continuous sampling in a hospital sewage line that allowed us to study longitudinal establishment of bacteria, concentrations of antibiotics, and selection of bacterial resistance in waste water, sediment and biofilm. The focus in this study was on fluoroquinolones, a widely used group of antibiotics with increasing resistance problems. We found low levels of ciprofloxacin and ofloxacin in waste water but high concentrations in sediment. Despite the high levels of fluoroquinolones bound to sediment, we did not find any development of resistance against fluoroquinolones in Enterobacteriacae spp. and faecal enterococci isolated from sediment.
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| 3. |
- Johannessen, Åse, et al.
(author)
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Strategies for building resilience to hazards in water, sanitation and hygiene (WASH) systems : the role of public private partnerships
- 2014
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In: International Journal of Disaster Risk Reduction. - : Elsevier BV. - 2212-4209. ; 10:part A, s. 102-115
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Journal article (peer-reviewed)abstract
- The aim of this paper is to enhance understanding of how the resilience of water, sanitation and hygiene (WASH) systems to hazards can be improved. In turn, this aims to inform different strategies for public and private partnerships (PPPs). In a new approach, to acknowledge the multi levelled nature of resilience; risk at the relevant levels are taken into account, (regional/river basin, urban area, and individual). For these levels, we first describe the different components of risk, vulnerability and resilience of the WASH system that influence people׳s exposure to hazards. We illustrate these components using examples from case studies in the literature. Using a social learning lens - a crucial ingredient of resilience - we examine opportunities for reducing risks through improving public–private engagement. These are presented as strategies which could guide investment decisions: As pressures from climate change and development add up, businesses must become aware of the risks involved in operating and investing without considering ecosystem health, both in terms of the services they provide for mitigating floods and droughts, as well as in terms of the development approaches that define how ecosystems are managed (e.g. “making space” for, rather than controlling water). There is a need to develop an institutional culture that strives towards greener and more resilient urban environments with the help of various quality assurance methods. Partnerships must reach the poorer customer base, encourage informal small entrepreneurs, and boost financial mechanisms (e.g. micro-insurance, micro-finance) to support the most vulnerable in society
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| 4. |
- Johannessen, Åse, et al.
(author)
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Transforming urban water governance through social (triple-loop) learning
- 2019
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In: Environmental Policy and Governance. - : Wiley. - 1756-932X .- 1756-9338. ; 29:2, s. 144-154
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Journal article (peer-reviewed)abstract
- The sustainable development of cities is threatened by a worldwide water crisis. Improved social learning is urgently needed to transform urban water governance and make it more integrated and adaptive. However, empirical studies remain few and fragmented. Therefore, the aim of this paper is to analyse how social learning has supported or inhibited sustainable transformations in urban water governance. On the basis of multiple case studies conducted in urban, flood-prone areas in Colombia, the Philippines, South Africa, India, and Sweden, we study learning processes related to different aspects of water management and governance. Our results show that transformations in water governance are often triggered by crises, whereas other potentials for transformation are not tapped into. Furthermore, learning is often inhibited by “lock-ins” created by powerful actors. We conclude that there is a need for more proactive design of governance structures for triple-loop learning that take into account the identified barriers and supporting principles.
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| 5. |
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| 6. |
- Ngubane, Zesizwe, et al.
(author)
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Multi-criteria decision analysis framework for engaging stakeholders in river pollution risk management
- 2024
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Journal article (peer-reviewed)abstract
- Water pollution presents a substantial environmental challenge with extensive implications for water resources, ecosystem sustainability, and human health. Using a South African catchment, this study aimed to provide watershed managers with a framework for selecting best management practices (BMPs) to reduce pollution and the related risk to river users, while also including the perspectives of key catchment stakeholders. The framework encompassed the identification of and consultation with key stakeholders within the catchment. A Multi-Criteria Decision Analysis (MCDA) methodology using the Simple Multi-Attribute Rating Technique for Enhanced Stakeholder Take-up (SMARTEST) was used to identify and prioritise suitable BMPs in a case study. Decision alternatives and assessment criteria as well as their weights were derived based on stakeholder responses to a two-stage survey. Stakeholders included those utilising the river for domestic and recreational purposes, municipal representatives, scientists, NGOs, and engineers. The assessment of decision alternatives considered environmental, economic, and social criteria. The aggregated scores for decision alternatives highlighted the significance of involving stakeholders throughout the decision process. This study recommends the pairing of structural and non-structural BMPs. The findings provide valuable insights for catchment managers, policymakers, and environmental stakeholders seeking inclusive and effective pollution mitigation strategies in a catchment.
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| 7. |
- Ngubane, Zesizwe, et al.
(author)
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Quantitative assessment of human health risks from chemical pollution in the uMsunduzi River, South Africa
- 2023
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In: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 30:55, s. 118013-118024
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Journal article (peer-reviewed)abstract
- A quantitative chemical risk assessment was performed using published data as well as data from the official monitoring programme for the uMsunduzi River in KwaZulu-Natal, South Africa. The chemicals assessed were organochlorinated pesticides (OCPs), pharmaceuticals and personal care products (PPCPs), heavy metals, and nitrates and phosphates. The water from uMsunduzi River is used locally without treatment. Consequently, the exposure routes investigated were via ingestion during domestic drinking and incidental ingestion during recreational activities, which were swimming and non-competitive canoeing, for both adults and children. For the individual chemicals, non-carcinogenic risks using the hazard quotient (HQ) and carcinogenic risks using the cancer risk (CR) were quantified. It was found that the exposed population is likely to experience non-carcinogenic effects from pesticides and phosphates, but not from PPCPs, heavy metals and nitrates. This study also found that the carcinogenic risks for OCPs were higher than the tolerable limit of 10-5, while for lead the risk was below the tolerable limit. Some of the activities that potentially contribute to chemicals onto the uMsunduzi River are subsistence farming, small plantations, illegal dumping, industries, and broken sewers. The findings of this study may act as the technical foundation for the introduction of pollution reduction measures within the catchment, including public education.
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| 8. |
- Ottoson, Jakob, et al.
(author)
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A longitudinal study of antimicrobial resistant faecal bacteria in sediments collected from a hospital wastewater system
- 2012
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In: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 2, s. 7438-
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Journal article (peer-reviewed)abstract
- Objective:The objective with this study was to determine and follow antimicrobial resistance in faecal bacteria over time in hospital wastewater pipe sediment. A further aim was to determine bacterial growth rates of sensitive, intermediate and resistant intestinal enterococci in different ciprofloxacin concentrations as a measure of bacterial fitness.Methods:A system enabling the collection of settled particles over time was installed at Kalmar County Hospital. Samples were collected bi-monthly for a 14-month period. Coliform bacteria and enterococci were isolated from the sediment with standard methods and investigated for resistance to ciprofloxacin (CIP), imipenem (IMI), trimetroprim-sulfamethoxazole (TS), ampicillin (AMP) and vancomycin (VAN) by the disc diffusion method. Resistant isolates were further typed with the PhenePlateTM system. Growth assessments were performed with an automated spectrophotometer.Results:The rate of intestinal enterococci resistance was < 0.6, 1.3, 1.9 and 13% to VAN, IMI, AMP and CIP respectively. Coliform resistance frequencies were 1.1, 2.2 and 2.2% to CIP, IMI and TS respectively. At two sampling occasions, significantly higher rates of ciprofloxacin resistant enterococci were found and the establishment of a resistant clone in the sewer was indicated by the PhP-analysis. Ciprofloxacin resistant intestinal enterococci had a significantly longer lag-phase time than sensitive isolates, but from 500 µg ml-1 (half MIC) resistant isolates had a competitive advantage in terms of significantly faster generation time.Discussion:Despite high concentration of antimicrobials in the sediment, resistance frequencies were generally low. This can depend on limited growth possibilities for faecal bacteria. However, the establishment of a resistant clone shows that hospital sewers can serve as a reservoir for antibiotic resistant bacteria.
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| 9. |
- Ottoson, Jakob, et al.
(author)
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Faecal contamination of greywater and associated microbial risks
- 2003
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In: Water Research. - 0043-1354 .- 1879-2448. ; 37:3, s. 645-655
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Journal article (peer-reviewed)abstract
- The faecal contamination of greywater in a local treatment system at Vibyasen, north of Stockholm, Sweden was quantified using faecal indicator bacteria and chemical biomarkers. Bacterial indicator densities overestimated the faecal load by 100-1000-fold when compared to chemical biomarkers. Based on measured levels of coprostanol, the faecal load was estimated to be 0.04 g person(-1) day(-1). Prevalence of pathogens in the population and the faccal load were used to form the basis of a screening-level quantitative microbial risk assessment (QMRA) that was undertaken for rotavirus, Salmonella typhimurium, Campylobacter jejuni, Giardia lamblia and Cryptosporidium parvum. The different exposure scenarios simulated-direct contact, irrigation of sport fields and groundwater recharge-gave unacceptably high rotavirus risks (0.04
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| 10. |
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| 11. |
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| 12. |
- Schönning, Caroline, et al.
(author)
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Microbial risk assessment of local handling and reuse of human faeces
- 2007
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In: Journal of Water and Health. - : I W A Publishing. - 1477-8920 .- 1996-7829. ; 5:1, s. 117-128
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Journal article (peer-reviewed)abstract
- Dry urine-diverting toilets may be used in order to collect excreta for the utilisation of nutrients. A quantitative microbial risk assessment was conducted in order to evaluate the risks of transmission of infectious disease related to the local use of faeces as a fertiliser. The human exposures evaluated included accidental ingestion of small amounts of faeces, or a mixture of faeces and soil, while emptying the storage container and applying the material in the garden, during recreational stays to the garden, and during gardening. A range of pathogens representing various groups of microorganisms was considered. Results showed that 12-months' storage before use was sufficient for the inactivation of most pathogens to acceptable levels. When working or spending time in the garden the annual risk of infection by Ascaris was still slightly above 10-4 in these scenarios, although the incidence rate for Ascaris is very low in the population in question. Measures to further reduce the hygienic risks include longer storage, or treatment, of the faeces. The results can easily be extended to other regions with different incidence rates.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Westrell, Therese, et al.
(author)
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A theoretical approach to assess microbial risks due to failures in drinking water systems
- 2003
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In: International Journal of Environmental Health Research. - : Informa UK Limited. - 0960-3123 .- 1369-1619. ; 13:2, s. 181-197
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Journal article (peer-reviewed)abstract
- A failure in treatment or in the distribution network of a surface water-works could have serious consequences due to the variable raw water quality in combination with an extended distribution. The aim of this study was to examine the theoretical impact of incidents in the drinking water system on the annual risk of infection in a population served by a large water treatment plant in Sweden. Reported incidents in the system were examined and a microbial risk assessment that included three pathogens, Cryptosporidium parvum, rotavirus and Campylobacter jejuni, was performed. The main risk incidents in water treatment were associated with sub-optimal particle removal or disinfection malfunction. Incidents in the distribution network included cross-connections and microbial pollution of reservoirs and local networks. The majority of the annual infections were likely to be due to pathogens passing treatment during normal operation and not due to failures, thus adding to the endemic rate. Among the model organisms, rotavirus caused the largest number of infections. Decentralised water treatment with membranes was also considered in which failures upstream fine-pored membranes would have little impact as long as the membranes were kept intact.
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| 17. |
- Westrell, Therese, et al.
(author)
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Drinking water consumption patterns in Sweden
- 2006
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In: Journal of Water and Health. - 1477-8920. ; 4:4, s. 511-522
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Journal article (peer-reviewed)abstract
- Estimates on drinking water consumption are necessary in risk assessments on microbial hazardsin drinking water. Large differences in consumption habits between countries have beenreported. In order to establish estimates for the Swedish population, water consumption datafrom a waterborne outbreak investigation (157 people), a small water consumption study(75 people) and a large study on health and environmental factors (10,957 people) were analysed.A lognormal distribution for the daily direct/cold water intake in litres with m¼20.299 ands ¼ 0.570 was fitted to the quantitative data, representing the general population. The averagedaily consumption of tap water as plain drinking water and as heated tap water, e.g. in coffeeand tea, was 0.86 ^ 0.48 l and 0.94 ^ 0.69 l, respectively. Women consumed more cold tap waterthan did men, while men appeared to have a higher consumption of heated tap water. Cold tapwater intake was highest in the oldest age group, ($70 years). The consumption of bottled waterwas very low (mean 0.06 l/d) when compared to other countries.
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| 18. |
- Westrell, Therese
(author)
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Microbial risk assessment and its implications for risk management in urban water systems
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Infectious disease can be transmitted via various environmental pathways, many of which are incorporated into our water and wastewater systems. Quantitative microbial risk assessment (QMRA) can be a valuable tool in identifying hazard exposure pathways and estimating their associated health impacts. QMRA can be applied to establish standards and guidelines and has been adopted by the World Health Organisation for the management of risks from water-related infectious diseases. This thesis aims at presenting a holistic approach for the assessment of microbial health risks in urban water and wastewater systems. The procedure of QMRA is presented, together with the data collected for the case studies, and the results are discussed in a risk management framework.Decentralised drinking water treatment with membranes was shown to be competitive with centralised conventional treatment regarding environmental impacts and health. To attain sufficient die-off of pathogens in order to reduce risks to acceptable levels, facilities that permit the long-term storage of locally collected faeces are required. Issues of operation and mangement are likely to determine the health risks in decentralised systems. While failures in distribution are more likely to result in detectable waterborne disease outbreaks, the number of people at risk of becoming infected with pathogens passing normal treatment, calculated on a yearly basis, can be larger. Site-specific pathogen monitoring of source waters was identified as an important factor for the accurate estimation of risk. Noroviruses, an emerging waterborne pathogen, were shown to have fluctuating concentrations in surface water, with significant peaks during the wintertime. Time series analysis has potential as an early warning system if complemented by regular monitoring to discriminate peaks from random fluctuations. Groups already sensitive to infection, i.e. the elderly, the sick and children, were shown to consume higher volumes of cold tap water than the rest of the population, which may call for special atention in the risk management of drinking water systems. Microbial health risks associated with the handling and reuse of wastewater and sludge were shown to be successfully addressed within the management system Hazard Analysis and Critical Control Points (HACCP). Most exposure points identified could be controlled through easy measures.
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| 19. |
- Westrell, Therese, et al.
(author)
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Short- and long-term variations of norovirus concentrations in the Meuse river during a 2-year study period
- 2006
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In: Water Research. - : Elsevier BV. - 0043-1354. ; 40:14, s. 2613-2620
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Journal article (peer-reviewed)abstract
- Faecally impacted surface waters used for drinking water production may encompass risk for norovirus infections. To be able to assess a possible health risk, noroviruses should be quantified and fluctuations identified. In 2001, norovirus concentrations in the river Meuse displayed a seasonal distribution with high peaks during wintertime as determined by RT-PCR on serially diluted RNA. An intensified day-by-day sampling scheme in the winter of 2002/2003 revealed that the winter peak consisted of several peaks of varying duration and magnitude, possibly due to contamination events in the catchment. The highest estimated concentration was 1700 PCR-detectable units per litre (95% CI 250–8000), which if coinciding with failing treatment could lead to significant numbers in drinking water. Adaptive dynamic filtering was shown to adequately predict subsequent sample concentrations. If valid, such analyses could prove to be useful as early warning systems in risk management of water sources.
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| 20. |
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| 21. |
- Åström, Johan, 1977, et al.
(author)
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Evaluation of the microbial risk reduction due to selective closure of the raw water intake before drinking water treatment
- 2007
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In: Journal of Water and Health. - 1996-7829 .- 1477-8920. ; 5:1, s. 81-97
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Journal article (peer-reviewed)abstract
- Short-term peaks in pathogen concentrations may increase the risks for waterborne diseases considerably. In this study the occurrence of indicator organisms and pathogens in the river Göta älv at the raw water intake to Göteborg was evaluated and related to risk for drinking water consumption. About half of the 24 pathogen samples, taken during event and non-event conditions, were positive for at least one of the following: Cryptosporidium, Giardia, norovirus, enterovirus, Campylobacter and E. coli O157. Positive pathogen detects were often associated with heavy rainfalls and viruses with a sewage emergency discharge. The annualised probability of infection from this type of event was calculated from pathogen concentrations in a QMRA model. Given that the water intake is not closed, the risk given present water treatment seems to be acceptable for Giardia; however, it is at a borderline for Cryptosporidium and insufficient for noro- and enteroviruses. Present results emphasise the need for an appropriate intake regulation with respect to high pathogen loads, as the risk increases with time of exposure to pathogen contaminants. Rather than a threshold level on E. coli, reports on upstream microbial discharges are valuable for quick pathogen indications.
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| 22. |
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| 23. |
- Åström, Johan, 1977, et al.
(author)
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Identification and management of microbial contaminations in a surface drinking water source
- 2007
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In: Journal of Water and Health. - 1996-7829 .- 1477-8920. ; 5:1, s. 67-79
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Journal article (peer-reviewed)abstract
- Microbial contamination of surface waters constitutes a health risk for drinking water consumers which may be lowered by closing the raw water intake. We have evaluated microbial discharge events reported in the river Göta älv, which is used for raw water supply to the city of Göteborg. Elevated levels of faecal indicator bacteria were observed during periods of closed raw water intake. High bacteria levels were, however, also occasionally detected during periods of open intake, probably as a result of microbial discharge far upstream in the river which may be difficult to predict and manage by closing the intake. Accumulated upstream precipitations, resulting in surface runoff and wastewater contaminations in the catchment, correlated positively with the levels of total coliforms, E. coli, intestinal enterococci and sulfite-reducing clostridia. Levels of faecal indicator organisms were negatively correlated to the water temperature due to enhanced survival at lower temperatures. Wastewater discharges from a municipality located just upstream of the water intake resulted in elevated E. coli concentrations downstream at the raw water intake for Göteborg. To improve the prediction of microbial contaminations within the river Göta älv, monitoring data on turbidity and upstream precipitation are of particular importance.
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| 24. |
- Åström, Johan, 1977, et al.
(author)
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Variability analysis of pathogen and indicator loads from urban sewer systems along a river
- 2009
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In: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 59:2, s. 203-212
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Journal article (peer-reviewed)abstract
- The pathogen loads within surface waters originating from urban wastewater sources needs to be assessed to support drinking water risk estimations and optimal selection of risk reduction measures. Locally reported discharges from sewer systems (>100,000 persons connected) were used to simulate the potential microbial loads into the Gota alv river, Sweden. Using Monte Carlo simulations, the median and 95% percentile (i.e. worst case) of total microbial load from wastewater treatment plants, sewer network overflows and emergency discharges were assessed and presented for dry and wet weather conditions. Wastewater treatment plants with secondary treatment represented a major source of E. coli, norovirus, Giardia and Cryptosporidium. During wet weather, comparably high microbial loads were found for sewer overflows due to heavy rains. Substantial loads were also associated with an incident of the emergency discharge of untreated wastewater. Simulated river water concentrations of faecal indicators (E. coli, sulfite reducing clostridia, somatic coliphages) and pathogens (norovirus, Giardia, Cryptosporidium) were confirmed by river sampling data, suggesting that urban wastewater is the major microbial source for this river.
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| 25. |
- Åström, Johan, 1977, et al.
(author)
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Variability analysis of pathogen and indicator loads from urban wastewater systems along a river for drinking water risk estimations
- 2007
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In: Abstract, WaterMicro 2007. 14th International Symposium on Health-Related Water Microbiology. ; Extended abstract:P1036, s. 2-
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Conference paper (other academic/artistic)abstract
- BACKGROUND AND OBJECTIVESPathogens in source waters represent a health risk for drinking water consumers that may result in waterborne diseases, if not sufficiently removed within water treatment plants. According to the water safety plans in the WHO Drinking Water Guidelines (3rd ed.), identification and comparison of drinking water hazards within the catchment is of significant importance to accomplish effective risk management. In comparison to baseline concentrations significantly higher levels have been documented after heavy rainfalls (Kistemann et al. 2002; Signor et al. 2005) and a large number of waterborne outbreaks documented have been preceded by periods of heavy rainfalls (Rose et al. 2000; Curriero et al. 2001). Heavy rainfalls with wastewater discharges, in combination with treatment failures, resulted in the largest waterborne outbreak in Sweden in 1988. In this paper we have assessed the spatial and temporal distribution of wastewater discharges from urban areas along the river Göta älv used for drinking water supply to about 700 000 people including the city of Göteborg. The objectives were to assess the pathogen loads and variability by simulations of wastewater discharges from the urban sewage systems. The simulations have been compared with measured concentrations of pathogens and faecal indicator bacteria in the river.METHODSMicrobial point sources in municipal sewage systems along the river Göta älv, upstream the raw water intake to the city of Göteborg, were identified and quantified in relation to time and magnitude. Data on discharges of treated wastewater from wastewater treatment plants (WWTPs), as well as untreated wastewater from combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs), were collected, including onsite monitoring and urban wastewater modelling results. Literature data on the concentrations as well as the reduction of indicator bacteria (E. coli and spores of clostridia), Campylobacter, noroviruses, Giardia and Cryptosporidium within sewage systems were used. Through Monte Carlo simulations the daily microbial loads to the river were calculated using pathogen concentrations and discharge information from the wastewater systems for each single discharge point. Microbial loads were calculated for baseline conditions and for rain event conditions, based on a half year data period. Baseline conditions were defined as dry weather periods with discharges predominantly of treated wastewater. Rain event conditions were separately described for two wet weather periods, including discharges from CSOs and SSOs. Assuming a total mixing of wastewater pathogens discharged into the river, the downstream microbial concentration was approximated and compared to sampling data on indicator and pathogens from the river Göta älv for the same data period.RESULTSThe discharge volumes of treated wastewater varied highly between WWTPs along the river as a function of persons connected and the portion of stormwater within the system. CSOs as well as SSOs activated during wet weather periods increased the discharge volumes from the urban sewer systems. Daily loads simulated for the indicator bacteria as well as the pathogens were presented in figures, showing the contributions for the separate municipalities along the river. In general, the pathogen loads during baseline conditions were defined by the flow and the number of persons connected to each system, while the pathogen loads during rain conditions were additionally set by the degree of combined and sanitary sewer overflows. Downstream positive detections of norovirus were made during a wet weather period with multiple discharges of combined and sanitary sewer overflows registered along the river, confirming the simulated results. Overall, the river concentrations approximated by these simulations, were in the same range for the faecal indicator bacteria as compared to sampling data for the same period, but higher for the Campylobacter and slightly lower for norovirus, Giardia and Cryptosporidium. CONCLUSIONS AND SIGNIFICANCE OF THE WORK In this study, local flow and volume registrations were used to theoretically assess the pathogen load along a river used as a source for drinking water production. The range of pathogen loads from the urban areas, as well as the differences between dry and wet weather conditions, illustrates the potential variability of source water pathogen concentrations. This information may be used for assumptions on pathogen concentration, such as within quantitative microbial risk assessments. Present simulation results also suggest a first prioritization for reduction of microbial loads within urban wastewater systems along this river, such as the need for local additional wastewater treatment steps in order to bring down the spread of pathogens. This investigation is also a starting point to further investigate presently unquantified microbial sources, such as unregistered CSOs, SSOs and animal contaminations, as well as the microbial effects from sedimentation, die-off and the downstream microbial transport mechanisms in the river.
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