Estimating the risk from sewage treatment plant effluent in the Sydney catchment area

2011 ◽  
Vol 63 (8) ◽  
pp. 1707-1715 ◽  
Author(s):  
B. van den Akker ◽  
V. Whiffin ◽  
P. Cox ◽  
P. Beatson ◽  
N. J. Ashbolt ◽  
...  
Keyword(s):  
Catchment Area ◽  
Heavy Rainfall ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Tolerable Risk ◽  
Hazardous Event

This study employed Quantitative Microbial Risk Assessment (QMRA) to estimate the gastrointestinal risks associated with Cryptosporidium and Giardia discharged from three STPs located within the Lake Burragorang catchment. The QMRA considered baseline and various hazardous event scenarios (e.g. plant failure and heavy rainfall). Under baseline conditions, the combined effect of constructed barriers, catchment barriers and dilution reduced pathogen numbers from the discharge of all three STPs by 10 to 14 orders of magnitude. This was sufficient for the risk to be well below currently mooted benchmarks of ‘tolerable risk’, even when relatively conservative assumptions were applied. For all hazardous event scenarios, the level of risk remained low, which illustrated the benefit of multiple barriers. Provisionally it appears that the STPs currently discharging into the waterways of the catchment do not pose an unacceptable or unmanageable risk to Sydney's drinking water consumers.

scholarly journals Quantification of the health risk associated with wastewater reuse in Accra, Ghana: a contribution toward local guidelines

2008 ◽  
Vol 6 (4) ◽  
pp. 461-471 ◽  
Author(s):  
Razak Seidu ◽  
Arve Heistad ◽  
Philip Amoah ◽  
Pay Drechsel ◽  
Petter D. Jenssen ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Health Hazard ◽  
Wastewater Reuse ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Post Harvest ◽  
Pipe Water ◽  
Tolerable Risk ◽  
Rotavirus Infections

Quantitative Microbial Risk Assessment (QMRA) models with 10,000 Monte Carlo simulations were applied to ascertain the risks of rotavirus and Ascaris infections for farmers using different irrigation water qualities and consumers of lettuce irrigated with the different water qualities after allowing post-harvest handling. A tolerable risk (TR) of infection of 7.7 × 10−4 and 1 × 10−2 per person per year were used for rotavirus and Ascaris respectively. The risk of Ascaris infection was within a magnitude of 10−2 for farmers accidentally ingesting drain or stream irrigation water; ∼100 for farmers accidentally ingesting farm soil and 100 for farmers ingesting any of the irrigation waters and contaminated soil. There was a very low risk (10−5) of Ascaris infection for farmers using pipe−water. For consumers, the annual risks of Ascaris and rotavirus infections were 100 and 10−3 for drain and stream irrigated lettuce respectively with slight increases for rotavirus infections along the post-harvest handling chain. Pipe irrigated lettuce recorded a rotavirus infection of 10−4 with no changes due to post harvest handling. The assessment identified on-farm soil contamination as the most significant health hazard.

scholarly journals Preliminary Analysis of the Palic Ludas Catchment

Hadmérnök ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 202-212
Author(s):  
Mirjana Horvat ◽  
Zoltan Horvat ◽  
Dániel Koch ◽  
Fruzsina Majer
Keyword(s):  
Water Budget ◽  
Preliminary Analysis ◽  
Catchment Area ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Hydraulic Structures ◽  
One Year ◽  
The Town ◽  
Existing Data

This paper presents the results of a preliminary analysis of Palic-Ludas catchment area near the town of Subotica in Serbia. With the aim of improving environmental situation of the considered catchment, the authors started by conducting a detailed investigation of the current situation of this area. The examination focused on obtaining and evaluating existing data in order to derive some conclusion about the present status of this catchment. This paper offers a description of the important water bodies on Palic-Luda catchment, while including the most influential hydraulic structures. After evaluating the gathered data, a basic water budget model ofPalic-Ludas lake system was constructed. The model included all the main water budget elements, the outflow from the sewage treatment plant into Lake Palic, precipitation, evaporation as well as the ground water interflow. After conducting a one year simulation the results were assessed and the influence of each component of the water budget was examined.

scholarly journals THE IMPACT OF SEWAGE TREATMENT PLANT ON THE AMOUNT OF HEAVY METALS IN WATER OF THE SUPRAŚL RIVER CATCHMENT AREA

2016 ◽  
Vol 17 (1) ◽  
pp. 136-142
Author(s):  
Mirosław Skorbiłowicz ◽  
Elżbieta Skorbiłowicz ◽  
Paulina Wójtowicz ◽  
Piotr Ofman ◽  
Emilia Zamojska
Keyword(s):  
Heavy Metals ◽  
Catchment Area ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
River Catchment ◽  
The Impact

QMRA (quantitative microbial risk assessment) and HACCP (hazard analysis and critical control points) for management of pathogens in wastewater and sewage sludge treatment and reuse

2004 ◽  
Vol 50 (2) ◽  
pp. 23-30 ◽  
Author(s):  
T. Westrell ◽  
C. Schönning ◽  
T.A. Stenström ◽  
N.J. Ashbolt
Keyword(s):  
Risk Assessment ◽  
Hazard Analysis ◽  
Treatment Plant ◽  
Storage Site ◽  
Control Points ◽  
Quantitative Microbial Risk Assessment ◽  
Worst Case ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Critical Control Points

Hazard Analysis and Critical Control Points (HACCP) was applied for identifying and controlling exposure to pathogenic microorganisms encountered during normal sludge and wastewater handling at a 12,500 m3/d treatment plant utilising tertiary wastewater treatment and mesophilic sludge digestion. The hazardous scenarios considered were human exposure during treatment, handling, soil application and crop consumption, and exposure via water at the wetland-area and recreational swimming. A quantitative microbial risk assessment (QMRA), including rotavirus, adenovirus, haemorrhagic E. coli, Salmonella, Giardia and Cryptosporidium, was performed in order to prioritise pathogen hazards for control purposes. Human exposures were treated as individual risks but also related to the endemic situation in the general population. The highest individual health risk from a single exposure was via aerosols for workers at the belt press for sludge dewatering (virus infection risk = 1). The largest impact on the community would arise if children ingested sludge at the unprotected storage site, although in the worst-case situation the largest number of infections would arise through vegetables fertilised with sludge and eaten raw (not allowed in Sweden). Acceptable risk for various hazardous scenarios, treatment and/or reuse strategies could be tested in the model.

Scenario-based quantitative microbial risk assessment to evaluate the robustness of a drinking water treatment plant

2016 ◽  
Vol 51 (2) ◽  
pp. 81-96 ◽  
Author(s):  
Mohamed A. Hamouda ◽  
William B. Anderson ◽  
Michele I. Van Dyke ◽  
Ian P. Douglas ◽  
Stéphanie D. McFadyen ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Operating Conditions ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Treatment Processes

While traditional application of quantitative microbial risk assessment (QMRA) models usually stops at analyzing the microbial risk under typical operating conditions, this paper proposes the use of scenario-based risk assessment to predict the impact of potential challenges on the expected risk. This study used a QMRA model developed by Health Canada to compare 14 scenarios created to assess the increase in risk due to potential treatment failures and unexpected variations in water quality and operating parameters of a water treatment plant. Under regular operating conditions, the annual risk of illness was found to be substantially lower than the acceptable limit. Scenario-based QMRA was shown to be useful in demonstrating which hypothetical treatment failures would be the most critical, resulting in an increased risk of illness. The analysis demonstrated that scenarios incorporating considerable failure in treatment processes resulted in risk levels surpassing the acceptable limit. This reiterates the importance of robust treatment processes and the multi-barrier approach voiced in drinking water safety studies. Knowing the probability of failure, and the risk involved, allows designers and operators to make effective plans for response to treatment failures and/or recovery actions involving potential exposures. This ensures the appropriate allocation of financial and human resources.

scholarly journals Quantitative microbial risk assessment used to evaluate seasonal wastewater treatment limits: case study in Vacaville, CA

2017 ◽  
Vol 18 (3) ◽  
pp. 910-925 ◽  
Author(s):  
Edmund Seto ◽  
Adam W. Olivieri ◽  
Richard E. Danielson
Keyword(s):  
Risk Assessment ◽  
Wastewater Treatment ◽  
Treatment Plant ◽  
Enteric Viruses ◽  
Secondary Effluent ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Annual Risk ◽  
Receiving Water

Abstract A quantitative microbial risk assessment (QMRA) was conducted to support renewal of the City of Vacaville wastewater discharge permit and seasonal (summer) filtration requirements. Influent and final disinfected effluent from the city's wastewater treatment plant, as well as 11 receiving water stations, were monitored for indicator organisms (i.e. total and fecal coliforms, Escherichia coli, Enterococcus, male-specific bacteriophage (MS2), and the Bacteroidales) and several pathogens (i.e. Giardia cysts, Cryptosporidium oocysts, infectious Cryptosporidium, and Norovirus GI and GII). QMRA annualized risks of infection for selected pathogens enteric viruses, Giardia and Cryptosporidium. Estimated median annualized risk for recreational exposure in either disinfected secondary and/or filtered disinfected secondary effluent is on the order of 1.1 × 10−3 per person per year (pppy) for enteric viruses and would be roughly one order of magnitude lower if local receiving water dilution of the treatment plant effluent was taken into account. Estimated median annual risk for recreation exposure in disinfected secondary effluent is 1.8 × 10−3 pppy for Cryptosporidium and 1 log10 less with filtration during the summer months. The estimated median annual risk for landscape exposure (e.g. golfing) to secondary disinfected effluent is 7.6 × 10−7 pppy for enteric viruses. Estimated median annualized risk is 1.7 × 10−7 pppy for enteric viruses and 3.0 × 10−5 to 3.6 × 10−6 pppy for parasites for use of secondary disinfected effluent with irrigated agriculture. Estimated annualized risks for recreational exposure to the local receiving waters were approximately 10 to 1,000 times greater than direct recreational exposure to the final filtered and disinfected effluent. All risk estimates associated with exposure to final treated plant effluent (i.e. secondary filtered and disinfected) were close to or lower than the California level of acceptable annual risk of infection of 10−4 pppy for recreational exposure. Risk estimates provide further evidence to support the use of seasonal treatment limits requiring summer filtration for public health protection.

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