scholarly journals Cost Analysis and Health Risk Assessment of Wastewater Reuse from Secondary and Tertiary Wastewater Treatment Plants

2021 ◽  
Vol 13 (23) ◽  
pp. 13125
Author(s):  
Sara AbdelMoula ◽  
Mohamed T. Sorour ◽  
Samia A. Abdelrahman Aly
Keyword(s):  
Risk Assessment ◽  
Health Risks ◽  
Reclaimed Water ◽  
Giardia Duodenalis ◽  
Assessment Model ◽  
Treated Wastewater ◽  
Systematic Evaluation ◽  
Quantitative Microbial Risk Assessment ◽  
Mena Region ◽  
Treatment Alternatives

Irrigation with reclaimed water is a widespread solution to coping with water scarcity, especially in the Middle East and North Africa (MENA) region. This paper presents a systematic evaluation approach of six treatment alternatives proposed for Alexandria WWTP in Egypt as an applied example. This approach evaluates the effluent quality and cubic meter price from the proposed treatment alternatives while managing the health risks associated with reclaimed water irrigation. Rotavirus, Salmonella, Giardia duodenalis, and Ascaris were studied as waterborne pathogens. A quantitative microbial risk assessment model was used for the estimation of annual infection risks. The exposure scenarios include farmers and vegetable consumers. Activated sludge provided the lowest costs; however, it gave the lowest efficiencies and highest health risks. On the other hand, the highest efficiency and lowest health risks were obtained by the membrane bioreactor. The resulting price of a cubic meter of treated wastewater, used in irrigation, ranged from 0.082 to 0.133 USD. Irrigation using tertiary-treated wastewater achieved the target infection risk for unrestricted irrigation without using advanced treatment facilities. The results of this study could give a comprehensive view of reusing wastewater to decision-makers to address both water and food poverty not only in Egypt but also in other countries in MENA with similar economic and agro-ecological conditions.

scholarly journals Estimating microbial risk in treated wastewater for reuse: a case study in Lund, Sweden

2014 ◽  
Vol 4 (4) ◽  
pp. 263-275 ◽  
Author(s):  
Shuang Liu ◽  
Kenneth M. Persson
Keyword(s):  
Risk Assessment ◽  
Water Reuse ◽  
Treatment Plant ◽  
Additional Treatment ◽  
Point Of View ◽  
Assessment Model ◽  
Treated Wastewater ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk ◽  
Pond System

The potential microbial risk from using treated wastewater is a burning issue to be studied. In Sweden, only a small part of treated wastewater is reused directly, although water reuse could be beneficial. Disinfection is virtually never practised and no protective guidelines for water reuse are found in Sweden. Based on a 1 year monitoring programme of water quality, this paper estimates the microbial risk of Escherichia coli and rotavirus in treated wastewater for different applications of irrigation, landscape, industry, unban non-potable water. A Quantitative Microbial Risk Assessment model is used and the samples were collected from the pond system of Källby wastewater treatment plant in Lund, Sweden. The results are used to evaluate if the treated wastewater after tertiary treatment process combined with pond system can be reused for different applications from a microbial point of view. The risk assessment results show that the studied water is only suitable for agriculture irrigation, while additional treatment or disinfection are needed for other applications since the potential risks are higher than the value that can be accepted. The protective guidelines are discussed based on the process and results of risk assessment and suggestions for establishing a structure of guidelines in Sweden are presented.

Comparing the Effect of Various Contamination Levels for Salmonella in Chicken Meat Preparations on the Probability of Illness in Belgium

2009 ◽  
Vol 72 (10) ◽  
pp. 2093-2105 ◽  
Author(s):  
MIEKE UYTTENDAELE ◽  
KATLEEN BAERT ◽  
KOEN GRIJSPEERDT ◽  
LIEVEN DE ZUTTER ◽  
BENOIT HORION ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Chicken Meat ◽  
Assessment Model ◽  
Contamination Level ◽  
Quantitative Microbial Risk Assessment ◽  
Risk Assessment Model ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Increased Risk ◽  
Fixed Input

At the urging of competent national authorities, a limited risk assessment on Salmonella in chicken meat preparations in Belgium was undertaken following a retail-to-table approach. The input distribution of Salmonella was based on surveillance data in Belgium. To analyze the relative impact of reducing the risk of salmonellosis associated with a decrease in the Salmonella contamination level, different distributions based on the actual situation but limiting the number of portions containing Salmonella at 1 CFU per 1, 10, and 25 g of meat were used in the quantitative microbial risk assessment model. The quantitative microbial risk assessment model also was run several times with a theoretical fixed input of Salmonella assuming all portions possessed the same fixed contamination level set at 1,000, 100, 10, and 1 CFU/g of meat and 1 CFU per 10, 25, 100, and 1,000 g of meat. With regard to the initial contamination level, the results indicate, both by the narrowing of the current distribution and by the fixed input, that especially the higher levels of contamination (>1 CFU/g) contribute to the increased risk for salmonellosis.

scholarly journals Energy forest irrigated with wastewater: a comparative microbial risk assessment

2009 ◽  
Vol 7 (3) ◽  
pp. 413-433 ◽  
Author(s):  
A. Carlander ◽  
C. Schönning ◽  
T. A. Stenström
Keyword(s):  
Risk Assessment ◽  
Municipal Wastewater ◽  
Human Infection ◽  
Treated Wastewater ◽  
Quantitative Microbial Risk Assessment ◽  
Indicator Organisms ◽  
Giardia Infection ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Short Rotation

In this study, risks for human infection associated with irrigation of municipal wastewater on short rotation willow coppice (Salix) were evaluated in three countries. The aim was also to determine the reduction of indicator organisms and pathogens in the treatment plants. Two of the field sites were chosen for further evaluation by QMRA (quantitative microbial risk assessment) applied to three scenarios: accidental ingestions of wastewater, exposure to aerosols and ingestion of groundwater. The risks of infection for bacteria (Salmonella), virus (rotavirus) and protozoa (Giardia, Cryptosporidium) were characterised as probability of infections per exposure and number of infections per year. The highest risk for infection was associated with exposure to rotavirus in Culmore (Northern Ireland), by either accidental ingestion of wastewater or ingestion of groundwater (Pinf 8 × 10−1). For Kvidinge (Sweden) the risk for virus infection by ingestion of wastewater were in the same range (Pinf 7 × 10−1). The risk for Giardia infection differed between the two sites due to differences in concentration of this pathogen in the wastewater. The groundwater was found to have suffered faecal contamination due to the wastewater irrigation. Use of partially treated wastewater for irrigation of energy crops could be a sustainable option if site-specific recommendations are developed.

scholarly journals Quantitative Microbial Risk Assessment Models for Consumption of Raw Vegetables Irrigated with Reclaimed Water

2006 ◽  
Vol 72 (5) ◽  
pp. 3284-3290 ◽  
Author(s):  
Andrew J. Hamilton ◽  
Frank Stagnitti ◽  
Robert Premier ◽  
Anne-Maree Boland ◽  
Glenn Hale
Keyword(s):  
Risk Assessment ◽  
Reclaimed Water ◽  
Quantitative Microbial Risk Assessment ◽  
Risk Of Infection ◽  
Worst Case ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Risk Assessment Models ◽  
Crop Type ◽  
Annual Risk

ABSTRACT Quantitative microbial risk assessment models for estimating the annual risk of enteric virus infection associated with consuming raw vegetables that have been overhead irrigated with nondisinfected secondary treated reclaimed water were constructed. We ran models for several different scenarios of crop type, viral concentration in effluent, and time since last irrigation event. The mean annual risk of infection was always less for cucumber than for broccoli, cabbage, or lettuce. Across the various crops, effluent qualities, and viral decay rates considered, the annual risk of infection ranged from 10−3 to 10−1 when reclaimed-water irrigation ceased 1 day before harvest and from 10−9 to 10−3 when it ceased 2 weeks before harvest. Two previously published decay coefficients were used to describe the die-off of viruses in the environment. For all combinations of crop type and effluent quality, application of the more aggressive decay coefficient led to annual risks of infection that satisfied the commonly propounded benchmark of ≤10−4, i.e., one infection or less per 10,000 people per year, providing that 14 days had elapsed since irrigation with reclaimed water. Conversely, this benchmark was not attained for any combination of crop and water quality when this withholding period was 1 day. The lower decay rate conferred markedly less protection, with broccoli and cucumber being the only crops satisfying the 10−4 standard for all water qualities after a 14-day withholding period. Sensitivity analyses on the models revealed that in nearly all cases, variation in the amount of produce consumed had the most significant effect on the total uncertainty surrounding the estimate of annual infection risk. The models presented cover what would generally be considered to be worst-case scenarios: overhead irrigation and consumption of vegetables raw. Practices such as subsurface, furrow, or drip irrigation and postharvest washing/disinfection and food preparation could substantially lower risks and need to be considered in future models, particularly for developed nations where these extra risk reduction measures are more common.

scholarly journals Evaluating the Risk of Salmonellosis from Dry Roasted Sunflower Seeds

2019 ◽  
Vol 83 (1) ◽  
pp. 17-27 ◽  
Author(s):  
BALASUBRAHMANYAM KOTTAPALLI ◽  
STEPHANIE P. V. NGUYEN ◽  
KELLY DAWSON ◽  
KAITLYN CASULLI ◽  
CATE KNOCKENHAUER ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Water Activity ◽  
The United States ◽  
Arithmetic Mean ◽  
Assessment Model ◽  
Quantitative Microbial Risk Assessment ◽  
Sunflower Seeds ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Log Reduction

ABSTRACT Outbreaks and recalls related to nuts and seeds in the United States have increased recently, and 80% of these recalls are due to Salmonella. The U.S. Food and Drug Administration's Food Safety Modernization Act requires food manufacturers to implement risk-based preventive controls based on scientific and technical evidence. Data are limited on the inactivation of Salmonella during processing of saltwater brined in-shell sunflower seeds. The goal of this research was to validate the adequacy of roasting in controlling Salmonella during the production of sunflower seeds and to assess the resulting risk. Four Salmonella strains were inoculated onto sunflower seeds and processed to simulate commercial manufacturing. Seeds were tumbled and roasted at 225°F (107.2°C) and 275°F (135°C) for roasting times from 5 to 45 min. Regression models for Salmonella inactivation and water activity change were developed. The inactivation model predicted a 5-log reduction in Salmonella when sunflower seeds were roasted at 135°C for 19.2 min, with a corresponding water activity of ∼0.61. Roasted sunflower seeds are typically not saleable at water activities >0.6 due to quality issues. Saleable water activities (0.03 to 0.04) were only achieved when the sunflower seeds were roasted for 45 min at 135°C, which resulted in a >7-log reduction in Salmonella. A quantitative microbial risk assessment based on literature values, expert opinion, and the above-mentioned models was used to predict risk of salmonellosis from sunflower seeds. The quantitative microbial risk assessment model predicted an arithmetic mean probability of illness of 1.45E−07 per 28-g serving based on roasting at 135°C for 20 min and an arithmetic mean probability of illness of 5.46E−10 per serving based on roasting at 135°C for >45 min (i.e., saleable product process parameters). This study demonstrates that sunflower seeds roasted to saleable parameters should not represent a public health risk from potential presence of Salmonella.

Sign in / Sign up

Export Citation Format

Share Document