Exposure and risk assessment of Salmonella in recycled residuals

2008 ◽  
Vol 57 (7) ◽  
pp. 1061-1065 ◽  
Author(s):  
Charles P. Gerba ◽  
Nohelia Castro-del Campo ◽  
John P. Brooks ◽  
Ian L. Pepper
Keyword(s):  
Risk Assessment ◽  
Direct Contact ◽  
Land Application ◽  
Human Infection ◽  
Application Site ◽  
Class A ◽  
Salmonella Infections ◽  
Class B ◽  
Airborne Transport ◽  
Class A Biosolids

The potential health effects of Salmonella found in wastewater residuals is dependent on the exposure of individuals to the organism. This paper provides a risk assessment for human infection from Salmonella due to direct contact with Class B biosolids, and from contact with Class A biosolids following regrowth of Salmonella. In addition, a risk assessment is provided for infection via airborne transport of bioaerosols from Class B biosolids and biosolids in which regrowth had occurred, to off-site communities. Results of the risk characterization imply that the risk of human infection from direct contact with Class B land applied residuals and subsequent ingestion is low. In contrast, the risk from direct contact with Class A residuals following regrowth is greater. Risks from airborne transport of Salmonella via bioaerosols away from a Class B land application site are also low. However, once again the risk from aerosols resulting from biosolids in which regrowth had occurred was greater. Based on these analyses, we conclude that it is highly unlikely that Salmonella infections will occur from land applied Class A or B residuals. However, risks become significant if Class A biosolids are stored anaerobically i.e. saturated, prior to land application.

scholarly journals Survey of Wastewater Indicators and Human Pathogen Genomes in Biosolids Produced by Class A and Class B Stabilization Treatments

2008 ◽  
Vol 75 (1) ◽  
pp. 164-174 ◽  
Author(s):  
Emily Viau ◽  
Jordan Peccia
Keyword(s):  
Anaerobic Digestion ◽  
Legionella Pneumophila ◽  
Human Adenovirus ◽  
Land Application ◽  
Fecal Coliforms ◽  
Class A ◽  
Stabilization Methods ◽  
Class B ◽  
Male Specific ◽  
Pathogen Genome

ABSTRACT Accurate modeling of the infectious aerosol risk associated with the land application of biosolids requires an in-depth knowledge of the magnitudes and changes in pathogen concentrations for a variety of class A and class B stabilization methods. The following survey used quantitative PCR (qPCR) and culture assays to detect environmentally resistant bacterial and viral pathogens and biosolid indicator organisms for 36 biosolid grab samples. Biosolids were collected from 14 U.S. states and included 16 class B mesophilic anaerobic digestion (MAD) samples and 20 class A biosolid samples from temperature-phased anaerobic digestion (TPAD), MAD plus composting (COM), and MAD plus heat pelletization processes. The indicator concentrations of fecal coliforms and male-specific coliphages as well as pathogen genome concentrations for human adenovirus species, Legionella pneumophila, Staphylococcus aureus, and Clostridium difficile were significantly lower in the class A samples, and a multivariate analysis of variance ranked the stabilization processes from the lowest pathogen/indicator load to the highest as (i) class A COM, (ii) class A TPAD, and (iii) class B MAD. Human adenovirus genomes were found in 88% of the class B samples and 70 to 100% of the class A samples. L. pneumophila, S. aureus, and C. difficile genomes were detected at the qPCR assay detection limits in 19 to 50% of the class B and class A anaerobic digestion samples, while L. pneumophila was detected in 50% of the class A compost samples. When considering all the stabilization methods, both the fecal coliform and the male-specific coliphage concentrations show a significant linear correlation with the pathogen genome concentrations. This survey provides the necessary pathogen concentrations to add to biosolid aerosol risk and pathogen exposure analyses and clarifies the effectiveness of class A stabilization methods with the pathogen and indicator loads in biosolids.

The measurement of aerosolized endotoxin from land application of Class B biosolids in Southeast Arizona

2006 ◽  
Vol 52 (2) ◽  
pp. 150-156 ◽  
Author(s):  
J P Brooks ◽  
B D Tanner ◽  
C P Gerba ◽  
I L Pepper
Keyword(s):  
Wastewater Treatment ◽  
Occupational Exposure ◽  
Treatment Plant ◽  
Land Application ◽  
Application Site ◽  
Research Needs ◽  
Wind Vector ◽  
Background Concentrations ◽  
Class B ◽  
Biosolids Application

The purpose of this study was to determine aerosolized endotoxin concentrations downwind of a biosolids land application site. Aerosol samples were collected from biosolids land application sites, tractor operation, and an aeration basin located within an open-air wastewater treatment plant. Aerosolized endotoxin above background concentrations was detected from all sites, at levels ranging from below detection up to 1800 EU m–3 of air. Biosolids loading operations resulted in the greatest concentrations of endotoxin (mean 344 EU m–3). As downwind (perpendicular to wind vector) distance increased from sources (2–200 m), levels of endotoxin decreased to near background (without biosolids application) concentrations. Overall, the detected levels of aerosolized endotoxin were within past proposed aerosolized endotoxin limits (250–2000 EU m–3) by other occupational exposure studies. Occasionally, peak concentrations were found to be above these limits. Sites in which soil was being aerosolized resulted in greater concentrations of endotoxin with or without biosolids, which suggested that the majority of endotoxin may in fact be of soil origin. This study evaluated the presence of aerosolized endotoxin from the land application of biosolids and showed that these levels were within ranges for concern suggested by other studies and that this area of research needs further investigation. Key words: biosolids, endotoxin, aerosol, bioaerosol, lipopolysaccharide.

مهارة الكلام منظور من عملية التعلم والتعليم في جامعة باتوسنجكر الاسلامية الحكومية سومطرى الغربية

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Suharmon Suharmon
Keyword(s):  
Teaching Strategies ◽  
Language Education ◽  
Arabic Language ◽  
Descriptive Statistics ◽  
Quantitative Approach ◽  
Motivation To Learn ◽  
Education Department ◽  
Class A ◽  
Class B ◽  
Speaking Skill

This research aims to obtain infomation about Arabic learning especially speaking skill in Arabic Language Education Department at IAIN Batusangkar. The research uses a quantitative approach. The instruments to collect the data are test and questionnaire. The data were analyzed using descriptive statistics. The results of the research state that the students’ speaking ability at class “ A “ are 28% low, 36% moderate, and 36% high. While, at class “B”, students’ speaking abilities are 36.4% low, 40,9% moderate, and 22.7% high. The cause of students’ low ability is the unappropriateness of teachers’ strategy in teaching speaking. There are about 96% students at class “A” agreed and 86.4% students at class “B” had similar answer. Another cause is students’ low motivation in learning. Class “A” students agreed for about 76% of them and 77% of class “B” students answered the same. From the finding, it can be concluded that the inability of students to speak Arabic can be overcomed by improving teaching strategies and encouraging maximum motivation  to learn Arabic.

Single-stage Sequencing Batch Process for Producing Class A Biosolids from AD Effluent at Terminal Island Treatment Plant

2006 ◽  
Vol 1 (4) ◽  
Author(s):  
Huub H.J. Cox ◽  
Steve Fan ◽  
Reza Iranpour
Keyword(s):  
Fecal Coliform ◽  
Treatment Plant ◽  
Batch Process ◽  
Single Stage ◽  
Fecal Coliforms ◽  
Class A ◽  
Truck Loading ◽  
Train Operation ◽  
Plant Control ◽  
Class A Biosolids

Terminal Island Treatment Plant converted its digesters to thermophilic operation with the objective to comply with the U.S. EPA Part 503 Biosolids Rule requirements for Class A biosolids. The following processes were tested: a) single-stage continuous; b) two-stage continuous; c) single-stage sequencing batch. Salmonella sp. were always non-detect in digester outflows (<3 MPN/4 g dry wt), whereas fecal coliform densities were usually below the Class A limit of 1000 MPN/g dry wt. However, the recurrence of fecal coliforms in post-digestion caused non-compliance with the Class A limit at the truck loading facility as the last point of plant control for compliance. After several design modifications of the post-digestion train, operation of the digesters as sequencing batch digesters according to the time-temperature requirement of Alternative 1 of the Part 503 Biosolids Rule achieved compliance for both Salmonella sp. and fecal coliforms at the last point of plant control (truck loading facility).

Class B Land Application: A Long-term, Highly Successful Public-Private Partnership

2017 ◽  
Vol 2017 (1) ◽  
pp. 1056-1064
Author(s):  
Jake Finlinson ◽  
Dave Ruud ◽  
Andy Bary ◽  
Maile Lono-Batura
Keyword(s):  
Land Application ◽  
Public Private Partnership ◽  
Private Partnership ◽  
Class B
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