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.

Characterisation and conditioning of Fenton sludges issued from wastewater treatment

2002 ◽  
Vol 46 (10) ◽  
pp. 43-49 ◽  
Author(s):  
R.M. Ramírez Zamora ◽  
M.T. Orta de Velásquez ◽  
A. Durán Moreno ◽  
J. Malpica de la Torre
Keyword(s):  
Wastewater Treatment ◽  
Specific Resistance ◽  
Land Application ◽  
Cationic Polymer ◽  
Fecal Coliforms ◽  
Fenton Reagent ◽  
Class B ◽  
Microbiological Parameters ◽  
Combined Action ◽  
Alum Sludge

Characterisation tests were conducted to determine the feasibility of land application of the sludges produced in wastewater treatment by means of Fenton's Reagent. Physicochemical and microbiological parameters of Fenton sludges were compared to the values obtained for raw alum sludges. The Fenton sludges presented preferable characteristics such as the specific resistance to filtration (SRF), metals and pathogen content (fecal and total coliforms, helminth ova, and Salmonella sp.). The SRF of the Fenton sludges (1.55 × 1013 m/kg) was 24% less than the alum sludge value (1.92 × 1013 m/kg). The concentrations of fecal coliforms (0 MPN/g TS), Salmonella sp. (0 MPN/g TS), Helminth ova (22 HH/g TS) and metals correspond to the limits for biosolids of Class B for land application of the Mexican legislation. The Fenton reagent efficiently removes most of the pathogens, considered by the norms, by means of the combined action of the different stages that constitute this process. These results exhibit the Fenton reagent as a feasible treatment for generating sludges with characteristics of biosolids of Class B for land application. The preliminary results of conditioning tests show that Fenton sludges present better dewatering characteristics with regard to the alum sludge, for a dose of cationic polymer of 1 mg/g TS.

scholarly journals Potential Regrowth and Recolonization of Salmonellae and Indicators in Biosolids and Biosolid-Amended Soil

2005 ◽  
Vol 71 (7) ◽  
pp. 3701-3708 ◽  
Author(s):  
Kathleen J. Zaleski ◽  
Karen L. Josephson ◽  
Charles P. Gerba ◽  
Ian L. Pepper
Keyword(s):  
Fecal Coliforms ◽  
Microbial Populations ◽  
Solar Drying ◽  
Laboratory Studies ◽  
Fecal Matter ◽  
Rainfall Events ◽  
Class A ◽  
Class B ◽  
External Sources ◽  
Amended Soil

ABSTRACT This study evaluated the potential for conversion of Class B to Class A biosolids with respect to salmonellae and fecal coliforms during solar drying in concrete lined drying beds. Anaerobically (8% solids) and aerobically (2% solids) digested Class B biosolids were pumped into field-scale drying beds, and microbial populations and environmental conditions were monitored. Numbers of fecal coliforms and salmonellae decreased as temperature and rate of desiccation increased. After 3 to 4 weeks, Class A requirements were achieved in both biosolids for the pathogens and the indicators. However, following rainfall events, significant increase in numbers was observed for both fecal coliforms and salmonellae. In laboratory studies, regrowth of fecal coliforms was observed in both biosolids and biosolid-amended soil, but the regrowth of salmonellae observed in the concrete-lined drying beds did not occur. These laboratory studies demonstrated that pathogens decreased in numbers when soil was amended with biosolids. Based on serotyping, the increased numbers of salmonellae seen in the concrete lined drying beds following rainfall events was most likely due to recolonization due to contamination from fecal matter introduced by animals and not from regrowth of salmonellae indigenous to biosolids. Overall, we conclude that the use of concrete-lined beds created a situation in which moisture added as rainfall accumulated in the beds, promoting the growth of fecal coliforms and salmonellae added from external sources.

Class B biosolids production from wastewater sludge with high pathogenic content generated in an advanced primary treatment

2000 ◽  
Vol 42 (9) ◽  
pp. 103-110 ◽  
Author(s):  
B. Jimenez ◽  
J. A. Barrios ◽  
C. Maya
Keyword(s):  
The United States ◽  
Primary Treatment ◽  
Land Application ◽  
Wastewater Sludge ◽  
Fecal Coliforms ◽  
Treatment Processes ◽  
Helminth Eggs ◽  
Class B ◽  
Us Epa ◽  
High Pathogenic

Alkaline post-stabilization of wastewater sludge with high pathogenic content (up to 1010 NMP/g TS of Salmonella sp. and up to 89.8 helminth eggs/g TS) was studied to evaluate the feasibility of producing Class B biosolids. The sludge was produced in pilot systems using different advanced primary treatment processes treating wastewater generated in Mexico City. Samples were dewatered to different dryness ranging from 11.5 to 29.0% TS and stabilized using quicklime in doses ranging from 15 to 40% (w/w). The levels of pathogens found in dewatered sludge were up to 8 log and 1.95 log higher than those found in primary sludge generated in the United States for Salmonella sp. and helminth eggs respectively. Distribution of genera of helminths indicated that more than 90% of the eggs found were Ascaris, while the rest were Hymenolepis, Trichuris, Toxocara and Taenia. Minimum and maximum removals ranged between 3.6 to 9.5 log for fecal coliforms; 3.7 to 7.9 log for Salmonella sp.; and 0.1 to 1.3 log for helminths. The recommended quicklime dose was determined for different solids contents in order to achieve the pH-time criteria and the levels of microorganisms required by the US EPA. Metal concentrations were below the maximum levels established for land application of biosolids.

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.

Removal of fecal coliforms by thermophilic anaerobic digestion processes

2002 ◽  
Vol 46 (10) ◽  
pp. 147-152 ◽  
Author(s):  
C. De Leén ◽  
D. Jenkins
Keyword(s):  
Anaerobic Digestion ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Single Stage ◽  
Fecal Coliforms ◽  
Two Stage ◽  
Class A ◽  
One Stage ◽  
Combustible Gas ◽  
Screening Study

Recent U.S. EPA regulations (40 CFR Section 503) specify maximum concentrations of pathogens and metals for Class A wastewater treatment plant sludges. The most common sludge process is mesophilic (35¡C) digestion which stabilizes the solids, produces a combustible gas but does not create an effluent that meets the 503 Class A pathogen requirements. This investigation was conducted to determine whether anaerobic digestion processes incorporating a thermophilic stage could achieve 503 Class A pathogen levels. The research reported here was a bench-scale screening study meant to identify the most promising process alternatives for further investigation. Fecal Coliform (FC) concentrations were used to assess disinfection efficiency. Digesters were 30 L capacity fed semi-continuously in draw-fill mode. Digester startup was rapid to produce true thermophiles. Temperature staging and pH were assessed in 3 sets of experiments: Set 1 were one stage (“acid phase”), Set 2 were one stage (“acid + methane phases”) and Set 3 were two stage (“acid phase” then “methanogenic phase”). Feed was a 1:1 mixture of Thickened Waste Activated Sludge and Primary Sludge. The following anaerobic digestion configurations and operating parameters allowed the production of digested sludge with a mean FC concentration statistically less than 103 (the regulatory value for Class A sludge): thermophilic single stage acid phase at 52 and 62°C; thermophilic single stage acid + methane phase at 48°C, 52°C and 62°C; two-stage mesophilic acid phase followed by mesophilic methane phase; two stage mesophilic acid phase followed by thermophilic methane phase at 48°C, 52°C and 62°C. If the maximum digested FC concentration must be below 103 MPN/g TS then the following digester configurations and operating conditions will be compliant: two stage mesophilic acid phase followed by thermophilic methane phase at 52°C and 62°C.

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

scholarly journals Some kinematics of halo coronal mass ejections

2020 ◽  
Vol 29 (1) ◽  
pp. 81-88
Author(s):  
Virendra Kumar Verma ◽  
Nishant Mittal ◽  
Ramesh Chandra
Keyword(s):  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Coronal Holes ◽  
Geomagnetic Disturbances ◽  
Class A ◽  
Heliospheric Physics ◽  
Class B ◽  
The Mean ◽  
Class C

AbstractWe present an investigation of halo coronal mass ejections (HCMEs) kinematics and other facts about the HCMEs. The study of HCMEs is very important because HCMEs are regarded as the main causes of heliospheric and geomagnetic disturbances. In this study, we have investigated 313 HCMEs observed during 1996-2012 by LASCO, coronal holes, and solar flares. We find that HCMEs are of two types: accelerated HCMEs and decelerated HCMEs. The mean space speed of HCMEs is 1283 km/s while the mean speed of decelerated HCMEs and accelerated HCMEs is 1349 km/s and 1174 km/s, respectively. The investigation shows that 1 (0.3%) HCME was associated with class A SXR, 14 (4.7%) HCMEs were associated with class B SXR-flares, 87 (29.4%) HCMEs were associated with class C SXR-flares, 125 (42.2%) HCMEs were associated with class M SXR-flares and 69 (23.3%) HCMEs were associated with class X SXR-flares. The speed of HCMEs increases with the importance of solar SXR-flares. The various results obtained in the present analysis are discussed in the light of the existing scenario of heliospheric physics.

scholarly journals Design and Validation of an Adjustable Large-Scale Solar Simulator

2021 ◽  
Vol 11 (4) ◽  
pp. 1964
Author(s):  
Daniele Colarossi ◽  
Eleonora Tagliolini ◽  
Paolo Principi ◽  
Roberto Fioretti
Keyword(s):  
Large Scale ◽  
Design Procedure ◽  
Spatial Arrangement ◽  
Luminous Flux ◽  
International Electrotechnical Commission ◽  
Solar Simulator ◽  
Class A ◽  
Pv Panel ◽  
Temporal Instability ◽  
Class B

This work presents an adjustable large-scale solar simulator based on metal halide lamps. The design procedure is described with regards to the construction and spatial arrangement of the lamps and the designed optical system. Rotation and translation of the lamp array allow setting the direction and the intensity of the luminous flux on the horizontal plane. To validate the built model, irradiance nonuniformity and temporal instability tests were carried out assigning Class A, B, or C for each test, according to the International Electrotechnical Commission (IEC) standards requirements. The simulator meets the Class C standards on a 200 × 90 cm test plane, Class B on 170 × 80 cm, and Class A on 80 × 40 cm. The temporal instability returns Class A results for all the measured points. Lastly, a PV panel is characterized by tracing the I–V curve under simulated radiation, under outdoor natural sunlight, and with a numerical method. The results show a good approximation.

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