Exposure to dust, endotoxin and airborne microorganisms in wastewater sludge thermal drying units

2011 ◽  
Vol 64 (5) ◽  
pp. 1073-1080 ◽  
Author(s):  
O. Schlosser ◽  
A. Huyard ◽  
V. Catalán
Keyword(s):  
Personal Exposure ◽  
Wastewater Sludge ◽  
Thermophilic Actinomycetes ◽  
Monitoring Task ◽  
Inhalable Dust ◽  
High Emission ◽  
Exposure Levels ◽  
Low Levels ◽  
Sludge Drying ◽  
Dried Sludge

The objective of this study was to assess workers' exposure to bioaerosols in sludge drying units. Simultaneous collection of inhalable dust and airborne biological agents was carried out using rotating cup samplers (CIP 10, Arelco). Sixteen stationary and 30 personal measurements were performed in three drying plants, during summer and winter. Microbial content of air was characterized by high amounts of Gram-negative bacteria, endotoxin, and thermophilic actinomycetes. High differences between exposure levels were observed with regard to workplaces and tasks. Dryers and conveyors in operation were closed, and the monitoring task in the dryer room was associated with low levels of personal exposure, close to background levels. Conversely, cleaning and maintenance of the dryer and conveyors required the equipment to be opened, giving significantly higher task-based personal exposure levels. The fall of dried sludge into indoor containers resulted in high emission and spreading of dust. Mean personal exposure levels to fungi were moderate or low for all tasks. Based on the results of this study, appropriate means of operational control and personal protection are being developed and implemented on sites.

Lack of Effects of Carbon Monoxide on Human Vigilance

1977 ◽  
Vol 45 (3) ◽  
pp. 1007-1014 ◽  
Author(s):  
Vernon A. Benignus ◽  
David A. Otto ◽  
James D. Prah ◽  
Gayla Benignus
Keyword(s):  
Carbon Monoxide ◽  
Critical Review ◽  
Statistical Test ◽  
Review Of The Literature ◽  
Vigilance Performance ◽  
Monitoring Task ◽  
Human Male ◽  
Exposure Levels ◽  
Low Levels ◽  
Male Subjects

Previous publications on the effects of low levels of carbon monoxide (CO) on human vigilance performance have found conflicting results. While several studies have found statistically reliable effects, none have gone unchallenged. This article presents a critical review of the literature and the results of a study employing 52 human male subjects performing a numeric monitoring task. CO levels were 0, 100, and 200 ppm which produced mean carboxyhemoglobin levels 0.01, 4.61 and 12.62 percent respectively. No CO-exposure levels produced any effect on vigilance performance. The power of the statistical test for CO effects was shown to be quite high, even for fairly trivial possible decrements of performance.

scholarly journals Advanced process for thermal treatment of wastewater sludge

2007 ◽  
pp. 23-33
Author(s):  
Mika Horttanainen ◽  
Juha Kaikko ◽  
Riikka Bergman ◽  
Katja Kakko ◽  
Hanna-Mari Manninen ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Combustion Process ◽  
Treatment Plant ◽  
Industrial Process ◽  
District Heating ◽  
Wastewater Sludge ◽  
Sludge Treatment ◽  
Pre Treatment ◽  
Sludge Drying ◽  
Dried Sludge

In addition to composting and anaerobic digestion, thermal treatment is one of the mostimportant treatment methods of wastewater sludge. There are special sludge incinerationplants, built for large volumes of wastewater sludge. Sludge is also burned with other fuels,especially in the forest industry. Energy from the combustion process is usually utilized asheat only or in combined heat and power production. Combustion diminishes the volume ofthe sludge by 80 to 96% depending on the moisture and ash content of the sludge. The delaytime of the material in the combustion process is a few seconds as opposed to several days inbiological processes. At the same time, all the pathogens are completely destroyed. Thechallenges in combustion are often related to the high moisture content of the sludge, whichcan cause problems to the stability of the combustion. Sludge can be dried thermally beforecombustion to avoid these problems.In this study, we introduce the modeling results of a sludge treatment process based onthermal drying and combustion. The process utilizes the released energy in distributedelectricity production.The process under review burns the dried sludge and produces high-pressure steam in anormal power plant process. The steam is led to the turbine where heat is converted tomechanical energy. After the backpressure turbine, the steam still contains a lot of thermalenergy. In the case study this heat is not used for district heating or industrial process heatingpurposes but utilized totally for sludge drying. One advantage of this process is that no heatload is required at the sludge treatment plant, often situated far from district heating networksor industry. The need for mechanical drying of sludge can also be optimized to save in thecosts of the mechanical drying facilities and energy. With the example case it is shown howthe pre-treatment, thermal drying and combustion should be designed to achieve a purelyelectricity producing process which does not need any other sources or consumption ofenergy.

A geothermal energy system for wastewater sludge drying and electricity production in a small island

Energy ◽  
2018 ◽  
Vol 163 ◽  
pp. 130-143 ◽  
Author(s):  
F. Calise ◽  
S. Di Fraia ◽  
A. Macaluso ◽  
N. Massarotti ◽  
L. Vanoli
Keyword(s):  
Geothermal Energy ◽  
Energy System ◽  
Wastewater Sludge ◽  
Electricity Production ◽  
Small Island ◽  
Sludge Drying

Comparison of VOCs Personal Exposure Levels According to Time-activity Patterns in Korea

Epidemiology ◽  
2011 ◽  
Vol 22 ◽  
pp. S98
Author(s):  
Wook-Hee Choi ◽  
Kyung-Hwa Park ◽  
Won-Ho Yang ◽  
Ki-Young Lee ◽  
Chung-Sik Yoon ◽  
...  
Keyword(s):  
Activity Patterns ◽  
Personal Exposure ◽  
Time Activity ◽  
Exposure Levels

scholarly journals Fungal Exposure and Low Levels of IL-10 in Patients with Sarcoidosis

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Marjeta Terčelj ◽  
Sanja Stopinšek ◽  
Alojz Ihan ◽  
Barbara Salobir ◽  
Saša Simčič ◽  
...  
Keyword(s):  
Inflammatory Cytokine ◽  
Serum Levels ◽  
Healthy Controls ◽  
Serum Cytokine ◽  
Fungal Cell ◽  
Fungal Exposure ◽  
Cytokine Levels ◽  
Exposure Levels ◽  
Low Levels ◽  
Anti Inflammatory Cytokine

Background and Objectives. Sarcoidosis is an inflammatory disease with increased levels of inflammatory cytokines. Previous studies have shown a relation between the degree of granuloma infiltration and serum cytokine levels, except for interleukin- (IL-) 10. The aim of the study was to further investigate the serum levels of IL-10 in patients with sarcoidosis and relate them to fungal exposure in terms of the amount of fungi in the air of their homes andβ-glucan in bronchoalveolar lavage (BAL) fluid.Methods. Patients with sarcoidosis (n=71) and healthy controls (n=27) were enrolled. IL-10 was determined in serum. BAL was performed and the amount ofβ-glucan was measured. Domestic exposure to fungi was determined by measuring airborneβ-N-acetylhexosaminidase (NAHA) in the bedrooms.Results. At high levels of fungal exposure (domestic fungal exposure andβ-glucan in BAL), serum IL-10 values were lower than at low and intermediate exposure levels.Conclusion. The low serum IL-10 values at high fungal exposure suggest that fungal cell wall agents play a role in granuloma formation in sarcoidosis by inhibiting the secretion of the anti-inflammatory cytokine IL-10.

Ecological stabilization of thickened wastewater sludge from CAST process

2008 ◽  
Vol 58 (10) ◽  
pp. 1911-1916 ◽  
Author(s):  
Y. B. Cui ◽  
X. H. Wu ◽  
Zh. Sh. Liu ◽  
J. Zh. Liu ◽  
Y. Z. Lin
Keyword(s):  
Protein Content ◽  
Operation Time ◽  
Pilot Scale ◽  
Quadratic Equation ◽  
Wastewater Sludge ◽  
Thickness Variation ◽  
Significant Difference ◽  
Treatment And Disposal ◽  
Dried Sludge ◽  
Relationship Of

Wastewater sludge ecological stabilization (WWSES) pilot scale experiments were conducted for thickening treatment and disposal of sludge which came from Cyclic Activated Sludge Technology (CAST) process. The study was performed over the periods from June to November 2005 and from May to November 2006, on a bed of 80 m2. The sludge loadings were stopped for the winter from December 2005 and resumed in May 2006. The results shows that dried sludge layer has higher permeation coefficients of 0.15–1.3 m/h. It is suggested that the percolate did not filtrate downwards evenly, part of percolate filtrates downwards along stems, roots and cracks existing in dried sludge which have lower flow resistance. The relationship of dried sludge thickness and operation time is in accord with quadratic equation under fluctuating sludge loadings. Linear regression equation can indicate dried sludge thickness variation under fixed sludge loading. In comparison with natural ones, coarse protein content of Phragmites australis roots in the system is twice as high, coarse fiber content of roots, coarse fat content of stems and leaf are obviously higher; and coarse protein content of Typha augustifolia in the system are obviously higher, while coarse fat and coarse fiber contents have no significant difference.

scholarly journals Assessment of Potential Health Risks of Portuguese Wildland Firefighters’ Occupational Exposure: Biomonitoring Approach

2021 ◽  
Author(s):  
Filipa Esteves ◽  
Joana Madureira ◽  
João Paulo Teixeira ◽  
Solange Costa
Keyword(s):  
Dna Damage ◽  
Occupational Exposure ◽  
Forest Fires ◽  
Oxidative Dna Damage ◽  
Personal Exposure ◽  
International Agency ◽  
Early Effect ◽  
Toxic Compounds ◽  
Exposure Levels ◽  
Risk Of Cancer

Introduction:Worldwide, forest fires are among the most common forms of natural disasters. In the closing years of the last century there was an increase of the burned area in some parts of the globe, including in Europe. Portugal has been particularly affected by large forest fires and megafires, which have been occurred mainly in the central and northern regions. The proximity of firefighters to fire exposes them to high levels of toxic compounds making this occupation one of the most dangerous and leading International Agency for Research on Cancer to classified occupational firefighting activity as possibly carcinogenic to humans. Up to date, the existing studies are mainly focused on environmental monitoring, existing limited information regarding biomonitoring assessments during real scenarios of wildland fires combat. This study aims to evaluate the impact of firefighting occupational exposure at molecular and cellular levels, considering personal exposure levels. Early-effect biomarkers (e.g., micronucleus, DNA strand breaks and oxidative DNA damage) will be analyzed in order to understand the mechanisms of action through which woodsmoke may impact firefighters’ health, including the risk of cancer. Methodology:This ongoing prospective longitudinal study will comprise three different stages, specifically pre-exposure, exposure, and post-exposure to fire season. Around 200 wildland northern Portuguese firefighters will be involved in this study. Characterization of the study population will be conducted via questionnaires. Firefighters’ personal exposurelevels will be assessed by means of metabolites in exhaled breath, using an artificial olfactory system (e-nose technology). Buccal and urine samples will be used to measure genomic instability through micronucleus test in buccal epithelial cells and urothelial cells. DNA damage and oxidative DNA damage will be evaluated in peripheral blood lymphocytes using the comet assay. Statistical analysis will be performed to determine the relationship between personal exposure levels to toxic compounds and the early-effect biomarkers over the three different phases of the study. Expected results: The obtained results will support a more accurate and comprehensive assessment of occupational risks among wildland firefighters, crucial to prevent/reduce the associated health impacts. This work will contribute tothe establishment of recommendations/good practices to improve firefighters’ working conditions, allowing better definitions of policies and prevention strategies highly needed in this sector.

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