scholarly journals Effect on water quality and control of chemically enhanced backwash by-products (CEBBPs) in the adsorption-ultrafiltration process

2020 ◽  
Vol 15 (3) ◽  
pp. 759-772
Author(s):  
Yue Zhang ◽  
Yongli Sun ◽  
Peng Huang ◽  
Xinbo Zhang
Keyword(s):  
Carcinogenic Risk ◽  
Haloacetic Acids ◽  
Halogenated Organic Compounds ◽  
Membrane Cleaning ◽  
Adverse Health Effects ◽  
Volatile Halogenated Organic Compounds ◽  
Local Residents ◽  
And Control ◽  
By Products ◽  
Ultrafiltration Process

Abstract The overall purpose of this research was to investigate the typical types of chemically enhanced backwash by-products (CEBBPs) produced in the chemically enhanced backwash (CEB) process and the influence of variability of CEB factors on typical CEBBPs in the adsorption-ultrafiltration process. Moreover, health risk assessment was utilized to assess the potential adverse health effects from exposure to effluent after the optimal online CEB. The results of the study found the NaClO backwash reagent could react with organic matter to produce CEBBPs, including 9 kinds of volatile halogenated organic compounds (VHOCs) and 9 kinds of haloacetic acids (HAAs) during the CEB process. After a comprehensive consideration of the influence of a single factor on the CEBBPs formation and membrane cleaning effect, the optimal CEB parameters were 6 min of BD, 120 min of BI, 30 L/(m2·h) of BF and 50 mg/L of RC. Under the optimum CEB cleaning parameters, the effluent does not pose a non-carcinogenic risk and posed potential carcinogenic risk to local residents. The lifetime carcinogenic risk (LCR) value for HAAs (6.68E-06) is very close to the LCR value of CEBBPs (6.78E-06), indicating that the HAAs are the main substances in the effluent after CEB.

Occurrence of haloacetic acids in chlorinated drinking water

2002 ◽  
Vol 2 (5-6) ◽  
pp. 487-492 ◽  
Author(s):  
P.C. Singer
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Haloacetic Acids ◽  
Field Scale ◽  
Treatment Practice ◽  
Stability And Control ◽  
Major Class ◽  
Chlorinated Drinking Water ◽  
And Control ◽  
By Products

Haloacetic acids (HAAs) are a second major class of disinfection by-products (DBPs) arising from the chlorination of drinking water. They have not been studied as extensively as the trihalomethanes (THMs), but in many waters they are found at concentrations equal to, or greater than, the concentration of THMs. Health effects research suggests that some HAA species are more harmful than THM species. This paper summarizes a number of the author's recent investigations concerning the formation, occurrence, stability, and control of HAAs in chlorinated drinking water. A number of examples linking observations made under controlled laboratory conditions to field-scale observations are presented, and the significance of the findings to water treatment practice is discussed.

Extremes of Temperature

2017 ◽  
Author(s):  
Ann M. Krake
Keyword(s):  
Control Measures ◽  
Temperature Extremes ◽  
Physiological Effects ◽  
Assessment And Evaluation ◽  
The Public ◽  
Adverse Health Effects ◽  
Extreme Cold ◽  
Prevention And Control Measures ◽  
And Control ◽  
Extremes Of Temperature

This chapter covers extremes of temperature conditions, physiological effects, and prevention. All deaths caused by exposure to hot and cold temperature extremes are preventable when proper measures are taken. Described in this chapter are the effects of extreme heat and extreme cold on the health of members of the public, particularly older people and young people, and workers employed in various workplace settings. The differences between heat stress and heat strain are also discussed, as are various regulations governing exposure to temperature extremes. The nature and magnitude of heat- and cold-related conditions and symptoms are described in detail. Final sections of the chapter address various assessment and evaluation tools as well as prevention and control measures. In addition, an appendix describes the hazards related to hyperbaric and hypobaric environments and adverse health effects.

scholarly journals Disinfection by-products in desalinated and blend water: formation and control strategy

2018 ◽  
Vol 17 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Shakhawat Chowdhury
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Cancer Risks ◽  
Domestic Water ◽  
Desalinated Water ◽  
Water Demands ◽  
Product Water ◽  
And Control ◽  
Different Sources ◽  
By Products

Abstract Desalinated seawater is the major source of drinking water in many countries. During desalination, several activities including pretreatment, desalination, stabilization, mixing, storage and distribution are performed. Few disinfectants are used during these activities to control the biofouling agents and microbiological regrowth. The reactions between the disinfectants and natural organic matter (NOM), bromide and iodide form disinfection by-products (DBPs) in product water. The product water is stabilized and mixed with treated freshwater (e.g., groundwater) to meet the domestic water demands. The DBPs in desalinated and blend water are an issue due to their possible cancer and non-cancer risks to humans. In this paper, formation and distribution of DBPs in different steps of desalination and water distribution systems prior to reaching the consumer tap were reviewed. The variability of DBPs among different sources and desalination processes was explained. The toxicities of DBPs were compared and the strategies to control DBPs in desalinated water were proposed. Several research directions were identified to achieve comprehensive control on DBPs in desalinated water, which are likely to protect humans from the adverse consequences of DBPs.

scholarly journals Preventing and controlling water pipe smoking: a systematic review of management interventions

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Javad Babaie ◽  
Ayat Ahmadi ◽  
Gholamreza Abdollahi ◽  
Leila Doshmangir
Keyword(s):  
Data Extraction ◽  
Water Pipe ◽  
Health Crisis ◽  
Adverse Health Effects ◽  
Analysis Process ◽  
School Based ◽  
Management Interventions ◽  
School Based Interventions ◽  
Global Arena ◽  
And Control

Abstract Background Water pipe smoking (WPS) is re-gaining widespread use and popularity among various groups of people, especially adolescents. Despite different adverse health effects of WPS, many of the WPS interventions have failed to control this type of tobacco smoking. This study was conducted to identify experienced management interventions in preventing and controlling WPS worldwide. Methods A systematic literature review was conducted. Electronic databases were searched for recordes which were published from beginning 1990 to August 2018. Studies aiming at evaluating, at least, one intervention in preventing and controlling WPS were included in this review, followed by performing the quality assessment and data extraction of eligible studies by two independent investigators. Finally, interventions that were identified from the content analysis process were discussed and classified into relevant categories. Results After deleting duplications, 2228 out of 4343 retrieved records remained and 38 studies were selected as the main corpus of the present study. Then, the identified 27 interventions were grouped into four main categories including preventive (5, 18.51%) and control (8, 29.62%) interventions, as well as the enactment and implementation of legislations and policies for controlling WPS at national (7, 25.92%) and international (7, 25.92%) levels. Conclusion The current enforced legislations for preventing and controlling WPS are not supported by rigorous evidence. Informed school-based interventions, especially among adolescents can lead to promising results in preventing and controlling WPS and decreasing the effects of this important social and health crisis in the global arena.

scholarly journals Distribution and Health Risk Assessment on Dietary Exposure of Polycyclic Aromatic Hydrocarbons in Vegetables in Nanjing, China

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Minmin Wu ◽  
Zhonghuan Xia ◽  
Qianqian Zhang ◽  
Jing Yin ◽  
Yanchi Zhou ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Health Effect ◽  
Dietary Exposure ◽  
Carcinogenic Risk ◽  
Source Analysis ◽  
Exposure Level ◽  
Critical Limit ◽  
Polycyclic Aromatic ◽  
Local Residents

In a market basket study made in Nanjing, China, in which the most common consumed nine kinds of vegetables foodstuffs were sampled, the contents of 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed using gas chromatography with mass spectrometer detector (GC-MS). The results showed that the total amount of 16 PAHs was within the range of 60.5~312 ng g−1 (wet weight). The ranking of total concentrations for different types of vegetables in decreasing order was leafy vegetable, fruit vegetable, and rhizome vegetable. Source analysis suggested that coal, oil, or other incomplete combustion of biomass mainly contributed to the concentration of PAHs. The margin of exposure (MOE) approach with age/gender group-specific daily dietary exposure level was used to estimate the carcinogenic risk. The calculated total mean MOE in the case of BaP and PAH4 (sum of BaA, CHR, BbF, and BaP) was 14960 and 7723, respectively, for local residents. In addition, the MOEs in PAH4 for some groups of both male and female were below the critical limit of 10 000 proposed by EFSA. Therefore, health effect owing to the consumption of vegetables on local residents needs high concern.

Identification of Bromohydrins in Ozonated Waters

1994 ◽  
Vol 48 (10) ◽  
pp. 1181-1192 ◽  
Author(s):  
Timothy W. Collette ◽  
Susan D. Richardson ◽  
Alfred D. Thruston
Keyword(s):  
Ir Spectra ◽  
Intramolecular Hydrogen Bonding ◽  
Infrared Spectrometry ◽  
Molecular Mechanics Calculations ◽  
Adverse Health Effects ◽  
Resolution Electron ◽  
Electron Impact Mass ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bound ◽  
By Products

Because ozonation is becoming a popular alternative to chlorination for disinfection of drinking water and little is known about the potential adverse health effects of ozonation disinfection by-products (DBPs), we have sought to identify ozone DBPs, particularly brominated organics, which are of principal concern due to their anticipated toxicity. Using gas chromatography coupled (independently) to low-resolution electron-impact mass spectrometry (LR-EI-MS), high-resolution EI-MS, chemical ionization MS (with 2% ammonia in methane), and Fourier transform infrared spectrometry, we have identified a series of bromohydrins and related compounds detected in extracts of an ozonated natural water sample that was artificially enhanced with bromide. The bromohydrins, which constituted the majority of by-products in the samples we studied, were detected but could not be identified by GC/LR-EI-MS, the technique used almost exclusively for environmental monitoring. A key to identifying the bromohydrins was the manifestation of intramolecular hydrogen bonding in the gas-phase IR spectra. Many of the by-products had two chiral centers, and both diastereomers were present and were separated by GC. In most cases, the IR spectra also permitted us to distinguish between diastereomers. We interpreted the IR and EI-MS spectra of several representative compounds in detail, and gave peak assignments for all that were identified. Molecular mechanics calculations and an experimental determination of the enthalpy change for conversion of free and hydrogen-bound conformers for a representative bromohydrin were used to verify the IR interpretations.

scholarly journals Formation of DBPs in the drinking eater of Athens, Greece: a Ten-Year study

2013 ◽  
Vol 7 (1) ◽  
pp. 106-118
Keyword(s):  
European Union ◽  
Drinking Water ◽  
Water Treatment ◽  
Chloral Hydrate ◽  
Haloacetic Acids ◽  
The European Union ◽  
Water Treatment Plants ◽  
Naturally Occurring ◽  
By Products ◽  
The Eu

The formation of Disinfection By-Products (DBPs) in drinking water results from the reaction of chlorine or other disinfectants added to the water with naturally occurring organic materials, and has raised concerns during the last decades because these compounds are harmful for human health. During the present work, the formation of different categories of DBPs was investigated in four water treatment plants (WTP) using chlorine as disinfectant, and in selected points of the distribution network of Athens, Greece, which is supplied from these four WTP, during a period of ten years. The concentrations of DBPs were generally low and the annual mean concentrations always well below the regulatory limit of the European Union (EU) for the total trihalomethanes (TTHMs). The haloacetic acids (HAAs) have not been regulated in the EU, but during this investigation they often occurred in significant levels, sometimes exceeding the levels of TTHMs, which highlights the importance of their monitoring in drinking water. Apart from THMs and HAAs, several other DBPs species were detected at much lower concentrations in the chlorinated waters: chloral hydrate, haloketones and, in a limited number of cases, haloacetonitriles.

scholarly journals Novel Antibiofilm Non-Biocidal Strategies

2021 ◽  
pp. 117-136
Author(s):  
Francesca Cappitelli ◽  
Federica Villa
Keyword(s):  
Control Strategies ◽  
Model Systems ◽  
Negative Effects ◽  
Alternative Strategies ◽  
Biofilm Model ◽  
Biocidal Products ◽  
Multiple Species ◽  
Cultural Heritage Objects ◽  
And Control ◽  
By Products

AbstractSubaerial biofilm (SAB) formation on cultural heritage objects is often considered an undesirable process in which microorganisms and their by-products, e.g., enzymes and pigments, cause damage or alteration to a surface. Since biofilms are widespread phenomena, there has been a high demand for preventive and control strategies that resist their formation or reduce their negative effects once formed. Up to date, the main strategy to control biofilms has been the use of biocides. Because of their intrinsic properties, biocidal products can pose risks to humans, animals, and the environment. In this chapter, the authors call “green” only those alternative strategies to biocides able to prevent/control biofilms but that do not kill microorganisms, i.e., irrespective of the use of natural compounds. Here, we describe some of the methods that are most commonly used to test the effectiveness of antibiofilm compounds with multiple-species biofilm model systems. A unified terminology and well described protocols and guidelines are still required to compare and test the effectiveness of traditional or novel compounds against biofilms retrieved on heritage surfaces.

scholarly journals Direct access to spirocycles by Pd/WingPhos-catalyzed enantioselective cycloaddition of 1,3-enynes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Long Li ◽  
Shan Wang ◽  
Pengfei Luo ◽  
Ran Wang ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Functional Groups ◽  
Organic Synthesis ◽  
Enantioselective Synthesis ◽  
Direct Access ◽  
Cycloaddition Reactions ◽  
Drug Discovery And Development ◽  
Spirocyclic Compounds ◽  
And Control ◽  
By Products

AbstractSpirocycles play an important role in drug discovery and development. The direct, catalytic, and enantioselective synthesis of spirocycles from readily available starting materials and in an atom economic manner remains a highly sought-after task in organic synthesis. Herein, an enantioselective Pd-hydride-catalyzed cycloaddition method for the synthesis of spirocyclic compounds directly from two classes of commonly available starting materials, 1,3-enynes and cyclic carbon−hydrogen (C−H) bonds, is reported. The reactions employ a chiral Pd/WingPhos catalyst to both suppress the formation of bis-allenyl by-products and control the stereoselectivity. 1,3-Enynes are used as dielectrophilic four-carbon units in the cycloaddition reactions, which also enables an enyne substrate-directed enantioselectivity switch with good levels of stereocontrol. The present spirocycle synthesis tolerates a broad range of functional groups of 1,3-enyne substrates, including alcohols, esters, nitriles, halides, and olefins. A variety of diverse cyclic nucleophiles, including pharmaceutically important heterocycles and carbocycles, can be flexibly incorporated with spiro scaffolds.

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