Evaluation of fluorescence excitation–emission and LC-OCD as methods of detecting removal of NOM and DBP precursors by enhanced coagulation

2011 ◽  
Vol 11 (5) ◽  
pp. 621-630 ◽  
Author(s):  
J. K. Wassink ◽  
R. C. Andrews ◽  
R. H. Peiris ◽  
R. L. Legge
Keyword(s):  
Natural Organic Matter ◽  
Principal Component ◽  
Close Correlation ◽  
Quantitative Detection ◽  
Aluminium Sulphate ◽  
Fluorescence Excitation ◽  
Enhanced Coagulation ◽  
Carbon Detection ◽  
Linear Correlations ◽  
By Products

Bench-scale tests were conducted to evaluate enhanced coagulation as a method for removing natural organic matter (NOM) from a surface water to reduce the formation of disinfection by-products (DBPs). Aluminium sulphate (alum) and two polyaluminium chloride (PACl) coagulants were used, as well as alum with pH depression. Using a PACl coagulant alone or alum with pH depression was shown to attain 35% removal of TOC at lower dosages (31 and 29 mg/L, respectively) when compared to the use of alum alone (43 mg/L). In addition to TOC and UV254, a fluorescence excitation–emission matrix (FEEM) approach and liquid chromatography–organic carbon detection (LC-OCD) were used to further characterize the removal of NOM in both untreated and filtered waters. Principal component analysis of FEEM was able to identify the presence of humic-like substances (HS), protein-like substances (PS), and colloidal/particulate matter (CPM); HS were found to have a close correlation with TOC and UV254. LC-OCD enabled the quantitative detection of hydrophobic and hydrophilic DOC; the latter was further separated into five components, the largest of which was HS. Strong linear correlations were calculated between TOC, UV254, HS, and hydrophilic DOC (r2 > 0.96); these parameters were also found to be closely correlated with the formation of trihalomethanes (THMs, r2 > 0.78) and haloacetic acids (HAAs, r2 > 0.92). Linear correlations with THMs and HAAs indicated that FEEM and LC-OCD provide good measures of DBP precursors when compared with TOC and UV254.

PARAFAC model as an innovative tool for monitoring natural organic matter removal in water treatment plants

2020 ◽  
Vol 81 (8) ◽  
pp. 1786-1796 ◽  
Author(s):  
Sikelelwa N. Ndiweni ◽  
Michael Chys ◽  
Nhamo Chaukura ◽  
Stijn W. H. Van Hulle ◽  
Thabo T. I. Nkambule
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
South African ◽  
Natural Organic Matter ◽  
Principal Component ◽  
Drinking Water Treatment ◽  
Fluorescence Excitation ◽  
Factors Affecting ◽  
Water Treatment Plants ◽  
Filter Clogging

Abstract The increase of fluorescent natural organic matter (fNOM) fractions during drinking water treatment might lead to an increased coagulant dose and filter clogging, and can be a precursor for disinfection by-products. Consequently, efficient fNOM removal is essential, for which characterisation of fNOM fractions is crucial. This study aims to develop a robust monitoring tool for assessing fNOM fractions across water treatment processes. To achieve this, water samples were collected from six South African water treatment plants (WTPs) during winter and summer, and two plants in Belgium during spring. The removal of fNOM was monitored by assessing fluorescence excitation–emission matrices datasets using parallel factor analysis. The removal of fNOM during summer for South African WTPs was in the range 69–85%, and decreased to 42–64% in winter. In Belgian WTPs, fNOM removal was in the range 74–78%. Principal component analysis revealed a positive correlation between total fluorescence and total organic carbon (TOC). However, TOC had an insignificant contribution to the factors affecting fNOM removal. Overall, the study demonstrated the appearance of fNOM in the final chlorinated water, indicating that fNOM requires a customised monitoring technique.

Contributions of spatial, temporal, and treatment impacts on natural organic matter character using fluorescence-based measures

2015 ◽  
Vol 15 (3) ◽  
pp. 589-598
Author(s):  
Nicolás M. Peleato ◽  
Robert C. Andrews
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Fluorescence Spectroscopy ◽  
Natural Organic Matter ◽  
Rayleigh Scattering ◽  
Treatment Plant ◽  
Principal Component ◽  
Fluorescence Excitation ◽  
Polyaluminum Chloride ◽  
Fluorescence Methods

The potential application of fluorescence spectroscopy for monitoring of organic matter concentration and character at four water treatment facilities was investigated. Results are presented showing impacts on natural organic matter (NOM) due to intake location on the same water body and from individual unit processes including ozonation, granular-activated carbon filtration, and coagulation/flocculation. For validation and comparison of fluorescence methods, organic matter was quantified and characterized using liquid chromatography-organic carbon detection (LC-OCD). Principal component analysis (PCA) and parallel factors analysis were used for dimensionality reduction and to represent individual organic components observed through fluorescence excitation-emission matrices. Fluorescence results generally agreed with LC-OCD characterization, indicating that complete treatment reduced organic concentrations and preferential removal of humic-like material was associated with coagulation/flocculation. PCA results indicated higher concentrations of humic-like material at the Island water treatment plant intake that was not well reduced by inline polyaluminum chloride coagulation and direct filtration. Through fluorescence spectroscopy, ozonation increased Rayleigh scattering, which is correlated to small colloidal/particulate concentrations. Full-scale results from four water treatment plants presented demonstrate that fluorescence methods can characterize NOM, providing similar identification of trends to LC-OCD, with possible online application and use in real-time water treatment process control.

Assessment of photo-oxidative alterations to natural organic matter in water using fluorescence excitation emission matrices and liquid chromatography-organic carbon detection techniques

2016 ◽  
Vol 8 (6) ◽  
pp. 1415-1424 ◽  
Author(s):  
G. O. Bosire ◽  
J. C. Ngila
Keyword(s):  
Organic Matter ◽  
Liquid Chromatography ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Fluorescence Excitation ◽  
Detection Techniques ◽  
Carbon Detection ◽  
Excitation Emission Matrices ◽  
Fluorescence Excitation Emission Matrices

Fluorescence excitation emission matrices (FEEMs) and liquid chromatography-organic carbon detection (LC-OCD) are relatively novel techniques currently used for analysing natural organic matter (NOM) in water.

scholarly journals Removal of natural organic matter for controlling disinfection by-products formation by enhanced coagulation: A case study

2012 ◽  
Vol 84 ◽  
pp. 41-45 ◽  
Author(s):  
Huijuan Liu ◽  
Ruiping Liu ◽  
Chuan Tian ◽  
Han Jiang ◽  
Xiaoling Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Enhanced Coagulation ◽  
By Products

Multivariate Analysis Aided Surface-Enhanced Raman Spectroscopy (MVA-SERS) Multiplex Quantitative Detection of Trace Fentanyl in Illicit Drug Mixtures Using a Handheld Raman Spectrometer

2021 ◽  
pp. 000370282110329
Author(s):  
Ling Wang ◽  
Mario O. Vendrell-Dones ◽  
Chiara Deriu ◽  
Sevde Doğruer ◽  
Peter de B. Harrington ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Principal Component ◽  
Surface Enhanced Raman Spectroscopy ◽  
Quantitative Detection ◽  
Least Squares Regression ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Current Screening

Recently there has been upsurge in reports that illicit seizures of cocaine and heroin have been adulterated with fentanyl. Surface-enhanced Raman spectroscopy (SERS) provides a useful alternative to current screening procedures that permits detection of trace levels of fentanyl in mixtures. Samples are solubilized and allowed to interact with aggregated colloidal nanostars to produce a rapid and sensitive assay. In this study, we present the quantitative determination of fentanyl in heroin and cocaine using SERS, using a point-and-shoot handheld Raman system. Our protocol is optimized to detect pure fentanyl down to 0.20 ± 0.06 ng/mL and can also distinguish pure cocaine and heroin at ng/mL levels. Multiplex analysis of mixtures is enabled by combining SERS detection with principal component analysis and super partial least squares regression discriminate analysis (SPLS-DA), which allow for the determination of fentanyl as low as 0.05% in simulated seized heroin and 0.10% in simulated seized cocaine samples.

scholarly journals Comprehensive Thermal Characteristics of Different Cultivars of Flaxseed Oil (Linum usittatissimum L.)

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1958
Author(s):  
Jolanta Tomaszewska-Gras ◽  
Mahbuba Islam ◽  
Liliana Grzeca ◽  
Anna Kaczmarek ◽  
Emilia Fornal
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heating Rate ◽  
Fatty Acid Content ◽  
Thermal Characteristics ◽  
Principal Component ◽  
Flaxseed Oil ◽  
Scanning Calorimetry ◽  
Total Oxidation ◽  
Increasing Temperature ◽  
Linear Correlations

The aim of this study was to describe the thermal properties of selected cultivars of flaxseed oil by the use of the differential scanning calorimetry (DSC) technique. The crystallization and melting profiles were analyzed depending on different scanning rates (1, 2, 5 °C/min) as well as oxidative induction time (OIT) isothermally at 120 °C and 140 °C, and oxidation onset temperatures (Ton) at 2 and 5 °C/min were measured. The crystallization was manifested as a single peak, differing for a cooling rate of 1 and 2 °C/min. The melting curves were more complex with differences among the cultivars for a heating rate of 1 and 2 °C/min, while for 5 °C/min, the profiles did not differ, which could be utilized in analytics for profiling in order to assess the authenticity of the flaxseed oil. Moreover, it was observed that flaxseed oil was highly susceptible to thermal oxidation, and its stability decreased with increasing temperature and decreasing heating rate. Significant negative linear correlations were found between unsaturated fatty acid content (C18:2, C18:3 n-3) and DSC parameters (OIT, Ton). Principal component analysis (PCA) also established a strong correlation between total oxidation value (TOTOX), peroxide value (PV) and all DSC parameters of thermo-oxidative stability.

Presence and formation of disinfection by-products in Cairo residential water supply

2009 ◽  
Vol 9 (2) ◽  
pp. 113-120 ◽  
Author(s):  
E. H. Smith ◽  
K. E. El-Deen
Keyword(s):  
Natural Organic Matter ◽  
Distribution System ◽  
Tap Water ◽  
Residential Community ◽  
Chlorine Disinfection ◽  
Sampling Program ◽  
The Impact ◽  
By Products ◽  
The U.S ◽  
Residential Water

A sampling program was conducted in a residential community in Cairo, Egypt in order to determine the presence of chlorine disinfection by-products (DBPs) in treated water and to observe the impact of the distribution system on DBP levels. Five campaigns were conducted over a 15-month period during 2005–2006. Trihalomethanes (THMs) and haloacetic acids (HAAs) exceeded local and international limits depending upon the season. Tap water concentrations of THMs were considerably higher in summer than during the rest of the year. In the Summer 2005 event, the average for the 20 tap water locations was 158 μg/l Total-THMs, well in excess of the U.S. EPA limit of 80 μg/L and the current Egyptian standard of 100 μg/l; all 20 locations exceeded the 100 μg/l limit. For the following event in late Fall 2005, the average dropped to 84 μg/l with 11 and 6 sites exceeding the U.S. EPA and Egyptian limits, respectively. HAA levels tended to be complementary to Total-THM values in that they were lower in summer but higher during fall and spring. The U.S. EPA limit on a select set of 5 HAAs (HAA5) is 60 μg/l (Egypt does not currently regulate HAAs). The average for HAA5 in the Summer 2005 event was 52 μg/l with 8 of the 20 tap samples equalling or exceeding the 60 μg/l standard. By contrast, in Fall 2005, the HAA5 average increased to 89 μg/l, with 15 of 20 sites exceeding the limit. THM and HAA concentrations generally increased with distance from the WTP along a targeted distribution main, while chlorine and natural organic matter tended to decrease.

scholarly journals Multivariate Monitoring of Surface Water Quality: Physico-Chemical, Microbiological and 3D Fluorescence Characterization

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1673
Author(s):  
Claude Daou ◽  
Mervat El Hoz ◽  
Amine Kassouf ◽  
Bernard Legube
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Anthropogenic Activities ◽  
Surface Water Quality ◽  
Principal Component ◽  
Specific Weight ◽  
Quality Parameters ◽  
Primary Objective ◽  
Fluorescence Excitation ◽  
Fluorescence Characteristics

The primary objective of this study is to explore a water quality database on two Mediterranean rivers (the Kadisha-Abou Ali and El Jaouz rivers—located in north Lebanon), considering their physicochemical, microbiological and fluorescence characteristics. Principal Component Analysis (PCA) was applied to the matrix gathering physicochemical and microbiological data while the Common Components and Specific Weight Analysis (CCSWA) or ComDim was used for fluorescence excitation-emission matrices (EEMs). This approach provided complementary and valuable information regarding water quality in such complex ecosystem. As highlighted by the PCA and ComDim scores, the Kadisha-Abou Ali River is highly influenced by anthropogenic activities because its watershed districts are intensively populated. This influence reveals the implication of organic and bacteriological parameters. To the contrary, the El Jaouz watershed is less inhabited and is characterized by mineral parameters, which determines its water quality. This work highlighted the relationship between fluorescence EEMs and major water quality parameters, enabling the selection of reliable water quality indicators for the studied rivers. The proposed methodology can surely be generalized to the monitoring of surface water quality in other rivers. Each customized water quality fingerprint should constantly be inspected in order to account for any emerging pollution.

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