Optimizing treatment for reduction of disinfection by-product (DBP) formation

2009 ◽  
Vol 9 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Edward Smith ◽  
Yasmine Kamal
Keyword(s):  
Natural Organic Matter ◽  
Cost Effective ◽  
Nile River ◽  
Source Water ◽  
Raw Water ◽  
Enhanced Coagulation ◽  
Regulatory Limits ◽  
Greater Cairo ◽  
Primary Fraction ◽  
High Alkalinity

Recent studies in communities in greater Cairo, Egypt have identified trihalomethanes (THMs) and haloacetic acids (HAAs) at levels that exceed regulatory limits depending upon the season. The objective of this study was to better understand the formation of DBPs in Nile River source water with a view toward optimizing conventional treatment, focusing on enhanced coagulation, to achieve reduction in DBP formation potential (FP) in a cost-effective scheme. To this end, characterisation of natural organic matter (NOM) in Nile raw water and after treatment by fractionating according to hydrophobic-hydrophilic properties was included in the analysis. Seasonal variations in raw water quality were found to be important for achieving optimum reduction of turbidity and DBP formation. In summer, alkalinity is lower; therefore, enhanced coagulation with 30 mg/L alum can be done at pH 6 without excessive additions of acid, and satisfactory reductions in turbidity and DBPs attained. During the remainder of the year, high alkalinity results in enhanced coagulation at about pH 6.5 and notably lower reduction of NOM, THMFP, and HAAs versus summer conditions. Supplementing enhanced coagulation with 10 mg/L PAC is highly recommended for these conditions as it improves removal of all DBP indicators. The transphilic fraction was the main contributor to DBP formation and the primary fraction removed by enhanced coagulation for achieving gains in THMFP reduction.

Fractionation of natural organic matter in the Nile River: implications for treated water quality

2009 ◽  
Vol 59 (10) ◽  
pp. 1989-1997 ◽  
Author(s):  
Edward H. Smith ◽  
Ahmed A. Alqabany
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Nile River ◽  
The Public ◽  
Chlorine Disinfection ◽  
Trihalomethane Formation Potential ◽  
Relative Contribution ◽  
Regulatory Limits ◽  
Greater Cairo ◽  
Hydrophobic Fraction

Recent sampling projects in greater Cairo, Egypt have indicated the presence of trihalomethanes and other chlorine disinfection by-products (DBPs) in the public water supply at levels that are periodically in excess of regulatory limits. Therefore, hydrophobic–hydrophilic fractionation of natural organic matter (NOM) was performed for raw Nile River water samples in order to identify the organic fractions that most readily react with chlorine to produce DBPs. Averages of five events over a 13-month period revealed that the hydrophilic neutral fraction made the highest contribution (35%) to the dissolved organic carbon (DOC), followed by hydrophobic (29%), transphilic (23%), and hydrophilic charged (13%) fractions. Relative contribution of NOM fractions to DBP formation was measured according to the trihalomethane formation potential (THMFP) test. Although the transphilic fraction was only the third highest contributor to DOC, on average it constituted the major contribution to THMFP (38%) followed by the hydrophobic fraction (31%). This finding was corroborated by the results of two events in which samples were collected in both Cairo and Luxor (750 km upstream). The transphilic fraction also yielded the best correlation between percent contributions to THMFP versus DOC.

Comparison of anion exchange resins and aluminum-based coagulants for natural organic matter (NOM) removal and disinfection by-product (DBP) formation

2014 ◽  
Vol 14 (4) ◽  
pp. 577-584 ◽  
Author(s):  
Elizabeth A. Crafton ◽  
Danyang Wu ◽  
Stephen E. Duirk
Keyword(s):  
Organic Matter ◽  
Anion Exchange ◽  
Natural Organic Matter ◽  
Source Water ◽  
Enhanced Coagulation ◽  
Excitation Emission Matrix ◽  
Anion Exchange Resins ◽  
Removal Processes ◽  
Exchange Resins ◽  
Chemical Sludge

Anion exchange resins (AERs) were compared with aluminum-based coagulants for reducing disinfection by-product (DBP) precursor concentrations from a source water collected in northeast Ohio, USA. Three AERs (IRA-910, IRA-958, and MIEX) were evaluated to determine which resin would remove the most natural organic matter (NOM) and moieties responsible for DBP formation. All the AERs were found to be highly proficient at NOM removal specifically the moieties that absorb UV254 (i.e., chromophores) over 75 min of contact time; however, MIEX removed NOM at a faster rate than IRA-910 and IRA-958 resins. Enhanced coagulation was effective at removing approximately 35% of the NOM and 40–60% of the chromophores and fluorophores (i.e., excitation–emission matrix pairs A and C). DBP formation was determined as a function of pH for the different NOM removal processes. MIEX treatment resulted in significant reduction in DBP concentrations when compared to chlorinating the raw source water. MIEX generally out-performed enhanced coagulation for reducing DBP formation. However, alum was found to remove more NOM and resulted in less DBPs compared to aluminum chlorohydrate. This could impact water utilities trying to balance the health effects due to DBP exposure verses chemical/sludge management costs.

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.

scholarly journals Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
G. O. Bosire ◽  
J. C. Ngila ◽  
H. Parshotam
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Natural Organic Matter ◽  
Solid Phase ◽  
Cooling Water ◽  
Raw Water ◽  
Aliphatic Carboxylic Acid ◽  
Hydrophobic Nature ◽  
Relationship Of

The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges.

Natural organic matter from catchment to drinking water: a case study of Pori waterworks, Finland

2008 ◽  
Vol 8 (6) ◽  
pp. 681-690 ◽  
Author(s):  
H. M. Szabo ◽  
I. Lindfors ◽  
T. Tuhkanen
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Raw Water ◽  
Lake Waters ◽  
Molecular Weight Fractions ◽  
Uv And Fluorescence Detection

In this study Natural organic matter (NOM) characteristics and variations of catchment samples (brooks and collector lakes) from Western Finland, and drinking water produced from the same catchment were examined. Seasonal and spatial NOM variations were followed by means of DOC and HPLC-SEC with UV and fluorescence detection. NOM decreased from drains to lakes by 35 to 75% and from drains to drinking water by 73 to 94%. Drains had a higher NOM content in summer and a lower NOM content in winter and spring. Lakes showed inverse patterns and had a higher NOM content in winter and spring and a lower NOM content in summer. HPLC-SEC separated 8 molecular weight fractions. In drains the HMW fractions represented up to 80% of the NOM, in lake waters HMW fractions accounted for 50 to 70% of the NOM. In drinking water IMW fractions dominated. Increased NOM in raw water during winter was associated with increased IMW fractions and the appearance of HMW fractions in drinking water, DOC increasing from 1.4 mg C/L in summer to 5.8 mg C/L in winter. SPH-Tryptophan correlated with the dissolved organic nitrogen and DOC of the samples. The drain affected by agriculture generally presented higher SPH-Tryptophan values than the unaffected drain.

Pre-ozonation of source water: Assessment of efficacy against Giardia duodenalis cysts and effects on natural organic matter

Chemosphere ◽  
2019 ◽  
Vol 214 ◽  
pp. 764-770 ◽  
Author(s):  
Liane Yuri Kondo Nakada ◽  
Regina Maura Bueno Franco ◽  
Vagner Ricardo da Silva Fiuza ◽  
Luciana Urbano dos Santos ◽  
Nilson Branco ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Giardia Duodenalis ◽  
Source Water ◽  
Water Assessment

Determination of Hydrophobic and Hydrophilic Fractions of Natural Organic Matter in Raw Water of Jalalieh and Tehranspars Water Treatment Plants (Tehran)

2007 ◽  
Vol 7 (18) ◽  
pp. 2651-2655 ◽  
Author(s):  
M.A. Zazouli ◽  
S. Nasseri . ◽  
A.H. Mahvi . ◽  
A.R. Mesdaghinia . ◽  
M. Younecian . ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Raw Water ◽  
Water Treatment Plants

Organic THMs precursors removal from surface water with low TOC and high alkalinity by enhanced coagulation

2004 ◽  
Vol 4 (5-6) ◽  
pp. 103-111 ◽  
Author(s):  
L. Rizzo ◽  
V. Belgiorno ◽  
S. Meriç
Keyword(s):  
Surface Water ◽  
Drinking Water Treatment ◽  
Residual Chlorine ◽  
Enhanced Coagulation ◽  
Toc Removal ◽  
Jar Test ◽  
High Alkalinity ◽  
Surface Water Resource ◽  
Free Residual Chlorine ◽  
Residual Al

NOM removal from surface waters is needed because of potentially carcinogen compound (trihalomethane, THM) formation due to reaction between NOM and free residual chlorine used for disinfection. The stringent limits for THMs (e.g., 30 μg/l in Italy) force conventional drinking water treatment plants to increase TOC removal efficiency by enhanced coagulation. This study was performed on 17 samples taken from a surface water resource with low TOC content (<3 mg/l) and high alkalinity (190 mg as CaCO3/l) to remove TOC and other parameters (DOC, UV254, SUVA, turbidity), typically used to characterize NOM content. Four different coagulants (Al2(SO4)3·18H2O, FeCl3·6H2O, FeSO4·7H2O and PACl) were used in jar test without adding polymer as flocculant. There was no correlation between DOC and SUVA in raw and treated water. TOC removal efficiencies (15–30%) required by the USEPA D/DBPs rule were obtained using 30–50 mg/l alum, 30–50 mg/l of FeCl3, and less than 20 mg/l of PACl (as Al2O3, 10%). The use of PACl is suggested for both lesser TTHMFP and residual Al levels (<100 μg/l) occurrences without any pH adjustment.

Experimental Studies on Enhanced Coagulation of Tail Water

2013 ◽  
Vol 295-298 ◽  
pp. 1478-1481
Author(s):  
Feng Xun Tan ◽  
Jiu Mei Wang ◽  
Dao Ji Wu
Keyword(s):  
Ferric Chloride ◽  
Removal Rate ◽  
Reclaimed Water ◽  
Experimental Studies ◽  
Ammonia Nitrogen ◽  
Raw Water ◽  
Nitrogen And Phosphorus ◽  
Enhanced Coagulation ◽  
Tail Water ◽  
Water Eutrophication

Traditional wastewater treatment methods can no longer remove effectively nitrogen and phosphorus that are the direct murderers of water eutrophication hazard. Enhanced coagulation method was adopted to improve the treatment effect by dosing suitable coagulants and coagulant aids. The raw water was from the reclaimed water in a University. TP and ammonia nitrogen removal of the water had been researched through an enhanced coagulation process with dosing ferric chloride, aluminum sulfate, polymeric ferric chloride, and poly-aluminum chloride (PAC) in this study. The coagulants effects were estimated by determining the removal rate of ammonia nitrogen, TP, COD and turbidity. When dosing the raw water with 80 mg/L PAC, the removal rates of ammonia nitrogen, TP, COD and turbidity are respectively 6.12%, 67.79%, 26.21%, 85.41%. The experimental results can be used as a reference of water treatment in the reclaimed water station.

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