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.

scholarly journals Simultaneous Compliance of TOC and Turbidity Related to Pathogen Breakthrough and THMs Control by Enhanced Coagulation

2013 ◽  
Vol 7 (1) ◽  
pp. 145-153
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Organic Carbon ◽  
Drinking Water Treatment ◽  
The Other ◽  
Haloacetic Acids ◽  
Enhanced Coagulation ◽  
Toc Removal ◽  
Jar Test ◽  
By Products

Since discovery of harmful disinfection by products (DBPs) like trihalomethanes (THMs) and haloacetic acids (HAAs) in chlorinated waters the removal of organic DBPs precursors gained priority in drinking water treatment. Historically, coagulation process was arranged to remove turbidity, typically related to pathogens occurrence, but nowadays it is usually optimized/enhanced for total organic carbon (TOC) reduction. This work dealt with the removal of TOC and turbidity by means of enhanced coagulation process using Al2(SO4)3⋅18 H2O and FeCl3⋅6H2O as coagulants for jar test without pH adjustment according to USEPA procedure. 15% of TOC removal required by USEPA D/DBPs rule (1998) was achieved using 30-50 mg l-1 of both coagulants. On the other hand, for compliance with more stringent MCL for total THMs in Italy (30 μg l-1) higher TOC removal (>30%) which needed of higher coagulants doses (80 mg l-1), was obviously required. Those high coagulant doses were also to be used for the compliance with the turbidity standard (<1NTU).

scholarly journals First Derivative UV Spectra of Surface Water as a Monitor of Chlorination in Drinking Water Treatment

2001 ◽  
Vol 1 ◽  
pp. 39-43 ◽  
Author(s):  
V. Zitko
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Surface Water ◽  
Distribution System ◽  
Drinking Water Treatment ◽  
Uv Spectra ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
First Derivative ◽  
Derivative Spectra

Many countries require the presence of free chlorine at about 0.1 mg/l in their drinking water supplies. For various reasons, such as cast-iron pipes or long residence times in the distribution system, free chlorine may decrease below detection limits. In such cases it is important to know whether or not the water was chlorinated or if nonchlorinated water entered the system by accident. Changes in UV spectra of natural organic matter in lakewater were used to assess qualitatively the degree of chlorination in the treatment to produce drinking water. The changes were more obvious in the first derivative spectra. In lakewater, the derivative spectra have a maximum at about 280 nm. This maximum shifts to longer wavelengths by up to 10 nm, decreases, and eventually disappears with an increasing dose of chlorine. The water treatment system was monitored by this technique for over 1 year and changes in the UV spectra of water samples were compared with experimental samples treated with known amounts of chlorine. The changes of the UV spectra with the concentration of added chlorine are presented. On several occasions, water, which received very little or no chlorination, may have entered the drinking water system. The results show that first derivative spectra are potentially a tool to determine, in the absence of residual chlorine, whether or not surface water was chlorinated during the treatment to produce potable water.

scholarly journals Enhancement of the free residual chlorine concentration at the ends of the water supply network: Case study of Souk Ahras city – Algeria

2018 ◽  
Vol 38 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Mohamed A. Bensoltane ◽  
Lotfi Zeghadnia ◽  
Lakhdar Djemili ◽  
Abdalhak Gheid ◽  
Yassine Djebbar
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Distribution Systems ◽  
Drinking Water Treatment ◽  
Field Measurements ◽  
Residual Chlorine ◽  
Water Utility ◽  
The Public ◽  
Point Of Use ◽  
Free Residual Chlorine

AbstractThe drinking-water supply sector has mostly targeted the water-borne transmission of pathogens. The most common method employed is the chlorination of drinking-water at treatment plants and in the distribution systems. In Algeria, the use of chlorine in drinking water treatment is a widespread practice. To enhance the concentration of the residual chlorine in the public water-supply system of a part of Souk Ahras city (Faubourg) (Algeria) known by its low concentration of the free residual chlorine (according to the water utility – Algérienne des Eaux: ADE investigation) especially at the point of use, practical steps were carried out. The method is a combination between numerical simulation using EPANET2 software and field measurements. Using statistical analysis the hydraulic model was calibrated and the observed values were very closer to the simulated results. The concentration was improved throughout the network after the injection of the appropriate dose.

Effects of pre-treatment with magnetic ion exchange resins on coagulation/flocculation process

2008 ◽  
Vol 57 (1) ◽  
pp. 57-64 ◽  
Author(s):  
B. Sani ◽  
E. Basile ◽  
C. Lubello ◽  
L. Rossi
Keyword(s):  
Ion Exchange ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Ion Exchange Resin ◽  
Test Procedures ◽  
Aggregation State ◽  
Jar Test ◽  
Pre Treatment ◽  
Magnetic Ion

A new Magnetic Ion EXchange resin for DOC (Dissolved Organic Carbon) removal (MIEX®DOC Resin) has been evaluated as water pre-treatment at the Drinking Water Treatment Plant (DWTP) of Florence in order to reduce the oxidant demand and disinfection by-products (DBPs) formation potential. This pre-treatment leads to several effects on downstream treatment processes. In this experimental study the effects of MIEX® pre-treatment on clariflocculation process were evaluated with respect to coagulant demand reduction and characteristics of flocs formed. The analysis was conducted using traditional jar test procedures and a Photometric Dispersion Analyser (PDA2000) which provided continuous information about the aggregation state of particles during the jar tests. For a fixed turbidity goal in clarified water, ion exchange pre-treatment led to coagulant dosage reduction up to 60% and PDA results shown that flocs formed in pre-treated water were bigger and more resistant to shearing effects than those formed by conventional clariflocculation.

scholarly journals Assessing efficiency of pre-ammonization aimed at reducing carcinogenic risks caused by trihalomethanes in drinking water

2020 ◽  
pp. 70-77
Author(s):  
L.A. Deryabkina ◽  
◽  
B.I. Marchenko ◽  
N.K. Plugotarenko ◽  
A.I. Yukhno ◽  
...  
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Natural Water ◽  
Water Source ◽  
Water Disinfection ◽  
Residual Chlorine ◽  
Gas Liquid Chromatography ◽  
Initial Water ◽  
Organic Chlorine ◽  
Deep Purification

In most Russian regions there is still a pressing issue related to providing population with high quality and safe drinking water. Up to now, chlorination has been the primary technique applied to disinfect drinking water as it is highly efficient, reliable, and relatively cheap. However, when chlorine is used to disinfect natural water that contains organic pollutants, it results in risks of by-products occurrence. These products are trihalomethanes, epigenetic carcinogenesis promoters that cause elevated carcinogenic risks under oral, inhalation, and subcutaneous exposure. Our research goal was to hygienically assess efficiency of pre-ammonization applied in water treatment procedures in order to prevent occurrence of carcinogenic organic chlorine compounds during chlorination and to minimize carcinogenic risks. We determined trihalomethanes and residual chlorine contents in model samples of natural water taken from a surface water source after chlorination with different doses of chlorine. We examined 52 pair parallel samples that had undergone pre-ammonization with ammonia sulfate and control ones. Trihalomethanes concentrations were determined in model water samples with gas-liquid chromatography. Basing on the results obtained via experiments on laboratory chlorination of river water, we determined quantitative characteristics and built regression models showing dependence between concentrations of organic chlorine compounds occurring due to chlorination (chloroform, dichlorobrommethane, dibromchloromethane) and chlorine doses and preammonization parameters. It was established that pre-ammonization was the most efficient in terms of preventing trihalomethanes occurrence under such disinfection modes when contents of residual active chlorine didn’t exceed recommended levels (0.8–1.2 mg/L). Basic ways to minimize carcinogenic risks caused by trihalomethanes are systemic control over their contents in drinking water during social and hygienic monitoring procedures; preliminary ammonization of water taken from surface water sources; prevention of unjustified hyper-chlorination; preliminary deep purification of initial water; disinfection with ultrasound radiation instead of preliminary chlorination; etc.

scholarly journals OPTIMIZATION OF THE DRINKING WATER TREATMENT PROCESS OF A SUGAR PLANT STATION IN COTE DIVOIRE

2021 ◽  
Vol 9 (01) ◽  
pp. 512-524
Author(s):  
Konan Lopez Kouame ◽  
◽  
Nogbou Emmanuel Assidjo ◽  
Andre Kone Ariban ◽  
◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Process ◽  
Polynomial Regression ◽  
Drinking Water Treatment ◽  
Optimal Dose ◽  
Raw Water ◽  
Water Treatment Process ◽  
Jar Test ◽  
Coagulation And Flocculation

This article presents an optimization of the drinking water treatment process at the SUCRIVOIRE treatment station. The objective is to optimize the coagulation and flocculation process (fundamental process of the treatment of said plant)by determining the optimal dosages of the products injected and then proposes a program for calculating the optimal dose of coagulant in order to automatically determine the optimal dose of the latter according to the raw water quality. This contribution has the advantage of saving the user from any calculations the latter simply enters the characteristics of the raw effluent using the physical interface of the program in order to obtain the optimum corresponding coagulant concentration. For the determination of the optimal coagulant doses, we performed Jar-Test flocculation tests in the laboratory over a period of three months. The results made it possible to set up a polynomial regression model of the optimal dose of alumina sulfate as a function of the raw water parameters. A program for calculating the optimal dose of coagulant was carried out on Visual Basic. The optimal doses of coagulant obtained vary from 25, 35, 40 and 45 mg/l depending on the characteristics of the raw effluent. The model obtained is: . Finally, verification tests were carried out using this model on the process. The results obtained meet the WHO drinkability standards for all parameters for a settling time of two hours.

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