scholarly journals Statistical analysis of trihalomethanes in treated-water tanks: seasonality, local variability and correlations

2013 ◽  
Vol 13 (1) ◽  
pp. 41-49
Keyword(s):  
Water Quality ◽  
Statistical Analysis ◽  
Total Concentration ◽  
Waterborne Diseases ◽  
Raw Water ◽  
Operational Parameters ◽  
Significant Group ◽  
Water Tanks ◽  
Local Variability ◽  
By Products

Chlorine was accepted as an effective disinfectant for drinking water in early 1900s. Because of chlorination, chlorine has dramatically reduced the incidence of waterborne diseases. An unwanted side effect is the formation of harmful by-products upon chlorination. The most significant group of disinfection by-products formed during chlorination is the trihalomethanes (THMs). In this reason, European Union initiated the maximum contaminant level (MCL) of total concentration of THMs to 100 μg L-1. Because of this regulation, operational parameters of the WTP and raw water quality characteristics need to be studied in depth in order for THMs to be minimised. Statistical analysis is necessary for this purpose employing the parametric two-way ANOVA for the concentrations of chloroform (CHCl3) and dichlorobromomethane (CHCl2Br) and the analysis of variance on data ranks of chlorodibromomethane (CHClBr2) concentration. Chlorine dose, postchlorination, bromide levels, reaction temperature, reaction duration and dissolved organic carbon levels as well as pH of raw water, are the factors that affect the rate of THMs formation and the total THMs yield. Athens Water Supply and Sewerage Company (EYDAP SA), as the water supplier of a city with 3.5 million inhabitants, makes continuous attempts to improve water quality.

The study of interrelationship between raw water quality parameters, chlorine demand and the formation of disinfection by-products

2009 ◽  
Vol 34 (13-16) ◽  
pp. 806-811 ◽  
Author(s):  
Md. Pauzi Abdullah ◽  
Lim Fang Yee ◽  
Sadia Ata ◽  
Abass Abdullah ◽  
Basar Ishak ◽  
...  
Keyword(s):  
Water Quality ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Raw Water ◽  
Chlorine Demand ◽  
Raw Water Quality ◽  
By Products

Chlorine dioxide by-products predictive models for drinking water oxidation treatment

2008 ◽  
Vol 8 (3) ◽  
pp. 331-338 ◽  
Author(s):  
Mariachiara Zanetti ◽  
Alberto Godio ◽  
Francesca Gilardi ◽  
Rita Binetti ◽  
Chiara Laureri
Keyword(s):  
Water Quality ◽  
Water Oxidation ◽  
Organic Content ◽  
Ammonium Concentration ◽  
Raw Water ◽  
Operational Parameters ◽  
Water Characteristics ◽  
Raw Water Quality ◽  
Model Equations ◽  
Using Data

This study was aimed at developing statistically based model equations capable of predicting chlorite and chlorate formation during the primary oxidation/disinfection treatment using data collected on two real scale treatment plants. In this phase many operational parameters, raw water quality as well as the second oxidant dose applied, sodium hypochlorite, importantly influence the chlorite and chlorate formation. The operational parameters and the raw water quality correlated with chlorite and chlorate formation were: contact time, chemical doses, temperature, turbidity, organic substances (non-purgeable organic carbon and UV254nm absorbance), pH, iron and ammonium concentration. Given the high numbers of variables two models have been developed. The first one (complex) includes all the studied parameters; the other model (simplified) takes into account only the parameters that gave a significant correlation (>0.55) with the dependent variable. Nearly 60% of the predictions for chlorite formation were observed to be within ±40% of the measured levels and the found key parameters were the water organic content and the physico-chemical characteristics (pH and temperature). Nearly 85% of the predictions for chlorate formation were observed to be within ±40% of the measured levels and the found key parameters were again the chemical physical water characteristics (pH and temperature) and the applied chemicals doses.

The effect of the molecular mass of the organic matter in raw water on the formation of disinfection by-products

2001 ◽  
Vol 50 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Chen-Yu Chang ◽  
Yung-Hsu Hsieh ◽  
Yu-Min Lin ◽  
Po-Yu Hu ◽  
Chin-Chuan Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Molecular Mass ◽  
Raw Water ◽  
By Products

Leading the City of Baltimore into the 21st Century: Flexible Treatment Solutions and Integrated Raw Water Management

2010 ◽  
Vol 5 (4) ◽  
Author(s):  
J. L. Manuszak ◽  
M. MacPhee ◽  
S. Liskovich ◽  
L. Feldsher
Keyword(s):  
Water Management ◽  
Water Quality ◽  
Water Supply ◽  
Conceptual Design ◽  
Membrane Filtration ◽  
Treatment Plant ◽  
Low Pressure ◽  
Management Tool ◽  
Raw Water ◽  
The City

The City of Baltimore, Maryland is one of many US cities faced with challenges related to increasing potable water demands, diminishing fresh water supplies, and aging infrastructure. To address these challenges, the City recently undertook a $7M study to evaluate water supply and treatment alternatives and develop the conceptual design for a new 120 million gallon per day (MGD) water treatment plant. As part of this study, an innovative raw water management tool was constructed to help model source water availability and predicted water quality based on integration of a new and more challenging surface water supply. A rigorous decision-making approach was then used to screen and select appropriate treatment processes. Short-listed treatment strategies were demonstrated through a year-long pilot study, and process design criteria were collected in order to assess capital and operational costs for the full-scale plant. Ultimately the City chose a treatment scheme that includes low-pressure membrane filtration and post-filter GAC adsorption, allowing for consistent finished water quality irrespective of which raw water supply is being used. The conceptual design includes several progressive concepts, which will: 1) alleviate treatment limitations at the City's existing plants by providing additional pre-clarification facilities at the new plant; and 2) take advantage of site conditions to design and operate the submerged membrane system by gravity-induced siphon, saving the City significant capital and operations and maintenance (O&M) costs. Once completed, the new Fullerton Water Filtration Plant (WFP) will be the largest low-pressure membrane plant in North America, and the largest gravity-siphon design in the world.

Optimisation of coagulation and chlorination in drinking water treatment: laboratory and full-scale studies

2002 ◽  
Vol 2 (2) ◽  
pp. 131-137
Author(s):  
N.D. Basson ◽  
C.F. Schutte
Keyword(s):  
Water Quality ◽  
Large Fraction ◽  
Drinking Water Treatment ◽  
Agricultural Runoff ◽  
Treatment Costs ◽  
Full Scale ◽  
Raw Water ◽  
Activated Carbon Adsorption ◽  
Treated Effluent ◽  
Quality Optimisation

The paper deals with laboratory and full-scale studies aimed at optimising treatment processes at the Balkfontein plant of Sedibeng Water in South Africa. The raw water is highly eutrophic and contains a large fraction of treated effluent from domestic and industrial sources as well as agricultural runoff. The eutrophic nature and changing raw water quality give rise to many operational difficulties and high treatment costs as well as problems with the final water quality. Optimisation of the coagulation and chlorination processes was seen as a cheaper solution to these problems than to install advanced processes such as ozonation and activated carbon adsorption that would add greatly to treatment costs. The laboratory studies indicated that through optimisation of coagulation-flocculation and by replacement of pre-chlorination by intermediate chlorination (after primary sedimentation) most of the treatment problems could be solved and final water of the required quality produced without a large increase in treatment costs.

Predictability of fouling-potential of raw water for ultrafiltration membranes

2011 ◽  
Vol 11 (4) ◽  
pp. 481-489
Author(s):  
S. Krause ◽  
A. Obermayer
Keyword(s):  
Water Quality ◽  
Membrane Fouling ◽  
Large Scale ◽  
High Capacity ◽  
Raw Water ◽  
Ultrafiltration Membranes ◽  
Small Water ◽  
Lab Experiments ◽  
Flux Decline ◽  
Public Drinking Water

The public drinking water supply of southern Germany is characterized by a rather decentralized network. Due to the hydrogeological setting in these parts of Germany many of the small water works with an average capacity of 50 m3/h have to treat raw water extracted from karstic or cliffy aquifers. These raw waters tend to be contaminated with particles and pathogens acquired during snowmelt or after strong rainfalls. In the last decade ultrafiltration has become the technology of choice for the removal of the aforementioned contaminants. Flux decline caused by unanticipated membrane fouling is the main limitation for the application of ultrafiltration membranes. This paper describes how membrane fouling phenomena can be predicted by using a statistical approach based on data from large scale filtration systems in combination with field and lab experiments on raw water quality and membrane performance. The data defines water quality and respective fouling phenomena both in technical scale filtration plants and in lab experiments of eleven different raw waters. The method described here is more economically feasible for small water works when compared to typical pilot experiments that are used for high capacity water works.

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