Drinking water treatment - understanding the processes and meeting the challenges

2001 ◽  
Vol 1 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Don Bursill

On and follow Natural organic matter (NOM) derived from soil and vegetation in water catchments is the key factor influencing most, if not all water treatment processes. The structure of the NOM and its involvement in water treatment processes requires better understanding. It seems likely that a better understanding of NOM reactions could lead to far better predictive capacity for water treatment designers and operators. Certainly the removal of NOM as a first step to the production of drinking water has many attractions. This paper provides an overview of work done by the author and many of his colleagues to advance this issue.

2015 ◽  
Vol 15 (3) ◽  
pp. 442-455 ◽  
Author(s):  
Yue Zhang ◽  
Xinhua Zhao ◽  
Xinbo Zhang ◽  
Sen Peng

In the past decades, natural organic matter (NOM), which is a complex heterogeneous mixture of organic materials that are commonly present in all surface, ground and soil waters, has had an adverse effect on drinking water treatment. The existence of NOM results in many problems in drinking water treatment processes, and the properties and amount of NOM can significantly affect the efficiency of these processes. NOM not only influences the water quality with respect to taste, color and odor problems, but it also reacts with disinfectants, increasing the amount of disinfection by-products. NOM can be removed from drinking water via several treatment processes, but different drinking water treatment processes have diverse influences on NOM removal and the safety of the drinking water. Several treatment options, including coagulation, adsorption, oxidation, membrane and biological treatment, have been widely used in drinking water purification processes. Therefore, it is of great importance to be able to study the influence of different treatment processes on NOM in raw waters. The present review focuses on the methods, including coagulation, adsorption, oxidation, membrane, biological treatment processes and the combination of different treatment processes, which are used for removing NOM from drinking water.


2010 ◽  
Vol 10 (1) ◽  
pp. 59-68 ◽  
Author(s):  
I. Kristiana ◽  
B. P. Allpike ◽  
C. A. Joll ◽  
A. Heitz ◽  
R. Trolio

Water utilities have experienced increasing pressure to minimise the formation of disinfection by-products (DBPs), as reflected in the increasingly stringent regulations and guidelines for the concentrations of DBPs in drinking water. Understanding the disinfection characteristics and molecular weight (MW) distribution of natural organic matter (NOM) will assist in the optimisation of drinking water treatment processes to minimise the formation of DBPs. This study investigated the disinfection behaviour of MW fractions of NOM isolated from a Western Australian source water. The NOM was fractionated and separated using preparative size exclusion chromatography (SEC) and the fractions were chlorinated in the presence of bromide ion. The larger MW fractions of NOM were found to produce the highest concentrations of DBPs (trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, and haloaldehydes), with the low MW fractions still producing significant amounts of these DBPs. The results also showed a trend of an increasing proportion of brominated DBPs with decreasing MW and aromatic character. Considering that the smaller MW fractions of NOM produce significant amounts of DBPs, with a higher relative contribution from brominated DBPs, water treatment processes need to be optimised for either bromide removal or the removal of aliphatic, small MW fractions of NOM, in order to meet DBP guidelines and regulations.


2013 ◽  
Vol 6 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
E. R. Cornelissen ◽  
L. C. Rietveld

Abstract. To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m−3), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.


2011 ◽  
Vol 11 (6) ◽  
pp. 668-674 ◽  
Author(s):  
B. Q. Zhao ◽  
C. P. Huang ◽  
S. Y. Chen ◽  
D. S. Wang ◽  
T. Li ◽  
...  

Natural organic matter (NOM) plays a significant role in the fouling of ultrafiltration membranes in drinking water treatment processes. For a better understanding of the interaction between fractional components of NOM and polysulfone (PS) ultrafiltration membranes used for drinking water treatment, fouling and especially the physically irreversible fouling of natural organic matter were investigated. Resin fractionation, fluorescence excitation–emission matrix (EEM) spectroscopy, fourier transform infrared spectroscopy (FTIR), contact angle and a scanning electron microscope (SEM) were employed to identify the potential foulants. The results showed that humic acid and fulvic acid of small size were likely to permeate the membrane, while the hydrophobic fraction of humic and fulvic acid and aromatic proteins tended to be rejected and retained. Organic compounds such as proteins, humic substances, and polysaccharide-like materials, were all detected in the fouling layer. The physically irreversible fouling of the PS membrane seemed to be mainly attributed to the hydrophobic fraction of humic substances.


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