Effect of Permanganate Preoxidation to Natural Organic Matter and Disinfection by-Products Formation Potential Removal

Trihalomethanes (THMs) are prevalent disinfection by-products. High THM formation is usually associated with natural organic matter with high molecular weight and aromatic characteristics, which is efficiently removed by nanofiltration (NF). In the Sea of Galilee and the Israeli National Water Carrier (NWC), water shows high THM formation potential, although it mainly contains low molecular weight and hydrophilic organic matter with low aromaticity. In the present study, NF removal abilities were tested on treated NWC water using three different spiral wound membranes (NF90, NF270, and DL). Rejections and fluxes were tested as a function of pressure, water recovery, and membrane type. Feed and permeate dissolved organic carbon (DOC), UVA254, total THM formation (THMF), and total THM formation potential (THMFP), as well as alkalinity, conductivity, hardness, Ca2+, Mg2+, and Cl− were measured to evaluate rejection and THM formation reduction. The results demonstrated that NF can efficiently remove natural organic matter (NOM) and reduce THM formation, even in this challenging type of water. At low water recovery, membranes showed average rejection of about 70–85% for THMFP and THM. Upon elevating recovery, average THM and THMFP rejection decreased to 55–70%, with THM content still well below regulation limits. Of the membranes tested, the higher permeability of NF270 appears to make it economically favorable for the applications tested in this work.

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The relationship between chlorine consumption and trihalomethane formation from hydrophobic and transphilic fractions: a comparative study between two dams of east Algeria

Journal of Water Reuse and Desalination ◽

10.2166/wrd.2014.032 ◽

2014 ◽

Vol 5 (1) ◽

pp. 72-82

Author(s):

Dhaouadi Mellahi ◽

Ridha Zerdoumi ◽

Nacer Rebbani ◽

Abdelhak Gheid

Keyword(s):

Drinking Water ◽

Organic Matter ◽

Natural Organic Matter ◽

Drinking Water Treatment ◽

Water Source ◽

Kinetic Behavior ◽

Complex Composition ◽

Formation Potential ◽

The Relationship ◽

By Products

In Algeria, the use of chlorine in drinking water treatment is a widespread practice. When chlorine combines with natural organic matter (NOM), it forms various chlorine by-products such as trihalomethanes (THMs). In this work, we studied the relationship between chlorine consumption and THM formation, by chlorination of hydrophobic and transphilic (TRS) fractions. We compared the kinetic behavior and the THM formation potential of two major dams in east Algeria. A nonlinear regression modeling study showed a good correlation of the specific chlorine consumption and the specific THM formation. In the case of Ain Zeda dam and at pH = 7, the specific THM yield coefficients αS were: 6.57 and 10.22 μg-THM/mg-Cl2.mg-C.L−1 for hydrophobic and TRS fractions, respectively, while at the same pH, they were 12.07 and 23.66 μg-THM/mg-Cl2.mg-C.L−1 for Ain Dalia dam. Although the NOM concentration of Ain Zeda dam was higher than that of Ain Dalia dam, the THM formation potential of Ain Dalia dam was greater than that of Ain Zeda dam. It seems clear that the water source origin and characteristics play a key role in this case. They affect the THM formation due to the complex composition of humic substances which differs from one source to another.

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