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Explora: Environment
and Resource Comparative analysis of THMs and THAAs in water distribution media

According to Clark et al., there are four main strategies and membrane technology, are well-known but cannot be
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for controlling DBPs and microbial contaminants in considered as cost-effective or sustainable when compared
drinking water: biological filtration, conventional filtration, to sand filtration media, granular activated carbon (GAC),
membrane technology, and coagulation. Chaukura or even the adsorbing filter made from banana peels
et al. further identified effective methods for DBP studied in Jahin et al. Moreover, multiple studies have
5
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removal, including adsorption, air stripping, ozonation, shown that sand filtration and GAC play a significant role
chlorination, enhanced coagulation, membrane filtration, in the removal of NOM, a known precursor of DBPs.
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and advanced oxidation processes. In general, Jiang et al. Specifically, carbon-based adsorbents have been shown
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categorized DBP control into three major strategies: to significantly reduce emerging contaminants in water.
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source control, the use of alternative disinfectants, and To the best of our knowledge, no comparative study has
precursor removal. Source control includes implementing examined the formation and removal of major DBPs in
environmental management policies or replacing chlorine relation to the cost-effective treatment of water distributed
with alternative disinfectants such as chloramines or through galvanized iron (GI) and HDPE pipes.
chlorine dioxide, although these alternatives can still pose This study was conducted in District Mardan
health risks. Due to its low cost, simplicity, and minimal (geographic coordinates: 34°05’N–34°32’N and
energy requirements, sand filtration is widely used in 71º48’E–72°25’E), one of the central districts of Khyber
drinking water treatment. Similarly, ultrafiltration has Pakhtunkhwa (KP) Province, Pakistan. The study area was
been recognized as a promising technique. However, divided into three zones based on groundwater hydrology:
the removal efficiency of ultrafiltration depends on the an urbanized/industrial zone (Shergarh and Takhtbhai)
membrane pore size and the characteristics of NOM. 30 and a non-industrial (control) zone (Surkhabi), referred
For the quantification of THMs and HAAs, Kennedy to as Zone 1, Zone 2, and Zone 3, respectively, as shown
et al. conducted a pipe setup experiment similar to in Figure 1. The industrial zones are characterized by
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that of Liao et al., in which a 56-day testing period was activities such as manufacturing, car washes, markets, and
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selected to investigate DBP formation under maintained other commercial processes, while the non-industrial zone
booster chlorination dosages throughout the experiment. involves anthropogenic activities unrelated to industrial
In addition, EPA examined the effects of initial chlorine production.
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dosages across various pipe materials and analyzed the A total of 10 water samples were collected across the
formation and transformation of DBPs in WDS following three zones for the identification and quantification of
booster chlorination. DBPs. Of these, six samples (three for each pipe type under
DBP concentrations in each sample were measured non-filtration conditions) and four samples (two for each
using gas chromatography-mass spectrometry equipped pipe type under filtration conditions) were analyzed. Each
with an electron capture detector (GC-MS [ECD]). sample was tested under controlled chlorine dosages.
In this study, chlorine dosage levels were separately A prototype laboratory-scale experimental setup was
assessed—ranging from initial chlorination (0.43 mg/L) constructed to replicate a municipal WDS, simulating
to booster chlorination (1.03 mg/L)—to evaluate their water flow through GI and HDPE pipes under controlled
impact on DBP formation. GC-MS(ECD) is employed in conditions. Water samples were analyzed both without
DBP research due to its high halogen sensitivity and has filtration and with filtration, using abatement techniques
been recommended by Chakraborty et al. In comparison, such as sand filtration media and a combined sand-GAC
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Seyed Khademi et al. utilized Raman spectroscopy to trace
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impurities in water, while González García et al. used ion
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spectroscopy to identify dissolved ions and contaminants.
Similarly, González García et al. explored the variation of
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HAAs in a laboratory-scale distribution system consisting
of four independent pipe loops made of HDPE, polyvinyl
chloride, PP, and galvanized steel.
Although the generation of these prominent harmful
chlorine DBPs in the water supply has been characterized
and quantified based on the nature of the pipe material,
there remains a need for cost-effective techniques suited
to the specific pipe medium used. Some techniques
discussed in Chaukura et al. such as adsorption, air
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stripping, ozonation followed by enhanced coagulation, Figure 1. Study area division

Volume 2 Issue 3 (2025) 3 doi: 10.36922/EER025240047