Page 95 - EER-2-3

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

filtration system in a rapid, small-scale column test. The organic matter (DOM) (using fluorescence spectrometry),
two main chlorination DBPs—THMs and THAAs—were temperature (measured with a thermometer), and water
quantified using GC-MS (ECD), both with and without the hardness (determined using the titration method), as
application of filtration media. shown in Table 1.
2. Materials and methods 2.3. Setup

2.1. Chemicals and reagents For all sampling procedures, appropriate glassware was
used throughout the entire analysis. Sampling containers
Granular chlorine powder (calcium hypochlorite) was were thoroughly washed with detergent, rinsed with
obtained from the Water Quality Laboratory, Public Health tap water, followed by ultrapure water, and then dried
Engineering Department, KP, Pakistan. Two DBP standard in an oven at 150°C for 1–2 h. Samples were collected
compounds—chloroform and THAAs—were purchased in 100 mL amber glass bottles with PP screw caps and
from certified chemical suppliers in Pakistan. The solvent tetrafluoroethylene-lined septa. Bottles were carefully
for liquid-liquid extraction (LLE), ethyl acetate, was also filled to avoid the presence of air bubbles.
obtained from the Public Health Engineering Department,
KP, Pakistan, and was used to separate solutes from water In addition, a laboratory-scale pilot WDS was
samples. Distilled water used throughout the study was constructed to evaluate the effects of different chlorine
obtained from the Water Quality Laboratory, Public Health dosages. It consisted of pipe loops made of GI and HDPE,
Engineering Department, KP, Pakistan. Fluorescence as shown in Figure 2. Each loop measured approximately
spectrometry was performed at the Central Resource 1.5–3 m in length, with a pipe diameter of 25 mm. The
Laboratory, University of Peshawar, KP, Pakistan. loops were equipped with ball valves, elbows, unions, and
sockets to monitor water flow behavior, as well as control
2.2. Sampling site pressure and velocity. They were also used to direct water

In this study, multi-stage random sampling was employed flow in the desired direction. Flow velocity was maintained
to ensure systematic and representative sampling across all between 0.2 m/s and 1.8 m/s. A 0.3 HP centrifugal pump
three zones of District Mardan. Primary sampling units (Model QB60, Taifu, Pakistan) was installed to ensure
were selected in each zone—two in industrial zones and one continuous water circulation.
in the controlled (non-industrial) zone—to identify and In the distribution network, a 0.189 m (50-gallon)
3
quantify the formation of chlorination DBPs. In contrast, water reservoir was used to receive water samples directly
secondary sampling units consisted of two samples—one from the field site. Special attention was given to collecting
from the industrial zone and one from the controlled or grab samples from different zones while monitoring
non-industrial zone—which were used for the assessment temperature and sunlight exposure using the mobile water
of DBP abatement techniques through both quantitative quality testing laboratory of the Public Health Engineering
and qualitative analysis.
Department, KP. Before introducing water samples into
In all three zones, groundwater was the selected the pilot-scale laboratory distribution system, the system
source, and elevated head tanks or overhead reservoirs was rinsed with ultrapure water for 30 min to remove any
were utilized to provide head elevation and facilitate residual contaminants.
water distribution to consumers. Tubewells served as the
intake source at each site. The groundwater potential for The methodology for operating the laboratory
most sources was between 90 m and 120 m, with a static distribution system consisted of four main steps: flushing,
water level ranging from 18 to 30 m. The average yield per Table 1. Summary of water sample characteristics and their
tubewell was 6–8 m, and the discharge rate varied between observed ranges
0.00315 m /s and 0.00526 m /s. For consistency in sample
3
3
analysis, only water from tubewells older than 10 years, Parameters Range
connected to a minimum 5 km distribution network, was pH 7.2–7.8
selected. All samples were collected at terminal (end-user) Dissolved oxygen 5–5.7 mg/L
points of the distribution system.
Turbidity 1–3 NTU
Before analysis with GC-MS (ECD), key water quality Taste Fair
parameters influencing DBP formation were measured. Temperature 30–38°C
These included pH (using a pH meter), dissolved
oxygen (DO) (using a DO meter), turbidity (using a Hardness Soft water
nephelometer), taste (evaluated by taste test), dissolved Dissolved organic matter 1.8–2.2 mg/L

Volume 2 Issue 3 (2025) 4 doi: 10.36922/EER025240047