Page 122 - AJWEP-v22i2

Vasudeva, et al.

2.2. Concrete cube sampling and curing indicating stable pH levels. In June, the mean pH was
Concrete was prepared by mixing cement with samples 7.16, and the median was 7.17, maintaining the same
of both primary and secondary treated wastewater. The trend. A slight decrease was observed in July, with both
fresh concrete was then cast into standard molds. These mean and median values at 7.13. In August, the mean
molds were subsequently cured in water for 7, 14, and was 7.15, and the median was 7.16, while in September,
28 days. After each curing period, the concrete cubes both values stood at 7.14. In October, the mean was
were tested to evaluate their physical and mechanical 7.13, with a median of 7.14. November showed a slight
properties. increase, with a mean of 7.17 and a median of 7.13.
Finally, in December, the mean pH was 7.13, and the
2.3. Analysis of concrete cubes median was 7.14. Overall, the pH values remained within
To evaluate the properties of cement concrete, various a narrow range, demonstrating effective treatment and
laboratory tests were performed. The parameters consistent effluent quality. The complete pH values for
tested and the associated test methods are listed in the 31-months period (April 2021 to October 2023) are
Table 1. presented in Figure 4.
To prepare the concrete samples, treated wastewater
obtained from the 10 MLD STP at Bambianwali was 3.1.2. Temperature
mixed with potable water in the following ratios: Figure 5 presents the monthly mean and median
(i) 100% potable water temperatures over the 3-year study period, including
(ii) 60:40 mixture of primary treated domestic April 2021 – March 2022. In April, the mean
wastewater (mechanical) and potable water temperature was 26.82°C, with a slightly higher median
(iii) 60:40 mixture of secondary treated domestic of 27.355°C. Temperatures increased in May, reaching a
wastewater (biological) and potable water. mean of 28.09°C and a median of 28.22°C. This upward
Concrete cubes were cast using each water trend continued in June (mean: 28.66°C; median:
combination and subsequently tested to assess their 28.81°C) and July (mean: 28.80°C; median: 28.90°C).
properties.
The highest temperatures were recorded in August, with
a mean of 29.42°C and a median of 29.35°C. A gradual
3. Results and discussion
decline began in September (mean: 28.46°C; median:
This section presents a comprehensive analysis of the 28.62°C), followed by a more noticeable decrease
wastewater samples collected over a 3-year period in October (mean and median: 27.00°C). Cooling
from the outlet of the 10 MLD STP at Bambianwali. continued through November (mean: 25.93°C; median:
It also includes a performance assessment of concrete 26.10°C), and reached the lowest values in December
cubes prepared using potable water, primary treated (mean: 20.68°C; median: 20.29°C). A slight increase
wastewater, and secondary treated wastewater. was observed in January (mean: 21.14°C; median:
21.19°C), with further increases in February (mean:
3.1. Analysis of treated sewage water parameters 21.39°C; median: 20.94°C) and March (mean: 23.29°C;
(April 2021 – March 2022) median: 23.11°C). Overall, the data exhibit a clear
3.1.1. pH seasonal pattern, with peak temperatures in the summer
The pH values of the treated wastewater from the and lower values in the winter, consistent with the
10 MLD STP at Bambianwali (Figure 3) were monitored regional climate.
monthly and exhibited consistent results throughout the
year. In April, the mean pH was 7.15, closely aligning 3.1.3. TSS
with the median of 7.16, indicating slightly alkaline Figure 6 illustrates the monthly mean and median values
conditions. May recorded a mean and median of 7.18, of TSS for April 2021 – March 2022, highlighting trends
in water quality. The mean TSS values ranged from 16.42
Table 1. Tests conducted for concrete property to 17.14 mg/L, with the lowest observed in November and
analysis the highest in December. Median values were relatively
Serial no. Parameter Test performed stable around 17 mg/L, except in August, where a drop to
1 Workability Slump test 16.5 mg/L indicated a slight decline in central tendency.
In other months – April, May, June, July, September,
2 Compressive strength Load test and October – the median remained stable (17 mg/L),

Volume 22 Issue 2 (2025) 116 doi: 10.36922/AJWEP025060033