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3. ABSTRACT
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5. Understanding the water hardness levels in the water supply framework is essential for assessing its suitability for drinking, agricultural, and industrial purposes. This study aimed to evaluate the water hardness levels of WASA water in the Baridhara area (Block A to M) of Dhaka, Bangladesh. Complexometric titration was employed to determine the hardness levels between March 2024 and April 2024. The findings revealed significant variations in water hardness across different blocks, ranging from 105 ppm (Block A) to 220 ppm (Block I). The permanent hardness values ranged from 95 ppm (Block A) to 145 ppm (Block I), while temporary hardness ranged from 5 ppm to 50 ppm. These results indicate that the water supplied by the Water Supply and Sewerage Authority (WASA) in the Baridhara area contains notable concentrations of divalent cations, primarily calcium and magnesium, contributing to water hardness. This study can serve as a guideline to provide insights into the water conditions in the Baridhara area and the quality of water provided by WASA. Furthermore, the findings can contribute to water quality management in urban areas to improve the water supply system.
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7. Keywords: Dhaka WASA; Hardness; Water Suitability; Public Health
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9. 1. INTRODUCTION
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11. Drinking water is a fundamental human right governed by the World Health Organization (WHO) [1–3]. Besides its domestic use, water plays crucial roles in various industrial purposes [4]. Consequently, investigations into water quality in different regions worldwide have been prevalent [5–7]. Surface water quality is primarily evaluated for domestic and industrial purposes [8–10], while groundwater is assessed mainly for drinking purposes [2,11,12]. In various studies, physical (color, odor, taste, etc.), chemical (pH, dissolved oxygen, biological oxygen demand, chemical oxygen demand, alkalinity, conductivity, hardness, etc.), and biological (coliform, salmonella, etc.) parameters have been investigated to determine the overall water quality using different indices [5,6,8–12].
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13. Among these parameters, water hardness is one of the most critical factors, considering both domestic and industrial implications. Hard water is characterized by elevated levels of divalent cations, primarily calcium (Ca2+) and magnesium (Mg2+) [13]. Hence, hard water can have a metallic or chalky taste, leading to unpleasant sensations [14]. When used with hard water, the effectiveness of detergents and soaps is reduced [15]. During domestic use, washing machines, dishwashers, and water heaters can be damaged by hard water [16]. Moreover, mineral deposits on plumbing appliances can form scale, potentially leading to damage [17]. Hard water can cause various health problems, such as skin irritation, cardiovascular issues, diabetes, reproductive failure, neural diseases, and renal dysfunction [18,19]. Therefore, studying water hardness has attracted researchers' attention [20–24].
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15. This investigation holds significant importance for several reasons. Firstly, understanding the significance of water hardness in various industrial, environmental, and household contexts is crucial for ensuring optimal performance and efficiency [25]. Secondly, focusing specifically on the Baridhara area in Dhaka city, the research addresses the pressing need to assess the suitability and quality of the water supply for drinking purposes. With the local population's reliance on water supplied by the Dhaka Water Supply and Sewerage Authority (WASA), it is essential to gain insight into the water conditions in the area and understand the quality of the water provided. The findings of this research can serve as a foundation for improving water resource management, ensuring the provision of safe drinking water, and identifying potential areas for improvement in water treatment processes.
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17. The Baridhara area is an upscale residential area located in Dhaka, Bangladesh. Although groundwater is a primary water source for drinking, domestic, and other purposes in Dhaka, WASA has also provided water supply to the residents of Baridhara to ensure safe drinking water. However, the supply system has been criticized in recent years, as many residents have reported issues with stinky odors and offensive tastes [26]. In 2019, WASA itself admitted that water in 57 areas of Dhaka city was polluted [27]. Thus, continuous monitoring of the water supplied by WASA is a pressing need to ensure safe drinking water for the residents of the Baridhara area.
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19. By addressing the issue of water hardness in Baridhara, the safe and sustainable use of water resources can be ensured, which is vital for the well-being and development of the local population. Furthermore, the outcomes of this research can contribute to broader efforts aimed at managing water quality in the area and promoting effective water resource management practices.