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Published in Frank R. Spellman, Fundamentals of Wastewater-Based Epidemiology, 2021
Alkalinity is defined as the ability of water to resist a change in pH when acid is added; it relates to the pH buffering capacity of the water. Almost all natural waters have some alkalinity. These alkaline compounds in the water such as bicarbonates (baking soda is one type), carbonates, and hydroxides remove H+ ions and lower the acidity of the water (which means increased pH). They usually do this by combining with the H+ ions to make new compounds. Without this acid-neutralizing capacity, any acid added to a stream would cause an immediate change in the pH. Measuring alkalinity is important in determining a stream’s ability to neutralize acidic pollution from rainfall or wastewater—one of the best measures of the sensitivity of the stream to acid inputs. Alkalinity in streams is influenced by rocks and soils, salts, certain plant activities, and certain industrial wastewater discharges.
Water Quality
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Another important characteristic of water is its alkalinity, which is a measure of the water’s ability to neutralize acid or really an expression of buffering capacity. The major chemical constituents of alkalinity in natural water supplies are the bicarbonate, carbonate, and hydroxyl ions. These compounds are mostly the carbonates and bicarbonates of sodium, potassium, magnesium, and calcium. These constituents originate from carbon dioxide (from the atmosphere and as a by-product of microbial decomposition of organic material) and from their mineral origin (primarily from chemical compounds dissolved from rocks and soil). Highly alkaline waters are unpalatable; however, this condition has little known significance for human health. The principal problem with alkaline water is the reactions that occur between alkalinity and certain substances in the water. Alkalinity is important for fish and aquatic life because it protects or buffers against rapid pH changes. Moreover, the resultant precipitate can foul water system appurtenances. In addition, alkalinity levels affect the efficiency of certain water treatment processes, especially the coagulation process.
Drinking Water Monitoring
Published in Frank R. Spellman, The Drinking Water Handbook, 2017
Alkalinity is a measure of the capacity of water to neutralize acids. Alkaline compounds in the water, such as bicarbonates (baking soda is one type), carbonates, and hydroxides, remove H+ ions and lower the acidity of the water (increasing the pH). They usually do this by combining with the H+ ions to make new compounds. Without this acid-neutralizing capacity, any acid added to a stream would cause an immediate change in the pH. Measuring alkalinity is important in determining the ability of a stream to neutralize acidic pollution from rainfall or wastewater—one of the best measures of the sensitivity of the stream to acid inputs. Alkalinity in streams is influenced by rocks and soils, salts, certain plant activities, and certain industrial wastewater discharges. Total alkalinity is determined by measuring the amount of acid (e.g., sulfuric acid) required to bring the sample to a pH of 4.2. At this pH, all the alkaline compounds in the sample are used up. The result is reported as milligrams per liter of calcium carbonate (mg/L CaCO3).
Water quality assessment of Noyyal river using water quality index (WQI) and multivariate statistical techniques
Published in Water Science, 2022
Abirami Subramanian, Sushmitha Baskar
Alkalinity is the buffering capacity of water to neutralize acids which maintains a stable pH. Total alkalinity is the measure of carbonate, bicarbonate, and all the hydroxyl ions (calcium, magnesium, sodium, and potassium) and is expressed as calcium carbonate (CaCO3). The tolerable limit of total alkalinity determined by the Bureau of Indian Standards (BIS, 2012) is 200 mg/L to 600 mg/L. The values of total alkalinity in the collected samples varied from 64 mg/L to 880 mg/L. The characteristic reason for the excess alkalinity may be because of the lithology of the area as the carbonate minerals get dissolved from the rocks and soils. The anthropogenic source might be because of the industrial effluents, especially textile and associated manufacturing, as they utilize salts and surfactants for the better binding of the color to the fabrics. Babu and their team in (2017), have reported a similar case that the excessive hardness and alkalinity in downstream of the Noyyal river near the Tirupur is because of the release of chemicals used by the textile and its associated industries.
Drinking water quality and human health risk evaluations in rural and urban areas of Ibeju-Lekki and Epe local government areas, Lagos, Nigeria
Published in Human and Ecological Risk Assessment: An International Journal, 2020
Temitope O. Sogbanmu, Sherifat O. Aitsegame, Olubunmi A. Otubanjo, John O. Odiyo
Most of the physicochemical parameters (EC, turbidity, TDS, chlorides and nitrates) analyzed in water samples from the study areas were below the maximum permissible limits by NSDWQ (2007). However, the pH of water samples collected from rural communities in Ibeju-Lekki was above the recommended maximum limit of 8.5 (NSDWQ 2007). Drinking water with a pH level above 8.5 indicates that high levels of alkaline minerals are present. High alkalinity does not pose a health risk but can cause esthetic problems such as alkali taste to water (WHO/United Nations International Children’s Fund 2010). Also, the mean concentrations of TOC in the study area exceeded the NSDWQ (2007) limit of 5 mg/L. TOC is used as an indicator of the natural organic matter (NOM) and inorganic matter (bromide) in water. All commonly used chemical disinfectants (such as chlorine, chlorine dioxide, chloramines and ozone) react with organic matter and/or bromide to varying degrees to form different disinfection byproducts (DBPs) such as trihalomethanes (THMs). People can be exposed to THMs in drinking water through ingestion of drinking water, inhalation of indoor air largely due to volatilization from drinking water, inhalation and dermal exposure during showering and bathing. THMs are suspected to have negative effects on birth such as low birth weight, intrauterine growth retardation in terms of births as well as gestational age and preterm delivery. THMs have also been found to be carcinogenic and mutagenic with the greatest amount of evidence being related to bladder cancer (Mohamadshafiee and Taghavi 2012).
Assessment of some physicochemical parameters and determining the corrosive characteristics of the Karnaphuli estuarine water, Chittagong, Bangladesh
Published in Water Science, 2020
Md. Ripaj Uddin, Md. Moazzem Hossain, Shakila Akter, Muhammad Edris Ali, Md. Aminul Ahsan
Alkalinity represents the ability of water to neutralize acids and indicates solution’s activity to react with acid and buffer its pH that is, the power to keep its pH from changing. It is due to the presence of bicarbonates, carbonates and hydroxide of calcium, magnesium, sodium, potassium, and salts of weak acids and strong bases as borates, silicates, phosphates, etc. Higher concentration of alkalinity offers a bitter taste, harmful for irrigation as it damages soil and hence reduces crop yields (Sundar and Saseetharan, 2008). Table 8 shows that the Alkalinity of the Karnaphuli river varied from 10 to 650 ppm. Sampling station RK2 showed highest Alkalinity during the winter and spring season and lowest during the rainy season. Urea plant, chemical industry, cement industry, soap and detergent are responsible for the higher Alkalinity at sampling station RK2 (Tables 6 and 7). Department of Environment (DoE) sets 200 mg/l as a standard for the surface water Alkalinity. Table 8 shows that the observed values of some parameters in winter & spring season exceeded the acceptable limits for some stations which are listed in Table 10 and also shown in Figure 2.