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Water Treatment
Published in Frank R. Spellman, The Science of Water, 2020
Hypochlorites must be stored properly to maintain their strengths. Calcium hypochlorite must be stored in airtight containers in cool, dry, dark locations. Sodium hypochlorite degrades relatively quickly even when properly stored; it can lose more than half of its strength in three to six months. Operators should purchase hypochlorites in small quantities to assure they are used while still strong. Old chemicals should be discarded safely.
Sanitary and Hydraulic Engineering
Published in Ervan Garrison, A History of Engineering and Technology Artful Methods, 2018
Calcium hypochlorite was manufactured industrially for use as a bleaching powder and was used in paper mills and textile industries. It was a cheap chemical and, hence, readily adaptable to use on the large scale necessary for drinking water. The first practical demonstration in the United States of its use in water supply was at the filter plant of the Chicago Stockyards, where it was introduced by G.A. Johnson in the fall of 1908.
Glossary of scientific and technical terms in bioengineering and biological engineering
Published in Megh R. Goyal, Scientific and Technical Terms in Bioengineering and Biological Engineering, 2018
Hypochlorite refers to the aqueous solutions of sodium hypochlorite, potassium hypochlorite or calcium hypochlorite, which are oxidizing agents and used for disinfecting surfaces and surface-sterilizing tissues, and for bleaching.
Consistent point-of-use water chlorination among households using unimproved water sources and treatment preference in Eastern Ethiopia
Published in International Journal of Environmental Health Research, 2019
Abraham Geremew, Bezatu Mengistie, Jonathan Mellor, Daniele Susan Lantagne, Esayas Alemayehu, Geremew Sahilu
The two chlorine-based treatment products, Waterguard and Bishan Gari, were obtained from producers (PSI Ethiopia and Bishan Gari Industry PLC). Bishan Gari is a flocculent-disinfectant locally produced and marketed by a private company, Bishan Gari Industry PLC in Ethiopia. Each sachet contains a mixture of aluminum sulfate, calcium hypochlorite and soda ash, in a 2.5 g package. Chlorine (calcium hypochlorite) functions as the disinfectant to kill bacteria and other pathogens. Aluminum sulfate functions as a coagulant for reducing the turbidity of the raw water. A single sachet of Bishan Gari purifies 20 l of drinking water. To use, household add one sachet of Bishan Gari into bucket that contains 20 l of water, stir rapidly for 2 min and stir slowly for 5 min, wait for 20 min until the flock settles and all germs die, strain the water through a thick cotton cloth into another container (jerrycan) and drink the water. Bishan Gari has an advantage of both removing turbidity and killing microbes. Waterguard (locally called Wuha Agar) is a disinfectant with a 1.25% sodium hypochlorite (NaOCl) concentration being marketed by Population Service International Ethiopia. To use, households add one cupful of Waterguard, close the container and shake thoroughly and wait for 30 min before using the treated water (mMoWIE 2014).
Chlorine dioxide: an evaluation based on a microbial decay approach during mango packing process
Published in International Journal of Environmental Health Research, 2021
Marí Contreras-Soto, José Medrano-Félix, Benigno Valdez-Torres, Cristó Chaidez, Nohelia Castro-del Campo
As product of the high volumes of water used and the scarcity of this liquid, it is difficult to consider as viable the total substitution of water used for mango processing, which favours organic matter accumulation. For that reason, it is necessary to evaluate alternatives for achieving the best disinfection and diminishing bacterial transference possibilities required to avoid surface or internal mango contamination (USDA-APHIS 2019). In this regard, water disinfection using sodium/calcium hypochlorite has been the most commonly used practice worldwide to reduce microbial load, given its low cost, ease to use and wide-spectrum action (USDA-APHIS 2015).
Durability performance evaluation of green geopolymer concrete
Published in European Journal of Environmental and Civil Engineering, 2022
Salmabanu Luhar, Ismail Luhar, Rishi Gupta
The capability of Chloride binding can be characterized by one or more parameters as an activity of the whole concentration of Chlorides. Generally, it is explained as a concentration of leapt Chloride Ion (CI) as an act of free concentration of CI. This ability of CI binding is associated with the development of ‘Friedel’s salt’ mostly in case of blended cement and afterwards the presence of oxide of Aluminium, i.e. Al2O3. The formation of the said salt in the course of Chloride binding in OPC can restrain the relocation of Chloride and diminish the Chloride and Hydroxide ions in pore solutions (Balonis et al., 2010). This system is employed for estimating the jeopardy of corrosion to reinforcing steel. In cases of Slag based Geopolymer mortars, the possible impact of NaCl could influence the time for setting and improvement of strength. Nevertheless, novel produce of crystallization, especially, ‘Salt of Friedel’ was unobserved (Brough et al., 2000). In context to Geopolymer materials, Ismail et al. (2013) have stated that the occurrence of Friedel’s salt was not found involved in the binding of Chloride. The binding of Chloride relies chiefly upon the absorption of products of reaction physically in place of a chemical reaction (Lee & Lee, 2016). As illustrated in Figure 16, the specimens of OPC have demonstrated the greater bound content of Chloride than fly ash and slag based Geopolymeric materials where the amount of bound chloride is diminishing as the slag quantity augmented. Still, the Chloride binding mechanism of Geopolymer materials requires certain clarifications and hence, more future investigations are desirable. Kayali et al. (2012) have revealed that formation of the ‘Hydrotalcite’ – Talc like alteration mineral with a high content of water, in Slag based Geopolymer could soak up ions of Chloride through its exclusive feature of exchange of anion. They have utilized 16 g. ‘Calcined Hydrotalcite’ in a solution of NaCl and stirred it for one day period and found that the said mineral eliminated 72 percent ions of Chloride. Moreover, Park et al. (2015) have recorded the development of ‘Calcium Hypochlorite {Ca(ClO)2}’ – an inorganic compound and key dynamic element of ‘bleaching or chlorine powder or chlorinated lime’, useful for the treatment of water and also as a bleaching agent – in Slag activated by Calcium hydroxide [Ca(OH)2]with 0.5 to 3.0 percent content of NaCl. This was attributed to the adsorption of Ca(OH)2 physically to neighbouring Chloride.