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Water Systems/Saving Our Valuable Resource
Published in Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo, Energy Conservation Guidebook, 2020
Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo
Most city water systems achieve purification by the filtration method. Water from the primary source is pumped or forced into a chemical building or area for the first phase of the purification process. Water arriving in this area is mixed with prescribed quantities of lime, activated carbon, alum, and chlorine. From this area the mixture then passes into a coagulation basin, where it is thoroughly mixed. A coagulant is a specific type of chemical that forms a small fluffy mass when placed in water. Aluminum sulfate or fiber alum is a common chemical used as a coagulant. The fluffy mass formed by this action is called floc. Floc particles are used to remove foreign material suspended in the water by adhering to it. Floc and other suspended material settle to the bottom of a basin after a short period of time. This action is representative of the coagulation and sedimentation function of the purification process.
Water Treatment
Published in Frank R. Spellman, The Science of Water, 2020
Coagulation is the reaction between one of these salts and water. The simplest coagulation process occurs between alum and water. Alum or aluminum sulfate is made by a chemical reaction of bauxite ore and sulfuric acid. The normal strength of liquid alum is adjusted to 8.3%, while the strength of dry alum is 17%.
Water Treatment Operations
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Coagulation is the reaction between one of these salts and water. The simplest coagulation process occurs between alum and water. Alum or aluminum sulfate is made by a chemical reaction of bauxite ore and sulfuric acid. The normal strength of liquid alum is adjusted to 8.3%, while the strength of dry alum is 17%.
Synthesis and characterisation of Portland cement clinker by exploiting waste oyster shells and alumina sludge
Published in European Journal of Environmental and Civil Engineering, 2021
Mohammed Dahhou, Muhammad Azeem Arshad, Mohammed El Moussaouiti
The research was carried out with alumina sludge, a waste from water treatment plant as elaborated in one of the authors’ previous studies (Dahhou et al., 2016), waste oyster shell, limestone, ash pyrrhotite and gypsum which were chosen as raw materials for the synthesis of clinker in order to eventually prepare Portland cement. Waste oyster shell specimens (Figure 1(a)) were taken from the province of Rabat, Morocco. The waste oyster shells were washed and dried in open air for 2 days. The studied alumina sludge is the one resulting from a conventional clarification treatment of raw water intended for human consumption. The raw sludge sample (Figure 1(b)) used in the experiments was collected from a purification plant at the Bouregreg complex (Rabat, Morocco) which discharges more than 3286 m3/day of sludge using coagulation, flocculation, sedimentation and sand filtration process. The aluminium sulphate was used as a coagulant during the purification process. After these steps, the obtained sludge is subjected to a thickening at 30 g/L and dehydration by centrifugation at 200 g/L and then evacuation to a storage area (Dahhou et al., 2016).
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).
Cellular stress strategies and harvesting methods to improve the feasibility of microalgae biofuel
Published in International Journal of Green Energy, 2022
Luciane Maria Colla, Munise Zaparoli, Francine de Souza Sossella, Naiara Elisa Kreling, Alan Rempel
Aluminum sulfate (Al2(SO4)3) is a low cost product, and is the most used in water treatment. However, wastewater with a high solid content requires a high dosage of Al2(SO4)3 and does not provide an adequate efficiency, which restricts its use. Ferric chloride (FeCl3) is often used in the treatment of effluents as a coagulant because it can operate in a wider pH range when compared to others (between 5 and 11). The disadvantage of using ferrous sulfate (FeSO4.7H2O) is the need for aeration of the medium because the formation of ferrous hydroxide, which is required for harvesting, occurs only in the presence of dissolved oxygen (Nunes 2004).