Water Softening methods and its Treatment Process 1. Lime soda process Lime and sodium carbonate are used to remove permanent hardness from water. Quick lime Cao or hydrated lime can be used for water softening.
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What are the different methods of water softening?
These must be softened by other methods, including lime soda or, more frequently, ion exchange softening described below. Conventional water softening is most often based a process known as ion exchange, utilizing a synthetic polymeric (plastic) material in the form of very small beads called ion exchange resin.
How to soften groundwater before aeration?
• Softening of groundwater should be done immediately before aeration takes place. • Water should not be chlorinated prior to this process. • Costlier for treating waters containing Fe and Mn because regeneration of zeolite is not possible. 17. Demineralization to remove hardness • Removal of minerals from water.
How to improve the quality of water softener?
To improve the quality of water demineralization is another method in water softening technique. It is similar to zeolite process with the difference that in the demineralization process the metallic ions such as calcium, magnesium, etc.. are exchanged for hydrogen ions.
What is lime softening in water treatment?
Water utilities struggling with source water that contains high amounts of calcium and/or magnesium often turn to lime softening to remove hardness. Raising treatment pH above 9.6 converts soluble calcium bicarbonate hardness to insoluble calcium carbonate.
How do water treatment plants soften water?
As hard water flows through the mineral tank, the resin beads exchange their sodium ions for hardness ions. Over time, this depletes the capacity of the resin to continue to effectively soften water.
How do you remove hardness of water from a water treatment plant?
Softeners use the method of ion exchange to remove hardness. They use a resin (small beads which form beds when they are applied to a columnar shaped tank). The beads have a natural affinity for hardness ions and will remove them from a water supply by exchanging them for sodium ions which are present on the resin.
What are two treatment methods to reduce water hardness?
MethodsThe most common means for removing water hardness rely on ion-exchange resin or reverse osmosis. ... Conventional water-softening appliances intended for household use depend on an ion-exchange resin in which "hardness ions"—mainly Ca2+ and Mg2+—are exchanged for sodium ions.More items...
Which method is used to soften water?
Water softening is achieved either by adding chemicals that form insoluble precipitates or by ion exchange. On a small scale, chemicals used for softening include ammonia, borax, calcium hydroxide (slaked lime), or trisodium phosphate, usually in conjunction with sodium carbonate (soda ash).
How do you convert hard water to soft water naturally?
How to Soften Hard Water Naturally Install an ion exchange shower head filter. Install an ion exchange softener for your entire water supply. Boil away impurities. Use baking soda in your cooking water. Add washing soda to your laundry. Use a reverse osmosis filter in aquariums.More items...
Which of the following methods are used to remove hardness?
Stnethetic resins and zeolite method Was this answer helpful?
How can water hardness be reduced?
Several ways to reduce the hardness:Diluting your hard water with some type of soft water. That is RO water, rainwater, deionized water. ... Filter your water over peat moss or peat plates. ... Filter thru commercially available water softening resins.
How can we reduce the effects of hard water?
7 easy ways to manage hard water issuesBoil “Temporary” Hard Water. ... Remove Soap Scum Using a Hard Water Cleaning Aid. ... Use Washing Soda When Doing the Laundry. ... Apply Some Distilled White Vinegar to Remove Hard Water Stains. ... Consider a Magnetic Water Conditioner. ... Install a Faucet Water Softener.More items...•
How to soften a hard water
Water treatment companies are inventing a variety of appliances and water softeners to overcome hard water issues. These water softeners come in different sizes and designs to address the size of the building. They are usually installed in the basement, garage, and beneath the house where the piping system is installed.
Benefits of using hard water treatment systems
A hard water treatment system is used to soften water by removing minerals such as calcium, magnesium, iron, aluminium, and manganese. When hard water is treated with hard water treatment systems, you will get benefits including:
What is water softening?
Conventional water softening is most often based a process known as ion exchange, utilizing a synthetic polymeric (plastic) material in the form of very small beads called ion exchange resin. The resin is porous so that each bead has tremendous surface area and the surface area is chemically constructed to contain billions of active or “exchange sites.” These sites have considerable affinity for metals in the water with valences (i.e., charges of +2 and +3). Thus, when water containing calcium, magnesium (the two major constituents of hard water), dissolved iron, copper or aluminum, the active sites attract and “hold” these ions.
What is the purpose of hard water softening?
The primary purpose of hard water softening is to prevent the precipitation and buildup of hard water minerals in equipment and piping. Reduction or elimination of hard water scaling can be performed using physical water treatment equipment, or, in limited circumstances, using chemical additives.
How does boiling water help to reduce soap scum?
Boiling the water promotes the reaction by driving off the carbon dioxide gas. 2 HCO 3 – → CO 32– + CO 2. The CO 32– reacts with Ca +2 or Mg +2 ions, to form insoluble calcium and magnesium carbonates which precipitate out. By tying up the metal ions in this way, the amounts available to form soap scum are greatly reduced.
How many tanks does a water softener have?
A water softener typically consists of two tanks, a larger one into which rock or pellet salt is added and a smaller tank containing the ion exchange resin through which the hard water passes. A control valve fixed atop the resin tank of the industrial water softener causes the system to recharge or regenerate based on passage ...
How much sodium is added to a gallon of water?
According to the Water Quality Association, the ion exchange softening process adds sodium at the rate of about 8 mg/liter for each grain of hardness removed per gallon of water. A “grain” of hardness is equal to 17.1 mg/l or ppm of calcium carbonate.
What is the source of hardness?
Definition and Source of Hardness. Limestone dissolved in water is termed “hardness.”. Ground water dissolves limestone from deposits formed eons ago through the following steps: a) carbon dioxide reacts with water to produce carbonic acid which in the environment exists primarily as the bicarbonate ion (HCO 3-1 );
Why is hard water treated?
The primary purpose of hard water softening is to prevent the precipitation and buildup of hard water minerals in equipment and piping.
What is water softening?
Water softening is a process in which the ions of calcium, magnesium and sometimes iron are removed. It is these ions in hard water that make it difficult for products with other positively charged ions to dissolve in the water. By doing this, the water softening removes the offending minerals from the water.
How to reduce water hardness?
Eliminating or reducing water hardness is done with a piece of equipment known as a water softener. It is inside this softener where the ion exchange process occurs. A softener is comprised of different components, each having their own unique purpose. The heart of the softener is the mineral tank which is a pressure vessel usually constructed out of fiberglass. These tanks are filled with negatively charged ion exchange resin. The brains of the softener lie in the control valve or softener head as it is commonly referred to. Most popular water softeners have an automatic regenerating system. The most basic type has an electric timer that flushes and recharges the system on a regular schedule. During recharging, soft water is not available. A second type of control uses a computer that watches how much water is used. When enough water has passed through the mineral tank to have depleted the beads of sodium, the computer triggers regeneration. These softeners often have reserve resin capacity, so that some soft water will be available during recharging. A third type of control uses a mechanical water meter to measure water usage and initiate recharging. The advantage of this system is that no electrical components are required and the mineral tank is only recharged when necessary.
What ions are exchanged in a water softener?
In the Softening cycle, water enters the softener and passes through the ion exchange resin charged with sodium (Na+) ions. As hard water passes through the resin, hardness ions (Ca2+ & Mg2+) are physically exchanged with the sodium ions on the ion exchange resin. This process continues until the resin becomes saturated with hardness ions ...
What is the definition of hardness in water?
Hardness in water is defined as concentration of multivalent cations. Multivalent cations are cations (metal ions) with a charge greater than 1+, mainly 2+. These cations include Ca 2+ and Mg 2+. These ions enter a water supply by leaching from minerals (such as limestone) within an aquifer.
Why does soap leave hard water stains?
It can also leave hard water stains on bathtubs or sinks and clog pipes. Water softening is a process in which the ions of calcium, magnesium and sometimes iron are removed.
What is the most common cause of hard water?
What this essentially does is take the cations of calcium and magnesium (the two most common causes of hard water) and replace them with the cations of another substance. Most typically the ions are exchanged with ions from dissolved sodium chloride salt (brine).
What is the primary media contained within a water softener?
The primary media contained within a water softener is known as ion exchange resin. This resin is basically an insoluble matrix typically in the shape of small (1-2 mm diameter) beads. The material has highly developed structure of pores on the surface of which are sites with easily trapped and released ions. This process of trapping of ions happens with a simultaneous releasing of other ions resulting in the term ion-exchange. Ion exchange resins can be manufactured to selectively prefer one, or perhaps several different types of ions. Typically, these resins are based on cross-linked polystyrene.
What is water treatment?
Water treatment means the cleansing of water through various phases to be available for end-use by the people. The treated water is then used for various purposes like irrigation, industrial water supply, drinking, river flow maintenance, or any other such uses. The treatment of water removes harmful contaminants and compounds or the concentration of these is reduced for public use. This treatment is mandatory to promote human health and its uses for drinking and irrigation.
What is the chemical used to disinfect water after sedimentation?
To further disinfect the water after sedimentation a chemical called chlorine is used to help remove pathogenic microorganisms. The remaining chlorine is known as residual chlorine which gets through the process of the distribution system.
What is treated raw water?
Raw water must be treated before use in utility processes. The treatment removes harmful substances like suspended and dissolved solids and other kinds of impurities that are present in large numbers. Treated raw water can be used for various purposes like cooling water, rinsing water, purified, and even drinking water. The process of raw water treatment includes:
What is the process of adsorption?
The adsorption process removes both organic and inorganic contaminants from water. Adsorption forms on the surface by the accumulation of a solid called adsorbents. They include stationary media like metal oxide, ion exchange, and activated carbon. Flocculation forms floc that can adsorb both inorganic and organic carbon like arsenic. Activated carbon helps in removing hundreds of organic contaminants.
Why is water treatment important?
The availability of pure water is of utmost importance in society. The water treatment process caters to this by supplying suitable water for industries or individuals. Only when the contaminants are removed from the water can they be used and accessible to everyone. Several processes like filtration and disinfection are used to purify water.
What is filtration in water?
These filters are composed of sand and gravel or crushed anthracite. Filtration combines all the dangerous impurities and particles that float on the water. This helps boost the effectiveness of disinfection. Filters are regularly serviced by backwashing for better filtration.
Why is fluoride used in water?
Fluoridation is used mainly in communities as it treats water supplies to bring a balance in the concentrated free fluoride ions. This is done till an optimal level is reached which helps avoid dental cavities.
What is the hard water level?
In the United States, hard water is mostly found in the mid western and western states. It ranges between 120-250 mg/L as CaCO3or beyond 250 mg/L as CaCO3 for very hard waters.
Why is soda ash added to lime?
Magnesium is removed due to the precipitation of magnesium hydroxide. In the lime soda ash process, lime is added to raise the pH while sodium carbonate is added to provide a source of carbonate ion.
How much magnesium noncarbonate hardness is needed for removal?
If the magnesium noncarbonate hardness and lime are expressed as CaCO3 , stoichiometric ratios suggest that for each mg/L of magnesium noncarbonate hardness present, 1 mg/L of lime expressed as CaCO3will be needed for its removal.
Environmental Engineering: Drinking Water Treatment
Understand what makes water clean or dirty and what are being done at water treatment facilities to make water safe to drink.
About this course
This course will cover fundamental science and engineering principles dealing with natural and water environmental systems. First, we focus on what influences water quality and what are sources, characteristics, and effects of water pollutants.
What you'll learn
l Relevant chemistry in water environment that are useful to understand how water quality is influenced by various chemical constituents and how to apply it for treatment processes