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How to lower chlorine in pool water

September 2, 2015April 12, 2019 Tasrik Leave a comment

During swimming pool maintenance, very often it is need to add chlorine. Sometimes the chlorine level becomes too much high. Therefore, it is need to lower swimming pool water chlorine level. Before, discussing “how to lower pool chlorine?” we discuss about why is chlorine used in pools water, how does chlorine work and dangers of chlorine.

Table of Contents:

Why is chlorine used in pools water

Why is chlorine used in pools? Due to insufficient chlorine in pool water algae, micro-organisms and bacteria are growth rapidly. These causes cloudy water, waterborne disease, and unsatisfactory sanitation of the water.

How does chlorine work

Chlorine kills microorganisms and bacteria in water by the process of chemical reaction. When the chlorine reagents discharge into the pool water then, it break into various chemicals such as hypochlorous acid (HOCl) and hypochlorite ion (OCl^–). Both these chemicals attack the lipids in the cell walls of bacteria and microorganisms and destroy the enzymes and structures inside the cell through the oxidizing reaction. Hypochlorous acid is more oxidizing agent then hypochlorite ion; normally it takes several second for this reaction in pool water whereas hypochlorite ion can takes up to 30 minutes. The production of HOCl and OCl^– depends on pH level of the pool water; it is highest when the pH level of pool water is between 7 and 8. Too high pH indicates lower production of HOCl (hypochlorous acid) and OCl^–. During cleaning the pool, they may combine with nitrogen compounds such as ammonia, or break into single atoms and deactivated. Moreover sunlight, water temperature also effects on the rate of this reactions. Therefore, more chlorine is required to the pool.

Cl₂ + H₂O → HOCl + HCl

Dangers of chlorine

Although proper dosages of chlorine is beneficial for pool water, but Extra chlorine is not good for human health. It has many side effects that can be aggravating to humans. Generally chlorine is a carcinogenic chemical. Additional chlorine in pool water can irritate the eye, nose and skin, creates coughing, wheezing, or even asthma. Here the chlorine is calculated with the combination of free and combined chlorine. Excess chlorine can also degrade the color of swimsuits and towels, damage hair, Pool surfaces and equipment. Therefore, it is essential to maintaining proper level of chlorine so that we can avoid the dangers of chlorine.

In The Swim Pool Water Chlorine Neutralizer – 2.25 lbs.

Swimming pool chlorine levels

Swimming pool chlorine levels should be kept at a certain range to ensure sufficient sanitation or avoiding dangers of chlorine. The desirable amount of free available chlorine in the pool water is 1.0-3.0ppm. It is better to keep 2.0ppm. In addition combined chlorine should be between 0 to 0.5 ppm.

How to lower pool chlorine

There are many easy way to reduce the chlorine level in pool water. Although indoor pool water can be more complicated to handle, but a lot of alternative are available. Some of them are described below:

1. Stop adding Chlorine:

If the chlorine level of your pool water is higher than 3ppm then, immediately stop adding more chlorine to the water until the level is suitable again. To stop adding chlorine, turn off automatic chlorinator, chlorine feeder or generator; remove the chlorine floater or chlorine tablet from the pool skimmer which system you are used.

2. By replacing existing pool water

By replacing some amount of pool water, someone can reduce the chlorine level; this may be one third. Then add same amount of fresh water, it will dilute the chlorine and you will able to lower the chorine level in pool water. This process is costly. Moreover, the water becomes out of balance such as calcium hardness, pH, alkalinity, and cyanuric acid levels.

3. With natural sunlight

Sunlight can remove chlorine naturally. Uncovered the pool and permit the sunlight to enter the pool so that it can reduce the chlorine level of pool water. This process may take a few days. It is recommended that it should be monitor if the chlorine level is lessening. If you have enough time before using the pool again, then this process is very good. You can use UV lamp as an alternatives of sunlight. On the other hand if you have few times, then you can follow other process. But you have to aware, it can effect on the water balance of the pool.

In The Swim Pool Water Chlorine Neutralizer – 15 lbs.

4. With a chlorine neutralizer

Several neutralizing chemicals such as Sodium Thiosulfate, Sodium Sulfite, Sodium Bisulfite, Sodium Metasulfite can reduce the chlorine in pool water. It is not wise decision to use too much chlorine neutralizer, it is also creates troubles.

4a. By using Sodium thiosulfate

The most common chlorine neutralizer is Sodium thiosulfate. Always discharge an accurate dose gradually; normally 75ml of sodium thiosulfate can reduce about 1 ppm of chlorine in 10,000 gallons of water. Since the Sodium thiosulfate is acidic, hence it reduces the pH level. Therefore, it is need to add pH increaser, after using this.

4b. By using Hydrogen Peroxide

Hydrogen peroxide is another chlorine neutralizer that can be used to lower the chlorine level. It works when the pH levels is higher than 7 and less effective at lower pH level. So if the pool has lower pH, then you have to adjust the pH before using hydrogen peroxide. It is a cheap chemical.

The other chlorine reducing chemicals are Sodium Sulfite, Ascorbic Acid, Sodium Bisulfite and Sodium Metasulfite. When you use any chemicals you should follow the instructions on the chemicals, otherwise it can lead to worse problems. Always test the pool pH after using these neutralizers.

In The Swim Pool Water Chlorine Neutralizer – 15 lbs.

Conclusion
So if the pool have high chlorine levels, you need not to worry, the above few steps will help you to lower pool chlorine level and back to normal.

How to remove algae from pool water

August 10, 2015May 8, 2018 Tasrik 1 Comment

The most common question from swimming pool owners are that “how to remove algae from pool water”. Reason, The development of algae is the general problem of them which is noticeable and looks ugly. They are single-celled organisms that grow quickly in the right conditions. Algae are microscopic size; hence they are invisible at naked eye, but visible when they accumulated. By keeping pool chemistry at right stage you can prevent their growth. On the other hand, if we are not able to control them, they will create slime, odor, discolor water etc. Here we discuss about the different types of swimming pool algae and how to prevent algae in pool.

Table of Contents:

Types of swimming pool algae
What causes algae in pools
Is it safe to swim in a pool with algae
How to prevent algae in pool
Swimming pool algaecide

Types of swimming pool algae

A wide variety species of algae are found in the world. They may be aquatic or non-aquatic. Only few of colors and types of algae are shown in swimming pool. They produce their energy and food by using photosynthesis process. They can be found as free floating, or walls and floor or inside of pipes and filters. The common swimming pool algae are green, black, yellow, pink etc.

Green algae

It is the most familiar among all the swimming pool algae and creates the swimming pool water green cloudy. Lack of proper filtration and sanitation are responsible for development of it. It is very often seen floating on the water and occasionally seen cling to the wall of pool or at the bottom. By brushing, it can be easily free from the wall. Removing green algae from pool is easy by using the accurate amount of shocking, and pool algaecide.

Yellow or mustard algae

The mustard algae look like yellowish green color or brown color. It is seen on the wall or on the bottom of the pool as pollen or sand, where is the lack of sufficient amount of sunlight. When it is started to grow, then it is very difficult to eliminate completely. After elimination, re-infection is common practice. Even treats with normal dose of sanitizer or pool algaecide. They can become chlorine resistant and can exist without sunlight. To kill it you need to use the best pool algaecide and super shocking.

Black algae

Black algae are responsible for stain in the swimming pools walls and floor. They can also become chlorine resistant and can exist without sunlight. It is the most irritating strain of algae. It is extremely hard to remove compare to green or blue-green algae particularly in plastered pools. Even compare to yellow algae. The roots of it are strong and grow deep into the plaster of pool walls. Even if you are taking care and maintenance swimming pool properly. Normally it does not change the clearness of the pool water. The Black algae seem to be as like tiny dark black spots.

Pink algae

Pink algae are not actually algae at all, but is a fungus called Paecilomyces lilacinus that creates slimy white, pink or grey colonies. It is slow to multiply and unusual that it will bloom over the whole swimming pool.

What causes algae in pools

The source of algae may be nearby stream, or a neighbor’s pool. The algae “spores” can dry out in the air and can be carried by the wind. The other sources of swimming pool algae are rain water, swimmer, swimsuits or equipment. If the conditions are in favor of algae bloom, then can occur within 24 hours. The suitable conditions are warm temperatures, sunlight, imbalance water, high pH level, low chlorine (level becomes 0.5 ppm or below) presence of nitrates and carbon dioxide. Organic substance and bacteria can also accelerate the development of algae in pool. July and August are suitable months for growth of swimming pool algae.

Is it safe to swim in a pool with algae?

Algae develop coloration of the water and make it cloudy. Moreover, it reduces the effectiveness of the filter by clogging up the pores. Therefore, it is needed additional backwashing or filter replacement. Swimming pool algae, itself is not dangerous. But it provides nutrients to bacteria (like E-coli) and micro-organisms with the help of sunlight and CO2. Therefore if we are not able to remove algae from pool water then the bacteria increases rapidly and cause disease.

How to prevent algae in pool

Properly swimming pool water maintenance (including regular circulation and filtration) and keeping minimum sanitizer levels will prevent any algae spores entering the pool water. Sufficient amount of free chlorine will help to prevent algae in pool from rising uncontrollable. If it is noticed that algae is growth then it needs treatment. It can be done with chlorine or pool algaecide. You can also remove algae from pool water by scrubbing the brush on the wall or floor where the algae grow. We should not allow blooming the algae in pool water.

Swimming pool algaecide

Algaecide is used to prevent or remove algae from pool water. Most of the pool algaecides are formulated such a way so that it can kill all types of algae. The most common type swimming pool algaecide are copper sulphate, chelated copper-based products, quaternary ammonia, benzalkonium chloride and simazine. It may create water foaming, increasing TDS and change total alkanity and pH. Although copper based algaecide is cheaper, but it is responsible for staining of the pool walls and floor and discolor of the water. So isolated copper based algaecide is recommended, even they are more costly. Quaternary ammonia type algae are fine but it has one problem that it creates foam which is annoying for some people.

Disadvantages of swimming pool algaecide:

The increase of copper in the sediments
It may clog the filters.

The swimming pool water should not be operating until the toxins and odors decreases and becomes normal position. Before using the chemicals you should be conform which type of algae is in your pool. It is recommended that, always use rubber gloves, goggles and keeps pool chlorine out of reach of children and pets. If you remove algae from pool water then the swimmers will get a clear and healthy pool to enjoy throughout summer.

Swimming pool water problems and testing

August 3, 2015March 12, 2018 Tasrik 2 Comments

The contaminants are responsible for swimming pool water problems. Most of the problems are directly related to our health. Therefore, it is essential to testing and correcting the pool water regularly. Without testing you are not able to identify a particular problem accurately. The pool water maintenance is one of the biggest challenges for the pool owners or operators. Inadequate knowledge and careless would brings the result of pool water problems. If we are not able to maintenance properly, then the health of our families are in danger.

Common swimming pool water problems

Cloudy swimming pool water

The presence of small particles in the water can create cloudiness. The main problems of cloudy water are improper filtration, insufficient water circulation, reduce flow rate, looks ugly etc.

Algae problems

creates Green cloudy water, Black (spongy) spots, Pink or white slime etc. The algae itself is not dangerous but it provides nutrients to bacteria and micro-organisms that are responsible for different disease.

Chlorination problems

The chlorine level may be low or high. Low chlorine can create algae problem, bacteria or microorganism problem. On the other hand high chlorine level can creates burning eyes and nose.

Staining of the pool

Although staining is not harmful for health but it reduce the attraction of the swimming pool. Therefore swimmers do not feel comfort to swimming.

Dust, sand etc

It will creates brown cloudy water.

Iron and copper problem

If the copper level is high, it can lead to green hair, fingernails, pool walls and water, as well as pool staining. High concentrations of iron can damage or discoloration of the pool surface.

Manganese problem

It can create stains on pool plaster and tile grouting.

TDS problem

TDS means total dissolved solids including debris, salts, chemicals, body fat etc. It increases with chemical addition in the pool. Higher TDS can create water clarity problem, stains on tile and plaster, scaling, salt taste, trouble to keep chlorine level and disturbance in water balance.

Others problem

Hardness especially calcium hardness
Overall health problem including Burning eyes and nose
Microorganisms including bacteria and viruses

Sources of the swimming pool water problems

There are many sources that create problems of pool water. The Water problems and pollution is interrelated which comes from environment, animals, wildlife or chemicals into the pool or carried by the swimmers. Some sources of the swimming pool water problems are described below:

Swimmers

Human body may contain microorganisms, sand, dusts etc. Moreover they use different types of cosmetics, oils. When they are swimming in the pool, then these unwanted contaminants get entered into the pool water. Human urine may also the pollutants of the water.

Environment around the pool

The environment around the pool can pollute the pool water. It contains different sorts of debris like dust, sand, leaves, grass, pollen, spores which can easily go into the water by the wind or other ways.

Animals and wildlife

Many animals including pets and wildlife may also the source of the pool water pollution. Occasionally the wildlife like frogs, lizards or insects may die in the swimming pool and would pollute the water.

Lack of proper maintenance

Lack of proper swimming pool maintenance, uses of over doges and poor quality chemicals are another source of swimming pool water problems.

Source of fresh water

Sources of water may be another source of contaminants in pool water. Sometimes the pool operators have to take some fresh water. If this water contains different contaminants, then it will also reduce the water quality of swimming pool.

Swimming pool water quality

It is recommended that your Swimming pool water should to maintain that are suggest as below:

Smell: water should not contain any bad smell.
pH value: The optimum pH value for pool water is 7.4; so try to maintain within the range 7.0 to 7.6. The pH value indicates the acidity or alkalinity of pool water. Both the lower or higher pH value can damage pool equipment, cause skin discomfort, and irritate the skin and eyes. Moreover it can effects on chlorine consumption.
Free chlorine: It should be keeping between from 0.5 to 1.5 ppm
Total alkalinity (TA): for public pools 80-120 ppm. It acts as a buffer and prevents the pH from fluctuation. These ranges of total alkalinity value may also increases equipment life and help the sanitizers so that they can work effectively.
Hardness (calcium hardness): acceptable range 100 – 300 ppm. The range can varies depends on the type and surface materials of the pools. High hardness is responsible for scale formation and circulation distress whereas the lower hardness can responsible for corrosion.
Stabilizer (Cyanuric Acid): 25-50 ppm
Total Bromine: 2-3 ppm
Temperature: 21 ⁰C to 32 ⁰C
TDS level: The maximum acceptable level is 1,500 ppm
Copper: maximum level 1.0ppm
Iron: maximum 0.3 ppm

swimming pool water testing

For maintaining water quality properly, testing is part and parcel of every pool owners. They have to test pool water regularly (daily, weekly or monthly) to avoid unwanted swimming pool water problems. It should be ensure that the chlorination, pH level, total alkalinity, TDS, iron, copper and calcium hardness level are exact as quality water rages. If your pool is salt water pool, then you also have to test salt levels. All the parameter should have not to check daily, some of them have to check weekly whereas some of them need to test monthly. Consequently you can able to detect the changes of water quality before problems develop. The water quality may differ from state to state. It is recommended that the pH and chlorine levels check daily basis before the first swim of the day. Rests of the parameters of pool water have to test weekly. If your fresh water sources are free from any metals and there is no possibility to entered, then the tests for those metals are unnecessary.

You will get many good pool water test kit at different market places but it should be reliable. It is advice that always keeps the pool kit in a cool dry place, out of sunlight and outside the reach of children. You can buy following swimming pool water test kit at Amazon.

Most of the swimming pools water problems can be avoided by maintained water quality. If you not able to maintained water quality then it would be harmful to the pool materials and equipment above all simmers health.

Niagara bottled water company has recalled its 14 bands bottled spring water

July 15, 2015July 15, 2015 Tasrik Leave a comment

Niagara Bottling, a family owned bottled Water Company in USA is a voluntary recall covering 14 brands of its water because of possible contaminant E. coli bacteria. The possible affected date is from June 10 to June 18 of this year. The affected bands are Niagara Spring Water, Acadia Spring Water, Acme Spring Water, Big Y Spring Water, Nature’s Place Spring Water, Pricerite Spring Water, Superchill Spring Water, Best Yet Spring Water, 7-11 Spring Water, Morning Fresh Spring Water, Shoprite Spring Water, Shaws Spring Water, Western Beef Blue Spring Water and Wegman’s Spring Water.

Throughout the 8 days, this effected bottled spring water was shipped to over 15 states including Pennsylvania, Connecticut, Maine, Delaware, District of Columbia, Virginia, West Virginia, Maryland, Massachusetts, Rhode Island, Vermont, New York, New Hampshire, New Jersey, and North Carolina.

These brands of bottled water are produced in two Pennsylvania manufacturing plants at Hamburg, Berks County and Upper Macungie, Lehigh County of the company. The company said that one of its spring bottled water sources was contaminated by traces amount of E. coli bacteria. Still, there are no reports of any illness linked to the above mentioned bottled Water. The voluntary removal effort is being implemented in collaboration with State and Federal Agencies. The Niagara bottled water company always tries to maintaining the maximum probable standards for product quality.

The Niagara bottled water company alerts this promptly due to the company’s good well and health concern of the people. The people who are lived of these 15 states and bottled water drinker, should to be check the manufacturing date of these 14 bands. If the product date between June 10 and June 18, 2015 and manufactured at Pennsylvania facilities than it must be avoid drinking. The bottled water that is produced outside of Pennsylvania or outside the June 10-18th, 2015 timeframe is completely safe to drink.

If anyone needs further information about this they can call at (888) 943-4894 to know more.

Internal treatment and control of boiler feed water

June 6, 2015June 6, 2015 Tasrik Leave a comment

Even if external water treatment is designed and executed, it is inevitable that problems such as corrosion and scale still occur in the long run of the boiler operation. Boiler water treatment chemicals are therefore used for protecting a boiler plant from the problems and are applied for the whole systems including the feed water line and the steam condensate line. In case of internal boiler water treatment, chemicals are added to the boiler to prevent the formation of scale by converting the scale forming compounds to free flowing sludges, which can be removed by-blow down. The chemicals are also added to prevent corrosion, priming and foaming.

Purpose of using boiler water treatment chemicals

Controlling pH and alkalinity to prevent scale formation and corrosion
Softening to prevent scale formation
Sludge dispersing for easy blow down to prevent scaling
Oxygen scavenging to prevent corrosion
Preventing foaming of boiler water
Neutralizing and film forming to prevent corrosion

Boiler water treatment chemicals and their functions

Phosphate base chemicals and alkali agent

Phosphate base boiler compounds for low-pressure boiler contain phosphates and alkali agents. Both phosphates and alkalies take part in preventing scale formation and corrosion on heating surfaces of a boiler by

reacting with hardness components
keeping silica substances water soluble
controlling of alkalinity of boiler water

In a medium pressure boiler caustic or coordinated phosphate treatment is applied. For high pressure boilers, in the light of high heat flux, a coordinated phosphate treatment is employed in order to prevent alkali corrosion caused by the concentrated free alkali. The chemicals generally used are : Na₃PO₄, NaHPO₄, (NaPO₃)₆, NaOH etc.

Non-phosphate base chemicals

1) Polymer base compounds
Synthetic polyelectrolyte, Natural polyelectrolyte, etc. are used to prevent scale formation. The difference between polymer base and phosphate base boiler compounds is in the function that they prevent the scale formation of hardness components. The preventive mechanism is considered as follows:

Inhibit the crystal growth of scale components
Inhibit the crystallization of scale components
Keep the solids in suspension

2) Chelating agent
In chelate treatment, the hardness components contaminated in feed water are kept in a soluble state by the chelating agent. Typical chelating agents are ethylenediamine tetra acetate (EDTA) and nitrilo triacetate.

Sludge dispersant:
Hardness compounds and silica which enter into the boiler from the feed water become sludges of hydroxyapatite, magnesium hydroxide, magnesium silicate etc. by the effect of boiler compounds. Most of these are easily suspensible in water and are discharged by blow down from the boiler. In order to prevent the accumulation of sludge on the bottom of drum and to prevent scaling on the heating surface by hydroxyapatite, etc., sludge dispersants are frequently employed. Synthetic polymer e.g. acrylic acid polymer is generally used as Sludge dispersant.

Oxygen scavenging chemicals
Although oxygen can be reduced to less than seven parts per billion in modern deaerators, it is still necessary to reduce oxygen even further. This is accomplished by chemical scavenging in which either sodium sulfite (Na₂SO₃), hydrazine ( N₂H₄), hydroxylamine derivatives, hydroquinone/progallol-based derivatives is fed into the boiler feed water.

Sodium sulfite
Sodium sulfite is the most common scavenger in industry. The reaction involved is the following,

Na₂SO₃: + O₂ → Na₂SO₄

Such that oxygen is removed to produce soluble sodium sulfite. Sulfite is fed at about 40 parts to 1 part oxygen.

Hydrazine
The alternative to sulfite treatment is hydrazine, which has traditionally been used on higher pressure boilers. One reaction by which hydrazine removes oxygen is a two step process.

4Fe₃O₄ + O₂ → 6Fe₂O₃

6Fe₂O₃ + N₂H₄ → 4Fe₃O₄ + 2H₂O + N₂

One interesting feature of these reactions is that in the first reaction the oxygen breaks down the protective oxide coating to form rust. In the second reaction, the hydrazine reduces the rust to the desired passive form. Only three parts 35 percent hydrazine solution is required per part of oxygen.
In using either hydrazine or sulfite, it is important to apply the following rules,

Feed the scavenger at earliest practical point
Feed continuously
Maintain residual sulfite or hydrazine according to levels recommended below

After the scavenging process of oxygen removal, the dissolved oxygen should be less than ten parts per billion.

Corrosion inhibitors
Volatile amines and filming amines are typically used as corrosion inhibitors to prevent the steam and condensate lines from corrosion. Volatile amines inhibit the corrosion by controlling the condensate pH. Filming amines are applied to form a water repellent film on metal surfaces which prevents direct contact with the corrosive substances such as oxygen and carbon di-oxide. Volatile amines eg., ammonia (NH₃), cyclohexyl amine (C₆H₁₁NH₂) etc., and filming amines eg., alkyl amines (RNH₂) ( R=C₁₀-C₂₂) are used as corrosion inhibitors.

Antifoaming agents
Antifoaming agents are chemicals used to control foaming on the boiler water surface, caused by an increase of the dissolved or suspended solids or by contamination of oil and fat or organic matter in the boiler water. Chemicals of amide based, alcohol based or fatty acid ester based chemicals are used as antifoaming agents. These chemicals change the surface tension of the water.

Water quality control method for boiler feed water system

1) Water quality control target value
The boiler water quality control target value is set on the basis of standard criteria and considerations of the structure and operation conditions of a boiler. The following standard values for different parameters of boiler water should be maintained for smooth operation of boiler.

a) Control items for feed water

pH
Total hardness
Dissolved oxygen
Total iron and total copper
Conductivity
Silica
Hydrazine

b) Control items for boiler water

pH
Alkalinity
Total evaporation residue
Electrical conductivity
Chloride ion
Phosphate ion
Sulfite ion or hydrazine
Silica

2) Boiler water treatment methods

Caustic treatment
Coordinated phosphate treatment
volatile treatment

3) Concentration control of boiler water
Blow down is done to control the concentration of boiler water and to discharge sludge, impurities contained in the feed water and solids in the chemicals added.

4) Control of chemical injection
The purpose of controlling the chemical injection includes the adjustment of the water quality of the boiler system to the specified values by sufficient effect of the functions of chemicals chosen for an individual boiler. Some chemicals do not exert their total effect and in addition, may cause secondary problems depending on the excess or shortage of dosage and the point or method of injection. The control of chemical injection involves the following

Dissolution and dilution
Determination of dosage-Initial dosage, maintenance dosage
Injection point

External Boiler feed water treatment

May 7, 2015May 6, 2015 Tasrik 1 Comment

Water is treated properly before feeding boiler. External Boiler Feed water treatment is the decrease or elimination of contaminants from water outside the boiler. It involves removal or reduction of some undesirable characteristics and addition of desirable characteristics to make water suitable and less troublesome for a proposed application before it is delivered to the point of use.

With object to prepare boiler feed water, the water after conventional treatment is further treated before using as boiler feed water. The following steps are associated in external boiler Feed water treatment.

Demineralization to remove dissolved minerals, salts or acids.
Dearation to remove dissolved oxygen

Demineralization of boiler feed water
The following steps consist in demineralization section:
– Cation exchanger
– Degasifier
– Anion exchanger
– mixed Bed polisher

Cation exchanger
In demineralization process, hydrogen cation exchanger is generally employed to remove all cations from water. Filtered water is passed though the cation tower, which is filled with hydrogen cation exchanger. In cation exchanger the following reactions are taken place. Therefore the scale forming cations such as Ca, Mg ions are replaced by the labile hydrogen, and water is set free from those ions.

Ca(HCO₃)₂ + 2HR = CaR₂ + 2H₂O + 2CO₂

Mg(HCO₃)₂ + 2HR = MgR₂ + 2H₂O + 2CO₂

NaHCO₃ + HR = NaR + H₂O + CO₂

Here the symbol R stand for the organic radical.
The following reactions are taken place between the resins and sulfates or chlorides ions.

CaSO₄ + 2HR = CaR₂ + H₂SO₄

MgSO₄ + 2HR = MgR₂ + H₂SO₄

NaCl + HR = NaR + HCl

Regeneration with sulfuric acid is the most widely used and most economical method of regeneration. The reactions, in condensed form, may be indicated as follows:

CaR₂ + H₂SO₄ = CaSO₄ + 2HR

MgR₂ + H₂SO₄ = MgSO₄ + 2HR

2NaR + H₂SO₄ = Na₂SO₄ + 2HR

Carbonic acid is produced by the reactions with bi-carbonate salts. In sequence which is removed as CO2 gas. Sulphate and chloride ions in water give rise to mineral acids. The resins are turn into corresponding salts and the feed water becomes acidic soft water.

Degasifier
Most of the CO2 is removed from acidic soft water in degasifier. This is obtained by spreading water over raching rings and air that flows there in counter current direction by the blower.

Anion Exchanger
Then water is passed though the anion exchanger. Which is filled with two types of organic synthetic resin, i.e highly basic or weakly basic. Both types can remove strongly ionized acids for example sulfuric acid, hydrochloric acid or nitric acid. But only highly basic anion exchange resin can remove weakly ionized acids such as silicic and carbonic acids. For the anion exchange of a strongly ionized acid the following reaction may take place, where R4N represents the complex anion-exchanger radical.

H₂SO₄ + 2R₄NOH → (R₄N)₂SO₄ + 2H₂O

Regeneration
Highly basic anion exchangers are regenerated with caustic soda, and weakly basic anion exchanger may be regenerated with caustic soda, soda ash or sometimes ammonium hydroxide.

(R₄N)₂SO₄ + 2NaOH → 2R₄NOH + Na₂SO₄

Mixed Bed Polisher
Lastly the water is passed though the mixed bed polisher containing cation exchange resins and anion exchange resins to remove the ions left in water after passing though anion exchange resins demineralized water thus produced is used as make-up for boiler feed water.

Deaeration
Mechanical Deaerator
The simplest process for removing dissolved gases like oxygen is by the use of an open tank containing the water and dissolved oxygen, where most of the dissolved oxygen is stripped of by means of low pressure steam.

The Deaerator consists of a horizontal tank provided with a packed tower. During normal operation, the demineralized water is introduced above the packed bed & the stripping steam is introduced under the bed, controlled by the pressure controller. During start up steam can be introduced at the bottom of the tank, to heat up the stored quality of water.

The deaerator is operated at approx. 132⁰C in order to ensure proper shipping of the water, it is significant that an additional of steam be available in the bed, as a result the inlet temperature of the water to the Deaerator is kept (5-20)⁰C bellow the temperature level in the deaerator. It is checked that a reasonable flow of steam leaves the deaerator through the flow orifice. The deaerated water is called as the boiler feed water. The quality of stripped demineralized water is determined by analyzing samples taken from sample line. The boiler feed water from the deaerator pumped by the BFW pumps to the auxiliary boiler.

Boiler feed water treatment

May 1, 2015December 8, 2015 Tasrik 1 Comment

The function of the boiler is producing steam. The effectiveness of the boiler is depends on the water. Hence the boiler feed water quality is an important factor for boiler system. Lots of problems in the boiler system caused by water can be prevented in many cases if the water quality is controlled properly. Therefore, it is required boiler feed water treatment perfectly. In boiler, water quality control target values are set on the basis of standard criteria and operation condition of a boiler and these are maintained for smooth running of the boiler.

Necessity of boiler feed water treatment:

To obtain maximum boiler efficiency
To enhance the life time of boiler tubes
To prevent corrosion due to condensate quality
To prevent down time caused by troubles arisen from water quality

Boiler Problems caused by water

Scale Problem: Scale development is highly unwanted. If the boiler water contaminant with some dissolved solids, it will reduce the boiler performance and boiler life. When the steam is generated, the solid content become concentrated and form deposit in the bottom of the boiler. As a result poor heat transfer and it need to be overheating the boiler tube. Therefore decreases the effectiveness of the boiler. More over increase the fuel and maintenance cost.
Corrosion Problem: If the boiler feed water contains some gases as like oxygen, carbondioxide, and ammonia it will harmful for boiler. These gases will react with the boiler plate and others metals and lead to boiler corrosion.
Priming and foaming problem

Water treatment for boiler
Water is treated suitably before feeding boiler. It also requires some physical and chemical treatment inside boiler to prevent any detrimental effects due to water. The main function of boiler water treatment is to protect the boiler from corrosion and scale formation. The water conditioning for boiler is broadly classified into two types of boiler feed water treatment:

Water pollution in yamuna river

April 5, 2015April 5, 2015 Tasrik Leave a comment

Yamuna is the most polluted and important river in north India. It passes through Uttarakhand, Haryana, Delhi, and Uttar Pradesh, before join together with the Ganga at Allahabad in Uttar Pradesh. About 60 million people depend on Yamuna waters. The peoples of Delhi and Agra’s are one of the most consumers of the Yamuna River. This river is the source of 70 per cent of Delhi’s water supplies. Downstream, at Agra point, this river becomes the main municipal drinking water source. In some point the River water is not fit for drinking, bathing or aquatic life; it is only fit for industrial cooling, irrigation, etc.

The level of water pollution in Yamuna is not same all through the year. During rainy season the water quality is better than others time. Starting rainy season the water quality is worsen due to washout different waste, chemicals, fertilizers, pesticides and fall into the river.

Municipal pollution
The whole lengths of the river are divided into five segments on the bases of hydrological and ecological conditions such as Himalayan Segment, Upper Segment, Delhi Segment, Eutriphicated Segment and Diluted Segment. The pollution of the river water of Yamuna begins from Tajewala in the upper segment and most polluted segment is Delhi segment. About 22 drains fall into the Yamuna River in the Delhi segment which are loaded with huge amount of biological and chemical wastage. Western Yamuna Canal (WYC) and the Eastern Yamuna Canal (EYC) are responsible for upper segment pollution. The Haiderpur water treatment plant which supplies part of delhi’s water is situated in the range of WYC. All household and industrial wastage and discharges from Yamuna Nagar are emit into this canal. There are many heavy industrial units such as 42 in Delhi, 22 in Haryana and 17 in Uttar Pradesh and a lot of small industrial units are situated in Yamuna River’s area; all wastage and discharges of these industries goes into the river.

Agricultural pollution
The Yamuna River is passing through a massive amount of agricultural areas; about 58% is agricultural area. The owner of these lands are used a huge amount of fertilizers and pesticides. These carcinogenic chemical polluted the river water which seriously affect on the aquatic environment as well as human being. The existing water treatment plant has no facilities to remove the traces amount of pesticide; even the laboratories are not able to detect them. When the people of Delhi and Agra consume this water as drinking purpose, they also consume indefinite amounts of toxic pesticide residues each time.

The Biochemical Oxygen Demand (BOD) in jumuna is 28mg/l, whereas the tolerable level is 3 mg/L. It also signifies the water pollution in Yamuna River. The presence of Cadmium, Nickel, Iron, Zinc and Chromium are cross the maximum level in some point in Yamuna River.

To prevent the water pollution in Yamuna River, it should not allow discharging the untreated sewage into the river and more sewerage treatment plants ought to be formed instantly. Farmers should using organic fertilizer, insecticides, pesticides; instead of chemical fertilizer, insecticides, pesticides.

Necessity of cooling tower water treatment

March 25, 2015March 25, 2015 Tasrik Leave a comment

Cooling water is used in any kind of industry and trouble in a cooling water system affects the operation of the whole production plant as well as the system itself. Therefore, the suitable quality of the cooling water must be controlled so that trouble free operation may be ensured.

Problems in cooling water system and their prevention
Problems commonly encountered with cooling water are

Corrosion
Scaling
Fouling

Cooling water corrosion
Corrosion is the destructive attack of a metal by chemical or electrochemical reaction with its environment. Corrosion can be viewed as the process of returning metals to their natural state – the ores from which they were originally obtained. Corrosion entails the conversion of a metal from the atomic to the ionic state, with the loss of one or more electrons. Corrosion of metals in water involves electrochemical reaction of the metal in presence of dissolved oxygen. The basic reactions of the electrochemical corrosion of carbon steel (the most widely used material for heat exchanger) are given below:
Anodic reaction Fe → Fe²⁺ + 2e^–

The electrons that are released flow through the steel, as they do through the wire of a galvanic cell, to a cathodic region where they react with dissolved oxygen.
Cathodic reaction O₂ + 2H₂O + 4e^– → 4OH^–

The Fe ions formed in the anodic region travel to the cathodic regions through the water adjacent to the steel, just as ions travel through a salt bridge in a galvanic cell. In the cathodic regions Fe²⁺ ions react with oxygen to form Ferrous hydroxide.
2Fe + 2H₂O + O₂ → 2Fe²⁺ + 4OH^– → 2Fe(OH)₂

Ferrous hydroxide precipitates from solution. However, this compound is unstable in oxygenated solutions and oxidized to the ferric salt (rust)
2Fe(OH)₂ + H₂O + O₂ → 2Fe(OH)₃
or Fe₂O₃ + 3H₂O (corrosion products)

The anodic reaction cannot proceed without a corresponding cathodic reaction, which is a reduction process.

Effects of cooling water corrosion

Reduction of the efficiency and life time of heat exchanger
Interruption of production and contamination of products
Accident due to sudden failure of cooling system
Reduction of the strength of material
Reduction of the flow rate of water
Increased cost of maintenance

Factors influencing corrosion in cooling water system

Dissolved salts
Dissolved gases
Water temperature
pH of the cooling Water
Flow rate of water
Deposits/Fouling

Control of cooling water corrosion

Changing corrosion environment
Removing aggressive components from cooling water
Using corrosion inhibitors in cooling water

Cooling water corrosion inhibitors: A corrosion inhibitor is a substance which when added in small concentrations to a corrosive environment decreases the corrosion rate.

Principles of cooling water corrosion inhibition action
Corrosion inhibitors for cooling water system are water soluble; however they form insoluble films on metal surfaces. This film is called protective film and inhibits corrosion reaction by preventing the hydration of metal ions or reduction of dissolved oxygen on the metal surface. An inhibitor becomes effective only after its concentration in water reaches a certain level. The minimum concentration required for an inhibitor to become effective is known as its critical concentration. Thus, a critical concentration must be maintained constantly if an inhibitor is to exhibit the desired effect.

Classification of cooling water corrosion inhibitors

Oxidized film type: Chromates, Molybdates, Nitrites
Precipitated film type: 1. Submerged ion type: Poly phosphate. Zn salt, phosphonets
2) Metal salt type: Triazol, Mercapto benzotriazole
Adsorption film type: Amine, surfactant- organic products
Mixed inhibitors: Zn/chromate, Zn /polyphosphates, Zn /phosphonates

Cooling water Scaling
Scaling is the formation of thick layer on metal surface of suspended or dissolved substances in cooling stream by means of different physical and chemical action.

Sources of water scale
Scale usually consists of calcium carbonate, iron oxides and sulfides, silica, calcium phosphates and sulfates etc. The sources of water scale are as follows:

From soluble constituents in water

Ca²⁺ + 2HCO₃^– → CaCO₃ + H₂O + CO₂
Mg²⁺ + SiO₂ → MgSiO₃
Ca²⁺ + SO₄^2- → CaSO₄

From treatment products

Ca + 2PO₄^3- → Ca₃(PO₄)₂
Zn²⁺ + 2PO₄^3- → Zn₃(PO₄)₂

From soluble contaminants in the air

H₂S + CrO₄^2- → Cr₂O₃
H₂S + Fe²⁺ + FeS

Mechanism of scale formation
Initially a very thin layer of the scale components is formed on the metal surface. Gradually crystal nuclei are formed from the numerous microcrystals to glow the crystal grains. The coarse grained crystals are then coagulated to promote the formation of scale. The solubility product of the dissolved ions, temperature, pH of the cooling stream and corrosion product are countable factors for scale formation in the heat exchanger.

Effect of scale formation
Since the thermal conductivity of the scale is extremely low in comparison with that of the tube material, the scale adhesion remarkably lowers the thermal efficiency of the heat exchanger. Excessive scale growth in the tube may clog them. Cooling water scale also accelerates the corrosion on the metal surface. Effects of scaling are as follows:

Reduced heat transfer
Loss of cooling capacity
Restriction of water flow
Obstruct spray nozzles
Acceleration of corrosion

Results in:
– Reduce System efficiency
– Production loss
– Unscheduled emergency equipment shutdown
– Increased-pumping energy cost
– Increased maintenance cost
– Increased wastewater treatment costs

Factors effecting scale formation
– Calcium and carbonate ion concentration
– pH of cooling water
– Water temperature
– Flow rate
– Dissolved salts

Control of water scale formation
Scale formation may be inhibited or controlled by taking the following measures
– Removing the hardness from the water using a water softener
– By adding scale inhibitors to the cooling stream which enlarge the solubility of the hardness salts
– By avoiding excessive temperature difference
– By adjusting pH of the cooling stream
– By keeping low concentration of suspended materials/ions in the cooling stream which the hardness salts can remain soluble.

Scale inhibitors
These are substances which when added to a cooling water system prevents the formation of scale on metal surfaces.

Mechanism of scale inhibition
Scale inhibitors present the scale formation by the following way
– Prevents the formation coarse grains of deposits
– Prevents coagulation of crystal grains
– prevents the formation of coarse grained crystals by distorting the crystal surface of the scale forming crystal nuclei.

Chemicals used for scale inhibition
– Poly phosphates, phosphonates, sulfonates, phosphate esters
-Synthetic polymer, polyacrylates, polymetltacrylates, maleic anhydride copolymers.

Fouling
Fouling is the formation of deposits of foreign materials on heat transfer surface of heat exchanger and other cooling equipment.

Types of fouling
– General fouling: porous deposits, dirt, silt, Sand, corrosion products
– Microbiological fouling: algae, fungi, Bacteria, Slime

Effects of fouling
– Loss of heat transfer
– Plugging pipe lines, heat exchanger
– Acceleration of corrosion
– Loss of cooling capacity
– Restriction of water flow
– Obstructs spry nozzle
– Increased-pumping energy cost
– increased maintenance cost

Control of fouling
– By adding inhibitors to cooling water
– Maintaining optimum velocity of cooling water (3-10 ft / sec )
– Minimizing suspended materials by filtration
– Using chlorine, slimicides or biocides

Factors influencing the slime formation by microorganism
– Water temperature
– pH of cooling water
– Nutrients in cooling water
– Dissolved oxygen

Monitoring of cooling water treatment
– Corrosion rate measurement with test coupons
– Corrosion rate measurement with corrosion meter
– Corrosion monitoring by using heat exchanger
– Estimation of scale inhibitor effect by water quality analysis
– Measurement of scaling rate by using monitor heat exchanger
– Monitoring of the prevention effects of slime adhesion and sludge accumulation.

Water crisis in Gaza strip

February 28, 2015February 28, 2015 Tasrik Leave a comment

According to a report of PWA, the water crisis levels in all over the Gaza Strip have risen to an alarming stage; over 95 percent of the Palestinian territory’s aquifer is polluted with high levels of nitrates and chloride. Different tests show that pollutants in Gaza water are three times higher than the normal level. Moreover in most parts of the Gaza Strip, the pH level of water is below the standard level of WHO. According to the UN report, if the deterioration of water crisis would increase at current rate the coastal aquifer water will be unusable by 2016 and permanently damaged by 2020.

Coastal Aquifer is the main source of Gaza’s water; they extract about 200 million cubic meters a year. Due to over extraction of the water for decades, significantly lowered the groundwater level. As a result the aquifer’s water becomes more salted by seeping the seawater. The people in Gaza fall into more difficulties to drink or cook with this salty and bad tasted water.

The people of Gaza are blockade by Israeli. During the Israeli military aggression the sewage treatment plants of Gaza are attacked and leaked the sewage line, as a result further the water resources are contaminated. For sack of security reasons, Israel also put stiff restrictions on the entrance of water treatment equipment into the blockaded area. Moreover many people are not connected with sewage system yet. Hence household waste flows into cesspits, it seeps into the groundwater and polluted. Due to sewage seeping into the aquifer, the water is contaminated by micro-organisms.

The nitrate levels in the water increase due to the use of pesticide in agriculture and sewage seeping into the aquifer. WHO allowable limit of Nitrate concentration less than 50 mg/l whereas most part of the Gaza (about 88%) are ranges from 50 to more than 200 mg/l.
By drinking this polluted water increase the health risk of people in Gaza, especially for infants. Many waterborne diseases are occurs including acute diarrhea, parasite infections, liver and kidney diseases, and methemoglobinemia (‘blue baby syndrome).

To resolve this serious water crisis in the Gaza Strip, it should stop the illegal siege in Gaza so that all the materials and equipment enter into the Gaza Strip for the water and waste water treatment projects.