Drinking Using and Process water Treatment Systems

As a result of a rapid increase in population and industrial development all around the world, there has been a serious decrease in water resources. With the aim of getting rid of this problem, recently protecting the water resources, treating the poor quality water comes from resources with the aim of using and drinking, making this poor quality water harmless has gained great importance the items existing water and treatment techniques in this technical leaf, 1 have been mentioned shortly.

The qualities of drinking water

• Water must be tasteless, colorless, clear and has a pleasant taste. In water must not be material giving bad and taste like phenol, oil etc.
• Water must be clear and colorless.
• Water must not include microorganisms making illness. Vibrio cholera, salmonella, typhus, hepatic virus in water causes illness by passing (though) water. Drinking water must not absolutely carry bacteriological contamination.
• Water must not include chemical materials giving harm to health. Some chemical materials may have poisonous effect like arsenic, cadmium, chrome, lead, mercury etc. besides this the materials like barium, nitrate, fluorine, radioactive materials, ammonium chlorine give negative effects to health if they are over limit value. At the same time some of them are indicators that contaminated water. 
  
• Water must be suitable for their usage aims
• In drinking water, industrial and using water; Iron, manganese hardness value are important. Water must be aggressive the aggresiness of water results from balance of free corbondioxide(CO₂) and  bicarbonate(HCO₃) ions. Aggresiness of water causes corrosion of pipes. In additional in case of corrosion of pipes, the elements separating from pipes cause the spoilage of the quality of water.
  

Turbidity

       Turbidity is a mesurement of light permeability of water including suspended solids.

       The reason of the turbidity can be everything from suspended solids in water to big sediments that can be seen by eyes. Materials like sand, clay, calcium carbonate, iron, manganese, and sulfide cause turbidity.

       High turbidity especially in river water results from household industrial wastewater which mix to river or the soil carried by rain

In addition during this contamination, organic and inorganic materials enter to water. This effect causes to grow up to bacterium populations therefore turbidity in water increase. As a result of sources of turbidity can be inorganic materials or lots of organic materials

The importance of turbidity.

Aesthetics

Filtration

If there is an increase in turbidity, this increases cost of filtration of water. High turbidity can make the open sand filters unusable (washing time decreases and costs increase). In water including high turbidity we can catch the suspended solids which causes turbidity in sand filters by softening them..

Disinfection

In order to the fact that disinfection is affective a complete contact between microbes in water and disinfectant must be provided. However, especially patogens in sewer system wastes have been able to get a rid of disinfectant by getting into the solid materials. For that reason in water to be used as drinking water, turbidity is wanted low level.

Color

Color in water; is formed dissolving of organic materials like leaves, cone tree fruit tree and vegetables waste during their contact with water. This kind of water includes alots of suspended solids.

The cells giving color to water are tannin, humic acid and humat (with the smash of lignin). Sometimes ironed water form high color potential by being the form of ferric humat in ironed water

Generally colored water has negative ions. For this reason trivalent metallic ions coagulation, color refining can be done.

The color of water resulting from organics is called “true color”. A part of this, especially in surface water, the color consisting of suspended solids can be observed. This is called “appereant color”.

Taste and Odor

The problem of taste and odor in water depends on lots of factor these are;

• Organic materials
• Living organisms activities
• Iron and manganese and corrosive metallic products
• Industrial wastes like a phenol
• Chlorinate
• High mineral consantration
• Dissolved gases.
   

Generally depending upon the above mentioned factors taste and odor problem is irritating for drinking and using water. This organic and inorganic items (aldehydes, ketones, sulphur) cause bad odor in closed systems like underground, lake, water tank and sewer system.

To express odor consantretion, following terms are used.

ATC: Absolute Treshold consantretion: İt is minimum consantretion that can be perceieved by people 100%.

TDN: Treshold Odor Number: it is reduce number to reduce consantration to ATC

TLV: Treshold Limit Value: it is the maximum consantration that people exposed to 8 hours a day 5 days a week 50 week  a year in 40 years working life

MAC: Maximum Acceptable Concentration: ıt is the maximum consantration that must not be over.

Taste tasted in mouth in fact, is a combination of odor, taste and heat. If water sample does not include specific odor and heat the sense you feel can be expressed as areal taste. It can be ineffective with the oxidants like ıron ,manganese, potassium, chlorine, potassiumpermanganate etc

Microorganisms

Microorganisms (bacterium, virus, protozoa etc.) are extremely small organisms. Some of them can not be seen even conventional microscopes. All the bacterium in the world is bigger than a 0.5 micron. Some of microorganisms in water make illness. Some microorganism’s names and harms that they cause are mentioned shortly in following items.

Some bacterium in drinking water ;

Salmonella: It caused food poisons.

Shigella: It caused bacterical dysentery.

Vibrioorganisms: they cause cholera

Campylobacter bacterium: It lives in stomach and intestine ıt may cause ulcer.

Sulphur bacterium: It gives rotten egg odor to water. It causes corrosion in an extremely fast way.

Actinomyectes: It gives bad taste and odor to water.

If there is bacterium causing illness or not in water can only be understood by tests. These tests must be done at least once a year. Most suitable time of test is the end of fall and the beginning of summer. It is difficult to make bacteriological analysis of microorganisms having illness factor mentioned above so indicator microorganisms are used. These a

• Coliform bacterium (especially scherichia known as e-coli)
  

• Streptoroccus Faecalis
• Clostridium Perfringens spores.

Being E-Coli in water is a sign of existence of harmful microorganisms. In 1 gram of feces there are 108-109 pieces e-coli is found, it is understood that this water get dirty  by the feces of humanbeing, mamma aninals or birdies. On getting rid of harmfull microorganisms, disinfection various methods are used..

Shortly these are;

Treetament with Chlorine (one step treatment): Chlorine concentration is given as 1 mg/lt and extra chlorine is taken by an active carbon filter

Treatment with Ozone: Ozone inject into water

Ultraviyolet treatment: Water is passed from ultraviolet machine and ultraviolet rays make the bacterias harmless.

Distillation: Water is boiled

None of the systems mentioned above is perfect. Every one of them has advantages and disadvantages. Although it is disinfectant and affect fast on bacteriums.ıt is an absolutely undecesive compound furthermore, its producing is expensive. Ultraviolet is also fast effect disinfection means. Chlorine is strong ans is more decisive disinfectant than ozone but it gives odor and taste to water. This odor and taste can be taken by active carbon. Chlorine maintains its affects until water is used by real meaning. This kind of effect isn’t mentioned about ozone and ultraviolet. Therefore ultraviolet units are used on short time and generally in the exit of tank. Distillation is not economic because of the high cost of energy.

Nitrogen

Nitrogen is a parameter that is frequently seen in water having a natural hardware, being used as a source of nowishment by bacteriums being in various oxidation levels by chemical ways..

       Kinds of Nitrogen:

      NH₃-N    : Ammonia nitrogen

      Org-N     : Organic nitrogen

      NO₂-N    : Nitric nitrogen

      NO₃-N    : Nitrate nitrogen

       Ammonia (NH₃): Ammonia is present as ammonium in natural water and this is called free or salt ammonia. In water ammonia, occurs as a result of chemical and physical events or microorganism activities. Ammonia formed as a result of chemical and physical events is harmless to health. However ammonia formed as a result of microorganism activities is dangerous in terms of the possibility of organic materials. Ammonia being bigger than 0.5 ppm is a sign of dirtiness 

       Nitrite (NO2):  It is not wanted in drinking water sun lights and some bacteriums transform nitrates to nitrit.

       Nitrate (NO3): These are last oxidation products. In well water nitrate generally is found more. Especially it causes on illness called blue baby in babies. This illness can cause death in babies which their bodies begin to turn purple.

Nitrates can pass water from soil. However it should be take precautions if it is results from ammonia and nitrite. Because presenting of nitirites means dirtiness on water. If nitrites are found high level of organic materials, there is more pollution ammonia also causes some kind of bacterium to incease, thus these give water bad odor.

When these kinds of nitrogen are given an environment with excessive amounts, they are used by organisms. In this receiver environment, it causes eutrofication (oxygen minority as a result of bursting of alg). To prevent bursting of alg in storage tanks N, P, C consantration must be decreased and light must be checked. In addition algs in tanks with various chemical materials is one of the ways of solution. However living life in tanks must be taken into consideration

Nitrogen Removing Methods:

• Biological purification with nitrification and denitrification
• Purification with dropping filters 
• Artificial feed of underground water or drawing it with well
• Chlorifying of breaking points
• Ventilating in high pH
• Ion exchange
• Reverse-Osmosis
   

TDS

( TOTAL DISSOLVED SOLIDS )

Total dissolved solids in water include organic salts and a small quantity of organic matters. Both surface water and underground water solve minerals from the soil, stone materials that they contact. Dissolved inorganic matters are found in ion in water. Wll known ions in water are mentioned in following;

       CATIONS                 ANIONS

       Ca⁺²                         Bicarbonate HCO₃-
       Mg⁺²                        CI^-1 
       Na⁺                           SO₄^-2
       Fe⁺²                         NO₃^-  Nitrate
       Mn⁺²                        CO₃^-2  carbonate

 In addition to these, water includes heavy metal ions (lead, mercury, cadmium etc.) and organic matters dissolved organic chemicals (like pesticites, herbicites etc.) shows a toxic effect on humanbeing and animals with even small amounts. Most of the organic matterslike a trichlorometane and dioxin make cancer. This kind of organics are in the forms of dissolved ions in water and are low consantrations

Above mentioned ions, provide electric conveyance in water. In a high level this pecularity is corrosive for metal surface. It can cause stratification in excessive TDS pipes. Its high concentration in drinking water can show the effect of diarrhea

Total dissolved solids can only be taken away with reverse osmosis and demineralization softening doesn’t do away with TDS.

Water that has a lowest level TDS is aggresive and corrosive. Therefore, it must be taken precautions at special usage. For example if this water is stored, it should be preffered plastic to metal in the container.

Dissolved Oxygen (DO)

Dissolved oxygen is oxygen consantration being dissolved in water and gives cathodic reaction. Solubility oxygen and air in fresh water at 1 atm pressure at 0 ^oC is 14.6 mg/lt and 7 mg/lt at 35 ^oC. Because oxygen is a kind of gas least dissolved in water, change directly with the atmospheric pressure and heat.
 

               Water including dissolved oxygen amount depends on the these factors;

       1.  Under high pressure, pretty high amount of oxygen dissolves. When decreased the pressure gas appears as decreased level. 

            ( Henry Law) 
                      Henry Law: The amount of gas dissolved in liquid at a fixed level is directly related to the amount of pressure. For example; if the heat is fixed, 1 g of oxygen is dissolved in 100 m³ water (under the atmospheric pressure), 2 g of oxygen is dissolved 2 times of atmospheric pressure. 

       2.      Amount of mineral in water affect the ability of oxygen’s dissolve. Distilled water can absorb more than water including high mineral sea water and well water include less dissolved oxygen than fresh surface water.

Fluoride F

Fluoride being in water can be useful or dangerous depending on amount of it. The value adviced it for drinking water is 1 mg/lt. it is known that this value is useful for teeth and less on the tooth decayed. A research done for the childrenunder 9 years old shows that water including 4 mg/lt fluorine causes the deformation of bones. Under these circumstances, according to the results of research, water including more than fluorine be treated. 

       Fluorine treatment methods

      1.      Reverse Osmosis
      2.      Treatment with the chemicals such as aluminium sulphate, magnesium or calcium phosphate.
      3.      Filtering with ions exchanging resins or active carbon, active aluminium oxide, granular tricalcium phosphate beds

First method has alots of advantages, second method needs treatment in detail, careful dosages and pH control. Third method does not need on detail control. Here fluorine is absorbed

Silica SiO₂

In much water silica SiO₂ is found. This is so normal because many elements in nature are silicones (Si₃) forms caldron stones. These stones have 10 times less ability of heat exchanging.than stones formed by sulphide and calcium carbonate.

Silica
Silica occurs with the forming of silicon and oxygen. It is expressed as the formula SiO₂. It is hard like glass. It is found in different forms like quarts, sandstone and granite. It is also found in the skeleton of many plants and animals.

Silicate
Silicates are the metal compounds like aluminium, calcium, magnesium, ıron, potassium, sodium nad they combine with silicon and oxygen. Silicates are classified like salt.  Silicates are divided in various groups like asbest, mica and talk powder. They can be found in the form of colloid and cristaloid. When they are in the form of colloid, they can be treating with coagulation and filter processing. When they are in the form of cristaloid, chemical and physical treatment is difficult.  

Chlorine (Cl)

Chlorine is a kind of ion found in all natural and used water widespreadly. It can be added into water the way of dissolving from the underground water or as a result of combination of salt water and fresh water. Approximately 6 g chlorine from human urinine is thrown in a day. It is known that normal consantrations chlorine does not form a harmless effect to health. However in high consantrations more than 250 mg/lt salt taste happen. Because chlorine increases the conductivity of water, it makes the corrosion easier. In water having high consantration, chlorine shows its existence with the reverse effect to taste, corrosive tendency or softening process..

Sulphate (SO₄^-2)  

Sulphate is the one of the most important ions mixing surrounding from natural ways. In all natural water sulphate is found is various amounts. In some industrial water, the amount of sulphate contents is high and when with mixed natural water they increase the amount of sulphate. Sulphur compound are in the forms of  important pollution with the problems like corrosion toxical , taste and odor   which they have formed at the end of various reactions the meaning of high suplhate in water is high hardness, high sodium salt and show as a laxative effect on people they are limited with a high boundry, 250mg/lt. This limit is determined as 1000 mg/lt for animals. Besides this, sulphate gives water a taste somewhat bitter.because sulphates  form CaSO₄ and MgSO₄ precipitates in drum water they sould be hold in very small accounts in this kind of water, they transformed SO₄-2H₂S with the bacterium activities and unaerobic conditions. H2S is collected in top part of canal and forms of H₂SO₄ by unioning with the humidity. In this kinds of pipes they are the the great cause of corrosion and deformation. When sulphates react with cement, th make big crystal to happen and so cause the the pipes to swell and to smash. Consantaration observed the corrosion effect it is determined as 100/250 mg/lt. Sulphate treating methods can be said as reverse osmosis, distillation, oxidation or anion exchanger. .

pH

pH is a kind of logarithmic measurement showing the acid and base state. It represents H⁺ ion consantration which undergoes solution. Pure water is balanced of H⁺ and OH^- ions nad pH it can be measured with color indicators or depending on the electrical potential of H⁺.

If pH<7, the surrounding is acidic

If pH>7, the surrounding is basic.

pH value used widely in environmental engineering applications, has a great importance some procedures like chemical coagulations, disinfections, removing hardness, controlling corrosion and providing water. According to Turkish Standarts-266 pH 6.5-8.5 is the value which is advised. This parameter doesn’t give directly information about safety of the drinking water. Water with low pH and TDS can solve some poisonous metals in pipes since they are corrosive in water having pH is harmful or not..

Hardness

Hardness is a result of existence of dissolved (+2) value ions (Ca⁺², Mg⁺², Sr⁺², Fe⁺², Mn⁺²) in water. Because Ca⁺² and Mg⁺² ions are found in natural water more than the other ions. Mostly hardness is expressed as the total of Ca⁺² and Mg⁺² as the other ions are generally the complex forms they don’t give any contribution to hardness.

Hardness of any kind of water is the measurement of the soap precipitation capacity. Soap is precipitated with ions of calcium and magnesium in water in common some other metals ions (Al, Fe, Mn, Sr, Zn) not only precipitated soap but also they don’t help hardness because of being complex form.

According to the hardness degress water can be classified following..

Materials creating hardness and their defined hardness degree is generally expressed in terms of French, English, German hardness degrees according to the their equivalent calcium carbonate types

           1F    =  10 mg/lt CaCO₃      French Hardness Degree

           1E    =  14.3 mg/lt CaCO₃  English Hardness Degree

           1R    =  17.8 mg/lt CaCO₃  German Hardness Degree

Hardness Degree

     Factors          German (^oD)     French(^oF)     English(^oE)     milival(mval)

    1) ^oD                          1                 1.79              1.25               0.357

    2) ^oF                     0.56                 1                    0.7                0.200

    3) ^oE                    0.80                 1.43               1                   0.285

    4) mval                2.80                  5.00              3.5                1

Increase in hardness of water causes the increase of conductivity of water. If hardness is removed ;

• The quantity of soap and detergent is decreased
• It helps to conrtol of corrosion.
• It is taken precaution of petrification

 Hardness removing methods;

• Calcium carbonate – sodium carbonate methods
• Using with NaOH
• Softening with Na₂SO₄
• Ions exchange

Iron and Manganese

Iron and manganese create problems in underground water almost all the time and because being in high consantration in some months of year in surface water. In terms of drinking and using water. Iron and manganese are found in waterin the forms of both as dissolved and not dissolved (Fe⁺², Mn⁺²) iron and manganese ions are generally found in underground water.

  Dissolved ferrous ions.

• Ferric ions (high pH values water)
• Ferric hydroxide (not dissolved natural or alkali water).
• Ferric oxide
• Organic materials or ferrous bacterium bodies

When water contacted with air while CO2 mixes with air O2 begins to mix with water Fe⁺² ions are transformed Fe⁺³ by oxidation. This compound has got a structure of undissolved gel form. And makes accumulations on the surface. In the same way Mn⁺² ions are transformed Mn⁺⁴.

  2Mn⁺² + O₂ +H₂O ®2MnO₂ + 4H⁺

Since iron and manganese are in high consantration in water causes of increasing ferrous bacterium in water pipeline. This kind of bacterium blocks give water the color of red-brown. Increasing of the ferrous bacterium some problem occur like becoming narrowing of crosssectional area in pipes. Pipes valve and pluging counter. Crenotrix, bgallionella, leptothrix can be given as an example ferrous and manganese bacterium.

Iron and manganese cause turbidity inside of the pipeline. At the same time water with high ferrous and manganese consantration unwanted. Because of causing some changing in term of color and taste which are used in industry like paper, plastic, food and weaving.