TYPES OF WATER • In general, water for drinking and cooking should be wholesome. It should be both potable and palatable. It must be bacteriologically and chemically safe for drinking and be good tasting. • It should be clear, colourless, and have no unpleasant taste or odour. • In general chemistry, we need at least three basic types of water of somewhat different quality, depending on the requirements of each use.

1 NATURAL WATER • This is water that comes naturally i.e . from rain and has dissolved minerals indigenous to the source. • Natural, untreated, spring waters, are naturally carbonated and may be slightly alkaline or salty. • Numerous health claims have been made for the benefits arising from the traces of a large number of minerals found in solution. • They are claimed to have therapeutic effect. • This water is useful for drinking • It has the following ions

Na,K,Mg,CO32-,Cl2-,Fe2- 2 3 POTABLE WATER • Potable water is fresh water that is sanitized with oxidizing biocides such as to kill bacteria and make it safe for drinking purposes. • it may be hard Water . • This is saturated with calcium, iron, magnesium, and many other inorganic minerals.

4 • All water in lakes, rivers, on the ground, in deep wells, is classified as hard water. • Potable water is fit for human consumption. • It has pathogens that are removed by 1. aeration 2. chlorination 3. • It may be odorless and tasteless. • unsuitable for pharmaceutical use

5 Aeration • Aeration is a treatment process in which water is brought into close contact with air for the primary purpose of increasing the oxygen content of the water. • The close contact between water and air required for aeration may be achieved by allowing water to trickle through one or more well- ventilated, perforated trays containing small stones, as shown in Figure below.

6 Diagram illustrating aeration

7 • This water must be collected in a container and allowed to stand for about 30 minutes in order to settle suspended particles.

8 CHLORINE TREATMENT • To disinfect by chlorination, use ordinary household chlorine bleach. {Sodium hypochlorite with a concentration of 5.25 to 6 percent should be the only active ingredient in the bleach}. • Add 16 drops (1/4 teaspoon) of liquid chlorine bleach per gallon of water, or 10 drops per 2-liter bottle of water. Stir to mix. If you do not have a dropper, use the following table to measure the correct amount of bleach

9 AMOUNTS OF BLEACH FOR ORDINARY CONTAINERS • 1 quart bottle 4 drops of bleach • 2 liter soda bottle 10 drops of bleach • 1 gallon jug 16 drops of bleach (1/8 tsp) • 2 gallon cooler 32 drops of bleach (1/4 tsp) • 5 gallon bottle 1 teaspoon of bleach

10 adv, • it’s effective against almost all pathogens, including viruses. • inexpensive Dis, • affects taste of water • Its temperature sensitive • not recommended for long term use Bleach loses it strength with time: products which have been on the shelf for one year will be only 50% as effective. In that case the amount used will have to be doubled

11 Filtration • Filtration is the passage of polluted water through a porous medium (such as sand). The process uses the principle of natural cleansing of the soil.

• Figure 4 shows a modified simple upward rapid flow filter.

12 Fig. 4 - A simple upflow rapid

A simple upflow rapid sand filter

13 • Simple filters may be put together inside clay, metal or plastic containers. • The vessels are filled with layers of sand and gravel and pipe work arranged to force the water to flow either upwards or downwards through the filter. • A filter such as this could be built from a 200 litre drum. It has a filter bed made up coarse sand (of about 0.3m depth) of grain size between 3 and 4mm diameter, and supported by gravel covered by a perforated metal tray. The effective filtration rate of such a

filter could be as high as 230 litres14 per hour. Pros and cons of Filtration • The procedure is suitable for treatment of drinking water and pre – treatment of water intended to be later processed to purified water. • Such filters must be dismantled regularly to clean the sand and gravel and remove any settled silt. • such filters are not effective for removing the pathogens. Therefore the water must be disinfected or stored for 48 hours in order to make it safe.

15 WATER FOR INJECTION • Water for Injection Description • Sterile Water for Injection, is sterile, non pyrogenic, distilled water in a single dose container for intravenous administration after addition of a suitable solute. • It may also be used as a dispensing container for diluent use. No antimicrobial or other substance has been added. • The pH is (6.0 to 7.0). • The osmolarity is 0. 16 Water for Injection - Clinical Pharmacology

• Sterile Water for Injection, is used for fluid replacement only after suitable additives are introduced to approximate isotonicity. • serve as a vehicle for suitable medications. • Made by of portable water where carbon free/air free is required.

17 • freshly prepared distillate is boiled for 20mins with little air exposure. • its distilled into final container and sterilized by autoclave. • used for preparing injections and weakly acidic drugs. • Its PH is 5 -7

18 Distilled water • Is water that has many of its impurities removed through distillation . • Distillation involves boiling the water and then condensing the steam into a clean container. • In a gradual evaporation process taking place in a boiler the substances get separated due to their different initial boiling point . The vapour then condenses after passing through a cooler. • distillation also works as a technique of .

19 20 The Process: • The distillation process utilizes a heat source to vaporize water. • The objective of distillation is to separate pure water molecules from contaminants with a higher boiling point than water. • In the distillation process, water is first heated until it reaches its boiling point and begins to evaporate. • The temperature is then kept at a constant.

21 • The stable temperature ensures continued water vaporization, but prohibits drinking water contaminants with a higher boiling point from evaporating. • Next, the evaporated water is captured and guided through a system of tubes to another container. • Finally, removed from the heat source, the steam condenses back into its original liquid form.

22 • NB: • Contaminants having a higher boiling point than water remain in the original container. • This process removes most minerals, most bacteria and viruses, and any chemicals that have a higher boiling point than water from drinking water. • For this reason, distillation is sometimes valued as a method of obtaining pure drinking water.

23 single-effect distiller

24 Pros • provides mineral-free water to be used in science laboratories or for printing purposes, as both functions require mineral-free water. • It removes heavy metal materials like lead, arsenic, and mercury from water and hardening agents like calcium and phosphorous .

25 • used as the preferred water purification method in developing nations, or areas where the risk of waterborne disease is high, due to its unique capabilities to remove bacteria and viruses from drinking water.

26 qualities that make it undesirable . • they do not remove chlorine, byproducts . • These chemicals, which have a lower boiling point than water, are the major contaminants of municipally treated water. • Most dangerous metals and bacteria are removed from water prior to its arrival at a home’s plumbing system. Thus, a distillation system, targeted at the removal of these contaminants, is unnecessary and irrelevant for most people. • Furthermore, distillation is an incredibly wasteful process. Typically, 80% of the water is discarded with the contaminants, leaving only one gallon of purified water for every five gallons treated.

27 Distilled water

Bottle for Distilled water

28 • Quick Facts... • The human body can survive for weeks without food, but only a few days without water. • In preparing for an emergency, store at least a three-day supply of water for each member of your family. • You can minimize the amount of water your body needs by reducing activity and staying cool. • Water can be purified for drinking by filtering and then either boiling or adding household bleach.

29 To be continued…….

30 PURIFIED WATER BP • Purified water refers to all types of water from which chemicals are removed via a variety of different processes • This is specially treated water free of impurities, ions and microorganisms. • It is used in different branches for many purposes. • However, it is vulnerable to fast contamination from the surrounding environment and therefore cannot be stored .

31 • Processes by 1. distillation, 2. demineralization{deioniz ation } of portable. • Has a PH of 5-7 • Useful for preparing water for injection. • Its tasteless and odorless

32 Water purifying methods • Purified water production represents a very demanding technological process . Various methods are available differing in the technology and the process efficiency level. • A combination of more methods is commonly used or, variantly, multiple use of a single technology is applied. • Such an approach guarantees the best results.

33 Demineralization via ion – exchanger (deionization) • Demineralized water is water that has had its mineral ions removed. • Mineral ions such as cations of sodium, calcium, iron, copper, etc and anions such as chloride, sulphate, nitrate, etc are common ions present in water. • Demineralization (deionization) is a method of capturing these ions through an agent referred to as ionex or ion – exchanger.

34 Ion – exchangers • Application of ion – exchangers is further step to increase the quality of finished water • Cations of dissolved salts are removed by cation exchangers and anions of dissolved salts are removed by anion exchangers • The station may consist of separate cation exchanger and anion exchanger filling or combined cation and anion exchanger column.

35 . Ion – exchange resins are capable of capturing salt ions and exchanging them for hydrogen and hydroxide ions this is so because they provide ion exchange site for the replacement of the mineral salts in water with water forming H+ and OH- ions. • Because the majority of water impurities are dissolved salts, deionization produces a high purity water that is generally similar to distilled water, and this process is quick and without scale buildup. • An example of a deionizer system is a mixed bed deionizer.

36 MIXED-BED DEIONIZERS

• In mixed-bed deionizers the cation and anion-exchange resins are intimately mixed and contained in a single pressure tank. • The thorough mixture of cation- exchangers and anion -exchangers in a single column makes a mixed- bed deionizers equivalent to a lengthy series of twin bed deionizers. • As a result, the water quality obtained from a mixed-bed deionizer is appreciably higher than that produced by a twin bed deionizer. 37 • Although its more efficient in purifying the incoming feed {raw} water, mixed-bed deionizer are more sensitive to impurities in the water supply and involve more complicated regeneration process. • Mixed-bed deionizers are normally used to ‘polish’ the water to higher levels of purity after it has been initially treated by a twin bed deionizer.

38 Process .. • Water meets the cation exchanger which exchanges the cation with hydrogen and converting the product into an acid • The acidic water then meets the anionic exchanger • In these case the resin traps the chlorine and the end result is purified water. • After exhausting the capacity of the exchangers both columns have to by chemically regenerated using hydrochloric acid or sodium hydroxide

39 INDURSTRIAL USE OF ION- EXCHANGE RESIN IN WATER PURIFICATION

40 OTHER METHODS OF DEMINERALIZATION

• • electrodialysis

41 OTHER METHODS FOR EFFECTIVE EMERGENCY .

• BOILING . • bring the water to a rolling boil and boil for a least 1 minute. Boil longer at high attitudes or if the water is from a source suspected to have Giardia or other protozoa (5 minutes boiling time is recommended.). •

42 – kills all pathogens, including viruses – no special equipment required – requires fuel(electricity assumed not available) – time consuming – impractical for all but a limited amount of

43 • The addition of iodine is another option for rendering contaminated water drinkable • dosage: using ordinary 2 percent tincture of iodine from the medicine chest, 3 drops per quart of clear water, or 6 drops to each quart of cloudy water, and stir thoroughly • . Iodine is preferable to bleach when one has a choice in the matter. • Halozones and related compounds. they destroy the cell membrane of microbs hence reduce the microbial count in water.eg KCl30,KHCl2O 44 • Radiation and water • Radio active material decay by releasing or converting mass to mass and energy • {uranium----->lead + energy} • U------>pb+energy • The particles leave the reaction site at high velocity and are highly energized by momentum. on collision with other matter they cause loss of valency/energy are elevated to higher energy levels.

45 • In the process the emit x-rays and gamma rays as they return to the normal states. • These rays cause tissues damage including de arrangement of DNA materials in the cells • Water contaminated with such materials is harmful and cant be used for drinking or in formulation as it may lead to mutations.

46 TO BE CONTINUED……………… ……….

NEXT TOPICS WILL COVER ……..

47 Reverse osmosis– membrane filtration

• Reverse osmosis is the most widespread principle used in purified water production equipment today. Reverse osmosis is a filtration method product of which is chemically pure water from virtually any source. This method is capable of separating impurities and particles smaller than nanometre ones. In comparison with traditional distillation apparatuses the systems based on reverse osmosis offer considerably lower water and energy consumption – 2,5 times lower volume of water is used to produce the same amount of treated water. Osmosis principle based on water pressure alone has essentially no demand for electric energy. Maintenance costs are lower, too, especially in areas with hard feed water.

48 (EDI) • is a water treatment process that removes ionizable species from liquids using electrically active media and an electrical potential to effect ion transport. It differs from other water purification technologies such as conventional ion exchange in that it does not require the use of chemicals such as acid and caustic for reactivation. EDI is commonly used as a polishing process to further remove trace ionic salts of the Reverse Osmosis (RO) permeate to high purity water of multi-megohm-cm quality. The continuous electrodeionization (EDI) process, is distinguished from other electrochemical collection/discharge processes such as electrochemical ion exchange (EIX) or capacitive deionization (CapDI), in that EDI performance is determined by the ionic transport properties of the active media, not the ionic capacity of the media. EDI devices typically contain semi-permeable ion- exchange membranes and permanently charged media such as ion-exchange resin. The EDI process is essentially a hybrid of two well-known separation processes - ion exchange deionization and electrodialysis, and is sometimes referred to as filled- cell electrodialysis.

49 • How it works • The electrically active media in EDI devices may function to alternately collect and discharge ionizable species, or to facilitate the transport of ions continuously by ionic or electronic substitution mechanisms. EDI devices may comprise media of permanent or temporary charge, and may be operated batchwise, intermittently, or continuously. There are two distinct operating regimes for EDI devices: enhanced transfer and electroregeneration (Ganzi, 1988). In the enhanced transfer regime, the resins within the device remain in the salt forms. In low conductivity solutions the ion exchange resin is orders of magnitude more conductive than the solution, and act as a medium for transport of ions across the compartments to the surface of the ion exchange membranes. This mode of ion removal is only applicable in devices that allow simultaneous removal of both anions and cations, in order to maintain electroneutrality.

H2O -> H+ + OH-

50 • The second operating regime for EDI devices is known as the electroregeneration regime. This regime is characterised by the continuous regeneration of resins by electrically produced hydrogen and hydroxide ions. The dissociation of water preferentially occurs at bipolar interfaces in the ion-depleting compartment where localized conditions of low solute concentrations are most likely to occur (Simons). The two primary types of interfaces in EDI devices are resin/resin and resin/membrane. The optimum location for water splitting depends on the configuration of the resin filler. For mixed-bed devices water splitting at both types of interface can result in effective resin regeneration, while in layered bed devices water is dissociated primarily at the resin/membrane interface. "Regenerating" the resins to their H+ and OH- forms allows EDI devices to remove weakly ionized compounds such as carbonic and silicic acids, and to remove weakly ionized organic compounds. This mode of ion removal occurs in all EDI devices that produce ultrapure water. Under Direct Current (DC) electrical potential, Water (H2O) behaves as follows:

51 • Technology Overview • A typical EDI device contains alternating semipermeable anion and cation ion- exchange membranes. The spaces between the membranes are configured to create liquid flow compartments with inlets and outlets. A transverse DC electrical field is applied by an external power source using electrodes at the ends of the membranes and compartments. When the compartments are subjected to an electric field, ions in the liquid are attracted to their respective counterelectrodes. The result is that the compartments bounded by the anion membrane facing the anode and the cation membrane facing the cathode become depleted of ions and are thus called purifying (or sometimes, diluting) compartments. The compartments bounded by the anion membrane facing the cathode and cation membrane facing the anode will then “trap” ions that have transferred in from the purifying compartments. Since the concentration of ions in these compartments increases relative to the feed, they are called concentrating compartments, and the water flowing through them is referred to as the concentrate stream (or sometimes, the reject stream). In an EDI device, the space within the ion depleting compartments (and in some cases in the ion concentrating compartments) is filled with electrically active media such as ion exchange resin. The ion-exchange resin enhances the transport of ions and can also participate as a substrate for electrochemical reactions, such as splitting of water into hydrogen (H+) and hydroxyl (OH-) ions. Different media configurations are possible, such as intimately mixed anion and cation exchange resins (mixed bed or MB) or separate sections of ion-exchange resin, each section substantially comprised of resins of the same polarity: e.g., either anion or cation resin.

52 • consumption. A typical EDI system will use approximately 1 kW-hr of electricity to deionize 1000 gallons from a feed conductivity of 50 microsiemen /cm to 0.1 µS/cm product conductivity. Since the EDI concentrate (or reject) stream contains only the feed water contaminants at 5-20 times higher concentration, it can usually be discharged without treatment, or used for another process. Thus facility costs can also be reduced since waste neutralisation equipment and ventilation for hazardous fumes are not necessary. There are also less tangible cost reductions, which are harder to quantify, but usually favor the use of EDI systems. By eliminating hazardous chemicals wherever possible, workplace health and safety conditions can be improved. With today's increasing regulatory influence on the workplace, the storage, use, neutralisation, and disposal of hazardous chemicals result in hidden costs associated with monitoring and paperwork to conform to EPA and OSHA requirements as well as the "Right To Know" laws. In addition, the fumes, particularly from acid, often cause corrosive structural damage to facilities and equipment. For the most part the elimination of regenerant chemicals is considered advantageous, but the chemicals do offer at least one benefit. In conventional demineralisers, acid and caustic is typically applied to the ion exchange resins at concentrations of 2-8% by weight. At these concentrations the chemicals not only regenerate the resins but clean them as well. The electrochemical regeneration that occurs in a EDI device does not provide the same level of resin cleaning. Therefore proper pretreatment is even more important with a EDI device, in order to prevent fouling or scaling. This is one of the reasons that RO pretreatment is normally required upstream of a EDI system. In general the feed water requirements for EDI systems are stricter than for a chemically regenerated demineraliser. •

53