دراسة جدوى انتاج وتعبئة مياه معدنية من تحلية مياه البحر والابار الشاطئية

A drinking water purification process

by
col.dr
bahaa badr
chemical consultant

Drinking water production from surface water

On this page you will find an explanation of a drinking water purification process. All process steps are numbered and the numbers correspond with the numbers in the schematic representation of the drinking water process found below.

This is a summing up of the process steps:

a: Prefiltration

1) The uptake of water from surface waters or groundwater and storage in reservoirs. Aeration of groundwater and natural treatment of surface water usually take place in the reservoirs. Often softening and pH-adjustments already happen during these natural processes.

2) Rapid sand filtration or in some cases microfiltration in drum filters
.
b: Addition of chemicals

3) pH adjustment through addition of calcium oxide and sodium hydroxide.

4) FeCl3 addition to induce flocculation for the removal of humic acids and suspended particulate matter, if necessary with the addition of an extra flocculation aid.

Flocs are than settled and removed through lamellae separators.
After that the flocs are concentrated in sludge and pumped to the exterior for safe removal of the particulates and sludge dewatering.
5) Softening in a reservoir, through natural aeration or with sodium hydroxide, on to 8,5 oD. This is not always necessary. For instance, in case natural filtration will be applied, softening takes place naturally.

c: Natural filtration

6) Drinking water preparation step that is specific for the Netherlands: Infiltration of the water in sand dunes for natural purification. This is not applied on all locations The water will enter the saturated zone where the groundwater is located and it will undergo further biological purification. As soon as it is needed for drinking water preparation, it will be extracted through drains.

d: Disinfection

7) Disinfection with sodium hypochlorite or ozone. Usually ozonation would be preferred, because ozone not only kills bacteria and viruses; it also improves taste and odour properties and breaks down micro pollutants. Ozone diffuses through the water as small bubbles and enters microrganisms cells by diffusion through cell walls. It destroys microrganisms either by disturbance of growth or by disturbance of respiratory functions and energy transfers of their cells. During these processes ozone is lost according to the reaction O3 -> O2 +(O).

e: Fine filtration

Slow sand (media) filtration for the removal of the residual turbidity and harmful bacteria. Sand filters are backwashed with water and air every day.

9) Active carbon filtration for further removal of matter affecting taste and odour and remaining micro pollutants. This takes place when water streams through a granular activated carbon layer in a filter. Backwash is required regularly due to silting up and reactivation of an active carbon filter should be done once a year.

f: Preservation and storage

10) Addition of 0.3 mg/L sodium hypochlorite to guarantee the preservation of the obtained quality. Not all companies chlorinate drinking water. The water will eventually be distributed to users through pipelines and distribution pumps.

11) Aeration for recovery oxygen supply of the water prior to storage. This is not always applied.

12) Remaining water can be stored in drinking water reservoirs.

In the following schematic representation of the drinking water preparation process dotted arrows represent the incoming chemicals and red arrows represent the outgoing flows.

Schematic representation of the drinking water preparation process
Water is not always infiltrated in sand dunes during treatment.

Holland clearly illustrates this:

- In Rotterdam water is stored in reservoirs in the Biesbosch, where it undergoes natural treatment
- In Amsterdam the water was stored and naturally treated in sand dunes on to the year 2000, now it is stored in reservoirs
- In The Hague the water is still stored and naturally treated in sand dunes
Drinking water standards

Regulations concerning the quality of the water intended for consumption:

• The World Health Organization

The World Health Organization (WHO), set up some guidelines for drinking-water quality which are the international reference point for standards setting and drinking-water safety. The latest guidelines drew up by the WHO are those agreed to in Geneva, 1993.

You will notice that there is no guideline for some of the elements and substances which are taken into account. This is because there have not been sufficient studies about the effects of the substance on the organism, and therefore it is not possible to define a guideline limit.

In other cases, the reason for a non-existing guideline is the impossibility of that substance to reach a dangerous concentration in water, due to its insolubility or its scarcity.

• The European Union

The European Union drew up the Council Directive 98/83/EC on the quality of water intended for human consumption, adopted by the Council on 3 November 1998. This was drawn up by reviewing the parametric values of the old Drinking Water Directive of 1980, and strengthening them where necessary in accordance with the latest available scientific knowledge (WHO guidelines and Scientific Committee on Toxicology and Ecotoxicology). This new Directive provides a sound basis for both the consumers throughout the EU and the suppliers of drinking water.

These were the main changes in the parametric values:
- Lead: The guideline was reduced from 50 µg/l to 10 µg/l, and a transition period

of 15 years was defined to allow replacing of lead distribution pipes.
- Pesticides: The values for individual substances and for total pesticides were
retained (0.1µg/l / 0.5µg/l), plus additional, more stringent values were
introduced for certain pesticides (0.03µg/l).

- Copper: The value was reduced from 3 to 2 mg/l.
- Some new standards were introduced for new parameters like trihalomethanes,
trichloroethene and tetracholoroethene, bromate, acrylamide etc.

[u]

WHO/EU drinking water standards comparative table
The EU standards are more recent (1998), complete and strict than the WHO standards (1993).

by
col.dr
bahaa badr
chemical consultant

Some examples are:

- Bromate (Br): Not mentioned by the WHO, 0.01 mg/l guideline in the EU standards.

- Manganese (Mn): Guideline reduced from 0.5 to 0.05 mg/l.

- Cyanide (CN): Guideline reduced from 0.07 to 0.005 mg/l.
But in some cases the EU guidelines are less strict than the WHO’s:

- Cadmium (Cd): Guideline rised from 0.003 to 0.005 mg/l.
Here is a comparative table of both WHO and EU standards:
WHO standards EU standards
1993 1998
Suspended solids No guideline Not mentioned
COD No guideline Not mentioned
BOD No guideline Not mentioned
Oxidisability 5.0 mg/l O2
Grease/oil
No guideline Not mentioned
Turbidity
No guideline(1) Not mentioned
pH
No guideline(2) Not mentioned
Conductivity
250 microS/cm 250 microS/cm
Color No guideline(3) Not mentioned
Dissolved oxygen
No guideline(4) Not mentioned
Hardness
No guideline(5) Not mentioned
TDS
No guideline Not mentioned

cations
(positive ions)
Aluminium (Al)
0.2 mg/l 0.2 mg/l
Ammonia (NH4) No guideline 0.50 mg/l
Antimony (Sb)
0.005 mg/l 0.005 mg/l
Arsenic (As)
0.01 mg/l 0.01 mg/l
Barium (Ba)
0.3 mg/l Not mentioned
Berillium (Be)
No guideline Not mentioned
Boron (B)
0.3 mg/l 1.00 mg/l
Bromate (Br)
Not mentioned 0.01 mg/l
Cadmium (Cd)
0.003 mg/l 0.005 mg/l
Chromium (Cr)
0.05 mg/l 0.05 mg/l
Copper (Cu)
2 mg/l 2.0 mg/l
Iron (Fe)
No guideline(6) 0.2
Lead (Pb)
0.01 mg/l 0.01 mg/l
Manganese (Mn)
0.5 mg/l 0.05 mg/l
Mercury (Hg)
0.001 mg/l 0.001 mg/l
Molibdenum (Mo)
0.07 mg/l Not mentioned
Nickel (Ni)
0.02 mg/l 0.02 mg/l
Nitrogen (total N)
50 mg/l Not mentioned
Selenium (Se)
0.01 mg/l 0.01 mg/l
Silver (Ag)
No guideline Not mentioned
Sodium (Na)
200 mg/l 200 mg/l
Tin (Sn) inorganic
No guideline Not mentioned
Uranium (U)
1.4 mg/l Not mentioned
Zinc (Zn)
3 mg/l Not mentioned

anions
(negative ions)
Chloride (Cl)
250 mg/l 250 mg/l
Cyanide (CN) 0.07 mg/l 0.05 mg/l
Fluoride (F)
1.5 mg/l 1.5 mg/l
Sulfate (SO4)
500 mg/l 250 mg/l
Nitrate (NO3)
(See Nitrogen) 50 mg/l
Nitrite (NO2)
(See Nitrogen) 0.50 mg/l

microbiological
parameters
Escherichia coli Not mentioned 0 in 250 ml
Enterococci Not mentioned 0 in 250 ml
Pseudomonas
aeruginosa Not mentioned 0 in 250 ml
Clostridium
perfringens Not mentioned 0 in 100 ml
Coliform bacteria Not mentioned 0 in 100 ml
Colony count 22oC Not mentioned 100/ml
Colony count 37oC Not mentioned 20/ml

other parameters
Acrylamide Not mentioned 0.0001 mg/l
Benzene (C6H6) Not mentioned 0.001 mg/l
Benzo(a)pyrene Not mentioned 0.00001 mg/l
Chlorine dioxide (ClO2) 0.4 mg/l
1,2-dichloroethane Not mentioned 0.003 mg/l
Epichlorohydrin Not mentioned 0.0001 mg/l
Pesticides Not mentioned 0.0001 mg/l
Pesticides - Total Not mentioned 0.0005 mg/l
PAHs Not mentioned 0.0001 mg/l
Tetrachloroethene Not mentioned 0.01 mg/l
Trichloroethene Not mentioned 0.01 mg/l
Trihalomethanes Not mentioned 0.1 mg/l
Tritium (H3) Not mentioned 100 Bq/l
Vinyl chloride Not mentioned 0.0005 mg/l
(1) Desirable: Less than 5 NTU
(2) Desirable: 6.5-8.5
(3) Desirable: 15 mg/l Pt-Co
(4) Desirable: less than 75% of the saturation concentration
(5) Desirable: 150-500 mg/l
(6) Desirable: 0.3 mg/l

bottled water
by
col.dr
bahaa badr
chemical consultant

Italians are the main consumers of drinking water in the world.

In the last 10 years the national mineral water production has grown from 6.100 million liters to 9.150 million litres, with an annual value of almost two and a half billion euros. The average annual cost is about 300 euros for every Italian family.

Almost half Italian population prefers bottle water to tap water and on average every inhabitant drinks about half a litre. 266 different brands of mineral water are present in Italy, bottled under their commercial names and with an indication of the place in which they well up and are bottled.
As a paradox Italy is a country rich in springs, usually of a very high quality. These springs are partially used for bottle water production, partially for the distribution in drinking water networks.
In Rome someone has even opened a drug store dedicated to mineral water. There you can choose between 60 water brands coming from all over Europe and US, even if in Rome there are more than 2080 fountains providing very good drinking water at the citizens' disposal.
Does all this make sense?
Bottled water means transportation problems, thus energy consumption and pollution, and waste problems: glass water bottles are recyclable and within a certain extent plastic bottles as well.

5 millions plastic bottles are used per year, which are not biodegradable and have a almost unlimited life when disposed in the environment.

At their end of life plastic bottles are incinerated and become responsible for the emission in atmosphere of toxic compounds such as chloric acids, heavy metals and dioxins.

More than one third in weight of the incinerated waste remains in form of ash, containing toxic compounds.

During their use plastic bottles do not ensure the hygienic safety ensured by glass bottles, since they can loose unwanted compounds in water, particularly if they are stocked in a warm place or under the sunlight.

American market researches showed that in US the most likely consumer of drinking water is a well educated, middle class adult between 18 and 34, who is aware of the existence of health problems.

He drinks bottled water to point put who he is and what he represents. In an age characterised by chemical pollution, bottled water is considered pure and untouched, becoming the good health symbol.

Even if bottled water quality is good, you should not forget that it is not above contamination: small amounts of pesticides and organics can reach the water spring. As tap water it is not sterile (unless it is ozonized) and it can contain usually not harmful bacteria.

American tap water quality is usually very high, as the Italian one, so bottled water does not seem to have many benefits compared to tap water, unless the taste.

For many people bottled water as a much better taste than tap water. Tap water is often disinfected using chlorine, which gives it a sour flavour. Tap water could also contain metals originated by pipes, which are unpleasant to ingest.

Normative

The directive 80/777/ECC states what can and what cannot be considered mineral water.

Controls

Water is a public good, even if its exploitation can be given in concession to private people, after payment of a bill.

Water is commercialised after authorisation by the Health Department and law foresees a periodical (monthly or biweekly) control of plants (entrusted to hospitals), seasonal controls of the spring and quinquennial controls for the label renewal.

Anyway producers are interested to look after the good name of the company and carry out controls to different production levels. Compared to tap water, which is daily controlled, bottled water offers less warranties of official controls.

The label
Information shown in the label varies depending one the brand. As for all the food many information indicates seriousness.

The most common information are:

1. Production plot in terms of day, month and year;
2. Commercial name;
3. Merchandise class (Mineral Water);
4. Content in l, cl or dl;
5. Main properties (composition in mineral salts, health effects etc.);
6. Bacteriological analysis or the saying 'Biologically pure')
7. Chemical analysis: physical-chemical features as pH, spring temperature, electric conductibility, total hardness, fixed residue at different temperatures, compounds and gasses dissolved in one liter of water;
8. membership class (mineral, mediomineral, oligomineral)
9. Selling authorisation by Health Department decree, number and date;
10. the saying 'do not dispose in the environment';
11. Bar code
Optional is the indication of salient qualities such: Possibility of diuretic effect, possibility of laxative effect, indicated for newborn feeding, indicated for sodium poor diets, it stimulates digestion (or similar), it can help ephatobiliar functions (or similar). Please notice that most waters point out the same functions, often very obvious: extolling mineral water purification and diuretic qualities is like doubting on the cleverness of the consumer, who should know that water has always these properties.

Mineral water types

Mineral water lightly mineralized
It forms about the 9% of all the mineral waters on sale in Italy. Its low mineral content, up to 50 mg/l and its usually low pH make it more diuretic. It is recommended in bladder stone cases or to dilute powder milk for young children. This kind of water can be too light for all the other people.
Oligomineral water lightly mineralized
It forms more than a half of all the bottled mineral water in Italy. The mineral content is included between 50 and 500 mg/l depending on the mineral content. Advertisements point out its lightness and its diuretic action, useful to prevent bladder stoning. It is not recommended to drink more than 2 or 3 litres/day in all cases of bladder dysfunctions and hypertension. Lightly mineralized water can have a slightly demineralising effect.

Mineralised water
It is the real mineral water, with a fixed residue up to 1500 mg/l. Usually this is the fixed residue contained in our tap water. The diuretic effect gets slightly lower proportionally to the increasing in fixed residue.
Type of water Fixed residue
Mineral water lightly mineralized < 50 mg/l
Oligomineral water >50 < 500 mg/l
Mediomineral water > 500 < 1500 mg/l
Water rich in minerals > 1500 mg/l

Which water should we choose?

Unfortunately advertisements are not a reliable guide in mineral water choice. All the companies producers of bottled water are willing to guarantee a very general effects appreciated by all the consumers and which make us inconscially hope to feel light, deflated, thin, active.
Mineral water choice should be made consulting the nutritionist doctor, particularly in case of people having health problems, starting from disorders. If no disorders are present, to choose the most suitable water for the whole family you should consider some basic criteria:
1. The most advertised and most expensive mineral water apparently is not the best: publicity can in fact influence the final price up to 50%;
2. Read the label carefully:
- a mediomineral water with a fixed residue between 500 and 800 mg/l can be the most suitable for your family;
- low values of nitrates and sulphates, ad eventually of chlorine and sodium, are very important;
- check the making date and choose the most recent;
3. Glass bottles and not sparking water should be preferred: the added carbon dioxide increases water acidity and our diets are already very rich in acidic compounds;
4. Bottles and packages should be perfectly intact. Do not buy water from dispenser where a storage outside, under the sunlight, is evident.
A brief description of some mineral waters follows. Please note that the following description has only illustrative purpose and every choice concerning nutrition, including mineral water, should be made consulting your doctor. For further information click on pure water web page.
Type of water: Content: mg/l
Bicarbonate water Bicarbonate > 600
Sulphate water Sulphates
> 200
Chlorine water Chlorine
> 200
Calcic water Calcium
> 150
Magnesium water Magnesium
> 50
Florurated water Fluorine
> 1
Irony water Iron
> 1
Sodic water Sodium
> 200
Low sodic water Sodium
< 20

Bicarbonated water
The anion HCO3 has a concentration higher than 600 mg/l or anyway it is dominant.
Effects: This water can accelerate gastric emptying if drunk during meals, fasting it limits gastric acidity.
For who: carbonated water is generally prescribed to who suffer epatobiliaric disorders and it is recommended to who practise sport, since bicarbonate and calcium are able to neutralise lactic acid. It is useful for babies who vomit frequently or anyway as food integration in first months, since it is rich in precious minerals.

Sulphated water
The SO4 content should be higher than 200 mg/l or it is anyway dominant.
Effects: sulphated water is slightly laxative. It relax biliaric muscles and has an equilibrating effect on the stomach.
For who: it is recommended for people suffering spastic cholite or colon diseases. It is not recommended during growth, since it can interfere with calcium adsorption.

Chlorinated water
Water in which the anion Cl is dominant.
Effects: if chlorine water has an high mineral content (hyper tonic), it increases internal peristalsis, if it has a low mineral concentration (hypotonic) it stimulates gastric secretion. It can have spasmodic, coleretic action and protect liver from toxic compounds.
For who: Chlorinated water is recommended for hyper tense people with renal problems.
Calcic water
Calcic water usually is calcic bicarbonate water. It should have a calcium content higher than 150 mg/l.
Effects: calcic water usually act on stomach and liver. It helps to prevent osteoporosis and to reduce hypertension. Calcic water cannot and should not be considered a food calcium source.
For who: it is useful for people who suffer stomach and liver disorders, to prevent high pressure, osteoporosis and for growing children.

Magnesic waters
Magnesic water has a magnesium content higher than 50 mg/l and in rather rare in the market.
Effects: Magnsiac water has a purging effect, but it is prescribed to prevent arteriosclerosis, since magnesiac waters containing lithium and potassium induce a sensible arteries dilatation.
For who: magnasiac water is useful for who suffer magensium lack, which can bring cramps, low stress resistance and fatigue.

Sodic water
Sodium content in sodic water is 200 mg/l.
Effects: Sodic water positively effects neuromuscular excitability.
For who: Usually it is believed that these waters are contraindicated for hyper tense people, but it is a debated topic. Sodic water is recommended in case of sodium lack and for who practices sport.

Fluorinated water
According to law fluorinated water is water which contain a concentration higher than 1 mg/l of fluorine. It is natural fluorine, than does not originate from industrial operation residues.
Effects: Fluorinated water contains fluorine that helps to reinforce teeth and dental caries. According to law the maximum admissible content in water is 1.7 mg/l and an excess can cause fluorosis, an accumulation of fluorine in teeth and bones.
For who: fluorinated water is recommended during the growth and for who is affected by osteoporosis, but an intake for long periods is not recommended.

Ferruginous water
Iron bivalent content should be higher than 1 mg/l.
Effects: Iron is assimilated by the intestine as ferric ion.
For who: Ferruginous water is recommended for haemic people, as integration to medical therapies. They are not recommended for who suffers gastritis or gastroenteritis.
On the earth there is no such important resource for the human kind as water. Water forms form 50 to 60% in weight of our body and play an active role in all the vital processes of our body: it allows digestion, food elaboration and waste elimination. Every day we drink water or we eat watery food to replenish our metabolic reserve.
But what is the water we drink made of? Can we rely on drinking tap water or it is preferable to buy bottled water? Among the several brand on sale, which one should we choose?
Here and in the related pages you'll find all the answers to these questions.
Which is the composition of the water we drink?

The water formula is H2O, two atoms of hydrogen and one of oxygen, but only distilled water has this structure. Rain water, snow and ice are quite similar to distilled water. Water presents in nature contains, even if in traces, minerals very important for our health: salt and oligoelements dissolved during its way through the soil or its flowing in rocky streams.
If you would like to have further information from health risks from drinking demineralized water, click here.

Mineral salts and oligoelements

Calcium (Ca)
Calcium is one of the most common elements on the earth. It is essential in our body for teeth and bones formation, blood coagulation, right functioning of our nervous system. Calcium ions are contained in almost all spring, drinking water. Health effects caused by hard water, very rich in calcium and magnesium, are unknown. An excess in calcium can alter the water taste or cause scaling problems in pipes and household appliances. If you use a device for the reduction of the content of calcium and magnesium ions dissolved in water (softener), it is important that the calcium content never goes under 60 mg/l. The World Health Organisation recommend a minimum calcium daily intake of about 700 mg. Drinking calcium poor water is considered dangerous for the risk of coronary diseases.

Magnesium (Mg)
Magnesium is, with sodium and calcium, among the cations most commonly found in drinking water. In humans magnesium is important for many metabolic functions and for muscular and nervous activity. The daily recommended intake is 150-500 mg.

Sodium (Na)
Sodium is an element very diffused on earth and in the biosphere, even if in nature it is almost never in its pure form, but mainly in form of salt (NaCl). Our body contains an average of 100 g of sodium which is an important metabolic regulator for nervous and muscular stimulations.

The daily sodium chlorine intake is 20 mg. Due to our diet very rich in salt it is recommended to drink water with a sodic content lower than 20 mg/l, particularly for ipertense people and children.

The salt consumption in industrialized countries is considered much higher than the recommended levels (about 3.9 g/day on average).

Drinking 2 liters of water containing 20 mg/l of sodium you reach 40 mg, that is about the 5% of the total intake. To reduce the daily sodium intake it would be more logical to change your nutrition: i.e. to eat only integral sea salt, more equilibrate and rich in mineral salts at home, and to avoid precooked food, always rich in refined salt.

Chromium (Cr)
Chromium is an important oligoelement for our organism, on condition that certain concentration are not exceeded and the element is not found in toxic or carcinogenic combinations (always due to industrial pollution). At present there is no recommended daily intake.

Copper (Cu)

Copper is an essential element for our health, but it is toxic at high concentration. A daily intake of 1.2 mg is recommended. Copper pollution in water can originate form copper pipes corrosion by soft, acidic water.

Iron (Fe)

Food rich in iron is very important, particularly for children and women in fertile age. The recommended daily intake is 10 mg. Iron is usually contained in low amount in drinking water. The WHO recommend a maximum of 0.3 mg/l the EEC of 0.2 mg/l. Possible increasing (lower than 200 mg/l) are not to be considered harmful, even if they make the water not nice to drink and give an unpleasant reddish colour.

Chlorine (Cl)
Chlorine is an important constituent of organic liquid and a daily intake of 7-15 g of NaCl is recommended.

Manganese (Mn)

Food usually covers the recommended daily intake of 2-3 mg. An excessive concentration in water is not necessarily harmful, but originates the same problems as iron (unpleasant taste and colour).

Selenium (Se)

Even if selenium is considered a toxic element taken is high dosage, it is an important anti-oxidant. Selenium is useful to attack free radicals and then prevent aging. The recommended daily intake by EEC is 40 picog. A possible lack of selenium can increase the risk of tumour and cardiovascular diseases.

Fluorine (F)

In someone opinion fluorine is useful for the good health of bones and teeth, sometimes it is even essential, in others opinion it is unnecessary when you are adult, above all if it is added.

Fluorine is an halogen and it is the most electronegative of all the elements, so it reacts easily with most of the elements. In 1945 the addition of fluorine in drinking water began to be experimented in New York State, followed by Australia and some areas in UK, with the declared purpose of preventing dental caries in population. Water fluorination is prohibited in Belgium, Denmark, the Netherlands and France; in Spain and Germany local authorities handle every decision and in Italy there is no specific law on this matter.
Fluorine values useful for our body are very close to toxic values, so a dispense not aimed and personalized can cause high risk of overdosing and chronicle poisoning, with consequent skeleton deformation, spots on tooth enamel, osteosclerosis, neurological disorders, damages on the thyroids and even tumours. According with some research 10% of fluoride doesn't deposit in teeth and bones, but in organisms such as kidneys. Fluorine has negative effects on the central nervous system, determining behaviour alterations, cognitive deficit, influencing on the foetus development even in concentration not harmful for the mother.

The calcium fluoride presents in nature is very different from the sodium-silica-fluoride (Na2SiF6) added in drinking water, an industrial waste that is toxic and difficult to digest.

People against drinking water fluorination argue that it is a violence that does not count individual choice freedom, not to mention the individual tolerance limit.

Other inorganic toxic substances
Many toxic minerals are contained in water supplies, usually at high levels. Treatment and potabilisation plants work very well reducing these minerals to safe levels. Minerals can enter surface or ground water through natural sources, industrial sewage, leach age from urban or agricultural areas, water pipes walls or even from domestic sources.

The list of organic substances that you can find in industrial applications is long, a brief description of the most common follows.

Phosphates

Phosphate in water originates from detergents and fertilisation and a level higher than 0.1 mg/l indicates pollution. Flora and fauna, very sensitive to phosphate presence, are the main victims.

Sulphates
Sulphates are sulphuric acid salts combined with metallic ions. Water can naturally contains small quantities of sulphates, but they are mostly transferred in water bodies from the atmosphere and in the atmosphere form road traffic, industries and energetic production. Sulphur oxidised in the air can come back on the soil as acid rain, causing serious environmental problems.

Nitrates and nitrites

Nitrates are the main source of nitrogen for plants and an essential constituent for nucleic acids and amino acids.

A nitrates water content of about 10 mg/l is considered normal and natural. Different concentration is due to human operations (mauring, air pollution due to transport). The problems resulting from excessive nitrate presence are due to the toxicity of nitrate for human body: nitrates are transformed in nitrites or in carcinogenic nitrosamines.

Aluminium (Al)

Aluminium is very abundant on the earth, but is not important for human nutrition. Aluminium can have toxic effects even in small quantities. These effects occur in nervous system, but health effects originating from aluminium intake through water are still on debate.

Aluminium concentration is usually lower than 200 mg/l in drinking water. If you drink 1.5 litre of water per day, your daily intake from water is lower than 300 mg/day, a negligible amount if compared with the amount taken by nutrition (10-20 mg/day).

There is no evidence that the aluminium assumed through water is more soluble and then more easily digestible, than the aluminium contained in food. Due to all these uncertainties at present there are no rules about its concentration allowed in drinking water. The WHO recommend a concentration lower than 20 mg/l.

Arsenic (As)
Arsenic can be toxic even in low amounts. Nevertheless the arsenic contained in food (amounts ranging from 0.01 to 1.5 mg/kg of dry weight) has a different influence: it carries out some positive metabolic function for our body. Its toxicity is strongly linked on the concentration.

Lead (Pb)
Lead is poisoning even in small amounts for microorganisms, interfering with haemoglobin formation and with the functionality of central nervous system. Lead is particularly harmful for children, who can suffer long term neurological and behavioural disorders. Major lead sources are paint, vehicle emissions, food and water. The European Directive about drinking water for human consumption 98/93/EC states that the maximum allowed lead concentration in drinking water should decrease from the actual 50 mg/l to 10 mg/l within 25 December 2013. The problem in Italy is that many pipes contain lead and acidic soft water, with a low phosphate content. If this water lingers for long time in the pipes it can adsorb lead. Some precautions can be taken to lower lead content in drinking water:

• flush the water before drinking it, since lingering water in pipes tends to accumulate lead; to avoid water dissipation it is recommended to collect the flushed water in bottles and tanks for a following use;
• do not use hot tap water for cooking, since hot water dissolve lead more easily than cold water;
• periodically remove clinker and slag from the pipes;
• to use an home water filter is certainly a good way for lead removal.

Cadmium (Cd)

Cadmium is a highly toxic heavy metal, considered carcinogen. Its harmful action is similar to the effect of lead and it can be released in drinking water by zinced iron pipes. Zinc always contains a small amount of cadmium.
Mercury (Hg)
Mercury can or can not be toxic, depending on its chemical bonds. The WHO recommend a daily intake of 0.3 mg/day for a 60 kg person. Mercury can be released in ground water or in surface water by industrial waste water discharge in rivers and estuaries, by leach age from toxic landfill, by mercury emissions from volcanoes, seismic underground activity, incineration and fossil fuels combustion. The mercury released in the atmosphere is very light, so it can reach long distances from the source and fall again on the soil through rain, entering water bodies.
However mercury is not commonly found as pollutant in our drinking water.
Asbestos
Asbestos can reach drinking water through natural sources, pipes built in a compound made of concrete and asbestos and from atmosphere. Hard water seems to bring to a lower asbestos loss compared to water poor in salts, which is much more corrosive.
Chlorine (Cl)
At present chlorination is the most used treatment to remove water bacteria which could cause health problems. The Italian law allows 30 mg/l of chlorine, while the guidelines of the European Directive indicate 1 mg/l and specify that the concentration should be as low as possible. According with international research the consumption of water containing compounds formed after the reaction between chlorine and microorganisms (trihalometanes) can contribute to the increasing of huro-genital tumours.
If when you open the tap you smell the chlorine odour typical of swimming pools, it is recommended to pour the water in a large tank and to leave it open or semi-open for about half an hour. Chlorine is in fact very volatile and tend to still on the water surface. To accelerate chlorine dispersion you can pour the water from a tank to another repetitively or mix very quickly.

Chemical organic compounds

Chemical organic compounds directly originates from plant or animal matter.

For instance plastics are chemical organics compounds made of petrol, which originates from plants and animals.

Nowadays there are more than 100.000 chemical organic compounds, which include synthetic fertilizers, pesticides, biocides, herbicides, paints, dyes, flavours and pharmaceutical substances.

Most of these compounds are toxic and many have been found in water reservoirs.

VOC (Volatile Organic Compounds) are very dangerous, because they are adsorbed by the skin in contact with the water carrying them. If chlorine used for the water disinfection is in contact with these chemical organic compounds, the carcinogens trihalometanes can form.
Phyto-pharmaceuticals
Phyto-pharmaceutical products are the most accused substances for ground water pollution. We are not going to spend too much time in the description of their use and abuse, but everybody should know cases of closed wells. Even if ground water pollution stopped immediately, impossible thing to happen, it would take a long to soil and water to recover. Not very much is known about the compound of phyto-pharmaceuctics, but metabolites can be much more toxic than water.
Surfactants
Surfactants are the substances used in detergents to lower the surface tension of the water, allowing it to wet the clothes better.

We all use substances containing surfactants, which are responsible of the pollution of the water we drink. They are also in cosmetics, anti freezing products, glues, colours. We can contribute to the reduction of this pollution source, using only the minimum necessary quantity or choosing biodegradable surfactants.

Microbiological pollution

Microorganisms include bacteria, virus and parasite.
Bacteria are carefully monitored in public water supplies, since they can be responsible of serious diseases as typhoid, cholera, hepatitis etc. and their presence can be easily detected. Bacteria are easily killed by adding chlorine.
Viruses are very abundant in water supplies as well. They are much more difficult to detect. Most viruses are killed by chlorination, and anyway most of the viruses carried by water are too week to be harmful for humans.
The third group of microorganisms commonly found in water are parasite, as giardia and cryptosporidium. They are very resistant and can be found in tap water even is a treatment system is present.

When drinking water has to be carried along long distances, the problem of a possible pollution occurs. This pollution can happen through the contact of water with porous surfaces or synthetic materials that are an ideal media for microorganisms.

A particular type of infection which can be transmitted through water is legionella. The risk occurs particularly in showers or Jacuzzis. The ideal environment for the bacteria of legionella phneumofila is included between 37 and 45 C.

Nowadays, desalination* has become a very affordable solution to cope with fresh water shortage typically in tropical as well as of off-shore
by
col.dr
bahaa badr
chemical consultant

The desalination core process is based on Reverse Osmosis Membrane technology, but stand alone, it doesn't provide safe drinking water, nor does it guarantee an efficient plant.

The pretreatment includes all the necessary treatment step ahead of the reverse osmosis plant. It is determining for plant life time and to minimise chemical cleaning and membrane replacement. It has a direct impact on the plant performance.

There are as many membrane types as applications. They range from "high rejection" to "ultra low energy" or " high boron rejection".

The reverse osmosis process can also be build with one or two passes, depending on the product water requirements and the seawater salinity and temperature. In most cases, 1 pass is sufficient to reach the EU drinking water standards, specially regarding the boron content (1 mg/L). To reach WHO boron guideline (0.5mg/L), a second pass might be necessary (Boron removal process)

The energy recovery device is the key factor that determines the plant electrical costs. It must be chosen carefully based on the local energy costs and environment policies.

Post-treatment and/or polishing steps are required to condition the water after the reverse osmosis membrane process to make it suitable to your application.

Brine disposal can be an environmental and economical issue in some areas where the fauna and flora are sensitive to local seawater salinity increase. Brine disposal should be studied and engineered case by case.

The art of desalination is to determine and combine available technologies to optimize water production costs and quality.

To adapt our Desalination Plants to your local needs, we offer containerized mobile units from Intake to Distribution up to a production capacity of 200 m3/h of desalinated water.

Desalination process
by
col.dr
bahaa badr
chemical consultant

1- sea water intake (tds=43000-53000ppm)

2- pretreatment steps
(prepchlorination)
(coagulation)
(flocculation)
(sedimentration)
(multi-media filteration)
(ultrafiltration)
(dechlorination)
(antiscalant)
(fine filteration)

3- reverse osmosis steps
(high pressure pump)
(energy recovery)
(sludge disposale)
(brine disposale)
(sea water reverse osmosis)

4- post treatment steps
(brackish water ro)
(ion exchanger)
(ph-neutralization)

5- the final steps
(process water=tds=50ppm)
(storage)
(distribution)

Desalination unit
by
col.dr
bahaa badr
chemical consultant

SWRO sea water reverse osmosis system is designed for commercial and residential applications where floor space is at a premium.

All major system elements are mounted within a sturdy tubular stainless steel frame, welded for long term rigidity and open for easy access to all components.

The SWRO Series sea water filter system is a compact, heavy duty sea water R.O. water purifier for users requiring 500, 1500, up to 10,000 gallons per day water production.

As with all of our purifier products, The SWRO system is fully equipped with the instruments and controls needed for reliable long term operation.

SWRO features include

SWRO-500 (500 GALLON PER DAY) SEA WATER REVERSE OSMOSIS SYSTEM FEATURES:

Designed For Sea Water Desalination & Brackish Well Water Filtration
• Stainless steel frame, structural ABS control panel
•
• Caster wheels for mobile portability - Each TV-SWRO unit is equipped with wheels for portability
•
• 316 SS High pressure pump with safety relief valve
•
• Fiber reinforced 1000 PSI pressure vessel
•
• 20" Prefilter for 2.5"x20" cartridge
•
• Quick connect brine and product connections
•
• Prefilter in & out and membrane vessel in & out pressure gauges
•
• Product water flowmeter
•
• Brine flow meter
•
• High Pressure control SS needle valve
•
• Panel mounted digital TDS product water quality monitor
•
• Portable Superior Water Quality Monitoring: Allows you to easily test your water before and after the SWRO-500. Portable waterproof tester offers high accuracy electrical conductivity (EC), total dissolved solids (TDS) and temperature measurements in a single tester!
•
• Low energy, thin film sea water membrane element
•
• Microprocessor system controller
•
• Automatic product water membrane flush - Clean water flushes the membrane upon start-up
•
• New 2011 Separate Feature: Water Alarm now included with every SWRO-500 Order. Portable water leak detection/water alarm system - Helps detects water leaks and moisture. Sounds a loud alarm when water is detected. Includes 6ft of wire attached to the sensor and up to 100 feet of additional wire can be spliced into the line. Perfect for monitoring from your office or work area.
SWRO-500 DESALINATION SYSTEM SPECIFICATIONS:
• Dimensions: 22"W x 26"D x 49"H
•
• Weight: 170 lbs.
•
• Output*: 500 GPD, 0.35 GPM - *Based on typical 35,000 ppm feed sea water at 72 degrees F
•
• Membrane: 1 Low energy, high rejection thin film sea water type
•
• Dissolved Solids Rejection: 98-99%
•
• Prefilter: 10 micron polypropylene depth type
•
• Power Req.: Standard - 208-220V 1-Phase. 60 Hz, Optional - 220V, 50 Hz
•
• Connections: Feed - 3/4" FPT, product and brine - 1/2" tube
•
• System Control: Microprocessor control by product tank level and feed pressure. Also provides product TDS monitoring.
•
• Salinity Monitoring: Automatic electronic monitoring. Temperature compensated with the digital continuous readout. The salinity monitoring components of the system provide TDS readout in ppm (parts per million) of product water.
•
• Salinity Range: Designed for seawater use up to 50,000PPM TDS (NaCl) (typical seawater salinity is 35,000 ppm)
•
• Automatic Membrane Flush: Membranes flushed with product water for 5 min. after every shutdown
•
• Temperature Range: Max. 113oF / 45oC, Min. 33oF / .5oC
•
• ** Required System Inlet Feed Water Flow: 6 gpm - If you do not have a well pump or inlet delivery pump a Booster Pump Will Be Required - On the sea water/ well water systems there is almost always a need for a boost pump to deliver the sea or well water to the R.O. and a pretreatment sand filter before the R.O.
•
• System Feed Water Pressure: Minimum 25 psi /1.8 bar, Maximum 80 psi / 5.6 bar
•
• RO System Operating Pressure (sea water): Nominal 700 psi / 49 bar
•
• pH Range: 3-11 (typical seawater pH is
•
• Operating Parameters:
•
• TDS-35000ppm,
• Total iron is less than .2ppm,
•
• Manganese is less than .04ppm,
•
• Water hardness below 10gpg.
•
• Chlorine Tolerance: 0.1 PPM
Compare! Featured Available Options

.. Storage Tank Options: 300, 550, and 1000 gallon atmospheric storage options available

.. Pretreatment Options: Antiscalant system needed to protect the desal membrane from hard water scale, silica and foulants.

.. Pretreatment Options: Automatic Backwashing Pre-Filter - High performance sand, silt, and turbidity pretreatment protection system.

.. Post-Treatment Options: *NSF Certified State Of The Art Self Cleaning Ultraviolet UV Bacteria,Virus,Microbiological Water Treatment.

[img]

دراسة جدوى انتاج وتعبئة مياه معدنية من تحلية مياه البحر والابار الشاطئية Ouuuuo11

[/img]
[img]

دراسة جدوى انتاج وتعبئة مياه معدنية من تحلية مياه البحر والابار الشاطئية Uoo111

[/img]

[img]

دراسة جدوى انتاج وتعبئة مياه معدنية من تحلية مياه البحر والابار الشاطئية Bw11

[/img]

» دراسة جدوى استخدام الطاقة الشمسية فى تحلية مياه البحر المتوسط للرى والزراعة ومياه الشرب
» مشروع استصلاح مساحة 10 فدان بوادى القويح مقسمة الى مساحة 3 افدنة مصنع انتاج وتعبئة المياه الطبيعية والمعدنية من الابار الجوفية ومصنع انتاج وتعبئة العصائر والمربات وانشاء بئر جوفى بعمق 500 متر لاستخراج المياه الطبيعية لتعبئتها تجاريا مساحة 7 افدنة منطق
» دراسة جدوى مالية واقتصادية وتسويقية لمصنع انتاج وتعبئة مياه معدنية(الباب الثالث)
» دراسة جدوى لاستخدام الكربون النشط فى تحلية مياه البحر
» دراسة جدوى مشروع اقامة محطات التحلية ومصانع انتاج وتعبئة المياه بالبحر الأحمر أفضل الممارسات البيئية لمحطات التحلي ومصانع انتاج وتعبئة المياه ة في البحر الأحمر