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Research show that drinking water contains over 2000 harmful chemicals and EPA regulations only set standards for about 50 of them...
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Source of Water

About Water

Kuwait is a hyper-arid state without rivers or fresh-water aquifers. Nonconventional water resources, including brackish groundwater, seawater desalination, and reclamation of treated waste water are the main current sources of water supply, of which the quality is as saline as 1,000-45,000 mg of total dissolved solids (TDS) per litre:

groundwater (shallow), 1,000-2,000 mg/l,
brackish groundwater, 2,000-8,000 mg/l, 
seawater, 45,000 mall, 
product water from MSF (multi-stage flash) desalination, 25-50 mg/l, 
reclaimed treated waste water, 2,500 mg/l. Well water

The availability of well water in Kuwait is very limited and even the finest sources requires further purification to reduce TDS. The table below shows the details of wellfields in Kuwait.
Field Aquifer No. of wells Yield(million m³/year)   Salinity (TDS, mg/l)
      Existing Potential
Rawdatain and
Um al-Aish
Dibdibba F 52 2.5 6.6 700-1,200
Shigaya A, B. C Kuwait G 60 53 66 3,000-4,000
Shigaya D, E DammanF 54 - 42 3,000-4,500
Sulaibiya Damman F 133 25-33 33 4,500-5,500
Abduliya Damman F 14 8 - 4,500
Wafra Kuwait G (110) 33-42 50 4,000-6,000
Abdali-Um Nigga Dibdibba F (110) 20-25 33-42 3,000-7,000
Source: Kuwait Institute for Scientific Research, in 1990.
Municipal Tap Water

Kuwait is one of the world's leaders in the production of fresh water from the sea. Large Multi Stage Flash (MSF) distillation plants are often paired with power plants in a Co-generation configuration. Waste heat from the power plant is used to heat the seawater, providing cooling for the power plant at the same time. Kuwait developed Co-generation stations, in the early 1950s and have been in use since then. The annual production of fresh (distilled) water is estimated to be now 366 million m³.

Installed capacity of co-generation stations in Kuwait
  Fresh water production Power generation (MW) Date
  Million m³/year Mig/day    
Shuwaikh 53 32 324 1960-70
Shuaiba North 21 14 400 1965-71
Shuaiba South 50 30 804 1971-75
Doha East 71 43 1,158 1978-79
Doha West 159 96 2,400 1985
Az-Zour South      
stage I 10 06    
stage II 119 72 2,511 1991
Total 366 221 5,769  
Source: Kuwait Institute for Scientific Research, in 1990.

Schematic of a Co-generation desalination plant



A variety of chemicals being introduced during thermal desalination process. Mostly these are intended for the safeguarding of plant machinery and pipe lines. Table below profiles chemicals which are most frequently used in seawater thermal desalination.

Dose rates are only indicative and are shown as mg/litre of chemical in the relevant process stream (MU=Make Up Water, CW=Cooling Water).

Table 2.1 Chemicals used in thermal desalination processes
Chemical Type Purpose of Use Dose And
Feed Location
Application
Scale inhibitor (Usually phosphonates, polyphosphate, polymaleic or polycarboxylic acids, or a blend of several of these) Usually crystal modifiers that avoid precipitation and development of deposits (primarily CaCO3, Mg (OH)2. Blends may include dispersant properties to prevent crystals adhering to equipment. 1-8 mg/litre, MU Used in all thermal desalination processes.
Acid (usually sulphuric acid), An alternative scale inhibitor.
By lowering pH calcium carbonate and magnesium hydroxide scale formation is avoided.
≈100 mg/litre, MU Used only in MSF desalination.
Antifoam (Poly Othelyne Ethylene Oxide or similar surfactant) Uncorrected foaming due to unusual feed water conditions may overwhelm the process indicated by high product TDS (carryover). ≈0.1 mg/litre, MU Used intermittently in all thermal processes but primarily MSF.
Oxidizing Agent: most To control bio-fouling and ≈1.0 mg/litre, Used for large surface and sea
often a form of chlorine, aquatic organism growth in CW water intakes.
however biocides may the intake and desalination
have some use, particularly equipment. Continuous
for smaller systems. dosing of 0.5-2 mg/L active Cl2 with intermittent shock dosing (site specific but may be 3.7 mg/L for 30-120 minutes every 1-5 days).
Sodium bisulfite. Oxygen scavenger to remove traces
of residual oxygen
or chlorine in the brine recirculation.
≈0.5 mg/litre,
MU
Used only in MSF desalination
systems and in intermittent mode.


Chlorination


Chlorine, the most common disinfectant, is effective in killing most pathogenic bacteria and viruses. The output water from desalination plants is chlorinated at local distribution centres to provide a residual concentration of 0.5 to 2.0 ppm. Chlorine is not effective in killing certain protozoans like cryptosporidium, however.

One complication that arises with chlorination is the formation of by-products during the disinfection process. Chlorination by-products are chemicals that result from the reaction of chlorine with organic substances in water. Table below lists some common chlorination by-products.


Concentrations found in chlorinated waters
Chloroform Range 0.7 - 540 µg/L, Mean 26.4 µg/L
Bromodichloromethane Range 1.9 - 183 µg/L, Mean 9.1 µg/L
Chlorodibromomethane Range 0.4 - 280 µg/L, Mean 5.7 µg/L
Bromoform Range 0.4 - 280 µg/L, Mean 5.7 µg/L
Chloroacetic Acid Range <1 - 5 µg/L
Dichloroacetic Acid Range 12 - 79 µg/L, Mean 47 µg/L
Trichloroacetic Acid Range 4 - 103 µg/L, Mean 38 µg/L
Dichloroacetonitrile Range 1.9 - 24 µg/L, Mean 2 µg/L




Disinfection by-products have been linked to adverse health effects, including cancer, in laboratory animals. Table 2 summarizes the health effects of some chlorination by-products.
Health effects
Chloroform Animal carcinogen that can induce liver tumors in mice and kidney tumors in rats.
Bromodichloromethane Produces liver and kidney damage in both mice and rats. Carcinogenic in mice and rats, producing renal, liver, and intestinal tumors.
Chlorodibromomethane Produces liver and kidney damage in both mice and rats. Induces tumors in the liver of mice.
Bromoform Low incidence of intestinal tumors in rats.
Chloroacetic Acid Neurologic effects in animals. No increased tumors.
Dichloroacetic Acid Major toxicities are damage to the nervous system and liver. Induces liver tumors in mice.
Trichloroacetic Acid Potent inducer of liver tumors in male mice.
Dichloroacetonitrile No specific toxicological effects reported, only nonspecific effects on body weight and some organ weights and some reproductive effects.
Long-term risks of consuming chlorinated water include excessive free radical formation, which accelerates aging, increases vulnerability to genetic mutation and cancer development, hinders cholesterol metabolism, and promotes hardening of arteries. Effect of boiling municipal water:

The recommend time bringing water to a boil for necessary disinfection, varies from 1-25 minutes. Boiling tap water for such prolonged period simply contributes to increased TDS. In reality, due to chlorination, the water is already disinfected. Boiling does not help to eliminate chlorination by-products or chemicals introduced during desalination process.

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