خطوات تعقيم وتطهير الابار الجوفية للاستخدام الادمى والصناعى

Steps for Chlorine Disinfection

Add the amount of unscented bleach determined in Table 1 to the bottom of the well and then agitate the water. Connect a garden hose to a nearby tap and wash down the inside wall of the well. This will ensure thorough mixing of the chlorine and the water throughout the well.

Start the pump and bleed air from the pressure tank. Open each tap and allow the water to run through all taps until a smell of chlorine is detected, then turn off the taps. If a strong smell is not detected, add more bleach to the well.

Allow the water to sit in the system for 12-24 hours.

Start the pump and run water through the outside hose away from grass and shrubbery until the strong smell of chlorine disappears. Make certain that the water does not enter any watercourse. Finally, open the indoor taps until the system is completely flushed.

Wait 48 hours, then sample the water using the instructions and bottle provided by the laboratory. In the meantime, find another source of water, or boil the water for one minute before drinking it. Two consecutive "safe" tests, performed on samples obtained over a period of one to three weeks, will probably indicate that the treatment has been effective.

If the shock treatment solves the problem, repeat bacteriological testing in three to four months.

If the above steps do not alleviate the problem, it is recommended that the source of the ongoing contamination be determined and corrected, possibly with professional help. If remediation is not possible, a permanent alternative solution, such as a new well or a drinking water disinfection device, should be considered.

Water Treatment Devices for Home Use

The water quality problems described in this fact sheet may be resolved by use of a drinking water treatment unit.

There are a wide variety of such devices available for home use.

Health Canada works closely with NSF International to develop performance standards for water treatment devices.

Consumers are encouraged to purchase products that have been certified to these standards.

Microbiological Contaminants

If elimination of the source of contamination is not possible after shock chlorine disinfection, consider the installation of a batch or continuous disinfection system or a new water supply. Some suitable devices are described in Table 2.

Table 2: Household Drinking Water Disinfection Devices[th]Water treatment method[/th][th]Uses[/th]

Distillation	Kills all microorganisms.
Ultraviolet light	Kills all microorganisms. Use in conjunction with microfiltration to improve inactivation and remove particulate matter, including parasites.
Chlorination	Kills bacteria and viruses. Use in conjunction with microfiltration to improve inactivation and remove particulate matter, including parasites.
Ozonation	Kills harmful microorganisms. Use in conjunction with microfiltration to improve inactivation and remove particulate matter, including parasites.
Ceramic candle filtration	Removes parasites and bacteria. Use in conjunction with chlorination to kill viruses.

Chemical Contaminants

Well water should also be tested for hazardous chemicals whenever contamination is suspected. Chemical analysis of water samples can be provided by commercial testing laboratories. Some provincial health laboratories will analyse water for nitrate, which typically originates from farming activities and seepage from septic tanks.

High concentrations of nitrate may cause "blue baby syndrome" (methaemoglobinaemia), a condition in which methaemoglobin cannot release oxygen to body tissues, and which mostly affects infants under three months of age.

Other chemical contaminants of concern include pesticides, heavy metals and volatile organic compounds. Guidelines for Canadian Drinking Water Quality provides a list of maximum acceptable concentrations for these chemicals.

If hazardous chemical contaminants are detected, you should consider the installation of a treatment device or a new water supply. Some suitable units are listed in Table 3.

Table 3: Chemical Removal Devices[th]Water treatment method[/th][th]Uses[/th]

Should not be used with microbiologically unsafe waters or water of unknown microbiological quality.
Activated carbon filtration	Removes organic compounds, including pesticides.
Reverse osmosis	Removes heavy metals and nitrates; often used in combination with activated carbon filters.
Distillation	Removes heavy metals and nitrates; often used in combination with activated carbon filters.
Ozonation	Removes organic compounds, including pesticides; often used in combination with activated carbon filters.

Hardness, Taste, Odour and Colour

Well water contains naturally occurring minerals, such as calcium, iron and sulphur. Although these minerals are not hazardous to human health, they can alter the hardness, taste, odour or colour of the water when present in excess quantities. Groundwaters may also contain natural organic materials (tannins). Table 4 describes some signs that may indicate the presence of these substances in your well water and some solutions. In order to select the best treatment method, a full testing of the suite of minerals should be conducted prior to the purchase of a device.

Common Aesthetic Water Quality Problems and Solutions[th]Problem[/th][th]Cause[/th][th]Solutions[/th]

Individuals on sodium-restricted diets should consult their physician before drinking artificially softened water. Iron and manganese can also be removed by a softener, provided the water is not too hard.
Hard water (scales/deposits in kettles and water heaters)	Excess calcium	Water softeners Reverse osmosis Distillation
Rusty (red to brown) staining of fixtures and laundry and/or metallic taste	Excess iron	Chlorination-filtration Greensand filtration Aeration-filtration Distillation
Black staining of fixtures and laundry and/or metallic taste	Excess manganese	Chlorination-filtration Greensand filtration Aeration-filtration Distillation
Rotten egg smell	Hydrogen sulphide	Chlorination-filtration Greensand filtration Aeration-filtration
Water has laxative effect	Excess sulphates	Reverse osmosis Distillation
Turbidity/grittiness	Mud/silt/clay/sediment in water	Sediment filters
Organic (tea) colour	Tannins	Chlorination-filtration Ozonation-filtration