cold water Flashcards
what is evaporation
evaporation is where water is heated up and turned into a gas and rises
what is transpiration
transpiration is where water moves and evaporates
what is precipitation
precipitation is another word for rain
what are the different types of water?
hard and soft
name a underground water source
deep well
what’s a aquifer
naturally occurring rock to keep water
what are bore holes
man made well drilled through the earths surface to a water source then extracted
whats the role of local authorities in regulating private water supplies
Conduct a risk assessment on every property with private water supply in their area.
whats The Role of Drinking Water Inspectorate
The DWI plays a statutory role in acting as technical advisors to Local Authorities in relation to the
implementation of the Private Water Supplies Regulations 2016.
whats The Water Supply (water quality) Regulations 2016
In the United Kingdom, all water, whether from a private source or supplied by a water undertaker, must
comply with the EU Drinking Water Directive 98/83/EC.
what are the stages for water cleaning and treatment
Screening
Flocculation
Sedimentation
Filtration
Disinfection
The water treatment process
Screening
First, the water is passed through a series of coarse meshes to remove large debris such as leaves, plant
material and other fragments
what is Flocculation
Here, a chemical coagulant is added to the water to act as a
binding agent to remove colour, turbidity and algae. This
process also allows any dissolved metals such as aluminium
and iron to precipitate. This leads to the formation of a ‘floc’
which can then be removed by other processes.
what is Sedimentation
Sedimentation is designed to slow down the velocity of the water to allow any solid matter, such as grit, mud
and decaying vegetation missed by the screening process, to sink under gravity to the bottom of the
sedimentation tanks. This process further reduces turbidity and bacteriological content of the water. After
further sedimentation, the water is pumped to a storage reservoir before being filtered.
what is Filtration
There are several types of filters used to filter drinking water:
what are Slow sand filters
these
provide the most common
method of filtration. Here, water
flows over a bed of graded sand.
The sand is full of minute algae
growth which assist in the
purification process of the water
what are Rapid sand filters
mainly
used to remove floc after the
flocculation process but can
effectively be used to remove
algae, iron and manganese from
raw water.
what are Pressure filters
here the filter bed is enclosed in a cylinder pressure vessel. They are sometimes
used where the need to maintain water pressure without the aid of a pump.
what is disinfection
The final stage of the water treatment process is disinfection. This is where a small amount of chlorine,
usually less than 1 milligram per litre of water, is added to kill off any bacteria that may have escaped all the
other processes. This is usually injected into the water just before it enters the water supply.
what is Distribution of water supply
After the water has gone through the treatment process, it is distributed to homes and businesses
throughout the UK by one of two ways: By gravity distribution, By pumped distribution
what is Gravity distribution
Gravity water distribution
begins when the reservoir is
sited on high ground. The
water, once it has gone
through the treatment
process, is fed to the
distribution network by
gravity.
what is Pumped distribution
After going through the
water treatment process,
the water is pumped to a
service reservoir held on a
tower. From here, the
water distributes to the
water network via gravity.
what is Distribution of water to cities, towns and villages
Water is supplied to cities, towns and villages via a grid network of pipes. These are known as trunk mains
and will vary in diameter depending on the population, the purpose of the cold water main or the likely
demand for water in a particular area.
what is Wholesome water for domestic purposes
Water that is supplied directly from the water main has several uses:
Personal hygiene – washing, bathing and ablutions
Cooking and food production
Drinking
what is Recycled water
Recycled water is water that has been previously used for another purpose such as bathing, washing etc, and
rainwater that has been collected in special cisterns but has not been treated to drinking water standard.
Both of these types of water are not fit for human consumption but can be used, with care, inside and outside
the dwelling for limited purposes:
WC flushing,
Water for outdoor use i.e. watering the garden or car washing
Clothes washing.
what is Direct systems
Generally speaking, most direct systems utilise a 15mm rising main with
15mm pipework to all cold water outlets. This is sufficient for small
installations where a combination boiler supplying hot water is installed,
without en-suite bathrooms and shower rooms.
what is Indirect systems
The indirect system of cold water supply is designed for areas where the
cold water supply pressure is low and not capable for supplying the full
water requirements of the system design. It utilizes a 15mm cold water
rising main, feeding cold water storage cisterns in the roof space.
what isBi-flow mixer taps
Bi-flow mixer taps are essentially two taps within a single tap body. The
tap is divided through the body and into the spout so that the hot and
cold water supplies do not mix until they emerge from the spout. They
do not require backflow protection.
what is Pillar taps
These are available with both 1⁄2” and 3⁄4” male BSP tails for use on
washbasins and baths. They are designed to give and AUK2 airgap at the
appliance, the outlet of the tap being higher than the spill-over level of
the appliance.
what is High Neck Pillar taps
Similar in design to pillar taps, high neck pillar taps
are designed for use on kitchen sinks. The high neck
provides an AUK3 air gap suitable for fluid category
5, which is a mandatory requirement for
kitchen/utility sinks, cleaners sinks, Belfast sinks and
any sink or washbasin installed in a health care
facility.
