Extensive infrastructure is required to supply clean water to communities around the world.
Water covers around 70 percent of Earth’s surface, but only a small fraction of it is available for human consumption.
Water supply systems are used to extract, treat, and distribute water to a community.
Water Supply System
A water supply system is infrastructure used to distribute drinking water to consumers.
Most modern water supply systems have 3 main components: a raw water source, a treatment plant, and a distribution system.
Raw Water Sources
Raw water is water in its natural state. Groundwater and surface water are the two main types of raw water sources.
Water abstraction is the process of extracting raw water from natural sources to be used in a water supply system.
Groundwater is found beneath Earth’s surface in underground reservoirs called aquifers. Aquifers are layers of permeable material and fractured rock that is saturated with water. Groundwater can be observed at varying depths depending on geological location and environmental factors. The closest depth from the surface that groundwater can be found is called the water table.
Groundwater abstraction is performed using extraction wells. Most modern day water wells are constructed by drilling or driving a pipe into the ground until it is through the water table and deep within an underground aquifer. Groundwater is then drawn to the surface using a pump. Once brought to the surface, the water is sent through a transmission line to a treatment facility for purification, or is used directly from the source.
Surface Water Abstraction
Any water that hasn’t been absorbed into the earth and exists above ground is surface water, More than half of the communities around the world depend on surface water as their main water source. This includes rivers, streams, lakes, reservoirs, and canals. Surface water constantly fluctuates with groundwater and rainwater activity. Surface water decreases as it leaches into the ground, increasing the amount of groundwater. Groundwater discharges onto the surface, increasing the amount of surface water. Surface water also decreases from evaporation, but is then replenished through rainwater and runoff.
Surface water abstraction can be advantageous over groundwater abstraction as it eliminates the cost of installing and operating a well. However, surface water can be more prone to pollution and is less available than groundwater.
Raw water collected through abstraction may contain undesirable contaminants that can pose health risks if left untreated.
Water pollution can occur naturally but is usually caused by human activity.
Types of Water Contaminants
There are many types of contaminants that can pollute a water source and make it unsafe for human consumption.
Physical contaminants like sediment and organic material from erosion can become suspended in a water source, changing its physical properties and appearance.
Natural or artificial chemicals are a common cause of water pollution. Heavy metals, nitrogen, pesticides, bleach, and salts are just some types of chemical contaminants.
Biological contamination can occur when there are organisms present in a water supply. Microbiological contaminants include parasites, bacteria, viruses, and protozoa.
Water treatment is the process of improving water quality for a particular end-use. This includes drinking, industrial use, irrigation, recreation, and more.
Before water can be distributed, it must be free of contaminants. Earth may have an abundance of water, but less than 1% of it is safe to drink. The rest is either saltwater or contaminated and must be processed through one of the many treatment processes developed by mankind.
Water Distribution System
A water distribution system is made up of pipe networks and storage facilities that deliver potable water from treatment plants or wells.
Parts of a Water Distribution System