288
and are often heavily subsidized. Raw water conveyance infrastructures usually
exist to implement a legal agreement on water use in a shared river basin. Their
physical operation is usually governed by a single jurisdiction such as a state or
county, but the water that they convey is frequently subject to laws and treaties
between that jurisdiction and other parties that share the freshwater source.
Large raw freshwater infrastructures are a tool of national political power, and
are frequently exploited by more powerful political actors to the detriment of the
less powerful actors in shared river basins. These infrastructures are sources of conflict (or cooperation) between nation-states. Some of the more notable examples of
river basins in recent tension are the Colorado River that is shared by US States and
Mexico, the Nile River that originates in the nations of Africa’s Rift Valley and
Ethiopia but is politically dominated by Egypt, the Jordan River that is politically
dominated by Israel but is fed by Lebanon, Syria, and Jordan, and the Mekong River
that drains southern China through Myanmar, Laos, Thailand, Cambodia, and
Vietnam. By contrast, the Danube River in Europe drains a large number of neighboring countries, but has been shared successfully.
Potable water and wastewater treatment infrastructures take raw water (or wastewater) as the primary input, utilizing a large amount of electricity to pump water
from the canal, river, lake, brackish, sewer, ocean, or aquifer source, and then treating that water to meet drinking water quality or other applicable standards. Surface
water intakes and wells feed pipes, which bring raw water to water treatment plants.
Water treatment ranges from the simple addition of chlorine to elaborate desalination techniques. Chlorination is very cost effective, but desalination of ocean and
brackish water requires heavy capital investment and also a large amount of electrical or thermal energy. Desalination usually involves distillation, which requires a lot
of thermal heating energy, or filtration, which requires a lot of electrical energy.
Advanced disinfection techniques are becoming more common, including UV
and ozone treatment. Because of the threats of environmental hazards like chemical
or mining spills, and terrorism, along with emerging contaminants like pharmaceuticals, the use of water quality testing and sensing techniques is becoming more
common. Treated water quality poses more of a long-term threat to environmental
quality than short-term security threat, however, because the large volumes of water
in these systems dilute contaminants rapidly and chlorine residuals quickly degrade
infectious agents, making municipal potable water systems resistant (albeit not
immune) to these threats.
A major topic of discussion in cities is the use of treated (or reclaimed) wastewater as the input to potable water systems. This is called direct potable reuse for the
case where wastewater is directly piped into potable water systems, or indirect potable reuse, in the case where wastewater is discharged to a river or aquifer before
being reused for potable supply. Potable water is usually produced by municipal
water providers, but is sometimes “self-supplied” by industries that operate their
own supplies. Industries tend to employ customized treatment processes that match
their processes, and often exceed drinking water quality standards.
Wastewaters originate from all human economic processes, including agriculture, industry, power generation, and urban uses. Agricultural wastewaters tend to
B. L. Ruddell et al.
and are often heavily subsidized. Raw water conveyance infrastructures usually
exist to implement a legal agreement on water use in a shared river basin. Their
physical operation is usually governed by a single jurisdiction such as a state or
county, but the water that they convey is frequently subject to laws and treaties
between that jurisdiction and other parties that share the freshwater source.
Large raw freshwater infrastructures are a tool of national political power, and
are frequently exploited by more powerful political actors to the detriment of the
less powerful actors in shared river basins. These infrastructures are sources of conflict (or cooperation) between nation-states. Some of the more notable examples of
river basins in recent tension are the Colorado River that is shared by US States and
Mexico, the Nile River that originates in the nations of Africa’s Rift Valley and
Ethiopia but is politically dominated by Egypt, the Jordan River that is politically
dominated by Israel but is fed by Lebanon, Syria, and Jordan, and the Mekong River
that drains southern China through Myanmar, Laos, Thailand, Cambodia, and
Vietnam. By contrast, the Danube River in Europe drains a large number of neighboring countries, but has been shared successfully.
Potable water and wastewater treatment infrastructures take raw water (or wastewater) as the primary input, utilizing a large amount of electricity to pump water
from the canal, river, lake, brackish, sewer, ocean, or aquifer source, and then treating that water to meet drinking water quality or other applicable standards. Surface
water intakes and wells feed pipes, which bring raw water to water treatment plants.
Water treatment ranges from the simple addition of chlorine to elaborate desalination techniques. Chlorination is very cost effective, but desalination of ocean and
brackish water requires heavy capital investment and also a large amount of electrical or thermal energy. Desalination usually involves distillation, which requires a lot
of thermal heating energy, or filtration, which requires a lot of electrical energy.
Advanced disinfection techniques are becoming more common, including UV
and ozone treatment. Because of the threats of environmental hazards like chemical
or mining spills, and terrorism, along with emerging contaminants like pharmaceuticals, the use of water quality testing and sensing techniques is becoming more
common. Treated water quality poses more of a long-term threat to environmental
quality than short-term security threat, however, because the large volumes of water
in these systems dilute contaminants rapidly and chlorine residuals quickly degrade
infectious agents, making municipal potable water systems resistant (albeit not
immune) to these threats.
A major topic of discussion in cities is the use of treated (or reclaimed) wastewater as the input to potable water systems. This is called direct potable reuse for the
case where wastewater is directly piped into potable water systems, or indirect potable reuse, in the case where wastewater is discharged to a river or aquifer before
being reused for potable supply. Potable water is usually produced by municipal
water providers, but is sometimes “self-supplied” by industries that operate their
own supplies. Industries tend to employ customized treatment processes that match
their processes, and often exceed drinking water quality standards.
Wastewaters originate from all human economic processes, including agriculture, industry, power generation, and urban uses. Agricultural wastewaters tend to
B. L. Ruddell et al.