Sustainability: Humanity Perspective - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 747

TABLE 15.1 Availability and Distribution of Water on Earth
(based on Igor Shiklomanov's Chapter “World fresh
water resources” in Peter H. Gleick, ed., 1993, Water
in Crisis: A Guide to the World's Fresh Water Resources,
Oxford University Press, New York)

Type or form of water Storage, Eg

Fresh water

Clouds 12.9

Surface water

Rivers 2.12

Swamps 11.5

Lakes 91

Ground water
Soil moisture 16.5

Subterranean reserves 10,500

Ice 24,365

Salt water

Oceans 1,340,000

Lakes 85.4

Aquifer 13,000

Biological water 1.12

conditions, water exists in three states: vapor, liquid, and solid. Altering among the three
states, water is able to buffer the temperature on earth surface to be around 14 Cby
absorbing radiant heat energy from the sun and releasing to the surroundings when it cools
or condenses. Comfortable level of temperature is the key supporting the life on earth.
Table 15.1 shows the availability of water on earth and its distributions. The abundance of
water on earth makes the use of water in bioprocesses less hazardous than the use of any
other agents that can be found or made on earth. The amount of water we need for bio-
processes is a very small fraction of water on earth. Water is in air, on land, and in oceans.
Care must be taken when redistribution of water on earth is to be made, while use of water
does not harm the environment as a whole.
Table 15.2 shows the properties of water based on the steam table. From Table 15.2 ,we
observe that the change of state (from solid ice to vapor, from solid ice to liquid water, and
from liquid water to vapor) for water results in significant change in internal energy or
enthalpy. The change of state occurring on earth and its atmosphere modulates the temper-
ature, intercepts, and stores radiation energy. It plays a key part in the nature cycle as
depicted in Fig. 15.1 .