Global warming The recent and ongoing global average increase in temperature
near the Earth’s surface.
Glycogen-accumulating organisms (GAOs) They are organisms that take up
glycogen and volatile fatty acids during metabolism, sometimes competing with
phosphorus-accumulating organisms for food sources.
Glycogen It is a polysaccharide of glucose, which is energy storage inside a cell. It
is present in all cells; however, microorganisms that accumulate glycogen in cells
during the anaerobic stage of a bio-P process are not able to perform biological
nutrient removal.
Good laboratory practices (GLPs) General guidelines or formal regulations for
performing basic laboratory operations or activities that are known or believed to
influence the quality and integrity of the results. The purpose of GLP is for
personal protection, laboratory protection, proper chemical storage, and proper
waste management.
Grab sample A single sample of water collected at a particular time and place,
which represents the composition of the water only at that time and place.
Grab sample A single sample which is collected at one point in time and place.
Granular activated carbon adsorption Granular activated carbon (GAC) is used
in wastewater substances. GAC systems generally consist of vessels in which the
carbon is placed, forming a “filter” bed. These systems can also include carbon
storage vessels and thermal regeneration facilities. Vessels are usually circular for
pressure systems or rectangular for gravity flow systems. Once the carbon
adsorptive capacity has been fully utilized, it must be disposed of or regenerated.
Usually, multiple carbon vessels are used to allow continuous operation. Columns can be operated in series or parallel modes. All vessels must be equipped
with carbon removal and loading mechanisms to allow for the removal of spent
carbon and the addition of new material. Flow can be either upward or downward
through the carbon bed. Vessels are backwashed periodically. Surface wash and
air scour systems can also be used as part of the backwash cycle. Small systems
usually dispose of spent carbon or regenerate it offsite. Systems above about 3 to
5 MGD (million gallons per day) usually provide on-site regeneration of carbon
for economic reasons.
Gravity belt thickening It is a process for removing water from a wet dilute sludge
using a moving belt. Dilute sludge is conditioned with a polymer and fed into a
feed/distribution box of a belt thickening device. The sludge distributes evenly on
the moving belt as water drains through the porous belt and the thickened sludge
is discharged.
Gravity thickening Its tank design is similar to a conventional sedimentation tank.
Dilute sludge is fed to a center feed well. The feed sludge is allowed to settle and
compact, and the thickened sludge is withdrawn.
Green solvent An environmentally friendly solvent, or biosolvents, which may be
derived from the processing of agricultural crops, such as corn.
Greenhouse effect Trapping and build-up of heat in the atmosphere (troposphere)
near the Earth’s surface. Some of the heat flowing back toward space from the
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near the Earth’s surface.
Glycogen-accumulating organisms (GAOs) They are organisms that take up
glycogen and volatile fatty acids during metabolism, sometimes competing with
phosphorus-accumulating organisms for food sources.
Glycogen It is a polysaccharide of glucose, which is energy storage inside a cell. It
is present in all cells; however, microorganisms that accumulate glycogen in cells
during the anaerobic stage of a bio-P process are not able to perform biological
nutrient removal.
Good laboratory practices (GLPs) General guidelines or formal regulations for
performing basic laboratory operations or activities that are known or believed to
influence the quality and integrity of the results. The purpose of GLP is for
personal protection, laboratory protection, proper chemical storage, and proper
waste management.
Grab sample A single sample of water collected at a particular time and place,
which represents the composition of the water only at that time and place.
Grab sample A single sample which is collected at one point in time and place.
Granular activated carbon adsorption Granular activated carbon (GAC) is used
in wastewater substances. GAC systems generally consist of vessels in which the
carbon is placed, forming a “filter” bed. These systems can also include carbon
storage vessels and thermal regeneration facilities. Vessels are usually circular for
pressure systems or rectangular for gravity flow systems. Once the carbon
adsorptive capacity has been fully utilized, it must be disposed of or regenerated.
Usually, multiple carbon vessels are used to allow continuous operation. Columns can be operated in series or parallel modes. All vessels must be equipped
with carbon removal and loading mechanisms to allow for the removal of spent
carbon and the addition of new material. Flow can be either upward or downward
through the carbon bed. Vessels are backwashed periodically. Surface wash and
air scour systems can also be used as part of the backwash cycle. Small systems
usually dispose of spent carbon or regenerate it offsite. Systems above about 3 to
5 MGD (million gallons per day) usually provide on-site regeneration of carbon
for economic reasons.
Gravity belt thickening It is a process for removing water from a wet dilute sludge
using a moving belt. Dilute sludge is conditioned with a polymer and fed into a
feed/distribution box of a belt thickening device. The sludge distributes evenly on
the moving belt as water drains through the porous belt and the thickened sludge
is discharged.
Gravity thickening Its tank design is similar to a conventional sedimentation tank.
Dilute sludge is fed to a center feed well. The feed sludge is allowed to settle and
compact, and the thickened sludge is withdrawn.
Green solvent An environmentally friendly solvent, or biosolvents, which may be
derived from the processing of agricultural crops, such as corn.
Greenhouse effect Trapping and build-up of heat in the atmosphere (troposphere)
near the Earth’s surface. Some of the heat flowing back toward space from the
12 Glossary of Natural Resources and Environmental Pollution Control
453