Up Close
With . . .
DANIEL L. THEOBALD
How Industry Can Help Maintain
a Healthy Environment
Conservation among residential consumers has become a mainstay of utility operations, but
opportunities abound among industrial users to put conservation measures into practice. This
e-mail interview with wastewater expert Daniel Theobald details the ways in which industry
can incorporate recycling and reuse into its daily operations. Theobald, proprietor of Environmental Services, is also a professional wastewater and safety consultant/trainer. He is known in
the industry as “Wastewater Dan” and has more than 24 years of hands-on industry experience operating various wastewater treatment processing units. Theobald is a trainer in wastewater and industrial health and safety topics and is eager to share his knowledge with others
to promote conservation of water (www.Conserve-On-Water.com).
In what ways can industry conserve water?
What is industrial water recycling and reuse?
In order to conserve water, industrial users
should first analyze the water requirements
of each procedure they implement, going
through each one step by step to determine
the most water-efficient ways to complete
each work task while also preserving the
locally restrained supply of quality potable
water. For instance, in our homes, we can do
things like install low-flow toilets, limit our
shower time, minimize water use by not letting the water run when we’re brushing our
teeth, adjusting the water level to match the
size of a load in the washing machine, and
only run the dishwasher when it’s full.
Similar principles can be applied to industrial
water use, such as analyzing exactly how
much water is needed for each process,
installing timers or high-pressure flow restrictors, reusing water, or eliminating water use
from tasks whenever possible.
Although recycling easily comes to mind
when people are disposing of aluminum
cans, glass bottles, and newspapers, water
is not always considered for recycling.
Industrial water recycling, which offers
both resource and financial savings, simply
means reusing treated wastewater in certain industrial processes. Wastewater treatment can be tailored to meet the water
quality requirements of virtually any proposed reuse.
Water is sometimes recycled and reused
onsite, such as when an industrial facility
recycles water used for cooling processes. A
common type of recycled water is water that
has been reclaimed from municipal wastewater or sewage. The term water recycling
can be used synonymously with water reclamation and water reuse. Recycled water can
comply with most water demands as long as
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it is adequately treated to ensure water quality that is
appropriate for the use.
Another type of recycled water is “gray water.” Gray
water includes reusable wastewater from industrial
bathroom sinks, bathtub shower drains, and clotheswashing equipment drains. The use of nontoxic and
low-sodium soap—which is defined as no added
sodium or substances that are naturally high in
sodium—and personal care products is required to protect vegetation when reusing gray water for irrigation.
Gray water is reused onsite, typically for landscape irrigation or general spray applications.
Recycled water is most commonly used for
nonpotable uses. However, recycled water can also be
used for a number of industrial purposes, including
boiler or cooling tower feedwater supplementation,
pH adjustment, washing equipment, hardstands and
vehicles, fire protection, process rinse water or
processing water for production lines in manufactur­
ing industries, toilet flushing, dust control, construc­
tion activities, and concrete mixing.
What are some of the benefits of recycling
industrial water?
In addition to providing a dependable, locally controlled water supply, water recycling provides tremendous environmental benefits. By providing an additional source of water, water recycling offers ways to
decrease the diversion of water from vital, sensitive
ecosystems, thus ensuring that sufficient water flows
to plant, wildlife, and fish habitats—allowing them to
live and reproduce. A lack of adequate flow, as a result
of diversion for agricultural, urban, and industrial
purposes, can cause deterioration of both water quality and ecosystem health. Water users can fulfill their
demands by using recycled water, which can free substantial amounts of water for the environment. Other
environmental benefits include a reduction in wastewater discharges and reducing or preventing the
potential for pollution.
Recycled water can save energy. As the demand for
water increases, more water is extracted, treated, and
transported—sometimes over great distances—which
can require a lot of energy. Also, if the local source of
water is groundwater, as more water is removed the
water level drops, which in turn increases the energy
needed to pump the water to the surface. Recycling
water onsite or nearby reduces the energy needed to
move water longer distances or to pump water from
deep within an aquifer. Tailoring water quality to a specific water use also reduces the energy needed to treat
water. The water quality required to flush a toilet is less
stringent than the water quality needed for drinking
water and requires less energy to achieve. Using recycled water that is of lower quality for uses that do not
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require high-quality water saves energy and money by
reducing water or wastewater treatment requirements.
What are the strategic industrial applications for recycling and reusing water?
Industries in general should adopt overall
management strategies for reducing the consumption
of and increasing the use of reclaimed water in a
number of ways:
• Group industries in a particular site, such as in an
industrial park, to support the utilization of combined
treatment methods and reuse policies.
• Ration water use within each unique industry by
analyzing each work task or process to define the
acceptable quantity of water that should be used.
Reorganizing water use in different processes allows for
greater efficiencies to be established in such processes as
countercurrent washing, high-pressure air-rinsing, cascading circuits, and so on.
• Replace a water use application by pneumatic or
mechanical systems instead of using water for transportation. These substitutions could easily be made in both
the poultry and food industries.
• Apply enforceable economic sanctions such as penalties, water charges, subventions, credits, and grants.
• Adopt process modification to minimize water consumption. These could involve open to closed systems
of manufacturing processes.
Specific industries should value critical strategic steps
in industrial water recycling and reuse, which include
an analysis of the quality and quantity of industrial
water produced. The resulting values may be highly
variable depending on a range of factors, including but
not limited to the raw process material; the industrial
process that generates the water—for example, raw
material washing, finished goods washwater, process
filtrates, centrifugations and pressings, and boiler and
cooling tower blow down; the number of times the
water has been reused, potentially increasing or
decreasing the concentration levels of contaminants; the
characteristics of the products and surfaces the water
contacts; reactions that occur during the industrial process; additives such as biocides, antiscaling agents, and
pH adjusters; and the temperature of the water.
Another vital step in industrial water recycling and
reuse includes an analysis of the quality and quantity of
industrial water use requirements that are highly variable, depending on specific industrial demands. There
are several major areas in which recycled wastewater
could be used by industry.
• Cooling consumes a large volume of water that can
easily be supplied by recycled wastewater. Cooling
water discharge generally contains low amounts of pollutants. Justifications for using recycled water for cooling purposes include the fact that more than half of all
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industrial water is used for cooling. Most
of the intake water in electric power
plants and oil refineries is used as cooling
water. Cooling water is easy to treat, and
thus it is easy to reuse. In addition, reusing cooling water would eliminate the
problems associated with discharging
heated water into aquatic environments.
• Boiler feedwater consumes a large volume of potable water that can be replaced
with recycled wastewater. Boiler feedwater
discharge is generally low in pollutants.
Boiler feedwater is used in a number of
industries primarily for the generation of
steam for manufacturing processes and
after simple treatment can be reused.
• Washing depletes a comparatively
This freshwater pond is preserved as a result of industry reusing and recycling water.
small volume of water that can be
supplied with recycled wastewater. Wash­
Are there other industries that could incorporate reuse
water discharge is generally high in
into their daily practices?
pollutants.
• Process water uses a comparatively small volume
Industries that produce wastewater, such as photoof water for which recycled wastewater could be subgraphic processing, could recover by-products.
stituted. Process water discharge is generally high in
Industries that have the potential for higher future
pollutants. Processes depend on varying water quality.
growth and water consumption include pharmaceutical
Washing and transporting processes such as flocculaproducts, semiconductor manufacturing, and computer
tion, sedimentation, and filtration of water for and
component parts.
from other processes require only low-quality water.
Oil well injection requires high-quality water that
How do water conservation and water recycling and
would need to undergo treatment by advanced memreuse protect aquifers?
brane filtration processes such as micro- and ultrafiltration. Reuse water for the chemical, food, and textile
Every gallon of water recycled and reused replaces
industries would generally require treatment by
water use formerly supplied by an aquifer. This strategy
reverse osmosis.
helps protect aquifers because such water bodies are
• Industry in general may make use of reclaimed
rapidly being depleted by human activities.
municipal wastewater. This practice has been in place for
years, especially for replacing cooling and boiler feedwater. Secondary effluent can be used in industrial processes
http://dx.doi.org/10.5942/jawwa.2014.106.0031
after proper disinfection, for example in the mining and
metal-processing industries for washout. Secondary effluent must undergo tertiary treatment before reuse. The
specific requirement of the treatment process depends on
the final industrial reuse application.
What are some industries that could easily accommodate reuse in their processes?
There are several industries that immediately come to
mind. Industries that consume large volumes of water
would be excellent prospects for reuse. These industries
include paper and pulp manufacturers, power plants,
water treatment plants, steel industries, and soft drink
and canned food manufacturers, to name a few.
Industries that discharge highly toxic effluent are also
candidates. These include organic and inorganic chemical
processes and plastics and resins manufacturers.
JOURNAL AWWA WELCOMES COMMENTS AND FEEDBACK
AT [email protected].
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