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NPDES
> Overview
The process for generating electricity is simple: a boiler fired by natural
gas burns fuel and air and water is converted to steam. The steam, under great
pressure drives turbines generating electricity. Steam is condensed by thermal
exchange with cooling tower water, then repumped to the boiler to repeat the
process. The heated water during this thermal exchange step is cooled by evaporation
in cooling towers, producing the vapor clouds seen often at power generation
facilities. There are three types of cooling water systems:
- One-pass cooling
- Closed recirculating systems
- Open recirculating systems
One issue regarding each of these cooling water systems is that various contaminants
may enter the cooling water. If cooling water is discharged from the power plant
to either a public treatment works or to a surface water, then water pollution
control regulatory requirements may be applicable to your power plant.
As you may know from having visited other locations on your EVC tour, the United
States Environmental Protection Agency (EPA) regulates the discharge of water
from facilities through provisions of the Clean Water Act, including provisions
of the National Pollutant Discharge Elimination System (NPDES) program. EPA
has authorized many states to implement and monitor the NPDES program. NPDES
permits establish the level of performance the discharger must maintain and
specify monitoring, inspection, and reporting requirements and other actions
necessary to achieve compliance. NPDES permits set specific requirements regulating
the characteristics of the discharged water based on national technology-based
effluent limitations and applicable water quality standards.
Applicability of NPDES requirements to a typical college or university power
plant vary greatly depending on the activities or discharges associated with
the facility and the interpretation by the state regulatory agency charged with
enforcing the Federal NPDES program (in states where that is the case; not all
states have been delegated with this authority).
Although the NPDES regulations include steam electric power generating facilities
as an “industrial activity”, activities conducted indoors do not
typically impact storm water quality, and therefore, do not generate “storm
water associated with industrial activity.” If you have an NPDES permit
for surface water discharges or for storm water discharge or believe one is
required for your power plant, continue on to the expanded content to learn
more about NPDES permit requirements.
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