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Publicly owned treatment works (POTWs) are municipal wastewater treatment
facilities responsible for handling local water supplies. POTWs receive and
treat sewage and/or wastewater from residences, commercial activities, and industries.
There are POTWs that primarily treat wastewater from industrial users. As the
planet becomes more urbanized and industrialized, POTWs are facing the challenges
of municipal growth, newly regulated pollutants, more stringent effluent limits,
and system overloads. More and more industries are discharging their wastewaters,
with or without pretreatment, into sewers servicing POTWs. Water utilities provide over 100 gallons of fresh, treated water every day
for each person in this country, or about 40 billion gallons per day nationwide.
Water is collected from various sources such as rivers, lakes, and wells. After
collection, water is filtered, treated, and sold for residential, industrial,
commercial, and public use. Depending on the population served by the water
system, the utility may be a small plant in a rural area that requires the occasional
monitoring of a single operator or a huge system of reservoirs, dams, pipelines,
and treatment plants, requiring the coordinated efforts of hundreds of people.
The collection, treatment and distribution of water is one of the largest and
most expensive tasks of local government. Water supply systems vary from community
to community depending on various factors such as the source of water, age and
infrastructure integrity, size and population of community, and the needs of
the population. According to the E.P.A., there are approximately 16,000 POTWs nationwide. There
are also an estimated 100,000 major pumping stations, 600,000 miles of sanitary
sewers, 200,000 miles of storm sewers treating more than 32 billion gallons
of wastewater daily. POTWs range in size from <0.1 million gallons treated
per day (MGD) to >500 MGD. However, the majority of these facilities (~80
percent) are 1 MGD or less. The NAICS code for POTWs is 221310. Additional NAICS codes related to
water treatment are: Water treatment equipment, manufacturing (NAICS 333319),
Water treatment equipment, industrial, merchant wholesalers (NAICS 423830),
Water treatment equipment, municipal, merchant wholesalers (NAICS 423850), and
Water treatment plant construction (NAICS 237110). There are two SIC
codes listed for water treatment: Water treatment construction – general
contractor (SIC 1629) and Water treatment equipment, industrial (SIC 3589).
A unique feature of the utilities industry is that urban areas with many inhabitants
generally have relatively few utility companies. For instance, there were about
54,000 community water systems in the United States in 2000 serving roughly
264 million people. The 45,900 small water systems served only 26 million people
while the 8,100 largest systems served almost 238 million. Alaska, with a 2000
population about 10 percent of that of Massachusetts, had about 3 times more
electric generating plants than Massachusetts. These examples show that economies
of scale in the utilities industry allow one or two large companies to serve
large numbers of customers in metropolitan areas more efficiently than many
smaller companies. According to the U.S. Department of Labor’s Bureau of Labor Statistics,
public utilities employed about 851,000 workers in 2000. Electric services provided
about 42 percent of all jobs, as shown in table 1. Furthermore, although electric utilities are among the biggest customers of
natural gas utilities, the processes used to produce their services are largely
unrelated. This diversity of production processes is reflected in the size of
the establishments that make up the utilities industry. The combination utility
industry consists of relatively large plants. In 2000, it accounted for less
than 7 percent of the reporting establishments, yet employed an average of more
than 90 workers per establishment. On the other hand, water supply utilities
accounted for 16 percent of workplaces, yet employed only an average of 8 workers
per establishment (table 2). Although many establishments are small, almost half of public utility workers
are employed in establishments with 250 or more workers. In the thirty years since the passage of the Clean Water Act, significant progress
has been made towards its primary goals of “swimmable and fishable”
waterways and “zero discharge” into our waterways. In 1972 60-70%
of our waters were not swimmable or fishable, while in 2002 the numbers had
dropped to 39% of rivers, 45% of lakes, and 51% of estuaries. The number of
Americans served by sewage treatment facilities doubled during that same period.
However, problems persist, particularly in our estuaries. Between 1994 and 2002
the percentage of estuaries that were deemed unsafe rose from 37% to 51%. According to Albert Slap of the University of Cincinnati College of Law, Sanitary
Sewer Overflows (SSOs) and Combined Sewer Overflows (CSOs) cause or contribute
to violations of Water Quality Standards in many states, especially those for
fecal contamination in waterways. Municipal pollution, and specifically fecal
pollution – keeps many areas from meeting clean water standards. Typical wastes associated with the water supply are: Municipalities are constantly searching for options when addressing these challenges.
Generally speaking, municipalities have two alternatives available: The EPA encourages municipalities to address these challenges through pollution
prevention programs, as opposed to expansion of existing POTWs or building new
POTWs. There are a variety of pollution prevention programs for POTWs, but the
focus of this topic hub is: Industrial pretreatment programs designed to reduce the toxicity of
the waste stream The National Pretreatment Program is a cooperative effort of federal, state,
and local regulatory environmental agencies established to protect water quality.
The program is designed to reduce the level of pollutants discharged by industry
and other non-domestic wastewater sources into municipal sewer systems, and
thereby, reduce the amount of pollutants released into the environment through
wastewater. The objectives of the program are to protect the Publicly Owned
Treatment Works (POTW) from pollutants that may interfere with plant operation
to prevent pollutants that may pass through untreated from being introduced
into the POTW, and to improve opportunities for the POTW to reuse wastewater
and sludge that are generated. The term "pretreatment" refers to the
requirement that nondomestic sources discharging wastewater to POTWs control
their discharges, and meet limits established by EPA, the State or local authority
on the amount of pollutants allowed to be discharged. The control of the pollutants
may necessitate treatment prior to discharge to the POTW (therefore the term
"pretreatment"). Limits may be met by the nondomestic source through
pollution prevention techniques (product substitution recycle and reuse of materials)
or treatment of the wastewater. Program objectives are: There are more than 1500 publicly owned treatment works that are required to
implement local Pretreatment programs. By reducing the level of pollutants discharged
by industry into municipal sewage systems, the program ensures the protection
of America's multi-billion dollar public investment in treatment infrastructure.
Sources: EPA, Office of Air Quality Planning and Standards, Emission Standards Division. Pacific Northwest Pollution Prevention Resource Center. http://www.pprc.org/ Slap, Albert J. Adjunct Professor at Law. University of Cincinnati College
of Law. Water Environment Federation, 601 Wythe St., Alexandria, VA 22314-1994.
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