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| Picture by CBS 2 Bay Ridge, Brooklyn sinkhole |
The pipes made early in the 20th century were rated for
an 80 year life span. New York sewer piping systems have reached the end of
their design lives, but there are no plans of a replacement and upgrade of the
system. There has been no systematic replacement program. New York has kept the
sewer system alive by repairing what breaks after it breaks and spraying it’s
mains with concrete. When the sewer systems were built in the 19th and 20th
centuries, the Boroughs of New York still had autonomy and financed and built
their own systems to address the problem in the least expensive way, by using a
combined storm and sanitary sewer system. The Manhattan and Brooklyn systems
were built around the same time modeling the designs of Hamburg, Germany. Nonetheless,
the sewers were never designed for the ages, they need to be maintained and
upgraded. New York and most of the United States has not maintained and
upgraded our sewer systems. According to the U.S. Environmental Protection
Agency, EPA, by 2020 half the sewer pipes in the U.S. will be crumbling and the
U.S. risks reversing
public health, and environmental gains of the past three decades.(Rose George in The Big Necessity, The Unmentionable World of Human Waste and Why it Matters.)
Failing sewer pipes can pose a significant threat to
public health and the environment. Systems with inadequate hydraulic capacity
and/or blockages in the sewer pipes may lead to sanitary sewer overflows and sewage
backing up into homes or onto streets. Some of the health hazards associated with
basement flooding by untreated wastewater include the potential presence of
pathogenic microorganisms such as viruses, bacteria, and protozoa (in a nice
moist dark environment). Pipe failures can be grouped into three general
categories: hydraulic restrictions (e.g. blockage), hydraulic capacity, and
structural condition.
Hydraulic restrictions are the most common problem in wastewater collection systems. Untreated wastewater carries sediment, grease, rags and
whatever else you can think to put down the drain or flush down the toilet. The
grease congeals with sediment and blockages form. In combined sewers, large
items thrown or washed into the storm system create obstructions and restrictions
during peak flow times. This can lead to street and basement flooding. Tree
root intrusion, sediment accumulation, and grease build-up all contribute to
hydraulic restrictions. Aging pipes that sag over time and joints that begin to
fail can slow pipe flow and create more favorable conditions for solids to
build up in pipes. An ongoing maintenance program for cleaning and flushing
sewers is typically adequate to control blockages. However, budgeting for
routine preventative maintenance and repairs has not taken place in New York or
the rest of the United States. We fix it when it breaks.
Failure caused by inadequate flow capacity is common in
combined sewer systems, but may also a sign of other types of problems such as
structural defects or design defects. Major sources of pipe structural defects
are cracks, broken pipes, and leaks. Pipes sag and sewage does not flow
properly, areas of inadequate pipe slope can be due to loss of pipe bedding or
inadequate initial slope. Structural failure as in Bay Ridge is typically
caused by defects of the pipe wall and/or the soil envelope used to support the
pipe.
The EPA reported that the total investment needs of America's publicly owned treatment works as of January 1, 2004, was $202.5 billion and increasing each year. Many systems besides New York have reached the end of their useful
design lives, and the nation’s wastewater systems are no longer resilient in their
ability to prevent failure, or restore service after a disruption. In addition,
the electrical generation and distribution system, the energy sector, contributes
to the lack of system’s resilience. Pumps and wastewater treatment plants do
not operate without power and reduced reliability of the power supply is
increasingly being addressed through the construction of dedicated emergency
power generation at wastewater treatment plants and drinking water delivery
systems. Clean and safe water should be
the national priority. If we had spent even a quarter of the $821 billion of the American Recovery and
Reinvestment Act of 2009 on the very unglamorous sewers and water treatment systems if the country we would have a
cleaner environment, part of our infrastructure would be ready for another
century and construction workers would have had jobs.
