Jess Welkey
Comparing Water Treatment Plants and Water Management Systems
Green vs. Grey: Sustaining and Improving Urban Ecosystems
30 April 2013
Comparing Water Treatment Plants and Water Management Systems
My home in the Poconos is located in a much more rural area than the city of
Philadelphia. The closest city in proximity to my house is Bethlehem. Bethlehem, although it
contains many more trees and natural spaces than Philadelphia, is a city nonetheless. I also
thought that it would be a good idea to compare these two cities in particular because they were
both founded very early on in our nation’s history. Therefore, I decided to compare and contrast
the water treatment plants as well as the water management systems that each city has in service.
By researching this topic, I found that these two cities have starkly different systems for treating
and managing their city’s water. Philadelphia has a combined system with three different waste
water treatment plants, while Bethlehem has a separate system with one main waste water
treatment plant. Each system poses its own challenges; however after research, one can see that
Philadelphia’s combined sewer system is polluting our fresh waterways and should be quickly
restructured into a separate sewer system.
The Philadelphia Water Department is a huge system that is made to accommodate all of
the people in the city. The PWD has approximately 3,000 miles of sewers, 79,000 stormwater
inlets, three drinking water treatment plants, three wastewater treatment plants, 175 combined
system overflow regulating chambers, 164 combined system overflow outfalls, 18 reservoirs,
five water storage tanks, and more than 450 stormwater outfalls. Philadelphia has three main
drinking water treatment facilities: Baxter, Belmont, and Queen Lane Water Treatment Plants.
These facilities draw their water from the Schuylkill and Delaware rivers. From there they
process their water through many different stages to make it safe for citizens of Philadelphia to
drink ("Water Infrastructure Management").
Philadelphia’s sewers are 60% combined sewers and 40% separate sewers. Combined
sewers are ones that collect sewage and stormwater runoff in a single pipe system. This is the
main cause for concern for Philadelphia’s watershed. Those areas with combined sewers are
typically the older parts of the city that have not been renovated in a long while. The combined
sewage system is not harmful until a storm comes through or until there is a lot of snow with the
potential to melt around the city. When the snow melts, or when the rain water goes into the
combined pipe, the water treatment plants in Philadelphia get overwhelmed with water, and are
physically unable to take all of the water in for treatment. The left over water in the pipe then
gets distributed into our freshwater rivers along with whatever sewage was in that same pipe
("Stormwater Management").
There are 164 combined sewer outfalls (CSOs) along the Delaware and Schuylkill rivers
and the Cobbs, Tookany/Tacony-Frankford, and lower Pennypack creeks. When there is an
excess of rainwater, which happens often during even slight rainfall, each of these rivers and
creeks become a little more polluted. The Office of Watersheds’ hydraulic and hydrologic
models approximate an annual CSO discharge of 16 billion gallons into the 164 CSO outfalls.
The primary reason that the water in Philadelphia has become unmanageable is because the
overwhelming majority of the city is covered in concrete, which is an impervious surface. The
water that would have originally sunk into the ground has now become runoff and is polluted as
it travels through the combined sewage pipes ("Combined Sewer System").
Bethlehem, on the other hand, has one main water treatment plant. There is actually a
long-planned $9.4 million project underway to upgrade the plant's facilities in order to make it
more efficient and expand its capacity ("Hellertown-Lower Saucon Patch"). Bethlehem
Township is considered a M4 or a Municipal Separate Storm Sewer System. A drainage system
in which sewage and groundwater are carried in separate pipes is called a separate sewage
system. With this type of system, the main waste water treatment plant does not become
overwhelmed when there is an excess of rain water, and the fresh bodies of water do not become
contaminated with sewage. A factor to keep in mind about Bethlehem’s water management
system in comparison to Philadelphia’s water system is that Bethlehem has much larger
percentage of pervious surfaces; therefore, the separate stormwater pipe is not under as much
stress as would Philadelphia’s stormwater pipe ("Storm Water Information").
Neither water management system, whether combined or separate, is perfect. I have
already addressed the flaws with a combined system, but a separate system contains some flaws
as well. When it rains, pollutants are washed down storms drains. Some common pollutants in
rural areas are as follows: oil and antifreeze dripping onto roads from cars as well as brake lining
dust and rubber from tires; chemicals such as pesticides, herbicides and fertilizers from lawn
maintenance, pet waste, litter, and soil erosion from construction activities. All of these things
will run over land and down storm drains, and eventually they will all make their way into our
fresh bodies of water. Thankfully, there are strides being made in Bethlehem to help keep the
stormwater that goes back into our freshwater clean. Bethlehem’s stormwater program is
federally-mandated and operated though the Pennsylvania Department of Environmental
Protection. Due to this mandated program, Bethlehem must meet six Minimum Control
Measures. The six MCMs are as follows: Public Education and Outreach, Public Participation
and Involvement, Illicit Discharge Detection and Elimination, Construction Site Runoff Control,
Post-Construction Stormwater Management in New Development and Redevelopment, and
Pollution Prevention and Good Housekeeping for Municipal Operations and Maintenance. Each
municipality is authorized to put each and every one of these control measures into action
("Storm Water Information").
In Philadelphia, there are a few more creative ways that they must go about managing
stormwater because of the impermeable surfaces. Green design is a great way to decrease the
amount of stormwater runoff completely. Some green initiatives could be as simple as having a
rain garden to creating green roofs or implementing semi-permeable pavements (Wellborn). In
addition to these strategies, Philadelphia Water Department's monitors water level via sensors
that record data throughout the combined sewer system (“Combined Sewer System”). Of course
Bethlehem could also apply these ingenuities to their city as well, but Philadelphia is in dire need
of green space and these are great ways to implement them into the city without taking up too
much space that could potentially be transformed into commercial buildings. Although these are
all great possibilities, the most beneficial way to reduce freshwater pollution, is to get rid of the
combined system altogether because, when we look at an old city like Bethlehem and see that
they have been able to put a healthy sewer system in place, Philadelphia does not have any
excuse for keeping an outdated system like the combined sewer system.
Works Cited
"Bethlehem BeginsSewage Treatment Plant Upgrade." Hellertown-Lower Saucon Patch. (2012):
n. page. Web. 29 Apr. 2013. <http://hellertown.patch.com/articles/bethlehem-beginssewage-treatment-plant-upgrade>.
"Combined Sewer System." Philadelphia Water Department. N.p., n.d. Web. 29 Apr 2013.
<http://www.phillywatersheds.org/watershed_issues/stormwater_management/combined
_sewer_system>.
"Stormwater Management." Philadelphia Water Department. N.p., n.d. Web. 29 Apr 2013.
<http://www.phillywatersheds.org/watershed_issues/stormwater_management>.
"Storm Water Information." Bethlehem Township. N.p.. Web. 29 Apr 2013.
<http://www.bethlehemtwp.com/btweb/stormwater.html>.
"Water Infrastructure Management." Philadelphia Water Department. N.p., n.d. Web. 29 Apr
2013. <http://www.phillywatersheds.org/watershed_issues/infrastructure_management>.
Wellborn, Bess. "Green Design." Green vs Gray: Sustaining and Improving Urban Ecosystems.
Pennssylvania, Philadelphia. 2013. Lecture.