Every Time It Rains Sh*t Pours into the River.....Really.

Yep....really. Many older cities in the Northeast, the Great Lakes region and the Pacific Northwest have combined sewers as opposed to separate pipes for sewage and stormwater. This means that the pipes, which carry industrial wastewater and domestic sewage also carry stormwater (the runoff from rain or snowmelt). These systems of pipes were put in place when sewage systems did not exist and therefore there was no advantage to separating the systems because it was all going to the same place (a waterway) anyway. This is an old design, which states have not allowed since the 1950s or so, now the pipes are separated. Combined sewer systems serve roughly 772 communities containing about 40 million people. The EPA map below provides a rough illustration of the prevalence of combined sewer systems in the U.S.:



Generally, when weather is dry, industrial wastewater and domestic sewage go into the combined sewer, are treated at a sewage treatment plant, and then are discharged into a nearby water body. However, when it rains or snow melts, the pipes fill up and there are outflows, which pour the untreated mix of rain, industrial filth and crap into our waterways. Allowing all of the wastewater to flow on to the treatment plant would overwhelm and shut down the system.



In New York City, as little as .25" of rain leads to raw sewage overflows, there are 422 sewage outfalls and 27 billion gallons of raw sewage pours into the waterways each year.



The two, seemingly obvious answers to this problem, are prohibitively expensive and in many cases impossible. To replace the pipes would mean ripping up entire cities and laying down a whole new system and to create larger treatment facilities is less difficult but difficult nonetheless. In many cities, such as New York City, land is scarce and certainly too scarce to install the facilities that would be required to even come close to handling the amount of wastewater necessary.

So because stopping it is so difficult, treatment facilities are actually given permits to discharge raw sewage into our waterways. Under the Clean Water Act (CWA) any point source, which emits effluent (wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged into surface waters) must have a National Pollutant Discharge Elimination System (NPDES) permit. In 1994, EPA published the Combined Sewer Overflows Control Policy. The first milestone under the CSO Policy was the January 1, 1997, deadline for implementing nine minimum technology-based controls.

These nine controls are:
1. Proper operation and regular maintenance programs for the sewer system and the CSOs
2. Maximum use of the collection system for storage
3. Review and modification of pretreatment requirements to assure CSO impacts are minimized
4. Maximization of flow to the publicly owned treatment works for treatment
5. Prohibition of CSOs during dry weather
6. Control of solid and floatable materials in CSOs
7. Pollution prevention
8. Public notification to ensure that the public receives adequate notification of CSO occurrences and CSO impacts
9. Monitoring to effectively characterize CSO impacts and the efficacy of CSO controls

The next step will be to develop long-term CSO control plans that will ultimately provide for full compliance with the CWA, including attainment of water quality standards. See Philadelphia's here, and New York City's is starting to take shape under PlaNYC.



The solutions to this issue may be death by a thousand cuts, we can't control how much it rains, but we can control how much water we use. Putting a brick in your toilet's water tank and generally conserving water when its raining and snow is melting will help alleviate the pressure on the system. Demanding that cities find a way to build bigger treatment plants to handle the flow will also go a long way. And the initiatives that have some of the greatest net positive effects are those that catch the rainwater and snowmelt before it makes its way into the sewer, called green infrastructure: tree pits, more park land, green roofs and rain barrels. Cement cannot catch any water and cities are filled with cement, replacing as much cement as we can with permeable, water-holding surfaces will keep that clean rain water from mixing with sewage and pouring into waterways.