Down the Drain, and Then What?

VIDEO

 

Water is rapidly becoming the most scarce human resource on the planet. Cities like Los 

Angeles and Phoenix already experience sporadic water shortages, and experts say problems like 

this will only get worse.1 In fact, the UN predicts that by 2025, 63% of the world’s population, some 5 

billion people, will be living in water-scarce areas.2 

 

With this prediction in mind, you might be thinking more about where your water comes from 

now and where it’s going to come from in the future. I can tell you that about 70% of the Earth’s 

population draws its supply from surface water, like lakes, streams and reservoirs, and 30% of the 

population taps into underground sources.2,3 Americans use more than 400 billion gallons of water a 

day.4 But the truth is, where our water comes from is only half of the equation that needs to be 

considered when we’re talking about our water supply. It’s becoming increasingly clear that we must 

be just as focused on managing the outflow side of water – where it all goes after we consume it or 

use it – in order to ensure that we continue to have clean water down the road. Every time we 

shower, flush, wash our cars, clothes, or dishes, America’s water infrastructure network, which spans 

more than 700,000 miles, takes over.4 How this water is treated and rehabilitated for reuse is 

complicated, but there are things we as water consumers can do to assist the process, ease the 

burden on our water systems, and help maintain a healthy water environment.  

 

I’ll talk more about what each of us can do in just a moment, but I think those points will make 

more sense if we first discuss how water treatment systems came to be and how the wastewater 

treatment process really works.  

 

I’d like to use New York City as an example. Let’s start  with a bit of history. In the years prior to 

the development of the city’s first upstate reservoir system in 1842, citizens depended on ponds, 

streams and wells for their water. There was no system for disposing of garbage, sewage, or human 

or animal waste. So the frequent epidemics and outbreaks of cholera and yellow fever were 

predictable. The first wastewater treatment plants were built in New York City in the 1890s.5  

 

By the early 1900s, as New York City’s population reached 3.5 million, the discovery of the link 

between bacteria-laden water and human disease stimulated a need for a master plan for the city’s 

water. In 1904, the Metropolitan Sewage Commission was formed and a progressive plan was drawn 

up. By 1968, there were 12 water treatment plants in the city, and while conditions were better, they 

were by no means perfect.5   

 

It was not until 1972 that the federal Clean Water Act created minimum standards for 

wastewater treatment.6  This forced New York City, then managing more than1 billion gallons of 

wastewater a day but removing only 65% of pollutants, to upgrade its entire system to reach the new 

standard of at least 85% pollutant extraction.5 

  

Today, some 8 million city residents consume about 1.3 billion gallons of water a day and 

release 1.4 billion gallons of wastewater. Since 2001, many New York waterways have been deemed 

 

suitable for bathing and there have been no beach closings.5 How does our water get so clean? To 

answer this question, we have to go behind the scenes and underground.  

 

Once it’s used, New York City’s water travels into the sewer, which is made up of 6,000 miles 

worth of pipes. From there, the entire water treatment process is overseen by the Bureau of Water 

Treatment, which has 1900 employees and an annual operating budget of $262 million.5 The group’s 

task?  To convert all the water we use in our homes, schools factories and businesses, combined 

with rainwater and street runoff, into high-quality wastewater that’s suitable for release into waterways 

and eventual reuse.  

 

How does the process work? In New York City, once the water hits the sewer, it meets up with 

runoff rain or snow and a variety of materials caught in street-side catch basins. It all travels 

underground to 14 plants around the city, and then goes through a seven-hour series of five steps 

that rehabilitates the water to a quality that would take weeks to be achieved in the natural 

environment. This five-step process, which I’m about to go into, eliminates up to 95% of pollutants 

and converts sludge to a biosolids form that can be used as a fertilizer or soil conditioner.5 

 

  Step one occurs several stories underground. Everything that makes it to the sewer hits 

screens that capture large pieces of trash and other material. The garbage is collected and 

transported to landfills. The remaining sewage is pumped up to ground level surface plants. 5  

 

In step two, the wastewater enters sedimentation tanks and over a period of one or two hours, 

the solids settle to the bottom while lighter materials float and are skimmed away. The settled solids 

are pumped to sludge-handling facilities. The remaining liquid flows on to step three. 5  

 

In step three, air is pumped into the liquid to stimulate the growth of oxygen-using bacteria. 

These micro-organisms consume most of the remaining organic material that’s polluting the water. 

This takes three to six hours and leads to a second set of settling tanks that allow solids to settle to 

the bottom as secondary sludge and be pumped along to sludge-handling facilities. 5  

 

Step four is disinfection. The water is mixed with sodium hypochlorite, the same material found 

in common bleach, and it purifies the water so it can be released into local waterways. 5  

 

Step five is sludge treatment. Untreated sludge is 99% water. The sludge is heated to 

encourage additional bacteria growth and consumption of organic materials. Methane gas is captured 

and used as an energy source for electricity for pumps and boilers. Spinning centrifuges then remove 

90% of the water and the addition of a polymer substance converts the material to a bio-solid “cake.” 

The biosolids are converted into fertilizers and soil conditioners that are used in parks and golf 

courses throughout New York. 5 

 

This is a 365-day-a-year process, and it will require ongoing investment. In fact, the U.S. 

Environmental Protection Agency estimates that infrastructure costs for the U.S. water and 

wastewater systems may be as much as $1 trillion over the next 20 years.1 That investment will 

ensure safe, clean drinking water for U.S. citizens, and safe, effective management of wastewater, 

plus disease control and clean recreational waters that are capable of supporting healthy fish and 

animal species. 

 

 

 

What can we as citizens do to help out and lessen the burden on our water systems?  First, 

conserve water. The more we use, the more we must manage. Second, do not put hazardous 

substances down sinks, storm drains or toilets. Third, don’t litter. Litter ends up with wastewater in 

treatments plants. Fourth, dispose of household items, like grease, properly. Don’t throw it down the 

drain. And finally, use mass transportation and practice energy conservation. Toxic chemicals from air 

pollution end up in wastewater and have to be removed.  

 

The job of wastewater management is large, but it becomes much more manageable if each of 

us does our part. 

 

For Health Politics, I’m Mike Magee. 

 

 

 

References 

 

1. Deutsch CH. There’s Money In Thirst; Global Demand for Clean Water Attracts Companies Big 

and Small. New York Times. August 10, 2006. 

2. United Nations Population Fund Press Release. “Investments in Reproductive Health Can 

Reduce Water Insecurity, Says UNFPA Report.” March 19, 2003. Available at: 

http://www.unfpa.org/news/news.cfm?ID=193&Language=1. 

3. Magee M. Healthy Waters. New York. Spencer Books. 2006. 

4. DrinkTap.org. “Straight Talk on Water Infrastructure.” Available at: 

http://www.drinktap.org/consumerdnn/Default.aspx?tabid=198. 

5. New York City Department of Environmental Protection. “New York City’s Wastewater 

Treatment System.” Available at: http://www.nyc.gov/html/dep/html/wwsystem.html. 

6. U.S. Environmental Protection Agency. “Safe Drinking Water Act (SDWA).” Available at: 

http://www.epa.gov/safewater/sdwa/index.html.