For most Americans, the handling and disposal of sewage is not something they normally think about, or would even want to for that matter. Once our, uh, ‘territory’ is marked and flushed down the toilet, it’s gone, never to be seen or thought of again. But where does all that sewage and wastewater go to, and how is it all redounding to the current problem that most of us didn’t even know existed? Well first, a few things need to be explained.
Around 20% of households in America use septic tanks (an underground tank that collects sewage and uses bacteria to decompose it before finally draining the remaining effluent wastewater in an adjacent leach field) that are considered a “decentralized” system and not connected to a sewerage system. However, they are predominantly found in rural areas, and the majority 80% of other people are serviced by municipal treatment plants. Pipelines, and their accompanying sewerage infrastructure, transports our waste to these treatment plants. Here, the sewage treatment plants are purposed with making sure the waste is sanitized and effluent (liquid waste that’s poured into a river or streams) and free from pollutants and toxins. This is done in a treatment process that generally follows three stages:
Primary treatment- in this stage, sewage is held momentarily in a large tank pre-settling basin to allow the heavier solid substances, like sewage sludge, to settle at the bottom, and the lighter liquid substances (oil, fat, and grease) to float to the top and be removed.
Secondary treatment- so after all the matter is separated, whatever biodegradable contaminants there are in the basin are removed by bacteria and protozoans (like in the aforementioned septic tank) that consume and metabolize the hazardous substances.
Tertiary treatment- and finally, one last stage is needed to further ensure the sewage is of the proper effluent quality before it’s considered treated waste and sent out to the environment. This final stage basically encompasses various methods to remove any remaining contaminants. So now you know a little more about the the sewerage system and you can tell your friends about it at parties.
The Problem And Its Solution
Of course, there are problems in the sewage system and many people can be at risk when these problems arise. The issue lies in combined sewers systems. These sewer systems are made to concomitantly gather excess surface runoff water and wastewater. Normally, this is not a problem when the weather’s dry. But during heavy rainfall (or any other time surface water flows extensively), sewage treatment plants and combined sewer systems can become overburdened and create ‘combined sewer overflow‘.
The excess untreated sewage waste can flow into bodies of water that people drink and bathe in. When the overflow is bad enough, 40 million Americans in 32 states, including D.C. (that could explain our congress’s inanity) are at risk of toilets over-flooding, beaches closing, contaminated drinking water, etc. But there is a silver lining. Recent advances in technology (using decision support systems in real-time to maneuver weather management systems to help prevent overflows) has done much to ameliorate the problems of Americas antiquated sewer system. But a complete overhaul to our current infrastructure is paramount. We should do more to be eco-conscious and take a active role in supporting environmentally friendly representatives.