In the film Finding Nemo, the phrase ‘all drains lead to the ocean’, said by Gill, has been believed and referenced for years. But is it really true?
No, not all drains lead to the ocean. The water leaving our homes generally goes to two different locations; either into a septic tank in your backyard (common for remote rural living) or it is sent to a sewage-treatment plant through the sewage pipe system.
What is Waste Water?
Wastewater is basically water you have used in your home and have flushed down the toilet or washed down the sink. This might be soapy dishwater, leftover water from washing your clothes, or sewage from the toilet. Whatever your wastewater is, it is all referred to as sewage and it travels through sewerage pipes.
Where Does Wastewater go First?
All wastewater follows the same route in the drainage system, whether it comes from a home, commercial building, or from the street. All wastewater is guided into the sewer system that runs under the roads. The drains from your home will join up with larger ones on your street and flow into even bigger sewer pipes – some pipes are bigger than a bus! The big sewer pipes transport the sewage to where it is to be treated; the treatment plant.
Why Does Sewage Need to be Treated?
It is extremely important all sewage is treated because it will eventually be sent into our rivers and oceans and sewage contains lots of germs that pose a health risk to humans and aquatic life. Treating this sewage gets rid of these germs and also removes items people may have flushed down the toilet accidentally, such as toys, jewellery, and even money. This process can be time-consuming – often taking a couple of days! So, it is important to avoid flushing certain items down the toilet.
Treated sewage is important as it ensures it’s clean and that it will not cause any environmental problems. This means it should not cause harm to any plants or fish that live in the ocean or river where it is released. If sewage or wastewater is not fully treated, it can cause water pollution, and this can have a detrimental effect on our wildlife and natural habitats! It can also make people sick if they go swimming and cause a whole host of other problems, so it’s pretty important that sewage is properly treated before being sent into our rivers and oceans.
Treating Waste Water
Marine biologists the world over are concerned about the wastewater ending up in the oceans as historically this has been a significant pollutant to marine life. However, the wastewater that leaves your property has to go through a variety of treatment methods and pass water-quality testing before leaving the plant.
Often, the first stage of treating wastewater is purely physical, letting solid particles settle at the bottom of the tank and filtering the waste water through a fine matter such as sand. At a minimum, a chemical treatment such as chlorine is added to kill any dangerous bacteria and microorganisms.
Returning Waste Water to the Sea
Some wastewater treatment companies may collect energy or other useful materials from wastewater during the treatment process. However, once the water has been treated and returned to a good state it is sent back into our rivers and oceans, but only once it has been strictly regulated and approved by the Environment Agency to ensure it meets high-quality standards.
The water cleansing process is so thorough that in some areas treated wastewater put back into the rivers and oceans can actually improve water quality and keep fish and aquatic life healthy. The treated water is then able to be released into a local river or ocean. Fun fact: if you live near the coast, it is likely your treated sewage goes into the ocean.
Rainwater Drain Systems
When you’ve experienced a lot of stormy weather, it is common for heavy, prolonged showers to overwhelm the drainage system. This is why we have storm drains available – to avoid sewage and other nasty wastewaters from overflowing onto the street. The great thing about rainwater is that it is either drained into an underground drain pipe beneath the road to be piped to a soakaway, or it drains to the soakaway in your garden where it is able to slowly percolate back into the soil.
So, there you have it! A little introduction into our drainage systems and whether or not all drains lead to the ocean. Just to be clear, they don’t and the ones that do go through significant treatment and testing processes to ensure the water being released back into our oceans is clean, clear, and not harmful to aquatic life. In fact, Singapore is famous for making drinking water out of treated sewage that is even cleaner and purer than the World Health Organisation’s standard for safe drinking water! Now that’s pretty incredible.