Wastewater treatment improves and purifies used water to make it fit to use again or send back to the environment. It can flow to surface water (rivers and streams) or to groundwater under the land surface. When untreated wastewater ends up back in the environment it causes water pollution and this affects all living creatures.
Water pollution has an impact on all aspects of modern life. It’s hard to imagine life without clean water but it shouldn’t be taken for granted. This is clearly discussed in the recent state of the environment report. It’s our responsibility to maintain and protect the natural habitat as best as possible and we can do this with proper wastewater treatment. Failing to do this we risk not only the health of the planet, but our own health too.
History of wastewater treatment
In the past, the environment could handle small amounts of water pollution through dilution and natural breakdown. The earliest sewage systems first appeared in cities around 3000 BC but this was a luxury that only the rich had the privilege of using! The majority of people dug open pits or emptied chamber pots into nearby rivers, seas or ditches.
The ancient Romans were more advanced than the rest of Europe where, for the most part, dumping household wastewater out into the streets continued right up to the modern era. Streets adorned with human waste couldn’t have been pleasant, but it was the norm. The population depended on the rain to wash it away but as the population grew, the occasional rain shower just wasn’t enough.
The first septic tank
As a result of the build up of waste, cesspits were invented in the 16th century. These were underground chambers near houses and dwellings where wastewater was sent to. Liquid waste seeped into the soil and solid waste was removed by tradesmen using shovels and wagons. This only happened every 8 to 10 years so at that point the waste was so toxic, tradesmen often suffocated. Not only that, groundwater sources were being contaminated by cesspits and causing outbreaks of waterborne diseases. As a result, stricter regulations for proper cesspit construction and maintenance were introduced.
In the mid 19th century, a man named Jean-Louis Mouras invented the “Fosse Mouras”. This was a type of cesspit that used two underground concrete chambers. The first held the solid waste while liquid waste flowed to a second tank before exiting into the soil. He made an unexpected discovery when he found far less solid material inside the first tank than expected. Lo and behold, the first septic tank was invented. In this sense of the word, “septic” refers to the conditions inside the tank that cause the breakdown of the solid waste.
Modern Wastewater Treatment Plants
Fast forward to modern times and rural unsewered areas still use septic systems. A basic septic tank is a watertight chamber through which domestic wastewater flows for primary treatment. Settling and anaerobic processes reduce solids and organics, but not entirely. The remaining solids need to be pumped out for separate disposal. Liquid waste flows through pipes to a site nearby (percolation area) or directly to surface water nearby. However, this basic form of treatment often isn’t enough to prevent water pollution.
The basic septic tank design is no longer widely accepted as the best form of wastewater treatment. This is clearly outlined in the water services acts. If coupled with additional wastewater treatment facilities it can operate far more effectively. Examples of such additions are biofilters, air blowers and/or pumps.
Advantages of Modern Wastewater Treatment Plants
A biofilter uses living material (microorganisms) to capture and consume pollutants inside the tank. It increases the quality of the wastewater without consuming too much water in the process. It works well even under changing conditions, like the volume of incoming wastewater. Bacteria naturally occurring in the wastewater can also act as a biofilter.
Low Running Costs
The biofiltration process requires oxygen to work. Oxygen naturally enters the wastewater as it flows through the pipes of a treatment system. We can speed up the whole process by adding oxygen artificially with an air blower. Air blowers create tiny bubbles of oxygen that allow the microorganisms to multiply quicker and break down more waste. Air blowers are well worth installing because they operate and run on low levels of electricity.
Higher Wastewater Treatment Standards
Today’s modern wastewater treatment plants use integrated systems like those mentioned above. It’s the combination of the different techniques that works best. The result is that the standard of the treated wastewater is much higher than the traditional septic tank. These higher standards mean much cleaner wastewater flowing back into the environment. Cleaner wastewater means cleaner ground water and surface water. As a result, harmful effects on streams, rivers and natural habitats are reduced. When we ensure that our wastewater is as clean as possible we are creating a healthier and safer environment to live in.