The treatment of wastewater is an important part of the water cycle and fundamental to the health of the environment. The water we use in our homes, businesses as well as that used in industry is likely to have gone through some form of wastewater treatment at some point. The amount of uses we have for water means that for a suitable supply to be maintained, wastewater treatment is essential, added to this it is vital for our environment.
Wastewater treatment for the lay reader can also be termed as the treatment of sewage, although the term wastewater also refers to industrial runoff as well as domestic. The reason we must put our wastewater through treatment facilities is that despite nature's excellent ability to cope with wastewater and filter it in its own way, without dedicated treatment plants the natural filtration processes would be inundated and overwhelmed.
The human civilisation produces billions of gallons of wastewater in any twelve month period and if this were not treated the environment would greatly suffer. The process of wastewater treatment is relatively complex and requires a multi-faceted approach. The separation of waste elements and the water that carries them is the ultimate goal.
The primary stage in wastewater treatment is designed to remove the majority of foreign elements. The treatment process includes letting the wastewater settle so the solid objects fall to the bottom. This solid matter is sometimes passed onto the agricultural industry to use as fertiliser. In addition, some treatment facilities use chemicals to speed up the settling process, this however can sometimes harm the environment.
In recent years the huge wastewater settlement tanks have been replaced by tall separators. These have been designed for sites where space is limited and in treatment plant that cannot expand. The system works by installing interconnected spirals in the tall tanks which spin slowly. This slow spinning causes the solid matter to fall to the bottom and rather than purely relying on gravity in the settling process, it actively works to push the waste matter to the bottom. Once again, the environment can benefit from this as natural fertiliser is obtained with no chemical additives.
In the past the wastewater would be chemically treated to remove remaining foreign elements, this was extremely bad for the environment as the chemicals were often pumped directly into rivers and the sea. Thankfully the secondary treatment process is far more eco-friendly.
It is now termed as biological treatment; instead of using chemicals to the wastewater it involves adding naturally occurring micro-organisms that feed on waste materials. The water is kept in tanks as these organisms feed off the matter; simultaneously oxygen is pumped through the water as the organisms also need this to survive. The use of oxygen does however have a dual effect, by aerating the water, waste matter is pushed through filters that also work towards cleaning it. Fortunately this method is far more environmentally friendly that those used in the past.
After this process the wastewater is not yet able to be released back into the environment, it needs another stage to ensure that any effects on ecology and wildlife will be practically non-existent. The final process once again involves a period of letting the water settle. In this final stage however the remaining foreign elements are left in the bottom of the tank as the now clean water is allowed back into the water cycle, ready to be used once more. The sludge, after extra processes is also used in the agricultural industry.
Thankfully the wastewater treatment process is now more environmentally friendly than it has been in the past. The removal of chemicals has been a major change that has meant that the ecological effects are lessened. Unfortunately, industry still produces wastewater that despite treatment still pollutes our environment. The methods discussed here, while being widely used in this country have not been adopted worldwide; as the environment is a global concern, an international responsibility should be taken to ensure its future health.
Environment expert Thomas Pretty looks into changes in wastewater treatment processes that are more ecologically viable.