Wastewater treatment

The world has a very large population, and this population is increasing steadily. This has many consequences and issues, but one fact is that so many people and industrial activity creates huge amounts of waste – and wastewater is a big factor in this equation and that also has major impacts on the environment, health etc. Wastewater treatment is an issue that’s relevant for every country in the world and also one that mankind has some very good and effective solution for.

In past years, when the consequences of human consumption and increasing population – that both lead to much more waste of all sorts – were not thought of or at least did not receive the public and governmental attention it deserves, enormous amounts of wastewater were left untreated and simply flowed to the ocean and other water sources. This still happens of course and causes serious damage to eco systems, human health, drinking water and much more.

Wastewater treatment technology and acts has improved immensely in recent years, in a global standard and across all countries. Some countries, like Israel for example, have wastewater treatment plants that recycle almost all the used water and then reuse it for agriculture (85% of wastewater in Israel is treated and reused).

Wastewater = Sewage

When speaking about wastewater treatment we are referring mostly to sewage, both human waste sewage systems and industrial wastewater systems. We are talking about huge amounts of contaminated water that have a large variety of contamination factors and in most cases that are very hazardous.

The main goal of wastewater treatment plants and sewage treatment is to eventually produce water that can be reused for various purposes or disposes of in a more ecological and healthy way. Some wastewater treatment methods produce water in very high purification level that can irrigate agricultural produce, other methods produce water that can be flowed to water sources with no bio-hazard. There are wastewater treatment methods that eliminates any sediments (remains of human waste for example) by biological processes while other still leave the treatment plant with sludge or waste byproducts that need disposing of.

Wastewater treatment common methods

There are about 50 wastewater treatment methods that are used or that were used in the past, some are suitable for large scale treatment and some are for minimal household use. Of course that the most relevant methods of wastewater treatment are the ones that are operated in large scale plants.

In most common wastewater treatment methods there is a pre-treatment stage that is followed, using various technologies and equipment, by the following stages: Screening, grit removal, fat and grease removal. Now comes the primary treatment stage of wastewater treatment, this is a sedimentation stage that separates sludge and other unwanted agents from the water. Now comes the secondary stage that has a few methods to degrade the biological parts of the sewage.

  • Fixed growth / attached growth: trickling filters, moving beds, rotating biological contactors.
  • Suspended growth: activated sludge systems.
  • Lagoons – Surface aerated basins: uses oxygen to treat the waste biologically.
  • Wetlands: uses special water plants and biological processes to purify the water.

There so many factors and differentials in wastewater treatment methods, basically the process uses oxygenation and biological processes/agents for the treatment process.

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