Wastewater treatment plant

Types of Biological Aerobic Wastewater Treatment Methods

Water, being a renewable yet increasingly scarce resource, has been the focus of many innovations in the world of recycling, sustainability and conservation efforts. There are different forms of waste from both residential and industrial applications. Liquid waste make up the biggest percentage of this.

Wastewater treatment is therefore vital to ensure liquid waste does not harm the water bodies it is released into or the groundwater it leaches into, notes industry expert Waterform. There are different wastewater treatment methods. These are primarily categorised as biological, chemical and physical methods.

In a bid to treat water in natural ways and with minimal use of chemicals, biological methods use microorganisms to break down the organic wastes in water into stable inorganic compounds. It is kind of like how in medical fields, some use maggots to clean wounds naturally.

The aerobic treatment system is a type of biological treatment that uses oxygen to remove at least 98% of the organic contaminants in your wastewater. It is fast, energy-efficient and produces cleaner water compared to anaerobic treatment.

Since there are many other ways to use oxygen to treat wastewater, under this subtype are even more subtypes of treatment methods. Here are some techniques of aerobic wastewater treatment.

Activated Sludge

This is the most commonly used aerobic wastewater treatment option. As the name suggests, it uses a liquid that closely resembles sludge. It involves the degradation of organic waste and the removal of nutrients from the wastewater using highly concentrated microorganisms.

Oxygen is pumped into a chamber known as an activated sludge to promote microbial growth. The effluent generated from this chamber is collected in a settling tank. The activated sludge method is low-cost, efficient and compact.

Aerated Lagoons

In this option, wastewater is treated in a shallow, large earthen basin with mechanical aeration to supply oxygen. The oxygen promotes the oxidation of wastewater and encourages the development and growth of algae and bacteria used for the water treatment.

This method takes a long time and involves more than one process. The effluent from an aerated lagoon is already suitable for re-use, but the sludge that settles at its bottom needs additional treatment steps before it can be used.

Trickling Filter

Engineer controlling water filter

In this method, wastewater is spread over a bed containing media such as plastic substrate, rocks, and gravel. The media’s surface has microorganisms that remove contaminants from the wastewater.

The water is then filtered through the media bed to eliminate the microorganisms and other particles in the water. The usable water is then collected into a groundwater or a collection tank.

The wastewater treatment techniques mentioned here were initiated initially for use in rural areas and to promote natural methods in wastewater treatment. They are best-suited for wastewater high in biodegradable and organic content.

They are hence routinely used for the treatment of municipal sewage and waste from food-related industries. However, industrial wastewater containing carbon molecules can also be treated using biological aerobic methods. The choice of treatment method depends on factors such as objectives, location and available resources.