A Brief Overview of the Process of Biological Wastewater Treatment

The biological wastewater treatment system is a technology used to cleanse water. These technologies uses protozoa, bacteria, and other specific microbes to purify wastewater. Wastewater basically holds organic substances, such as wastes, garbage, and partly digested foods. Moreover, it also contains, in many instances, heavy metals, toxins, and pathogenic organisms. When these microorganisms break down organic impurities for food, a flocculation effect is created which allows the organic matter to settle out of the solution. An easier-to-manage sludge is produced during the process which is then dewatered and disposed of as solid waste.

Although the biological wastewater treatment seems to be a simple and easy process on the surface level, in fact, this is a complex process of the intersection of biochemistry and biology. Natural processes are used to help with the disintegration of organic constituents in the process. In order to break down the organic wastes, biological treatments uses common cellular processes that bank on on small organisms, bacteria, and nematodes. 

Generally, the biological treatment process is bifurcated into two main processes:

1. Aerobic processes- In the aerobic process, oxygen is required to decompose the effluents.
2. Anaerobic processes- In this biological process, the treatment is done in an oxygen-free zone. 

Experts and scientists have achieved success in controlling and refining both aerobic and anaerobic biological treatment processes to totally remove the organic affluences from wastewater.

The process of biological wastewater treatment is typically used as a secondary treatment process to eliminate the remaining material after the primary treatment methods comprising dissolved air flotation (DAF). Sediments and affluences are exterminated from the wastewater in the primary treatment process.

Aerobic Wastewater Treatment-

• Aerobic wastewater treatment processes include:
• Aerobic or simple septic tanks,
• oxidation ditches; 
• spray and surface aeration; 
• activated sludge; 
• trickling filters; 
• lagoon and pond-based treatments; 
• aerobic digestion. 

Apart from these, the constructed swamplands and different types of purification are also considered as biological treatment processes. To intensify the level of oxygen transmission and minimalize odors during the wastewater treatment process, diffused aeration systems are used. Aeration is used to provide oxygen to the useful bacteria and other organic entities as they decompose organic affluences in the wastewater.

The activated sludge process is a long-standing instance of an aerobic biological treatment process. This sludge process is extensively used for the secondary treatment of both industrial and domestic wastewater. This process is widely used for purifying waste streams that are high in organic or decomposable content such as municipal sewage; wastewater produced from pulp and paper mills or meat processing industries; and industrial waste streams which hold carbon molecules.

Anaerobic Treatment

In the anaerobic treatment, bacteria and other organisms are used to help deteriorate the organic substance in an environment which is free of oxygen. This process can be used in septic tanks and lagoons. However, the best type of anaerobic treatment which is called anaerobic digestion, used for the treatment of sewage from food and beverage production, municipal wastewater, agricultural waste and chemical effluent.

Energy recovery, one of the most forceful areas of resource recovery, is driven by anaerobic assimilation. The anaerobic digestion is used to harvest biogas composed of methane in this form of energy recovery. Workers can use it for different usages such as generating energy and help fuel operations on the way to become energy net zero, or even turning waste streams into revenue streams.

To sum up…

The biological treatment process selection depends on variety of factors which includes compliance with environmental discharge quality regulations. These factors help in selecting the right type of treatment process whether aerobic or anaerobic.

These biological treatments are often complemented with some extra treatment stages. The stages include chlorination and UV treatment, a range of filtration options such as reverse osmosis, carbon filtration, and ultrafiltration.

About the Author(s)

Princy A. J

Princy holds a bachelor’s degree in Civil Engineering from the prestigious Tamil Nadu Dr. M.G.R. University at Chennai, India. After a successful academic record, she pursued her passion for writing. A thorough professional and enthusiastic writer, she enjoys writing on various categories and advancements in the global industries. She plays an instrumental role in writing about current updates, news, blogs, and trends.