Why is domestic wastewater treatment important?

Characteristics of domestic wastewater

Domestic wastewater often contains many impurities. The main part, namely 52% is composed of organic content and inorganic substances account for the remaining 48%. Moreover, there are a large number of viruses and disease-causing bacteria. Besides, there are also types of bacteria that are not harmful but on the contrary help to decompose some types of waste.

Why is wastewater treatment important?

-       Domestic wastewater inherently contains many impurities as well as environmental pollutants, specifically chemicals and microorganisms. If wastewater is not treated properly, it can lead to problems such as clogged pipes, cloudy water, and ecological imbalance, thereby causing environmental pollution, soil, water and air pollution.

-       If not treated, domestic wastewater also contains many types of bacteria and viruses that cause many dangerous diseases such as diarrhea, malaria, water-borne diseases, etc. Besides, chemical compounds found in wastewater also greatly affect human health if a direct exposure for a longer time.

-       When wastewater treatment is not carried out properly, domestic wastewater can lead to clogged pipes and therefore cause damages to facilities and water treatment systems. This can have some effects on human health and seriously affect both water and soil environments.

-       Domestic wastewater can also cause specific problems such as reducing the oxygen concentration in water, thereby posing a serious threat to the life of animals and plants.

How does the domestic wastewater treatment process work ?

-       Domestic wastewater is water discharged after people use it to serve daily activities such as cooking, washing, bathing or water discharged from shopping centres, entertainment areas, restaurants, cafes, etc.

- Domestic wastewater treatment is an activity to remove impurities from daily wastewater to create a suitable type of wastewater without polluting or affecting the surrounding environment. From there, water pollution can be prevented from untreated wastewater discharged directly into the environment.

Domestic wastewater treatment process:

Domestic wastewater treatment using AAO technology.

·         Step 1: Usually, large-sized trash will be removed through the trash screen, then oil and grease will be separated and pre-treated before that the wastewater is sent into the centralized tank. This process will partly help to increase the lifespan and performance of the wastewater treatment system.

·         Step 2: The wastewater is sent directly from the collection tank to the equalization tank. The latter neutralizes the concentration and flow of wastewater to conduct domestic wastewater treatment. The equalization tank will receive water brought from the collection tank and then continuously aerate so that the wastewater treatment process is not overloaded and reduces the size of wastewater treatment works.

·         Step 3: In the anoxic tank, the nitrification and decomposition of other organic substances takes place, and the BOD content decreases. The wastewater will be treated with the support of anoxic microorganisms that perform phosphorus reduction, then continue to participate in the process of synthesizing and storing energy in microbial cells.

·         Step 4: Microorganisms directly adhere to the substrate through consecutive motion processes, so the decomposition time of organic compounds will take place faster. Therefore, organisms are considered to play a very important role in the wastewater treatment process. During the entire process, it must be ensured that the BOD content doesn’t exceed the threshold of 5mg/litre.

·         Step 5: The residue is settled in the sedimentation tank, the biological sludge will be retained, and the settled sludge will be pumped to the aerobic tank to maintain the concentration of microorganisms. The rest will be returned to the tank for sludge storage for treatment. After being treated, the water will be pumped through the intermediate tank.

·         Step 6: The pressure filter tank is a place for sediment deposition and removal of suspended particles in the water source. Afterwards, the wastewater continues to be treated to reach the prescribed standards.

·         Step 7: The domestic water, after going through the above treatment process, will be disinfected before being used directly. Waste sludge participates in the process of compressing and pressing sludge to separate the water and the sediments. The water sludge will be pumped to the collection pit, while the remaining sludge will be used for other purposes. 

There have been many cases of diseases spread through the water environment that are dangerous to human health such as typhoid, cholera, polio, hepatitis, etc. Therefore, properly treating domestic wastewater has a great impact on the population’s health. Domestic wastewater treatment technology is important in the process of removing pollutants. Hopefully, the FEC's shared article will help you in the process of finding ways to treat domestic wastewater.