Wastewater treatment methods

Wastewater treatment has some methods that have evolved over time. In Carewater, we are always keen to use the best methods and the latest technology. You can read more about sewage treatment units with the best water treatment plant construction and maintenance company in Saudi Arabia Carewater.

Wastewater treatment stages

The sewage treatment process goes through several stages as follows:

Preliminary Treatment

At this stage, all materials that may hinder the subsequent treatment processes, such as tree branches, gravel, oils, sand, and soil, are removed using the following tools:

Screens

It holds large items.

Grit Chambers

deposition of inorganic materials such as oils, sand, soil, and gravel; Wastewater is passed through sand sedimentation basins, and the sedimentation is controlled by controlling the sedimentation speed, to be stored in specific basins and sent to the landfill later. These basins are characterized by their small size.

Primary sedimentation stage

At this stage, the high-density materials that may be organic or inorganic are removed, and this stage leads to a decrease in the concentration of suspended materials by up to 55%.

Biological treatment stage

It is the stage in which the organic materials in wastewater are oxidized by aerobic bacteria, and the treatment method is used according to the biological growth system used for microorganisms, as follows: Aerobic biological growth suspended bacteria are suspended in wastewater during the mixing process.

biological treatment methods

Activated Sludge

In it, microorganisms are activated by adding a small amount of previously activated sludge, then mixing the wastewater and stirring to ventilate it, so that the bacteria oxidize the organic materials, and the continuous stirring process leads to coagulation of suspended materials and an increase in their concentration to be disposed of later in the secondary sedimentation process.

Stabilization ponds

They are simple ponds, in which the water is treated in a natural way based on algae, sunlight, and the elements present in the wastewater. Successive aerobic biological growth The bacteria are attached to supports, and the following methods of biological treatment are used:

Trickling filters

Biological filters consist of basins built of bricks or reinforced concrete and filled with gravel or plastic. And when the wastewater exits from the primary sedimentation basin. It is distributed on the surface of the filters by perforated tubes so that the water penetrates the gaps between the gravel, and thus a gelatinous layer is formed on the surface that contains bacteria and organisms microorganisms to carry out the oxidation process.

Rotating Biological Contactors

They are circular discs made of plastic that rotate slowly and are immersed in the middle of the wastewater. As a result of the rotation, a biological layer is formed that begins the treatment process when these discs are immersed in wastewater and then exposed to the atmosphere.

Final sedimentation stage

When the water reaches this stage, it contains many suspended substances such as bacteria, and this stage is an integral part of the treatment process. Turbidity and pollutants in the water are removed, and wastewater is treated in this step based on a modern water supply system, as this system helps slow the flow of water, which leads to water purification and the deposition of particles outside the water.

The sediment settles at the bottom to form a substance called sludge due to the accumulation of solid materials extracted from sewage water, and this substance is usually removed periodically.

Types of wastewater

Wastewater is classified according to its source into:

Domestic Wastewater

It is wastewater coming from homes, commercial places such as markets, restaurants, banks, and institutional places such as schools and hospitals.

Industrial Wastewater

It is the wastewater coming from different factories.

Infiltration and Inflow Water

It is the water that infiltrates the sewage networks from groundwater wells through infiltration and leakage through damaged pipes or through pipe connections. In addition to rainwater that enters through manholes and drains.

Storm Water

It is rainwater or water resulting from melting snow that enters sewage networks. Wastewater consists of approximately 99% of water, and 1% of organic and inorganic materials in the form of dissolved and suspended matter. Where protein, cellulose, lipids, and inorganic substances are present in the form of suspended substances, while alcoholic substances, acidic fats, and amino acids are in the form of dissolved substances.

The pH value of domestic wastewater ranges between 6.7-8. As for the pH of industrial wastewater, it varies according to its chemical components. Reference is made to the diversity of microorganisms present in wastewater between fungi, bacteria, protozoa, viruses, and microalgae.

The impact of sewage water on the environment

Wastewater negatively affects humans and the surrounding environment as follows:

• Wastewater aids in the spread of microbes and pathogens. This negatively affects human health and increases the likelihood of contracting incurable diseases. Where bacteria in wastewater cause many diseases, the most important of which are: enteritis, ulcers of the small intestine, cholera, typhoid, respiratory diseases, fever, and jaundice.
• Viruses in sewage cause intestinal infections, meningitis, paralysis, jaundice, respiratory diseases, and uncommon heart diseases. The primary organisms also cause human diarrhea, amoebiasis, liver epidemics, and other diseases.
• The consumption of oxygen dissolved in water by microbes. It leads to the death of aquatic organisms, the occurrence of mold in the water, and the spread of unpleasant odors.
• An imbalance in biodiversity.
• Cause soil pollution when wastewater leaks and reaches agricultural lands.
• It has become necessary to make use of sewage water for daily uses. Where a wastewater treatment system was created so that it can be reused in factories, agricultural facilities, or others. The water treatment system goes through a number of stages to ensure obtaining pure water free of all impurities. From the initial treatment to the final sedimentation stage.

Ensure the quality and quality of the water produced from the treatment of sewage water

The operator of private sewage treatment plants shall conduct periodic analyzes and checks in laboratories accredited by the Ministry of Water and Electricity. Ensuring the quality and quality of the produced water, and its conformity with the specifications as shown below:

• Bio-oxygen content (BOD5): once a week.
• Chemical oxygen content (COD): once a week.
• Suspended solids (TSS): once a week.
• Total dissolved substances (TDS): once a week.
• Acidity level (pH): once a week.
• Fecal coliform (FC): once a week.
• Intestinal worms eggs: once a week.