Understanding Sedimentation Water Treatment
Water treatment is the process of making water ready for human use. While there are several critical aspects, sedimentation water treatment is of particular importance. It is essential to understand the whole water treatment process in order to ensure the process is completed safely and efficiently for the general public.
What Is Sedimentation?
Sedimentation is the process of separating small particles and sediments in water. This process happens naturally when water is still because gravity will pull the heavier sediments down to form a sludge layer. However, this action can be artificially stimulated in the water treatment process. This mechanical assistance is called thickening.
Why Is Sedimentation Used?
The sedimentation process is used to reduce particle concentration in the water. The advantage of sedimentation is that it minimizes the need for coagulation and flocculation. Typically, chemicals are needed for coagulation and flocculation, but improved sedimentation controls the need for additional chemicals. Additionally, sedimentation can be used after coagulation to increase the effectiveness of ongoing filtration in the process.
What Are Technical Aspects of Sedimentation?
Although sedimentation is an accepted process within the water treatment industry, it is still theoretical. The process can be varied depending on the concentration of particles. For example, small concentrations often settle unhindered or without mechanical assistance. As concentrations increase, there are more hindrances to settling and additional support will be needed to aid the process.
Types of Sedimentation Tanks
Sedimentation water treatment requires the use of specialized tanks. A sedimentation tank provides the necessary support to make sure that the particles settle. Sedimentation will happen naturally over time, but water treatment requires a tank to streamline the process.
Horizontal Flow Tank
Horizontal flow tanks are the simplest option. These rectangular tanks allow water to flow horizontally, ensuring that particles are separated from the water during the movement through the tank. This way, the sediment has been collected before the water leaves the far end of the tank. The tank is equipped to clean the sediment out periodically in order to allow the process to continue.
A variation of the horizontal flow tank is the multi-layer tank. The process is still the same in a multi-layer tank. However, multiple decks have been built in the tank. Water is passed from one layer to the next until the sediment is properly separated.
Radial Flow Tank
Radial flow tanks approach this process differently. These tanks are circular, and sediment is moved centrally to be collected and discharged. Radial tanks can be enhanced for flocculation and recirculation in some cases.
Another tool used for sedimentation is a settling tank. A settling tank is inclined to assist with the collection of sediment. Inclined settling tanks can be unhindered, which means they may work without additional mechanical stimulation. Instead, the process is facilitated by the size of the tank, the depth of the water and the placement of the inclined plates at the bottom. The flow of the water can move in multiple directions depending on the sedimentation needs.
Ballasted sedimentation is another option. This is preferred when additional flocculation is needed to help with coagulation. Ballasted sedimentation relies on the application of high molecular weight polymers. These polyelectrolytes are used to increase particle density, which promotes separation. In particular, ballasting agents are used. In most cases, this is a fine sand or Bentonite.
Floc Blanket Sedimentation
Another option is floc blanket sedimentation. These tanks look like inverted pyramids and feature a short vertical section. Floc is circulated in the tank, attracting particles. Eventually, the floc and sediment turn into sludge on the floor. Because of the shape of these tanks, the suspension is moved downward into the pyramid and eventually discharged.
Finally, a Sirofloc® process can also be used. This process is used selectively for waters with little mineral turbidity. In a Sirofloc® process, fine magnetite is prepared with high acidity. This attracts certain particles in the water. As water is passed through a magnetic field, the magnetite particles start to clump together. Then, the water is passed through a radial flow tank to allow the magnetite to be collected. One great thing about a Sirofloc® process is that the collected magnetite can then be recycled for a fresh batch.
How Can Cloud-Based SCADA Help With Sedimentation?
Understanding types of sedimentation and the options for a sedimentation tank is only part of the process. Sedimentation is only one aspect of water treatment. In order to facilitate the overall process, cloud-based SCADA software offers critical tools and data measurement capabilities.
SCADA is a supervisory computer system that continuously collects and analyzes data. SCADA systems that operate in the cloud are faster and more efficient, streamlining plant operations. When SCADA is used to oversee sedimentation, the process can be monitored and controlled via the computer system for real-time changes that enhance the process of water treatment.