Steps of Water Treatment

The water treatment process is carried out in various industries including the food industry in order to obtain clean and pure water for use. Waste is removed from the water. The process involves several stages including adding flocculants and coagulants PAC chemical to the water to purify it. The aim of this process is to provide the food industry with clean water that they can use in their operations. The treatment is also used in other industries such as pharmacology, medicine, and chemistry, which use similar treatment methods to remove concentrations of contaminants such as fungi, viruses, algae, bacteria, parasites, and particulate matter from the water.

In the food industry In the food industry, water treatment begins with the pretreatment of the water. The pre-treatment process removes chemicals, biological contaminants, and other materials from the water. It comprises three main stages:

Large materials and debris, such as rubbish and sticks, are removed from the surface in the sieving process. Sieving should be done when collecting water from rivers and lakes. Surface water is more likely to become infected, and pre-treatment for screening may include adding chemicals to the water to control bacterial growth in tanks and pipes. It can also contain a sand filter stage that promotes the deposition of suspended matter at the bottom of the container. Screening, a preconditioning process in which sodium carbonate is added to water with a higher mineral content, a step in which the chemical is incorporated into the water to eliminate calcium carbonate, one of the main constituents of marine life.This stage ensures that hard water, which leaves mineral deposits that can clog the pipes, is modified to achieve the consistency of soft water.

Pre-chlorination

This is the final step in the pre-treatment process, adding chlorine to the water, which may contain natural organic materials in higher concentrations. This step is done to sanitize the water before the next steps begin. Steps of the water treatment process after pre-treatment.  

Coagulation and flocculation

During the coagulation process, positively charged chemicals are enclosed in water in order to neutralize negative charges. These negative charges are generally retained by solids, including dissolved organic materials, clay, and dirt. It is mainly used as a flocculant and has a light yellow or white powdery appearance.It has a faster rate of flocculation and a faster sedimentation process. It is non-corrosive to pipeline equipment and can also remove heavy metal ions. Once the charge is neutralized, larger particles are created with the chemical being added.

After the coagulation process, flocculation occurs. It is a gentle mixing process in which micro-flakes collide and bond together to create suspended particles called flakes that, with additional mixing, continuously increase in size and eventually reach the right strength and size to prepare for the next step.

The sedimentation step takes place as soon as suspended pathogens and substances settle on the bottom of the container. The longer this remains undisturbed, the more solids would fall to the bottom of the water container. The coagulation process makes sedimentation more effective by making the materials heavier and larger, and by causing them to sink quickly. If the water is treated for municipal supply, this step must be carried out continuously in large basins. Sedimentation is a simple and inexpensive step that is required prior to the disinfection and filtration stage.

The next step is filtration to remove the tiny dissolved particles that are still in the water, including bacteria, viruses, chemicals, parasites, and dust particles. Water penetrates physical particles that vary in composition and size. Common materials are charcoal, gravel, and sand. Plants often use slow sand filtration to clear up gastrointestinal disturbances caused by bacteria. This filtration combines chemical, physical and biological processes in one step. On the other hand, fast sand filtration is a physical process. Purification stage, which is mainly used in countries with sufficient resources to treat a larger amount of water.It is an expensive and complex process.