COAGULATION AND FLOCCULATION

Coagulation and flocculation processes are used in drinking water treatment and wastewater treatment. The purpose of these processes is to remove colloids from water by precipitation. The diameter of colloids that can be precipitated by the coagulation-flocculation process varies between 1 micron and 1 millimicron. Most of the suspended agent in water is colloidal. This is the cause of turbidity and color. Colloidal substances carry a negative charge. Therefore, they are coagulated by using the trivalent metal salts such as iron and aluminum. This process takes place by polar attraction.

Chemical coagulation of waters is done for various purposes as follows:

• Elimination of organic and inorganic turbidity
• Decoloration
• Bacteria and pathogen elimination
• Elimination of algae and organisms
• Elimination of odor and flavoring agents
• Phosphate elimination
• Elimination of Biological Oxygen Demand and Chemical Oxygen Demand parameters
• Elimination of suspended solids
• Elimination of metals

FLOCCULATION PROCESS

The flocculation process is a process of mixing the wastewater slowly and properly for a period of time to allow small particles and clots to grow, combine with each other, flocculate and thus form the flocs that can easily participate. These formed flocs are separated from the wastewater by precipitating then at the next precipitation stage. The flocs is coarsened by using the auxiliary coagulants. The most important of these are Polyelectrolytes. In practice, flocculation is a slow mixing process to ensure a floc formation.

The factors, which affect the flocculation process, are as follows:

• Waste water quality
• Amount of suspended solids, colloids and other pollutants in wastewater
• PH value
• Holding time in coagulation and flocculation sections, type of mixing, and characteristics of precipitation section.
• The temperature of the water
• Alkalinity
• Properties of ions in water
• Type and dosage of coagulant

POLYELECTROLYTES:

Polyelectrolytes are divided into two: natural and synthetic. Natural polyelectrolytes are of biological origin and are obtained from starch products or cellulose. Synthetic polyelectrolytes are classified according to their charges and are called Anionic, Cationic and non-ionic according to their negative, positive and neutral status. Polyelectrolytes enlarge the bonds between particles and ensure that large flocs form. Two or more particles attach to the polyelectrolyte bonds and form a bridge. This bridge joins with other bridges formed in the same way. Thus, the flocs become larger and are removed more easily in the precipitation process. Use of the polymers in the chemical wastewater treatment plants has become very important especially in the last 15 years. Polyelectrolyte has a chemical structure consisting of a series of repeating chemical units (manomer units) joined together by the covalent bonds. The positively charged cationic polymers can be used directly as coagulants or as coagulant aids. These types of polyelectrolytes are also used as filtration aids and chemical conditioners in sludge dehydration. The uncharged non-ionic and negatively charged anionic polymers are used in a coagulant aid, filtration aid and sludge conditioning.

WASTEWATER TREATMENT SERVICES

Contact Liberta Kimya for your wastewater requirements. We can provide expert advice and support on maintenance, management and treatment of the commercial and industrial boilers and steam generation systems to help you to optimize the costs and operational efficiencies, reduce the downtime, save water and energy, maintain the steam quality and increase plant reliability. We apply the following processes by taking samples from your wastewater in your plants:

• Sample Jar tests (completed within 5 working days)
• Laboratory Reporting (completed no later within 2 working days after the Jar test results)
• Site Jar Testing (the Jar Test work that we will do together again in the facility with our product/products determined in the survey)
• Site Reporting (completed no later within 2 working days after the on-site Jar test results)
• A Quotation (based on annual consumption amounts and contract conditions)
• Site tests (the site tests with chemicals with their results obtained)