Flocculation and wastewater treatment – How flocculation is used in wastewater treatment. One of the requirements for treated water leaving wastewater plants is the removal of suspended solids. Small solid particles affect the colour of the water and carry impurities into our natural water sources like rivers and the ocean.Phosphorus content must also be limited in wastewater as a release of phosphorus into rivers promotes algae growth and with uncontrolled releases, it has been known to cause mass die-offs of fish and other aquatic life. Some industrial applications generate high levels of phosphorus in their wastewater, which may even require pre-treatment before releasing it to wastewater treatment plants.
Enduramaaxx offers a wide variety of wastewater holding tanks and equipment. Find out more here.
How does flocculation work?
Flocculation is based on a chemical process involving adding chemicals to the wastewater in sequence and allowing tiny solid particles to collect together in a larger mass called a floc. As a treatment of wastewater, flocculation is carried out in stages.
Suspended solid particles in wastewater are negatively charged. In the first stage of flocculation, a coagulant like aluminium sulphate is added to the wastewater and the positively charged coagulant molecules neutralize the negatively charged solid particles suspended in the water. This paves the way for them to flocculate together into a larger mass.
The wastewater must be agitated with mixers with a high energy mixer required initially to ensure that the coagulant spreads throughout the water. When flocculation is in progress the mixing energy is reduced to prevent the mass of particles from separating.
Once floc is beginning to form, a polymer chemical is added to the wastewater. Polymers bridge the flocculant from micro to macro flocculant making the mass of particles get bigger. This chemical also binds the collected mass together so that it does not easily disintegrate.
After flocculation is complete, the large solid masses can be removed from the wastewater stream through settling where the floc drops to the bottom for removal or through the use of filters. Care must be taken when cleaning the filters to ensure that the phosphorus-rich floc is contained and treated.
Where is flocculation used in wastewater?
Phosphate enters our wastewater systems from human and animal waste, detergents and food residues. Food and Beverage plants are therefore prime sources of phosphate in wastewater and flocculation is a key method for the removal of phosphate.
Enduramaxx wastewater storage tanks
Enduramaxx offers a number of solutions for the wastewater storage to help store pre-treated and treated water and chemicals for this treatment process. Chemical dosing, pH dosing, is a common method of wastewater treatment. Regulations require treated wastewater to be in a neutral pH range when discharged into the environment and our range of dosing tanks and bunds can be used. Dosing systems can be set-up as in-line or in a recirculating configuration using both alkaline or acid dosing to correct for low or high pH respectively.
Disinfection is a process that kills off remaining bacteria in wastewater streams and generally, chlorine-based systems are used to achieve this. This protects workers and the general public from potential health hazards associated with unwanted bacteria in the wastewater system. It is particularly important where water is recycled for use.