Flotation is one of the basic methods of preliminary treatment of industrial wastewater, leading to the separation of
individual wastewater fractions. The final result of the process is a clear liquid and flotation sludge, i.e. a type of
sludge that, after being collected from the surface, can be relatively easily removed and dehydrated on a belt or
screw-plate press. The characteristic scum forming on the surface of the wastewater is the result of proper coagulation
and flocculation. Its purpose is to precipitate insoluble agglomerates of solid particles from the liquid. Thanks to
specialized devices and chemicals, molecules are combined into a light suspension floating upwards. Then the sludge is
separated in the upper layer. Thus, a process, which takes place very slowly in natural conditions, is significantly
accelerated. The wastewater is treated with chemicals in a reactor upstream of the flotation chamber. Chemicals are
usually long-chain polymers that combine with compounds and molecules in wastewater to form agglomerates that are easy
to precipitate and separate from the liquid. When leaving the reactor (a tubular flocculator being part of the flotation
system), the precipitated suspensions want to flow up spontaneously because they are lighter than water. In order to
intensify the process of outflow of suspensions and their concentration to an easily removable sludge, recirculated
purified sewage saturated with air microbubbles is introduced into the reactor. The process of saturating the liquid
with air is achieved using a highly efficient cavitation pump, which is standard equipment of our DAF cell. DAF is an
abbreviation for Dissolved Air Flotation that defines the technology used in this solution. After combining saturated
water and sewage with precipitated pollutants and introducing such a mixture into the flotation chamber, the sludge can
be easily and effectively collected from the upper surface into a separate chamber and further pumped for dewatering.
After treatment with a DAF flotation unit, the wastewater reaches parameters that usually allow it to be discharged into
the sewage system. Sometimes it is a completely clear liquid, colored only with substances that can no longer be
precipitated with the available chemicals. If further treatment of wastewater is required to meet the parameters
discharge permit we have no choice but to design a complete biological wastewater treatment plant equipped with
ancillary equipment. The post-flotation sludge can be further dewatered using our belt or screw presses.
