The flotation technology is based on raising the water-contained particles to the surface with the aid of micro-sized air bubbles. Untreated water is fed into a mixing tube where air bubbles force the solid matter particles to rise to the surface. The particles on the surface are collected using a scraper and removed from the basin.

The flotation equipment has a minimal space requirement and can be used to expand the existing clarification basin capacity, without additional space, by means of a so-called hybrid method.

Minimal energy is consumed by this method. Thanks to the use of advanced technology, the floating air bubbles can be generated by significantly less energy compared to conventional methods. The efficient flotation process also helps to minimise the energy required.


Bubbling innovation

Particle flotation uses small, micron-sized air bubbles that are generated by dissolving air in water in a pressurised chamber: the result is a mixture of air and water called dispersion water. As decompression occurs, the dissolved air is released into the water in the form of micro-bubbles. The patented dispersion water production method is based on the dissolving of air in pumps instead of using a conventional compressor plus pressure vessel solution. Pump-based dissolution consumes significantly less energy than the use of compressors. Separate pressure vessel inspections can also be avoided at the same time.

The method includes a patented flotation nozzle that enables the generation of bubbles of various sizes, plus the efficient control of the dispersion water flow. In addition, the nozzle capacity is higher than that of conventional tubular nozzles. The nozzle is non-clogging, due to its automatic cleaning function. Consequently, the flotation system’s maintenance requirement is minimal, thus allowing at least two years’ uninterrupted operation, without major maintenance procedures.

The third patented core element is the mixing tube. The mixing tube confines the micro-bubbles and the solid matter within a restricted space, thus ensuring collisions as the bubbles move upward. This improves the purification result and accelerates the ascent of solid matter to the surface.


Hybrid method – additional capacity without extra space

When the capacity of a clarification basin-based wastewater treatment plant is running out, the flotation method is the easiest and cheapest way to boost the treatment capacity. The flotation method requires no additional surrounding space. Instead, the system can be installed inside the existing basin where it only requires about 10% of the basin volume. The construction costs of a hybrid treatment plant are also in a category of their own: typically, only a third of those required for building a basin extension.

The flotation method used by Biower is based on technology and patents developed by Wiser. For additional information, please visit: www.wiser.fi