Affluent water comes through a stainless steel separator in which rough and floating impurities are separated, and then washed with treated water. Rakes are dewatered by pressing, and removed to a large-capacity container. In the area itself mineral impurities (sand and fine grit) are separated, and then removed to the sand container.
The complete unit - washing, aeration and transport of separated portion - is controlled by processor unit.
Redundancy (for the event of drop-out) is provided with a stainless drum filter, which stays during normal conditions in stand-by mode.
Next, water flows into multistage (3 or 4 stages) aerobic selector of which task is to suppress the growth of fibre-form bacteria which can cause the washing out of the part of activated sludge (so called biological foaming in secondary settling tanks of waste water treatment plants).
Waste water coming into the selector is mixed with aerobically "regenerated" sludge that is pumped from the bottom of the secondary settling tank by means of controlled pump. The following aerobic regeneration improves physiological properties of activated sludge to be in good condition for further treatment process.
Then, the mixture of waste water and treatment culture flows into the denitrification area, where in anoxic environment (i.e. the environment in which the only source of oxygen is the oxygen contained in nitrates) and along with sufficient proportion of biologically easily decomposable pollution the biological denitrification is performed. The whole denitrification area is stirred, and in case the temperature falls under 10oC it is equipped with aeration diffusers.