õhutamispaak

õhutamispaak, also known as an aeration tank, is a crucial component in wastewater treatment processes. Its primary function is to provide oxygen to the microorganisms that break down organic pollutants in the wastewater. This biological treatment process, often referred to as activated sludge, relies on aerobic bacteria, which require a constant supply of oxygen to survive and effectively consume waste.

The aeration tank is typically a large basin, either covered or open, where air is introduced either by mechanical aerators (such as surface aerators or aspirators) or by diffused air systems (which use blowers to force air through diffusers at the bottom of the tank). The mechanical action of surface aerators also helps to mix the wastewater, ensuring uniform distribution of oxygen and microorganisms. The diffusers create fine bubbles that rise through the wastewater, providing a large surface area for oxygen transfer from the air into the liquid.

Within the tank, a mixed liquor, consisting of wastewater and active microbial biomass (sludge), is circulated. As air is supplied, the microorganisms metabolize dissolved and suspended organic matter, converting it into carbon dioxide, water, and new cell mass. The residence time in the aeration tank is carefully controlled to allow sufficient time for this biological degradation to occur. The efficiency of the õhutamispaak directly impacts the quality of the treated effluent, aiming to significantly reduce the biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the wastewater before it moves to the next stage of treatment, typically clarification.