aeratietanks

Aeratietanks, or aeration tanks, are basin-shaped vessels used to introduce air into water or wastewater to promote biological oxidation of organic matter by microorganisms. They are a central element of many biological treatment processes, especially the activated sludge system, where influent wastewater is mixed with active biomass and exposed to dissolved oxygen to sustain aerobic degradation of pollutants. In addition to carbon removal, nitrification can occur in these tanks under proper oxygen supply and temperature conditions.

Air is supplied to aeration tanks through either diffused aeration systems or mechanical surface aerators. Diffused systems use fine or coarse bubble diffusers located near the tank floor to maximize oxygen transfer efficiency, while surface aerators rely on impellers or propellers to circulate and mix the liquid. The combination of oxygen transfer and thorough mixing keeps microorganisms in suspension and ensures uniform treatment throughout the tank. Baffles and proper tank geometry help prevent short-circuiting and dead zones.

Typical operation involves maintaining dissolved oxygen in the range of about 2 to 4 mg/L, with hydraulic retention times generally in the order of 4 to 8 hours and mixed liquor suspended solids around 3 to 6 g/L. Energy consumption for aeration is a major operating cost, so plants optimize diffuser configuration, air flow, and control strategies, sometimes employing on/off cycles or DO-based control.

Besides wastewater treatment, aeration tanks are used in fermentation and bioprocessing to supply oxygen for aerobic microbial growth, and in aquaculture to maintain adequate dissolved oxygen in fish culture systems. Construction commonly uses concrete or steel basins, with diffusers, blowers, and piping as key components, and requires regular maintenance to prevent diffuser fouling and ensure efficient oxygen transfer.