In biological treatments, the organic substances present in the effluent are biodegraded and partly converted into biomass, which comes out of the system as excess biological sludge.

This bio-degradation is possible thanks to specific micro-organisms that can colonize themselves in suspension flocs (suspended biomass treatments) or can adhere to a mobile or fixed support, generating a biofilm (attached growth treatments).

A suitably selected and sized biological treatment allows you to remove the biodegradable organic substance from the effluent and reduce the related polluting parameters, firstly COD (Chemical oxygen demand) and BOD5 (Biological oxygen demand in 5 days).

In wastewater with high nitrogen concentration (in tannery or slaughterhouses, for example), it is possible to develop specific biomass also for nitrogen removal: through a combined process of nitrification / denitrification, it is possible to convert nitrogen into nitrates and therefore nitrates in gaseous nitrogen, which being an inert gas can be released into the atmosphere.

The most common biological treatments are the aerobic ones, where microorganisms need oxygen for their activity. To aerate the biological systems, Italprogetti has developed two types of submerged air diffusers, which are installed directly on the bottom of the reactors through a network of pipes.

Thanks to decades of experience in the water treatment field, Italprogetti is able to offer to its customers various aerobic biological treatment technologies.