4. Due to continuous sludge sedimentation problems, a device was created and installed whose function is exclusively to create an hydraulic discontinuity between the MBBR tank and the clarifier, which highlights the presence of a hydraulic jump of about 3 meters .
That jump cause turbulence and rising air trapped between the sludge flakes which negatively influence the sedimentation of the corpuscular part.
5. After the degassing phase, the wastewater is sent to the subsequent sedimentation phase carried out by placing a circular clarifier which ensures larger surfaces with better separation efficiency and reduced maintenance. The clarifier is entirely made of stainless- steel.
With the first tranche of works, it was possible to overcome most of the critical issues that had been
highlighted in the preliminary investigation phase:
• the mixing process within the pimary tank has been significantly improved;
• An efficient exchange of oxygen with the wastewater has been ensured thanks to a system of high performance fine bubble air diffusion;
• The sedimentation process has been significantly improved by replacing the old one Lamella clarifier with a radial flow settler and placing between the MBBR tank and the clarifier itself, a degassing tower that acts as an energy sink;
• maintenance works on the dissolved oxygen measuring probe has been reduced to the minimum necessary as it has been protected by a perforated tube which allows contact with the effluents but protects the lens from continuous impacts with the floating carriers;
• precise and punctual control was allowed, and therefore easier management of the process, through the installation of two automated spindle valves.