HYBACS System
Treatment Stages
First Treatment Stage
The first treatment stage comprises one or several reactors operating in parallel. Each reactor contains a rotating shaft along which plates are mounted perpendicular to the shaft. The plates provide support for the attached biomass. As in conventional rotating biological contactors (RBCs), each part of the biomass is alternatively submerged and then exposed to air. However, whereas lamellae in conventional RBCs are generally constructed from solid plate, those used in the HYBACS’ Process are manufactured in the form of a three-dimensional reticulated structure, having a high voidage for supporting biomass.
The first stage reactors are called SMART units, denoting Shaft Mounted Advanced Reactor Technology.
Concentrations of substrate, nutrients and dissolved oxygen in the biomass vary with depth from the surfaces of the plates. Biochemical reactions are aerobic at the surface but anaerobic at depth. With such biochemical diversity, SMART units remove much of the nitrogen from the wastewater as well as carbonaceous matter. Further, owing to the three-dimensional structure of the plates the treatment capacity per unit volume is considerably higher than found in conventional RBCs.
SMART units consume little electrical energy since the aeration is derived from the rotation of the plates. The aeration efficiency of a SMART unit is 6-8kg O2/KWH, which is 3-4 times more efficient than live bubble aeration. The high aeration efficiency is the main factor contributing to the power savings in the HYBACS process.
Second Treatment Stage
The second stage comprises biological reactors that are aerated using a fine-bubble diffused-air system as in conventional activated sludge processes. However the operating conditions are specific to the HYBACS Process.
