The FLOTAMET™ process consists of a mixed anaerobic reactor, GWE’s ANAMIX™, followed by a sludge flotation stage using biogas, GWE’s SUPERFLOT™ – BIOGAS. Anaerobic sludge separation via flotation works particularly well in applications with high suspended solids (TSS) and/or fats, oils and grease (FOG) concentrations or with salt-rich wastewaters. It is suited for wastewaters with COD values up to 100,000 mg/l and even higher, and can handle single waste streams or a combination of several.
In the ANAMIX™ reactor portion of the FLOTAMET™, the actual anaerobic treatment takes place. This is a completely mixed reactor, equipped with an agitation system to prevent sludge settling or flotation. Dissolved and suspended organic matter is largely degraded by anaerobic bacteria (sludge), and converted into biogas. As it is an anaerobic process, very little sludge growth takes place during this process, ensuring a minimal amount of waste sludge to manage.
The effluent from the digester flows via an effluent collection tank to a special GWE’s Dissolved Biogas Flotation cell, called the SUPERFLOT™ – BIOGAS unit. In the SUPERFLOT™ – BIOGAS unit, the anaerobic biomass that escapes the anaerobic reactor with the treated effluent, are separated from the treated wastewater by flotation and returned to the digester. Because the anaerobic biomass is returned to the reactor, the sludge retention time is increased, and the overall mass of microorganisms available to perform the treatment can be enhanced.
Consequently, the size of the anaerobic treatment system can be reduced significantly. The higher biomass concentration also imparts added resiliency to the process and resistance to shock loads or abnormal operating conditions. From time to time some excess sludge is removed and disposed of, as needed.
The operating principle of the SUPERFLOT™ – BIOGAS dissolved biogas flotation (DBF) unit is similar to a Dissolved Air Flotation (DAF) system, but it utilizes biogas instead of air, for flotation. In comparison to a DAF, the DBF unit provides the advantages of a sealed, odor-free separation system and ensures no impact from the dissolved air, as could be possible with a DAF, on the anaerobic process.
After injection of the recycle flow in the SUPERFLOT™ – BIOGAS unit, the sudden pressure release results in the formation of fine biogas bubbles, which float to the surface, dragging the sludge flocs with them and separating the sludge from the anaerobic effluent.
Since biogas is used instead of air, the system has a completely enclosed design, preventing odors and ensuring optimal performance. Transparent roof elements are employed for monitoring of the operation of the flotation unit. The SUPERFLOT™ – BIOGAS can also be supplied with a bottom auger for sediment removal, in applications with large amounts of heavy, settleable solids that accumulate within the flotation unit.
Industries and applications: as a treatment of wastewater from various sectors, such as dairy processing, chocolate production, confectionery, distilleries, palm oil production, pet food production and a wide range of food processing applications.