S-Select® System – Enhancing the Capacity of Aerobic Facility.

First-ever S-select Technology was invented in Glarnerland, Switzerland for municipal wastewater treatment facilities. The urgent necessity to bond the water effluents from a number of neighboring villages to common municipal wastewater treatment facilities became a prerequisite for a technological innovation in Glarnerland. It was mainly focused on the expansion of waste treatment facility capabilities, the need for new investments and seeking some alternative technologies to enhance the capacity of wastewater treatment facilities. The attempts resulted in the S-select Technology, which did not require the expansion of new aerobic reactors or secondary clarifiers. The fundamental principle of the named technology was the introduction of MIMICS®. The system aggregates two hydraulic cyclones, which separate the MIMICS® and feed it to the biological (aerobic) reactor while the aerobically treated wastewaters are pumped into secondary clarifier for separation into purified water and sludge. In addition, the compressor is installed to amplify aeration system in bioreactor. The system is also equipped with technological pipelines, isolation valves, monitoring and measurement equipment and automatic control system.


Coagulants * flocculants * caustic * industrial effluents * raw wastewater pumping room * mechanical treatment * averaging tank * pumping room * DAF * pumping room * denitrification * nitrification * secondary clarifier * discharge into receiving water * pumping room * unit of hydraulic cyclones * flotation sludge pumping room * excess biomass * sludge collector * filtering press * organic and mineral fertilizer * fields

The scheme of aerobic wastewater treatment facilities using the S-Select Technology.

The invention of this technology allowed the Glarnerland Administration to stop two out of four 24h biological reactors at existing wastewater treatment facilities, to save money for expansion of newly constructed facilities and running two bioreactors earlier put in dead storage, and as the experience of S-Select Technology has shown, to counter finally the negative effect of the filamentous bacteria growth and the sludge swelling that are a common problem of aerobic treatment facilities and significantly affect the capacity of municipal or industrial effluent treatment.

The example of saving policy, Glarnerland

Two running municipal treatment facilities in Glarnerland

Two aerobic reactors put in dead storage and secondary clarifiers upon the implementation of S-Select, indicated with the red rectangle.

S-Select® operating principle

excess sludge * MIMICS® granules * return of granules * sludge recycle * secondary clarifier

Synthetic granules <0.3 mm in size are added to biological reactor and then removed through the cyclone.

Granular Recovery 100%

S-Select® – A Revolution in Wastewater Treatment

Sediment sampling without S-Select on the left; applying S-Select on the right. Measurement time – 0 (launch)

Sediment sampling without S-Select on the left; applying S-Select on the right. Measurement time – 1 minute

Measurement time – 2 minutes * Measurement time – 3 minutes

Sediment precipitation with (cylinder on the right) is much more efficient.

The result is substantial improvement of sediment precipitation without granules

With granules

Sedimentation rate increased from 0.5 m/h to 5 m/h within a month.

It is possible to sustain the sediment concentration rate up to 15 kg/m3 on condition usual secondary clarifiers are used.

Examples of certain treatment facilities brought into operation.