S-Select® solves the problem of bulking sludge and multiplies the capacity of the Biological Reactor

S-Select® - drastically improves sludge settleability for sedimentation in the final clarifiers, even with massive problems due to filaments and bulking sludge

Sedimentation of activated sludge, i.e. settling velocity, is the central parameter for the design and operation of an entire wastewater treatment plant. S-Select® drastically accelerates sedimentation of the activated sludge in the final clarifiers. As a result, the content of biomass in the aeration tanks can be increased enormously, thus multiplying the removal performance of this biological reactor basin. This will hold true even if there are massive problems with bulking sludge.
The nitrification performance is significantly increased while maintaining a high denitrification capacity (ref. Biology). With S-Control®, the removal performance is continuously optimized according to the respective load conditions. The energy requirement is minimized and the optimal sludge retention time (SRT) is maintained permanently.


For example, WWTP Glarnerland:

Instead of expanding, biological reactor basins are being decommissioned.
Additional municipalities are to be connected in the near future, resulting in a projected load increase of 30%. To make matters worse, the system suffered for decades form bulking sludge (ISV up to 800 ml/g) - particularly in the winter months. After S-Select® was successfully implemented; the planned expansion from 4 to 6 process trains was canceled. In addition, 2 of the 4 existing trains were decommissioned. Despite the significant load increase of the remaining process trains (more than doubled), the effluent quality tendencially improved (suspended solids <= 3 mg/l).

S-Select® - the technological breakthrough (Pat. pend.):

By means of S-Control®, the SRT of the biological reactor basins (BRBs) is adjusted to the lowest acceptable level (ensured nitrification). Additionally, structuring agents, MIMICS®, on which the biomass settles, may be introduced to the aeration tanks. The biomass is separated from the MIMICS® via hydrocyclone. The common floccular sludge structure transforms into a granular sludge and the sedimentation properties are being improved drastically. The granular sludge structure is permanently maintained because the SRT is being continuously limited via S-Control®.

S-Select® - the advantages:

Instead of an activated sludge concentration of 2 - 3 kg/m3, the plant can be operated at a significantly increased concentration. The required basin volumes shrink accordingly by a factor of 2 - 3, the savings are enormous.
The removal performance is very good. Due to their large specific surface area, the filamentous organisms provide a high contribution to the overall removal performance. Together with the granules, they form the much-quoted dense sludge bed, which has a significant filtering effect and ensures extremely low suspensor values – all while settling reliably and with very high settling velocity in the final clarifier.

The case for S-Select®:

• doubling / tripling of capacity
• high settling velocity
• excellent sludge volume indices (SVI)
• excellent discharge values
• improvement of the sludge thickening with simultaneous reduction of the polymer consumption
• easily integrated into any existing plant (without construction)
• realization within a few weeks
• easily combined with Deammonification process DEMON®
• extremely economical
DEMON GmbH  |  Rietwiesstrasse 39  |  CH-8737 Gommiswald  |  SWITZERLAND  |  Phone +41 55 290 11 41  |  5iny.fow6@Et'ssn)Des5mog*n.g5cog+mh