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

S::Select® - drastically improves sludge settleability

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, thus increasing the removal performance. This holds true especially 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 (30%). To make matters worse, the system did suffer form bulking sludge (ISV up to 800 ml/g) for decades - particularly in the winter months from December to May. 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 improved significantly (suspended solids 3-5 mg/l, visibility >=2,0 m).

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). Structuring agents, MIMICS®, on which the biomass settles, may be additionally 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:

The activated sludge settles much faster (guaranteed >3 m/h). Corresponding to this, volumes of the biological reactor basins and settling tanks can be set much smaller. It is further possible to operate the plant at a higher sludge concentration. At the same time, the specific sludge activity is also increased significantly (see S-Biology®).
In addition to the nitrification capacity, the denitrification capacity also increases to a large extent. This results in a strong recovery of alkalinity, a stable flocculant structure, a low suspensa concentration and a very good visibility depth.
Filamentous organisms are part of the floc. 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 provides a significant filtering effect and ensures extremely low suspensa 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 effluent values
• improvement of the sludge thickening with simultaneous reduction of the polymer consumption
• Higher solids concentrations in dewatered sludge
• Higher levels of digestion
• Less sludge for disposal
• easily integrated into any existing plant (without construction)
• realization within a few weeks
• easily combined with Deammonification process EssDe®
• extremely economical
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