The membrane ultra-filtration process not only provides an effective filtering action, thus preventing the entrainment of biomass and colloidal particles in the effluent but also operates at high sludge concentrations with accurate sludge age control. In traditional technologies, where sludge-water separation is performed by a static settler, the efficiency of the purification process depends on the settling speed of the sludge flocs, on which the concentration of solids in the oxidation tank depends (a key parameter for successful treatment). In membrane processes, sludge-water separation is ensured by a semi-permeable membrane. Consequently, the settling capacity of the suspended solids does not affect the plant’s capacity in any way.  Basically, the membrane bioreactor allows the system to be operated with operating parameters that are significantly different from those of traditional activated sludge technologies. The possibility of separating the sludge with a physical system such as membranes allows a very high sludge concentration (8÷10 g/l) to be maintained in the bioreactor without compromising the capacity of the filtration system.


By using the application of membranes to biological plants, we exploit all the advantages of the biological process. The process itself has significant advantages, which you can find listed here:

Rating: 5 out of 5.

Reduced sensitivity to changes in the feed: the efficiency of ultrafiltration membranes is not dependent on the settling of the biological flocs; the sludge is retained even if the bioreactor undergoes the entry of a toxic substance or a sudden increase in organic or hydraulic load or even a pH shock. 

Rating: 5 out of 5.

Another benefit of using ultrafiltration membranes is the possibility of maintaining biomass concentrations in circulation that are significantly higher than those characteristic of traditional technologies.

Rating: 5 out of 5.

Improved effluent quality: the ultrafiltration membranes guarantee absolute separation of suspended solids, preventing the entrainment of biological sludge responsible for high COD and suspended solids values in the effluent and thus allowing subsequent treatment stages normally sensitive to suspended solids (such as reverse osmosis or, as in the present case, tertiary ozonation).

Rating: 5 out of 5.

Ease of management: the high technological level expressed by the system makes it easy to manage.

Rating: 5 out of 5.

Accurate control of the average age of the biological sludge: since virtually no solids pass through the membranes and since the sludge purge is strictly regulated, the age of the sludge can be precisely controlled, thus guaranteeing the management parameters chosen by the operators.

Rating: 5 out of 5.

Reduced sludge production: as a consequence of being able to maintain a significantly higher sludge age than traditional plants, sludge production is reduced (resulting in lower dewatering and sludge disposal costs).

Rating: 5 out of 5.

Extremely reduced overall dimensions: the possibility of developing the bioreactor in height (MBR) and the absence of the final clarification basin allow for a high space saving compared to other traditional solutions (with the same abated polluting load).

Here below some of works

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The intervention involved the construction of an ultrafiltration section, with hollow fiber membranes, for the optimization and implementation of the performance of the existing biological activated sludge purification system, in addition to the replacement of the sedimentation unit of the first biological oxidation stage.

Waste sector

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Sede legale: Via Enrico Fermi 32 – 24020 Scanzorosciate (BG)

Sede operativa, magazzino e officina: Via A. Moro 1 – 24020 Scanzorosciate (BG)

Cap. Soc. € 500.000,00 i.v.

R.I. BG, Cod. Fisc. e P.I. 02887960165

Cod. Univoco SUBM70N

REA 331280

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