The purpose of this procedure is to carry out all the works and supplies necessary for the implementation of the intervention called Adaptation works of the inter-municipal plant of Bergamo – Lot 2.

The services covered by the contract concern the adaptation of the Bergamo inter-municipal wastewater treatment plant in order to increase the capacity of the existing plant, so as to guarantee the treatment of 170,000 PE.

The services covered by the contract include:

- The construction of new treatment lines located in the expansion area adjacent to the existing plant and the construction of electromechanical works serving two of the three biological lines planned with a total potential of 80,000 PE.

- The enhancement of the recirculation of the aerated mixture serving the 2 existing biological lines in order to optimize the operation of the existing pre-denitrification section.

The main interventions consist in the implementation of:

• n. 2 derivative artifacts with gravity gravel pickers;

• n.1 cast-in-situ screening building measuring 14m x 11m x 6m in which 2 coarse grids and related grating discharge system and 1 dry scrubber will be installed to serve the building;

• 1 lifting station divided into two chambers in which 3 pumps will be installed and the preparation for the fourth;

• n.1 pre-treatment building to be carried out by means of a prefabricated elevated structure, measuring about 49m x 24m x 8m, in which 3 fine rotating drum grids will be installed, with 2 mm filtration ports with circular holes, n.3 compact sand-de-oiling plants, n. 2 sand classifiers, n. 2 tanks and related Pac dosing system and n. 2 dry scrubbers for the treatment of exhaust air;

• 3 biological treatment lines, each consisting of: an activated sludge tank aerated by plates, measuring about 39m x 15m x 6m, 2 tanks housing the membrane trains measuring about 11m x 3m x 4.5m in which a total of 8 membrane packs will be installed, 1 deoxygenation tank measuring about 11m x 9m x 7m in which 3 aerated mixture recirculation pumps and mixers will be installed mud stirring. Of these lines, only 2 will be electromechanically equipped, while for the third only preparation is planned. An overhead crane will also be built to serve the three MBR lines;

• n.1 technical building measuring approximately 49m x 11m x 7m, containing all the pumps and instrumentation for MBR treatment including lobe pumps for permeate extraction, blowers for membrane aeration, self-priming pumps for emptying membrane trains, mono pumps for removing excess sludge, tanks and reagent dosing system for membrane cleaning operations, service water pressurization unit, compressed air production unit;

• n.1 technical building measuring about 42m x 7m x 5m, containing: the blower room in which 3 turbochargers will be installed for the ventilation of the biological compartment and space will be prepared for a quarter of future installation, new office room, new transformer and QE room;

• 1 electrical substation to be built by means of a prefabricated building for the reception and transformation of the medium voltage line serving the new plant.

• technical water network serving the plant with pressurization unit to be installed in the building serving the MBR;

• rainwater collection network with drainage system and rainwater lifting system from dirty rooms;

• photovoltaic system with panels with an estimated total power of 254 kWp to be installed on the roof of the pre-treatment room and technical-office room;

• external and internal viability of the plant;

• driveway walkway for the overpass of the canal – Colatore Dalcio, connecting to the existing purification plant;

• sludge disposal pipe;

• new purified water discharge pipe to be built by the MBR technical building;

• upgrading of the aerated mixture recirculation plant to be built on the UNOX activated sludge tanks of the existing plant.