Procurement of dewatering screw press

The contracting authority intends to procure a screw press machine operating on the screw press principle, suitable for dewatering digested mixed sewage sludge. A further task is to install it in place of existing belt filter presses in the sludge treatment building of the consolidated technological building, on the roof of the thickened sludge storage, and to establish an interface connection for process control. The sludge dewatering screw press is a mechanical sludge dewatering device that, after polyelectrolyte conditioning, performs sludge dewatering using a slowly rotating screw and a rotating body-shaped stainless steel filter surface surrounding the screw. The filter surface is made of trapezoidal cross-section profiles, with the slots ensuring water drainage widening outwards (wedge wire sieve) or a filter surface with a different structure that is capable of achieving results at least equivalent to a device with a "wedge wire sieve" surface in terms of • filtration capacity, • cake dry matter content, • filtrate concentration, • specific polyelectrolyte consumption, • clogging tendency, • washing water demand. The screw press must be of the same system as the named system and must treat digested municipal sludge. The screw gradually pushes the sludge forward inside the filter. Water squeezed out of the sludge exits through the filter surface, while the solid material gradually thickens and exits at the end of the press in a controlled manner by a counter-pressure cone. The system is enclosed. An integrated washing system ensures periodic cleaning of the filter surface as needed. The screw speed is regulated by automation, typically around 1 revolution per minute. The documents relating to the screw press must include all procurement, equipment, and work necessary for operational capability and compliance with legal regulations, especially environmental regulations, safety, occupational health, and fire protection regulations. Technological target values: • Daily digested sludge quantity to be processed: 168 m3 (130 – 180 m3) • Incoming sludge flow rate: 14 m3/hour • Sludge quality: digested, degassed, • Incoming dry matter content*: average: 2.7 % • Organic content of incoming sludge dry matter (loss on ignition): 70 % (68 – 72 %) • Daily operating time: 12 hours (in one or more shifts) • Water consumption: maximum 1 m3/operating hour, 20 m3/day (including washing requirement after daily shutdown) • Electrical power consumption simultaneously: maximum 10 kW * the dry matter content of the sludge to be dewatered does not exceed 3% in 87% of the samples. The incoming sludge flow rate of 14 m3/h may decrease above 3% dry matter content. The parts of the screw press in contact with sludge, filtrate, and vapors originating from them must be made of materials resistant to these corrosive environmental effects. The steel grade must be 304L (1.4307) or equivalent in terms of resistance to the effects of the given environment. The Contracting Authority informs the Tenderer that any reference to a specific manufacturer, origin, or type of product in the technical description is made to clearly define the subject matter; the Contracting Authority accepts equivalents, provided that the Tenderer proves the equivalence in their offer. Detailed tasks and technical information are included in the Technical Description and Price List.