Sludge dewatering at the Trillo nuclear power plant

The Trillo Nuclear Power Plant has a water pretreatment facility to ensure the quality of the process water. This pretreatment consists of a physicochemical process and a primary settling operation, which was recently upgraded owing to constraints in current legislation governing discharge and also due to planned enhancements for the operation of systems at the power plant. AEMA took up the challenge of carrying out the planned modifications and implementing a sludge treatment line.
The facility is made up of 2 independent sludge dewatering lines with 2 automatic filter presses (Diemme GHS 1000, figure 1). The sludge from the thickener is sent to the filter presses by 2 pumping systems, one per line, comprising 2 (1+1 standby) Mono helical pumps (model C17DC10RM) and their corresponding frequency inverters (Siemens SINAMICS G120), which regulate the treatment flow in accordance with the pressure inside the filter press.

Mechanical sludge dewatering takes place in the filter presses as a result of the pressure and operating flows of these units, as well as the use of polyelectrolyte, which favours the drying process. Solid-liquid separation takes place in the filter presses in such a way that the water taken from the sludge is sent to the pretreatment plant, while the dewatered sludge, in the form of cakes, is collected in containers. This sludge is classed as non-hazardous waste and its subsequent management is carried out by duly authorised companies.

Article published in: FuturENVIRO September 2014