WWEM - Abstract

Abstract Information :

We would like to present our Valmet Sludge Dewatering Optimiser and associated solids measurement technology for use in sludge dewatering centrifuges. rnrnTo describe the Valmet Sludge Dewatering Optimiser (Valmet SDO) optimises the solids content of centrate (minimises)rnand sludge cake (maximises) whilst minimising polymer usage in dewatering centrifuges. Using real-time solidsrnmeasurements, the setpoints for sludge flow, polymer dosing and centrifuge torque can be automatically controlled. Thernsystem uses up to three types of sensor: Valmet TS (total solids); DS (dry solids) and LS (low solids). The Valmet TS is usedrnat the centrifuge inlet, measuring from 0% - 40% DS. The Valmet DS is used at the dewatered sludge outlet, measuringrnfrom 15% - 35% DS. The Valmet LS is used at the centrate outlet, measuring from 0% - 0.5% DS. The TS uses a microwaverntime of flight measurement technique. The DS uses microwave resonance and amplitude signals. The LS is an opticalrnsolution, using two LED light sources at different wavelengths. It has an automatic cleaning mechanism. The Valmet SDOrnis a modular system and can be implemented gradually or immediately as a full solution.rnrnThe use of multivariable controls and reliable measurements to optimise centrifuge operation is arnunique offering in wastewater treatment. The Valmet TS and DS instruments are based on advanced microwaverntechnology. Sampling of the continuous falling dry solids flow, as it leaves the centrifuge, is unique to the Valmet DS. ThernValmet LS solutions has unique automatic chemical cleaning and self-diagnostic features.rnrnBased on several case studies, reductions in chemical and energy use, plus improvements in the DSrncontent of dewatered sludge, savings of €0.70 - €1.00 /PE /year (£0.60 - £0.90 /PE /year) can be realised. The typical timernto ROI is 1 to 1.5 yearsrn