A large treatment plant in south-eastern Poland was fundamentally redesigned. Two ultrasonic GSD reactors from VTA are now in use in the new sludge line – with an impressive impact and yet still highly cost effective.
Ruled over the centuries by Poles, Ukrainians, Russians and Austrians, the city of Chelm near Lublin not only has an eventful history, but also has a claim to fame in wastewater circles: with a capacity of around 125,000 PE, the local treatment plant was the biggest in Poland without a digestion system. In 2013, a decision was taken to modernise the plant from the ground up. It was to be equipped not only with a digestion system, but also with a sewage sludge disintegration system. In the city’s international tender, the VTA approach proved best and won the day.
The patented VTA GSD disintegration technology from VTA uses ultrasonic pre-treatment of the excess sludge to break down the organic mass in the digestion more quickly, ultimately leading to better digestion. That means a higher gas yield, less sludge production and better conditions for dewatering.
This state-of-the-art technology, the best available today, makes it possible to reduce the size of digesters to a minimum during planning of the treatment plant, which saves on enormous construction costs and therefore also on operating costs. This applied equally to the Chelm treatment plant, where the VTA GSD system started operation in 2015. It consists of two reactors with a total of 22 ultrasonic transducers. The size of the plant makes it possible to treat up to 100% of the excess sludge produced.
DEWATERING ‘EXORBITANTLY GOOD’
Conclusion after around a year of operation: there are no comparative figures, as Chelm had no digestion before the conversion. ‘What can be said is that the rate of dewatering of a centrifuge with an annual average of 30 percent is exorbitantly good, and with a consumption of flocculant of only seven to eight grams per kilogram of dry residue’, says graduate engineer Dr Bernhard Eder, Head of Research and Development at VTA Technologie.
During the startup phase, several sludge samples were taken before and after VTA ultrasound disintegration and compared both visually and analytically. In visually terms alone, the difference is remarkable. This degree of viscosity and cell disruption in particular can only be achieved in this form with ultrasonic treatment.
Field report from the VTA Group’s scientific journal “Laubfrosch”, issue 73