The 90,000 PE plant in the city of Târgu Mureș is – as previously reported in Laubfrosch – the first Romanian treatment plant with sludge disintegration. It was supplied by the Spanish company Passavant España S. A., which as general supplier was commissioned with the machine technology for the entire treatment plant. VTA Technologie GmbH had previously worked very successfully with this company in Spain (Banyoles) and succeeded in winning over the decision-makers in Romania with the best price-performance ratio. After various construction delays, the VTA GSD 18 was finally put into operation in June 2015 and has been running smoothly ever since. After almost one and a half years, the first operating results can now be presented: the organic degree of degradation was increased from the previous value of 42% to over 50%. This also produces an increase in the gas yield of about 20%. As a further consequence, the lower organic content in the digested sludge leads to an improvement in dewatering (1 to 2 percentage points) and ultimately ensures that there is approx. 10-12% less sludge for disposal.
Cost effective at all times
Disintegration means that the energy potential of the sludge is better exploited. Under these conditions, a VTA disintegration plant can always be used cost effectively. Because of the increased production of gas, more electricity is generated than is needed by the unit itself. More stable digestion results in less work for plant staff, and in terms of sludge disposal, there are savings both from improved sludge degradation in the digestion system and from the better rate of dewatering.
The disintegration plant with ultrasound (GSD) developed and patented by VTA Technologie GmbH is mainly used for the treatment of thickened sludge (excess or raw sludge) immediately before it is pumped into the digestion system. The goal is to optimise the digestion process, as the potential of the existing sludge is exploited more effectively in the digestion system by pre-treatment with ultrasound. In most cases, it is sufficient to treat a partial stream of the sludge in order to optimise the biological, enzymatic digestion process.
In addition, the VTA ultrasonic disintegration system also helps with problems with foam in the treatment plant. Filamentous microorganisms cause problems in the ecosystem, in the secondary clarifier and in the digester. With the VTA GSD system, these filamentous organisms are fragmented, as a result of which the problem with foam is resolved and these facultative anaerobic bacteria can be broken down in the digestion system.
Depending on the objective, an individually adapted VTA GSD system is developed and integrated into the existing process step without major structural work.
Praxisbericht aus dem Wissensmagazin der VTA Gruppe „Der Laubfrosch“, Ausgabe 74