Neuer Zeitschriftenbeitrag von Bardi et al. 2022

Stimulating effect of hydrostatic pressure on ultrasonic sewage sludge treatment for COD solubilization and methane production

The performance of ultrasonic treatment was assessed under different hydrostatic pressures for two different waste activated sludges. The impact of pressurized sonication was evaluated based on the degree of disintegration (DDCOD) and the specific methane yield (SMY). An enhancement of DDCOD was observed at an intermediate pressure level (max. 53% at 1.0 bar), but at higher pressure levels (up to 3.5 bar), the enhancement was not as pronounced as for the intermediate ranges (max. 11%). In contrast to DDCOD, SMY increased with increasing pressure for both sludge samples tested (max 17% at 3.5 bar) so that SMY did not show a notable correlation with DDCOD. A positive energy balance (max. 167%) considering the energy input for ultrasonication and the additional methane generated was only achieved in samples treated under elevated hydrostatic pressure. Since this can be achieved with negligible effort, the enhancement can be considered as “methane for free”. 

Bardi et al. 2022