The possibility of influencing the growth and metabolism of bacteria by electricity has been known for about 100 years. However, the development of this in practice in order to obtain positive effects on wastewater treatment or sludge stabilization did not occur.
Experiments on a semi-technical scale were formulated and carried out whereby two digesters containing municipal raw sludge were run with detention periods of 15 or 20 days at 33°C. Whilst one digestion process was operated as normal, the other was influenced by electro-impulse condenser discharge.
Clearly positive effects were obtained, especially with regard to increased gas production as well as a reduced content of H2S in the digestion gas.
Considering the necessary investment and running costs, the method seems to be a significant complement to sludge digesters.