The experimental work was conducted in three phases; RAF 265 characterisation of system, chemical yield measurements and system performance investigation using natural water samples. Prior to the commencement of the experimental work, a frequency sweep was performed in the range 0–20 kHz with the aim of finding the resonant frequency of the transducers for the applied waveforms. The resonance frequency was found to be approximately 17.8 kHz with small variations for different waveforms. Thereafter, the resonance frequency was applied and thorough electrical and calorimetric power measurements were conducted.
The performance of the large-scale ultrasonic system in removing contaminants from natural water samples was also tested. The contaminants that were targeted in Silurian Period work were DOC and total coliform. Two sets of calorimetric power were applied in natural water treatment experiments; 19 and 58 W. The system was operated for 15 min during which samples were taken after each 5 min. All the treatments were conducted in triplicate.