M Rantalankila, H Koivistoinen, L Sarvasidze… – Separation and Purification …, 2016
Deep ultraviolet light emitting diodes (LED) were studied in water disinfection using Asterionellopsis glacialis as a model microorganism. Ultraviolet treatment reactors were constructed and LEDs with peak emission wavelengths 256, 262, 268, 274 and 278 nm and combinations 256+262, 262+268, 268+274 and 274+278 were investigated. The photosynthetic activity of the algae was measured using PAM fluorometry and flow cytometry. Dose-based efficiency evaluation with PAM fluorometry did not present any significant distinction between different wavelength LEDs, best performance being with 256+262 combination (0.0017 cm2/mJ). Best performance using flow cytometry analysis was observed with 256 nm LEDs. Best time-based performance with PAM fluorometry was observed using 274 and 278 nm LEDs with inactivation constants of 0.0715 and 0.0680 1/min respectively. The combination 274+278 nm performed best according to flow cytometry analysis with inactivation rate constant of 0.1296 1/min. The dose-based efficiency of lower wavelength LEDs can be significantly compensated with higher output power, lower energy consumption and longer lifetime of LEDs with higher wavelengths.
… Input electrical power was calculated from input voltage and current. Ultraviolet irradiance was monitored from using a spectroradiometer (Stellarnet Black Comet) with a cosine receptor (Stellarnet CR2). A batch type reactor was constructed for the experiments (Fig. …
