AUTOMATION OF DELIVERY DEVICE FOR CHLORINE DIOXIDE DISINFECTION

Although water reuse has been practiced in many countries for centuries, severe water scarcity in many parts of the world has aroused renewed interest. In addition, it is imperative to destroy the dangerous pathogens transmitted by the fecal-oral route by adequately disinfecting wastewater. Though chlorine has been used widely as a disinfectant, its inability to inactivate certain viruses and protozoan parasites and its reaction with certain contaminants to form carcinogenic trihalomethanes has made imperative the search for alternatives. Chlorine dioxide has been found to be an effective USEPA-approved replacement, though it poses safety issues, being explosive at concentrations of 10% (w/w) or more, sensitive to pressure, and somewhat toxic to juvenile fish. Small packets of precursor chemicals are now commercially available to generate small quantities of chlorine dioxide onsite. The aim of this research was to develop an automated delivery device for dispensing this disinfectant in the form of a packet, which would strongly mitigate the safety issues and make the dispenser user-friendly. The automation of the delivery device involved the design of a 30-slot Geneva mechanism to drop the packet into a reaction chamber. This packet-dropping mechanism was designed for use both in a manual mode, requiring no electricity, and an automated mode, powered through electricity. A fully functional prototype was built to demonstrate the automation of a disinfection delivery device. Disinfected water is safe for discharge on open lawns and gardens since the chlorite ion, a byproduct, is present in low concentration. However, wastewater discharge and reuse may be subject to local or state regulations.