Ecology, Environment and Conservation Paper

DISINFECTION OF DRINKING WATER USING UV-LED

P. Niroopa and S. Kanmani

Abstract

This paper describes about the disinfection of drinking water using Ultraviolet Light Emitting Diodes (UV LED). The rain water harvesting structures or village ponds (i.e. Ooranies) are one of the traditional sources to cover the drinking water demand in rural communities in the State of Tamil Nadu in India. Since, these ponds are not protected properly, the water in the ponds are found to have high turbidity (8-75 NTU) and bacterial count (100 to 5000 CFU/mL). After the conventional filtration, turbidity (1-5 NTU) and bacterial count (10-100 CFU/mL) are not meeting the drinking water quality standards. Hence, the disinfection of filtered water becomes necessary to provide safe drinking water to rural communities. The conventional methods used for disinfecting drinking water have got some disadvantages. Hence, UV LED technology is widely promoted for water disinfection. Rural communities are well equipped with hand pump for discharging water. In this research study, the existing Mark II hand pump was modified for the Zero Energy Technology development using UV LED(254 nm). The water sample was collected in Pattikadu pond in Tamil Nadu in India for disinfection. Mark II is a hydraulic pressure hand pump used to generate electricity, which is stored in a 6V rechargeable battery to supply power for the UV LED lamp. (The UV LED(254 nm) reactors was fabricated to fix the UV LEDs. The efficiency of the reactor was found with total coliform removal UV LEDs (254nm) were efficient in Total coliform destruction. Almost, complete bacterial reductions were achieved in 95 seconds in all experiments conducted for the flow rate 300mL/min. It has been found that the increase in exposure time increases the removal of total coliform. Generation of electricity from the hand pump mechanical setup was found to be 6-7 volts with number of strokes 50-80 per minute. This research study is complying with the drinking water quality standards. Thus Zero Energy Technology is made applicable for rural decentralized Village ponds in the state of Tamil Nadu, India.