Instant quality check of rivers

Electronic sensors to monitor pollutants in Yamuna, Ganga

Published on:

14 May 2011, 6:12 am

IN THE first week of April, the Central Pollution Control Board (CPCB) oversaw an experiment to monitor, minute to minute, the water quality of the river Yamuna. The two-week trial at the water intake point of the Wazirabad water treatment plant in north-east Delhi was conducted by a private firm to ascertain the feasibility of monitoring water quality real time.

Talk of installing an online water quality monitoring system began in earnest after the Delhi government complained to environment minister Jairam Ramesh about spikes in pollutants in the Yamuna because upstream state Haryana has not adopted pollution abatement measures. The spikes leave Delhi Jal Board with no choice but to cut supply to consumers. The two-week monitoring, however, did not show any sudden increase in pollutants.

Online alerts and trend analysis

Constant monitoring can help keep track of pollution episodes and detect clandestine discharge of untreated waste, says CPCB. It will provide instant alerts as well as trend analyses.

TECHNOLOGY IN USE

	Ion selective electrodes: These have probes that measure specific ions and gases in a solution. Ions that can be measured include flouride, bromide, cadmium and gases such as ammonia, CO₂ and nitrogen oxide Photometric sensors: Water passes through a light beam emitted by a lamp, and the probe measures the weakening of the beam caused by the substances in the liquid. After contact with the medium, the beam’s intensity is measured by a detector over a range of wavelengths specific to the application