New Chandrawal water treatment plant to be made operational in September

With water availability in the Yamuna expected to improve during the monsoon, the Delhi Jal Board (DJB) is aiming to fully operationalise its new Chandrawal Water Treatment Plant (WTP) by September, with trial runs likely to begin next month, senior officials said on Sunday

With water availability in the Yamuna expected to improve during the monsoon, the Delhi Jal Board (DJB) is aiming to fully operationalise its new Chandrawal Water Treatment Plant (WTP) by September, with trial runs likely to begin next month, senior officials said on Sunday.

The new 105-million-gallons-per-day (MGD) plant is expected to significantly improve Delhi’s ability to cope with recurring ammonia pollution in the Yamuna, an official said. (HT Archive)

The new 105-million-gallons-per-day (MGD) plant is expected to significantly improve Delhi’s ability to cope with recurring ammonia pollution in the Yamuna – one of the primary reasons behind frequent disruptions in the Capital’s water supply.

It will also replace two of the city’s oldest operational treatment units at Chandrawal, which have been in service since 1935 and 1955 and have suffered repeated breakdowns in recent years.

A senior DJB official said the new facility has been equipped with advanced treatment technologies, including ozonation, granular activated carbon (GAC) filtration and rapid gravity filters, enabling it to treat raw water even when ammonia levels in the Yamuna rise sharply.

“At present, our conventional chlorination-based treatment system can handle ammonia concentrations only up to 1 part per million (ppm). Beyond that, treatment becomes difficult because chlorination can lead to the formation of toxic chloramine compounds, forcing disruptions in water supply. The ozonation-based system at the new plant will be able to treat water with ammonia levels of up to 5 ppm, which covers more than 90% of such pollution episodes,” the official said.

Old unit prone to breakdowns

The existing Chandrawal treatment units have a combined capacity of 90 MGD – 35 MGD from the 1935 plant and 55 MGD from the 1955 unit. The new plant will raise this to 105 MGD while replacing ageing infrastructure spread across nearly 75,000 square metres. It supplies drinking water to large parts of central, north and New Delhi, serving an estimated 2.2 million residents.

The ageing treatment units have witnessed repeated outages over the past year because of equipment failures and maintenance works. The plant underwent scheduled maintenance in July and August last year, while a leakage in the main rising pipeline in November and valve damage in August also disrupted operations.

This year, the plant suffered another leakage in February, followed by one of its longest shutdowns in March. On March 22, operations at Chandrawal WTP-II came to a complete halt after a 600-mm-diameter backwash pipeline near the pump house burst, causing extensive waterlogging inside the premises. The flooding rendered all electrical and mechanical equipment non-operational, bringing pumping activities to a standstill for nine days.

Delhi currently operates nine water treatment plants with a combined production capacity of around 864 MGD. An additional 136 MGD is sourced through groundwater extracted from tubewells and borewells. Despite this, the city faces an estimated demand-supply gap of about 250 MGD, which widens during the summer months.

Officials said the government is planning three additional water treatment plants to bridge the deficit. Another new facility at Dwarka Phase II has already been constructed but remains idle because of the absence of an assured source of raw water. “The Dwarka Phase-II plant is ready, but it cannot be commissioned without additional water allocation through the Munak Canal from Haryana. Tubewells alone cannot sustain its operations,” an official said.