‘Smaller toilet tanks could save 10% of water’

India could save millions of litres of water simply by changing the size of the water cistern or tank attached to flush type toilets, according to a technical note submitted to the government by science policy advocacy group Delhi Science Forum (DSF). Most advanced countries have smaller cisterns while India continues with the water guzzling 10 litres cistern for full flush and 6 litres for low flush options. Reducing this to 6 litres for full flush and 3 litres for low flush would reduce water use in toilets by around 40% and total water use in cities by around 8-10%, the group says.

Taking the example of Delhi, calculations done by DSF say that current usage of water for flushing toilets is about 200 litres per household of five persons per day. With about 2 million households - about 70% of the total 2.9 million households - having flush toilets in Delhi as per Census 2011, the total amount of water flushed down the toilet every day is a staggering 400 million litres. All of this water is treated drinkable water.

If the new standard is introduced and a 3-5 year transition time given, Delhi could well save up to nearly 160 million litres of drinking water per day or nearly 59 billion litres per year.

Most of India's big cities are facing a growing drinking water crisis and huge savings in drinking water can be achieved by transiting to the smaller toilet cistern, D Raghunandan of the DSF told TOI.

But, will the lesser amount of water work for flushing? According to the DSF technical note, toilet cistern standards prevalent in many advanced countries, including the US and EU, are much lower and work perfectly.

"The current European Commission (EC) maximum permissible full flush volume is 6 litres per flush. In fact, the EC's EcoLabel voluntary guidelines for certified eco-efficient goods seeks to further lower it to 4 litres per flush," Raghunandan said.

"In the US, all major manufacturers make toilet cisterns of 6 litres per flush capacity and this has been codified in a 1998 rule by the Department of Energy based on the industry standards published by the American Society of Mechanical Engineers (ASME)," he added.

In its petition sent to Birender Singh, the Union minister for drinking water and sanitation, and the PMO, DSF has urged that the relevant Indian Standard (IS:774 of 2004 amended in 2006) should be amended and new water saving standards be adopted to bring India in line with global best practices. It says that a lead time of 3-5 years may be given to "make it mandatory that all WC cistern and flush systems sold anywhere in India should conform to the new standard".

It also urges that the ministries of industry, urban development, water resources and environment may be involved, as also the Bureau of Energy Efficiency and the Niti Ayog.

DSF has also sent the petition to the Lt Governor and Chief Minister of Delhi as the current AAP government is trying to bring about more efficient and equitable distribution of water in Delhi.

http://ift.tt/1neOADT Science Forum,American Society of Mechanical Engineers

Stay updated on the go with Times of India News App. Click here to download it for your device.