PUNE: World over, efforts are being made to use technology to improve water efficiency with minimum compromise on performance. Considering the urban water crisis in India, the Centre for Science and Environment (CSE), New Delhi, has developed a ‘Roadmap for rating system for water efficient fixtures: A way to sustainable water management in India’.
Water-using fixtures in a building include cisterns and commodes, faucets, showerheads, urinals, etc, apart from other appliances like washing machines and dishwashers. The Maharashtra state government has appealed to the builders and developers associations across the state to opt for water saving measures wherever possible.
According to the draft civic budget presented by municipal commissioner Mahesh Pathak, the PMC expects about 4,000 building permission proposals this year, which will fetch a revenue of Rs 699 crore to the civic body. Last year, the building permission department had sanctioned 1,872 proposals by November 2012 and generated Rs 384.54 crore revenue.
“Every single drop of water matters. A woman in Marathwada or even parts of western Maharashtra has to walk miles to get a pail of water. Consider this on the backdrop of the water used for flushing the toilets in urban areas. Every small step to save water is going to help all of us in the long term,” said activist Sampatrao Pawar, working in the drought-affected areas of western Maharashtra.
“Developing and promoting water efficient technology for fixtures would lead to reduction in water use across all types of buildings. In addition, installing water efficient fixtures, setting standards for performance and measuring water efficiency according to these standards would provide credibility and widen its adoption across the building sector,” states the CSE roadmap. It adds that with labelling and rating of water efficient fixtures, consumers can identify products that are more water efficient without compromising on performance and the manufactures can benefit in the marketplace by offering rated water efficient fixtures that perform equally or better than available models using more water.
“Excess use of water in Pune is a cause for concern. I have directed the municipal corporation to take every possible step to save water. The rural areas of the district should not suffer because of the city’s excess use of water,” deputy chief minister Ajit Pawar said recently.
“The Pune Municipal Corporation should initiate steps and make it mandatory to opt for water saving steps in new constructions,” Congress leader Aba Bagul said, adding that the party has suggested a slew of measures in the new development plan to make new constructions water efficient.
The CSE has suggested several specifications and improvements in the fixtures normally used in toilets and kitchens (see box).
* Dual-flush toilets: A significant way to save water in buildings is to replace single-flush toilets with dual flush toilets. The standard dual-flush toilets use six litres of water on full and three litres on a half-flush. A 4.5/3 litres dual-flush toilet is available in select models
* Interruptible flush cistern: The flushing action can be interrupted at will. The discharge begins once the button is pressed and a second press interrupts it, so using just the amount of water necessary
* High-efficiency toilets: High-efficiency toilets go beyond the standard six litres and use 4.8 litres of water per flush
* Waterless toilets or composting or ecosan toilets: Although not very common for commercial buildings, urine-separating toilets separate the waste at the source and reduce the nutrient load by composting
* Pressure-assist toilets: These toilets use either water line pressure or a device in the tank to create additional force from air pressure to flush the toilet. The water used for a single flush varies from 4.1 to 4.5 litres per flush
* Power-assist toilets: These toilets operate by using a pump to force water down at a higher velocity than gravity toilets. They require a 120V power source to operate a small fractional horsepower pump. Typical flush volumes are between 3.78 and 4.9 litres per flush and dual-flush models are also available
* Low water use urinals: In some of the standard systems, water is applied automatically through a continuous drip-feeding system or by automated flushing at a set frequency, 24×7, regardless of whether or not the urinal has been used. Water consumption varies with the system model at an average of 4 litres per flush. Water-efficient urinals use 2.8 litres per flush and in recent times smart flush systems using 0.8 litres per flush have also been launched
* Sensor operated: Urinals detect the presence of people through movement sensors or door switches (combined with an electronic delay to stop flushing for a set period after flushing)
* Waterless urinals: There are various technologies available for waterless urinals. In oil barrier technology, the urinals operate through the use of an oil wall between the urine and the atmosphere, preventing odours from escaping. In another technology, the barrier has been replaced by a seal with a collapsible silicone tube that closes after the fluid has passed through it, to prevent gases from flowing into room. A third system uses biological blocks which include microbial spores and surfactants which can be placed into any urinal, thus eliminating water use. By breaking down the urine into components, build up of sludge and crystals which causes blockages are prevented
* Aerators: Modern taps often have aerators at the top to help save water and reduce splashes. Without an aerator, water flows out of the tap in one big stream. An aerator spreads the water flow into many small droplets. Conventional faucet aerators don’t compensate for changes in inlet pressure, so the greater the water pressure, the more water you use. New technology compensates for pressure and provides the same flow regardless of pressure
* Flow fixtures: Controls the flow and deliver a precise volume of water in faucets, showerheads and hose outlets, typically 5.6 to 8.3 litres per minute, irrespective of line pressure. Aerators add air to the water stream to make the flow feel stronger, while flow controls work by producing dozens of parallel streams of water
* Sensor taps: These are automatic shut-off taps, such as push-button or lever operated taps that shut off automatically after a set time to reduce the potential for taps to be left running too long or not turned off. These taps cut off water supply when the hands are removed from under the tap, or when the preset timing of 30 or 60 seconds is reached, whichever is earlier
* Thermostatically controlled electronic dual-purpose mixing or diverting valves: These valves are used for industrial and commercial applications (hotels, corporate offices, etc.) to automatically provide liquids as required
* Water efficient showerheads: Deliver water at 9 litres per second or less than that. Further, showers can also be fitted with digital read-out meters that show the user the amount of water being consumed and the duration of the shower.
Front loading: In general, front loading washing machines are much more water efficient than top-loading ones.