Urban News

The Deccan Herald  13.12.2010

Govt comes up with RWH regulations

Bangalore, Dec 12, DHNS:

The Bangalore Water Supply and Sewerage Board (BWSSB) has gazetted the rain water harvesting regulations, giving a clear picture on how to install the RWH system.

As per the regulations, under the roof-based RWH, rainwater has to be harvested for use through a filter into a storage tank or for recharge of an open well.  In case of a borewell in the building, artificial recharge structure or pits have to be installed irrespective of the nature of sub-soil conditions.

Rain water from rooftop such as tiled/slope roof and flat/RCC may be collected using appropriate size of gutters or pipelines respectively and stored either in collection tank storage structure of appropriate size placed over the ground or underground after proper filtering and disinfection.  

Appropriate filter should be used for filtering rain water and should be used for non portable purpose.  In case the water is to be used for portable purpose, the owner/occupier shall follow prescribed standards before using.  Surplus water available after filling the storage tank/sump may be diverted to the open well or borewell through recharge structure or pits.

Land-based RWH will involve appropriate ground water recharge structure or pits depending on the nature of sub-soil conditions. A provision for 20 litres or more capacity per sq mt of the roof area should be adopted. In case of artificial recharge structure to ground water, a provision at the rate of 10 litres or more capacity per sq mt of land surface should be adopted.

In case the rainwater harvested has be to diverted to the open well, it has to  pass through a filter before recharging the well. Appropriate disinfection methods should be practiced before using for artificial recharge of ground water. Contaminated water should not be used as source of water for recharging the open well. In case of storage, rain water harvested should be filtered through proper filter, stored and stabilised in the sedimentation tank before recharging into bore well.  Adequate bypass or safety arrangements should be provided in the system where an expert advice may be obtained before recharging the borewell.

Indian Express  11.12.2010

Net zero buildings: Take no power from municipal grid

With talk much ripe about green buildings, there’s a new dimension that’s now being added — that of net zero buildings. “These are buildings that are sustainable and take no power from the municipal grid,” said Ashish Rakheja, chairman of the Green Building Committee and Technical Committee, Indian Green Building Council, as he took his seat at a national seminar on Green Buildings organised by the Indian Society of Heating Refrigerating and Air Conditioning Engineers (ISHRAE) at CII, Sector 31.

Rakheja spoke about how these can be created by using renewable resources like wind in the coastal areas and solar energy in this part of the country. “With the help of solar panels, we can make a building 100 per cent sustainable. The use of solar heaters in the city is just a step towards this,” he elaborated.

Though considered an expensive option as it takes more than 10 years to recover the installation cost, “it is now getting government backing,” he said. “As for the operational expense, that’s minimal,” he informed, adding that these are gaining popularity across the country. But then there are prerequisites to this kind of a building.

“For starters one needs to reduce the energy requirements of the building,” chipped in architect and International Fenestration Forum president Sheetal, who bagged the LEED platinum awards for green buildings. “This can be done by insulating the building with thick walls and using glass with caution.”

Sheetal recommended the generous use of glass on the north side, glass with a little shade on the south and glass that attracts only indirect sunlight on the east and west surfaces, explaining that the air-conditioning cost can be reduced this way.

She also suggested the use of white colour tiles on the roof, green electrical fittings like LED and T5 lights and occupancy censors, along with the use of autoclaved concrete blocks. “These can reduce the energy requirement from, say about 10 watts per square feet, to about two to three watts,” she said. This way the solar panel’s installation cost also comes down.

Vaneet Nanda of ISHRAE’s Chandigarh Chapter nods in agreement. “The concept of net zero building, though new, is fast catching up. Considered the highest step in green buildings because of the cost involved, it will surely reduces carbon footprints and help shape the future for a sustainable tomorrow,” he concluded.