Went to a workshop on water related issues last Sunday, 06 Dec at SJR Redwoods, Bangalore. Did expect the session to be informative, but was pretty sure the topic would be dull and might even border on boring. Must admit that ApartmentAdda and Rain Water Club did a splendid job of putting together an interesting and fun seminar. Those were the best utilized four hours in recent times for me. Here is a snapshot of my take-aways from the workshop. For a much more detailed account, please go here.
We started off with a handful of facts by Narahari from BWSSB. The key takeaways for me from this session were these
- Primary source for water for BWSSB is Cauvery
- Cauvery can support BWSSB’s expansion plans till 2012 only, beyond which there simply is no water available
- Currently BWSSB caters to around 60% of the city’s demand of 1500 MLD, the rest being groundwater (via borewell, tanker)
- Groundwater levels of Bangalore are fast depleting
All that basically underlined one fact that if we the residents of this city didn’t act – and act fast – it’ll be chaos in around 5 to 6 years from now. Most apartment complexes are already realising this, with water bill running to huge amounts.
Once we were all scared, the initialization part was over 
. Then came the solution part where BIOME (the commercial wing of RWC) presented us with the importance of doing Rain Water Harvesting (RWH) and various methods to do recharge or reuse. Some of the points presented were
- If you go verrrrry deep, you can be sure to hit lava but not necessarily water
- Water tables are replenished over several years and if we exploit at rates higher than replenishment, the 1200 ft borewell is not going to help
- One way to help the underground shallow and deep water tables is by recharging it with rain water
- For Bangalore, the wells for recharge purpose should be around 20 ft deep
- Bangalore receives 3000 MLD rain (on average) for 59 days in an year. If we take BWSSB’s estimate of 1500 MLD demand that the city has, the rainfall is enough to cater to 4 months of city’s demand (theoretical math, but indicative)
The way I look at this, it is not a doomsday message. It is a very positive message on how pretty simple things and reasonable investments can ensure us water safety for some more time to come.
Probably if all of us do RWH the chaos date will get pushed from 2015 to 2025, but it alone can’t do miracles and be an eternal solution. The most important thing is awareness about water being a limited resource (in its potable, piped form) and to use it judiciously and reuse to the extent possible. Sewage treatment related awareness was discussed in this light. Mr. Ranganathan did not mince words while pointing out state of the city in this regard. Below are some of the things discussed.
- Sewage Treatment Plant (STP) in most apartments and layouts are not operational
- STPs are expected to discharge water good enough for reuse, with acceptable COD/BOD
- With a dual-piping system we should be able to use this for tasks like cleaning cars, flushing, gardening
- Reuse this way can cut your water demand to almost half
- Purification methods like RO/Softening are over-hyped and not necessary in most cases
- RO systems (especially small domestic ones) have a very high water wastage rate
The reassuring part was that certain apartments and layouts have implemented RWH and STP systems very effectively and has seen measurable improvement in their water levels. This was something that inspired the rest of us to implement/enhance our RWH/STP systems.
The inevitable question of ROI did come up. Apparently the ROI will be between 3 to 8 years depending on your alternative options for water. The punch-line of the day came because of this discussion though… that in case of water we should be worried more about “Return on Lack of Investment” where sewage gets into your drinking water in the absence of proper STP investment
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