Rain-water harvesting session-3 in Telugu Govt School

INTRODUCTION-

The session Started off with recap of last two sessions
It was asked if rain-water could be consumed for water. 'Yes' and 'No'.
Water quality was introduced. Various tests for the testing of water quality was introduced- Physical, chemical and bacterial impurities test.

Water quality test-

Physical impurities of water quality, colour and odour. Physical impurities can be removed by Normal filtration. When impurities cannot be determined by colour and odour, chemical indicator tests are done.
Chemical impurities test are fluoride, chlorine, nitrate. These cannot be determined by colour and odour. There are tests for TDS(total dissolved solids), fluoride, chloride and nitrate indicator tests. All these chemical substance are harmful to human body and hence have to be purified before consumption. RO plant can be used to filtrate chemical impurities.
Bacterial test - It is difficult to detect bacteria in water. There is only one test. The best solution to kill harmful bacteria in water is by boiling.
A water quality kit is been given to the school and were taught to them the way to perform these tests. The experiments were made by children.

TDS meter test - TDS meter indicates the amount of dissolved solids in water. More the dissolved solids, hard is the water, which means it is non-potable.
The meter should indicate less than 500 for human consumption. In telugu school, Borewell water showed 58, drinking water showed 32, rainwater showed 66. This is the simple and primary test.

Fluoride indicative test- If the fluoride content is in excess, the water color is generally yellow in color. However this test will allow to understand better. The solution is put into the water. If it turns pink, fluoride content is less. If it turns yellow, then fluoride content is in excess.
This test at school was done for borewell, drinking water and rainwater. All types of water turned pink in colour indicating less fluoride content.

Nitrate indicative test- Tablet like substance is added to the water. 1 tablet of nitrate a and nitrate b for 10ml of water. Dark pink indicates less nitrate. Light pink indicates excess of nitrate in water. This test at school was done for borewell, drinking water and rainwater. All types of water turned dark pink indicating less/no content of nitrate
If water with nitrate is consumed, there are health effects to it

Chlorine indicative test - The powder like substance is added to the 10 ml of water. First added to drinking water and then to borewell water. If it turns pink, then chlorine is in excess. If it remains colourless, the water has less or no chlorine content. In both the type, the water remained colourless.

Bacteria indicative test- Drinking water and rainwater is put in the tube which already has bacterial indicator stuck onto it. The water is left for 24 hours. If it turns bluish green in colour, it means there are harmful bacteria (for eg; cyanobacteria) in the water. Then it is safe to assume that water is potable.

This completes the water quality test. It was advised to children to test the water every 2 months.

Rain-water harvesting session-2 in Telugu Govt School

It started off with revising on the Session 1. 

'Do you remember what happened last class?'

Children replied, 'water cycle', 'water demand' 

'What was the demand?'

'It was 3 lack liter demand for the year', they replied

'Now let's see how much of rain water is harvested.' 

Rainwater harvesting process-

The diagram on the board was explained to them- The rain water from the cloud that is fallen in the roof is collected through a pipe, then a valve which flushes the first flow which is filled with dirt, then the rest(clean water) is sent to filter, following to the sump. From there it is collected for different purposes. In your case, it is for washing and toilet purposes. 

Calculation-
The water obtained from rainwater harvesting was calculated. Calculations were involved by the students.

Roof area- 115sqm x 900mm of water considering Bangalore annual rain fall without run off. Considering 0.9 of the acquired water there is nearly 1 lack liter of water in roof top of the school.

With the rain water collected water, we can reduce our demand to 2 lack liter that is,

3,00,000 liter(demand) - 1,00,000 liter = 2,00,000

Children were then asked, 
'how the water in rainwater could be utilized?

In reference to the question the movie of importance of rain water was shown. The context of the movie was relatable to students. They thoroughly enjoyed and learnt about rainwater harvesting. 

On site RWH-

Later students were taken to the place to help them understand the existing infrastructure of rainwater harvesting in their school. We showed and explained about the first flush, filter and tank. The procedure of the water reaches the tank and utilization for washing and in bathroom was explained.

Finally, it was handed over to school to take care of this infrastructure.

Students were left with the question, 'How do you know the water is clean?' 

Rain-water harvesting session-1 in Telugu Govt School

In a small school called Telugu Govt School in Murphy town of 40 children, we were given opportunity to explain the importance of Rain water harvesting in their school vicinity.

With all our excitement, we gathered around in a small room to explain the importance of rainwater harvesting.

It began by asking children,

'what is water'?
'Water is liquid', they said


'What do you use water for?'
'It's used for the gardening, drinking, washing, cooking. Also agricultural' children said.


'From where do we get water?'
'Ground, cloud, rivers dams lake', they replied

It was explained to them about the source of water school is relying on for their activities, which is, Cauvery water and borewell.

Water cycle-

Water from rain is distributed to the lake river etc. From there the evaporation takes place, then condensation and precipitation to form water in the form of rain.
The videos on water cycle in Kannada was displayed.
It was asked, 'how much percentage water do we have on earth?' '75 percent', kids answered.
On the same note, the video on distribution of water on earth was displayed.

Water demand-

What do we use water for?
Each of the activity was practically shown to children using simple methods. The activities one by one was written on the board to arrive at the water demand in the school. Mathmatics of the following activities were involved by children from the session
Hand wash- 250ml x 3 times =750ml
Toilet flush- 10 liters x 1=10 liters
Cleaning classrooms- 15x10rooms=150 liters
Drinking- 1 liters
Gardening-10 liters
Washing vessels - 10.5 liters
Total- 174 liters. Therefore, Leaving classroom cleaning it is approximately 25liters/day/student.
Total No of students- 40, considering 10 working months, for total number of students for a year is approximately 3 lack liters including the cleaning of classrooms

It is then explained that we need rain water to harvest since the demand is high.
It was gradually concluded saying, 'Next time when we come, we will understand rain water harvesting. We can deduct the demand by calculating them. Hence we are relying less on the external water source'.
The same activity of calculations and experiments shown in videos were handed over to the children. It was requested to the teacher to encourage children to repeat the same experiments and calculations.

HOW A SCHOOL IN WHITEFIELD IS MANAGING ITS WATER NEEDS, WITHOUT A MUNICIPAL WATER SUPPLY!

BRIEF OVERVIEW

Situated in Whitefield, Bangalore, Sisa Swiss-Indo Academy is a private school recognized by govt. of Karnataka - founded in 1981. It has a pre-primary, primary and high school, with about 630+ children and 50+ staff. Everyday about 700 people visit the campus. There are 2 main buildings in the school – BEVERIN and PASCUMIN. The school premise is over 4 decades old and has been gradually improved.

Sisa Swiss-Indo Academy, Whitefield, Bangalore

Water situation in Whitefield: 

Whitefield is located towards the south-east of Bengaluru and has emerged as the heart of Bengaluru’s IT corridor and has seen rapid development over the last decade. Cauvery water pipeline work for these areas only began as late as 2017, and the suburban population here mainly depends on borewell water. In some areas, the water level has reached 1,700 ft below the ground, which previously used to be between 300-500ft. In many places the borewells have dried up.

Water situation in Sisa Kendra:

With no choice of Municipal water supply, Sisa Kendra school opted for a bore-well that was established in (or about) 1992, dug for 300ft depth, that used to supply water to all the bathroom-toilets and landscape needs, but ran dry in 2009. Thus, the school had to start depending on tankers, throughout the year.  Additionally, drinking water cans were bought (120LPD) every day. It is in this context that BIOME’s help was sought in 2012, to be able to augment supply. 

PROPOSAL FOR WATER MANAGEMENT

Challenge:

·       The average daily domestic demand (for all purposes other than drinking) was 5000LPD in 2012. This works out to a per capita daily demand of about 8 litres, which was judicious use of water. The current per capita daily demand has now gone up to 10 litres.

·       Hefty amounts were being paid for ensuring supply of water through tankers, and this source is also unpredictable with private tanker companies.

Structure study & area calculation:

Given that the catchment areas on campus is rooftop and open areas, the following table shows us the potential for RWH

Catchment description	Area (sqm)	Annual Run-off 970mm (KL)	Run off for 30 mm rain in KL (average rain)	Run off for 60 mm rain in KL (heavy rain)
Total Campus (0.5 acres)	6069	5887	182	364
BEVERIN (4500sqft, 90% runoff coefficient)	413	361	11	22
PASCUMIN (5000sqft, 90% runoff coefficient)	459	401	12	25

·       Total rooftop and surface area = 4500 sqft + 5000 sqft = 9500 sqft

·       Average annual rainfall in Bangalore is 970mm

·       Total volume of rainwater harvested: 361+401 KLPD

·       There is potential to harvest upto ~150 days of water (361+401/5KLPD) for domestic    consumption.

Biome’s Intervention of an RWH system:

After a careful study of the scenario, BIOME team proposed both rainwater storage and ground water recharge strategies in the recommended order of implementation.

Phase 1

·       Building a 30KL sump next to the existing sump (5KL capacity) near BEVERIN and connected to the old sump on the top for overflow.

·       Redirection of 13 rainwater downpipes from Beverin into this new underground brick masonry sump after filtration.

·       Redirection of all downpipes from Pascumin rooftop and storing of water in the new sump.

·       Redirection of rainwater from the old sump to the dried borewell.

Phase 2

·       Further treatment and usage of the overflow water from the septic tank for gardening. (Yet to be implemented)

IMPACT

Water demand vs supply -

• The average daily domestic demand (for all purposes other than drinking) has been increasing due to increase in student intake. The daily demand has gone up to 6500-7000 litres, from the erstwhile 5000 litres in 2012. This works out to a per capita daily demand of about 10 litres currently.
• With implementation of the RWH system in 2012, initially SISA Kendra was able to supplement 50%- 55% of its water needs. With current demands, the RWH supply suffices only for 45% of their needs.
• The first rain filter water is also captured in a 3’ x 3’ x 2’ tank and used for their landscaping needs. The support staff are very careful and ensure that wastage of water is minimal.

Cost analysis and savings –

·       The overall installation cost for RWH system was 5Lakhs.

·       With an average offset from annual RWH of 762 KL, the school is able to save ~ INR 76,200 annually, by reducing its dependence on tanker supply by 55%.

·       There is an annual expenditure of 1Lakh on buying water from private tankers. In the past year, INR 90,250 was spent to buy 1332KL of water from tankers. There is a need to look at other options for supplementing their needs.

Current functioning & Maintenance -  

·       The school’s support staff do daily maintenance and cleanliness of the terrace space and the filter. The terrace is cleaned every 15 days, and the filter once every month.

·       The underground sump is cleaned every 3-4 months, through an external agency, which costs INR 5000 per cleaning. The septic tank is also cleaned every 3-4 months, for a cost of INR 5000.

“It was my dream project to get the Rainwater Harvesting system for the school and ensure that we are less dependent on borewell and municipal water supply. While maintenance is the main task, the RWH system has helped us be 50% sufficient so far”, says Mr Suriya Narayana, Manager, Sisa Swiss-Indo Academy, Whitefield, Bangalore 560066.

Click here to access the report with the video. 

All is *well*. We are monsoon-ready!

A brief documentation of my first visit to an apartment complex in Harlur Road, to understand recharge wells with the help of a well-digger: 

“There are about 2000 flats and 40 recharge wells, that store rainwater collected from the terraces of all the towers in this apartment complex!” says Bullet Ravi, a well digger at an apartment complex in Harlur Road. “And all the recharge wells have water!” he says, gleaming with pride.

Photograph of an apartment in Harlur Road

Ravi escorts me into the property from the entrance and he pauses briefly pointing towards the direction of Kasanavahalli lake, located just a few meters away from the apartment complex. For a first timer, it’s hard to notice this huge lake as it is concealed by the trees in the park that borders the perimeter of the apartment. The park not only has trees and a lawn but also has many recharge wells! As we step into the park, we examine three different recharge wells, located a few meters away from each other– all of which have 4 feet diameter but varying depths of 12 ft, 20 ft and 30 ft. Most of the wells have water at depths of 6ft to 10ft below ground level.

Recharge Wells

Ravi passes on bits of information as I jot down the details of these wells. He says these wells are interconnected by pipes allowing surplus water from one well to easily flow to adjacent wells. Although, some of the pipes are still being installed most of the recharge wells are interconnected.  

Installing pipes to connect recharge wells

Standing beside a recharge well, all that I had to do was to look up at the skies to picture the journey a raindrop would take: falling from the sky, to the roof of the apartment towers, flowing through a system of pipes into the basement and finally to the network of recharge wells that lie beneath my feet. 

Journey of a raindrop

I clicked a few more pictures and thanked Ravi for his patience and his work in making this apartment monsoon-ready!

- Jeevitha Balakrishnan