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?'