The GCIL 2020 team had the opportunity to visit ten government schools around Bangalore today, and assess the repairs needed on each of the rainwater harvesting systems implemented. We visited Arasenahalli Higher Primary School, Urdu Higher Primary and High Schools, Rajiv Nagar Higher Primary School, Government Higher Primary School Vijayapura (East Kannada School), Government Lower Primary School Hunsur, Government Higher Primary School Gangawara, Government Lower Primary School Gopalapuram, Government High School Kadusonnapanahalli, and Government Primary School Kannur. There were three types of filters implemented at these schools: the basic rainwater filter, the reverse osmosis filter, and the commercial filter. I will further elaborate on these different types of filters, their uses, and the issues we found when viewing them.
The conventional jelly filter was set up in the same way at every school which used one: from bottom to top, a 40 mm jelly (gravel sized), then mesh, then charcoal, then mesh, then 20 mm jelly, and a final mesh layer. The filters have a pipe at the bottom which leads to a sump tank, where the water is stored. These sump tanks often have pipes to pump up to storage tanks on the roof of buildings, which are used for gravity uses in those specific buildings (i.e, a storage tank on top of the pre-school building is used for washing in that building only). These filters must be cleaned out every month during the rainy season, and only the top layer must be maintained during the dry season. These filters require a first rain outflow pipe, which allows the dirtiest water during a rain episode to flow out of the system, leaving only the cleaner water to be filtered and used. There was one school, Urdu Higher Primary and High Schools, whose filters did not have a first rain separator on either of their tanks; this is one of the additions which needs to be done at this school. The water from this filter was used for hand washing, for toilets, and for gardening and watering the trees. Many of the schools with this filter type also have municipal water connections, which often flow into the same sump tank. In kitchens, there is a smaller tap which only uses municipal water, as this is cleaner water. During the rainy season, there is a gate valve which can be turned to block off the municipal water access to the sump tank (not the kitchen taps), to decrease municipal water demand.
Most of the schools had the conventional jelly filter, but at the Urdu Higher Primary and High Schools, their filters were bowl shaped, included in the tanks rather than having pipes leading into the filter system. Another type of system, which was used by two schools, was the reverse osmosis filter. This system uses a semi permeable membrane to remove unwanted ions, large particles, and molecules from the water. In order to clean the water, a pressure is applied to pull the water through the membrane. This way, the unwanted particles remain on the pressurized part of filter, while the cleaned water flows to the other side. Like the jelly filters, the water that passes through this filter is not used as drinking water. For the two schools, they used the filters to water the trees and plants on their campuses, as well as for washing stations. A problem that we noticed with the reverse osmosis filters is that they waste a lot of water. Because of this, at Government Lower Primary School Hunsur, they only use the reverse osmosis system for watering trees, and have a jelly filter for their other uses at the school.
The final filtration system we encountered was the commercial filter. Unfortunately, this school was closed by the time we got there, and we were not able to closely examine it or ask questions. Basically, this is a filter that is commercially available, meaning it was bought at a store and is being used. This filter was used at the Government Primary School Kannur. Another challenge we faced at this school was that there was construction being done at this school, so the filter cleaning was put off because all of the pipes will have to be replaced when the construction is done.
This blog post is long because our day was long, but it was incredibly productive and as a team we learned so much. We missed our teammate Eric, who had a stomach bug and was missing, but teaching and telling him what he missed only provided an additional learning opportunity. The ingenuity and effort put in by both Biome and by the schools in creating and maintaining these systems was very inspiring. It was also encouraging, and rewarding, to see the dedication of Manjunath, the plumber, and his knowledge of each school
We hope to go back to continue building the relationship with the teachers and students at these schools, who benefit from these systems every day, in order to best build proposals for more schools around the city.
-Veronique (GCIL 2020, with Eric, Kayla and Tessa)
The conventional jelly filter was set up in the same way at every school which used one: from bottom to top, a 40 mm jelly (gravel sized), then mesh, then charcoal, then mesh, then 20 mm jelly, and a final mesh layer. The filters have a pipe at the bottom which leads to a sump tank, where the water is stored. These sump tanks often have pipes to pump up to storage tanks on the roof of buildings, which are used for gravity uses in those specific buildings (i.e, a storage tank on top of the pre-school building is used for washing in that building only). These filters must be cleaned out every month during the rainy season, and only the top layer must be maintained during the dry season. These filters require a first rain outflow pipe, which allows the dirtiest water during a rain episode to flow out of the system, leaving only the cleaner water to be filtered and used. There was one school, Urdu Higher Primary and High Schools, whose filters did not have a first rain separator on either of their tanks; this is one of the additions which needs to be done at this school. The water from this filter was used for hand washing, for toilets, and for gardening and watering the trees. Many of the schools with this filter type also have municipal water connections, which often flow into the same sump tank. In kitchens, there is a smaller tap which only uses municipal water, as this is cleaner water. During the rainy season, there is a gate valve which can be turned to block off the municipal water access to the sump tank (not the kitchen taps), to decrease municipal water demand.
Most of the schools had the conventional jelly filter, but at the Urdu Higher Primary and High Schools, their filters were bowl shaped, included in the tanks rather than having pipes leading into the filter system. Another type of system, which was used by two schools, was the reverse osmosis filter. This system uses a semi permeable membrane to remove unwanted ions, large particles, and molecules from the water. In order to clean the water, a pressure is applied to pull the water through the membrane. This way, the unwanted particles remain on the pressurized part of filter, while the cleaned water flows to the other side. Like the jelly filters, the water that passes through this filter is not used as drinking water. For the two schools, they used the filters to water the trees and plants on their campuses, as well as for washing stations. A problem that we noticed with the reverse osmosis filters is that they waste a lot of water. Because of this, at Government Lower Primary School Hunsur, they only use the reverse osmosis system for watering trees, and have a jelly filter for their other uses at the school.
The final filtration system we encountered was the commercial filter. Unfortunately, this school was closed by the time we got there, and we were not able to closely examine it or ask questions. Basically, this is a filter that is commercially available, meaning it was bought at a store and is being used. This filter was used at the Government Primary School Kannur. Another challenge we faced at this school was that there was construction being done at this school, so the filter cleaning was put off because all of the pipes will have to be replaced when the construction is done.
This blog post is long because our day was long, but it was incredibly productive and as a team we learned so much. We missed our teammate Eric, who had a stomach bug and was missing, but teaching and telling him what he missed only provided an additional learning opportunity. The ingenuity and effort put in by both Biome and by the schools in creating and maintaining these systems was very inspiring. It was also encouraging, and rewarding, to see the dedication of Manjunath, the plumber, and his knowledge of each school
We hope to go back to continue building the relationship with the teachers and students at these schools, who benefit from these systems every day, in order to best build proposals for more schools around the city.
-Veronique (GCIL 2020, with Eric, Kayla and Tessa)
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