SUMP OVERFLOW PIPE:
Often, rainwater harvesting sump is provided with an overflow pipe so that when the sump is full with rainwater, the excess is carted away to ground water recharge pit or in some cases to the drainage, etc., through such overflow pipe.
In rare cases, even sumps for other purposes like bore well water or even Cauvery water sump is also similarly connected to an overflow pipe.
We all strive to keep the sump clean from cockroaches, lizards, earth worms, other insects, and rarely rats also.
Now, the overflow pipe opens the possibility for entry of living organisms like above from the other end of the overflow pipe, which is beyond our observation and control. Even covering the overflow pipe with steel wire mesh, etc., only limits the chances but not totally eliminate them.
Hence it is of utmost importance that NO SUCH OVERFLOW PIPE IS PROVIDED from sump tank/s.
In case of rainwater, when overflow of sump occurs, the best way is to cart away the excess rainwater by opening the valve provided for First Flush.
Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
FIRST FLUSH and Rainwater harvesting for storage:
First Flush is a term which every Rainwater harvesting (for storage and reuse) enthusiast is familiar with.
Rooftop is naturally susceptible to accumulate dust and other impurities besides dead/living insects, etc. because of its very location. When it rains after many days, the amount of accumulated impurities on the rooftop would be substantial and it is better to flush this water out. This is referred to as FIRST FLUSH. First flush water is generally sent for groundwater recharge or sometimes routed to the storm water drain.
However, one can reduce the incidence of impurities by trying to periodically clean the rooftop.
While first flush water is certainly not fit for domestic usage, let alone for potable purposes, yet one can think of using this water for purposes like watering plants, floor washing, vehicle washing and such other miscellaneous purposes.
The first flush water may be collected in a suitable storage like plastic tank, etc., generally placed at ground level (actually slightly raised, so that the water can be tapped out). This water has both floating as well as sinking impurities. The floating impurities, to a large extent, can simply be removed by using a large strainer. The heavier impurities will settle down at the bottom of the storage. Even the dispersed dust particles will also settle down in a couple of days. Thus, the stored water would be fairly clear and can be used for miscellaneous purposes specified above.
Thus one can ensure that even the FIRST FLUSH rainwater is put to good use.
I am following this method for the last few years and am enjoying its benefit and am quite happy with it.
First Flush is a term which every Rainwater harvesting (for storage and reuse) enthusiast is familiar with.
Rooftop is naturally susceptible to accumulate dust and other impurities besides dead/living insects, etc. because of its very location. When it rains after many days, the amount of accumulated impurities on the rooftop would be substantial and it is better to flush this water out. This is referred to as FIRST FLUSH. First flush water is generally sent for groundwater recharge or sometimes routed to the storm water drain.
However, one can reduce the incidence of impurities by trying to periodically clean the rooftop.
While first flush water is certainly not fit for domestic usage, let alone for potable purposes, yet one can think of using this water for purposes like watering plants, floor washing, vehicle washing and such other miscellaneous purposes.
The first flush water may be collected in a suitable storage like plastic tank, etc., generally placed at ground level (actually slightly raised, so that the water can be tapped out). This water has both floating as well as sinking impurities. The floating impurities, to a large extent, can simply be removed by using a large strainer. The heavier impurities will settle down at the bottom of the storage. Even the dispersed dust particles will also settle down in a couple of days. Thus, the stored water would be fairly clear and can be used for miscellaneous purposes specified above.
Thus one can ensure that even the FIRST FLUSH rainwater is put to good use.
I am following this method for the last few years and am enjoying its benefit and am quite happy with it.
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Pre-monsoon rains have started in Bengaluru yesterday.
It is time to be ready with your EFFECTIVE RAINWATER HARVESTING FILTERS to harvest the rainwater.
To make the bucket cuttings for EFFECTIVE FILTERS, while one can very well use simple tools like the hacksaw blade and a poker tool, today we have multi use power tools available widely at reasonable cost and these tools invariably form part of the arsenal of DO IT YOURSELF enthusiasts. Power tools make the work effortless and also accurate.
Here are the pictures of the simple tools as well as the power tools that may be used:
Hacksaw blade
Poker tool
Adjustable circle cutter drill bit
(Continued in next post)
It is time to be ready with your EFFECTIVE RAINWATER HARVESTING FILTERS to harvest the rainwater.
To make the bucket cuttings for EFFECTIVE FILTERS, while one can very well use simple tools like the hacksaw blade and a poker tool, today we have multi use power tools available widely at reasonable cost and these tools invariably form part of the arsenal of DO IT YOURSELF enthusiasts. Power tools make the work effortless and also accurate.
Here are the pictures of the simple tools as well as the power tools that may be used:
Hacksaw blade
- hacksaw blade.jpg (10.55 KiB) Viewed 22989 times
- Adjustable circle cutter drill bit.jpg (20.46 KiB) Viewed 22989 times
(Continued in next post)
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
(continued from previous post)
Drilling machine
Jigsaw machine
Angle grinder machine
It is better to avoid Angle grinder machine as it rotates at about 12,000 RPM which not only makes it difficult to control the cutting, but also generates substantial heat which can somewhat burn the plastic.
In subsequent posts, further details of making of the EFFECTIVE FILTER buckets would be provided.
Drilling machine
- Drilling machine.jpg (13.8 KiB) Viewed 22989 times
- Jigsaw.jpeg (15.45 KiB) Viewed 22989 times
- Angle grinder.jpg (9.73 KiB) Viewed 22989 times
It is better to avoid Angle grinder machine as it rotates at about 12,000 RPM which not only makes it difficult to control the cutting, but also generates substantial heat which can somewhat burn the plastic.
In subsequent posts, further details of making of the EFFECTIVE FILTER buckets would be provided.
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Type 1 filter – Inner bucket – Bottom slot cutting:
Please download and watch the video (link below). The cutting is made using drilling machine and JigSaw.
https://drive.google.com/file/d/1oOeQjqeK1gOX8D0tXdcATovVcyJy6Rk8/view?usp=sharing
First an outline of the portions to be cut out is made using an object like ruler scale or any similar object. The width may be half an inch to one inch, smaller will be better.
For drilling holes, instead of the drilling machine, one can use a poker (may be mildly warm for ease of poking). Bare hacksaw blade may be pushed through the hole and cutting may be done in a similar fashion. Even a serrated kitchen knife may also be used in place of hacksaw blade. Mildly warm hacksaw blade / kitchen knife would help in faster cutting.
Please download and watch the video (link below). The cutting is made using drilling machine and JigSaw.
https://drive.google.com/file/d/1oOeQjqeK1gOX8D0tXdcATovVcyJy6Rk8/view?usp=sharing
First an outline of the portions to be cut out is made using an object like ruler scale or any similar object. The width may be half an inch to one inch, smaller will be better.
For drilling holes, instead of the drilling machine, one can use a poker (may be mildly warm for ease of poking). Bare hacksaw blade may be pushed through the hole and cutting may be done in a similar fashion. Even a serrated kitchen knife may also be used in place of hacksaw blade. Mildly warm hacksaw blade / kitchen knife would help in faster cutting.
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Type 1 & 2 Effective RWH Filter – Circular cutting of outer bucket for fixing 75mm PVC collar:
The circular cutting is somewhat critical in the sense that unless the required size is cut, it may not be possible to push the PVC collar. However, if the cutting becomes somewhat big, then the collar will become wobbly.
It is necessary that the collar fits snugly into the circular hole so that even if you hold the collar (before pasting) and shake the bucket, the collar should not detach. Irregular cutting is also not advisable as there will be some weak points.
The fact is that the collar is held in place just by the thickness of the bucket, as the collar needs to be almost flush with the inner bottom of the bucket. This will ensure that after pasting, the joint will not be dislodged by the future shocks due to rough handling.
As in the picture above, mark the outer perimeter (circle) by placing the collar at the center. Close to the inner side of the marking, punch a hole using the poker (similar to the position of the small circle in the picture) to allow the hacksaw blade to pass through. Now carefully cut along the circle drawn so that you do not transgress the circle as far as possible. After the cutting and corrections if any, the PVC collar should fit snugly into the hole.
The circular cutting is also possible using the Jigsaw. A hole is first drilled (at the place where a hole was punched above using poker) and the jigsaw blade is inserted there and cutting done slowly and carefully along the circular marking.
The diameter of the hole is 81 mm (as measured by me). Unfortunately there is no circular hole saw available corresponding to this diameter. Hence I have used a variable hole cutter (pictured earlier) and adjusted the arms to achieve this diameter of 81 mm after multiple tests and resetting. In case you would like to make use of this, please carryout several test checking and get satisfied.
With the setting done to the cutter, I could cut the perfect hole in flat three seconds, as could be seen from the following video.
https://drive.google.com/file/d/1ieohtivfoenPIzXXQAB7UhbRSor8I8Su/view?usp=sharing
The video below shows cutting the circular hole and the PVC collar snugly fitting in the hole so tightly that even an amount of pulling does not detach the collar.
https://drive.google.com/file/d/1WBiQbffFwF25daShSUkelVG7SNDAFVmG/view?usp=sharing
The collar is finally pasted at the bottom of the bucket, keeping the inner side of the collar flush with the bucket. This will ensure that no (or very little) water will stagnate in the bucket. Continuous water stagnation may lead to fungus formation, which should be avoided.
Picture after the pasting of the collar (as seen from inside and outside the bucket) has been posted earlier.
The circular cutting is somewhat critical in the sense that unless the required size is cut, it may not be possible to push the PVC collar. However, if the cutting becomes somewhat big, then the collar will become wobbly.
It is necessary that the collar fits snugly into the circular hole so that even if you hold the collar (before pasting) and shake the bucket, the collar should not detach. Irregular cutting is also not advisable as there will be some weak points.
The fact is that the collar is held in place just by the thickness of the bucket, as the collar needs to be almost flush with the inner bottom of the bucket. This will ensure that after pasting, the joint will not be dislodged by the future shocks due to rough handling.
- Marking for cutting of circular hole for PVC collar
- PVC collar cutting marking.jpg (22.74 KiB) Viewed 22755 times
As in the picture above, mark the outer perimeter (circle) by placing the collar at the center. Close to the inner side of the marking, punch a hole using the poker (similar to the position of the small circle in the picture) to allow the hacksaw blade to pass through. Now carefully cut along the circle drawn so that you do not transgress the circle as far as possible. After the cutting and corrections if any, the PVC collar should fit snugly into the hole.
The circular cutting is also possible using the Jigsaw. A hole is first drilled (at the place where a hole was punched above using poker) and the jigsaw blade is inserted there and cutting done slowly and carefully along the circular marking.
The diameter of the hole is 81 mm (as measured by me). Unfortunately there is no circular hole saw available corresponding to this diameter. Hence I have used a variable hole cutter (pictured earlier) and adjusted the arms to achieve this diameter of 81 mm after multiple tests and resetting. In case you would like to make use of this, please carryout several test checking and get satisfied.
With the setting done to the cutter, I could cut the perfect hole in flat three seconds, as could be seen from the following video.
https://drive.google.com/file/d/1ieohtivfoenPIzXXQAB7UhbRSor8I8Su/view?usp=sharing
The video below shows cutting the circular hole and the PVC collar snugly fitting in the hole so tightly that even an amount of pulling does not detach the collar.
https://drive.google.com/file/d/1WBiQbffFwF25daShSUkelVG7SNDAFVmG/view?usp=sharing
The collar is finally pasted at the bottom of the bucket, keeping the inner side of the collar flush with the bucket. This will ensure that no (or very little) water will stagnate in the bucket. Continuous water stagnation may lead to fungus formation, which should be avoided.
Picture after the pasting of the collar (as seen from inside and outside the bucket) has been posted earlier.
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Cutting of inner bucket for Type 2 Filter:
Cutting of inner bucket for Type 2 filter involves cutting the sides of the bucket for pasting filter mesh, in addition to the cutting at the bottom for Type 1 filter, which was already shown.
The cutting involves two portions of the side. A picture of the bucket cut in the side is below:
Before marking the area for cutting, spread the mesh (one at a time on each side) on the bucket side and mark the size of the mesh with a pen/pencil/marker. Allow about half to one inch at the bottom. On the sides, allow about one inch on each side. At the top allow about an inch. With these margins, make a fresh marking for the actual cutting to be made. In effect, it will be about 1 inch less on each of the four sides. For the top marking for cutting, ensure that the maximum cutting is below any projection in the bucket.
Similarly mark on the other side of the bucket also.
Now at each of the four inside corners of the marking for cutting, make a hole using the poker/drilling machine. Then insert the hacksaw blade through the hole made and cut out the marked portion. Others who use power tools like jigsaw may also complete the cutting.
The bucket, after being cut, will look like in above picture.
Now place the mesh inside the bucket side and paste using M-seal adhesive from inside the bucket on all four sides. Also paste the mesh from outside the bucket at the cut edges so that the mesh stays fixed to the bucket firmly.
The picture of Type 2 filter bucket with mesh pasted on the sides has already been displayed earlier.
With this, the fabrication of Type 1 and Type 2 filters is complete.
Cutting of inner bucket for Type 2 filter involves cutting the sides of the bucket for pasting filter mesh, in addition to the cutting at the bottom for Type 1 filter, which was already shown.
The cutting involves two portions of the side. A picture of the bucket cut in the side is below:
- Inner bucket with sides cut for fixing filter mesh
- Inner bucket with sides cut.jpg (23.21 KiB) Viewed 22328 times
Before marking the area for cutting, spread the mesh (one at a time on each side) on the bucket side and mark the size of the mesh with a pen/pencil/marker. Allow about half to one inch at the bottom. On the sides, allow about one inch on each side. At the top allow about an inch. With these margins, make a fresh marking for the actual cutting to be made. In effect, it will be about 1 inch less on each of the four sides. For the top marking for cutting, ensure that the maximum cutting is below any projection in the bucket.
Similarly mark on the other side of the bucket also.
Now at each of the four inside corners of the marking for cutting, make a hole using the poker/drilling machine. Then insert the hacksaw blade through the hole made and cut out the marked portion. Others who use power tools like jigsaw may also complete the cutting.
The bucket, after being cut, will look like in above picture.
Now place the mesh inside the bucket side and paste using M-seal adhesive from inside the bucket on all four sides. Also paste the mesh from outside the bucket at the cut edges so that the mesh stays fixed to the bucket firmly.
The picture of Type 2 filter bucket with mesh pasted on the sides has already been displayed earlier.
With this, the fabrication of Type 1 and Type 2 filters is complete.
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Important tip for Type 2 filter:
The inner bucket of type 2 filter has filter mesh pasted on the sides, in addition to the bottom. This is done to easily filter out large quantity of rainwater from bigger roof area. These filters can also filter rainwater through the sides in case of more impurities. Thus, the outer container (bucket) needs to be accordingly bigger. The clearance at the bottom should be about 2 inches (minimum 1”) and at the sides, about half to one inch each.
Because of these constraints, the inner mesh bucket would naturally settle at the bottom of the outer bucket, defeating the requirement of about 2 inches gap at the bottom. To achieve this gap and also to hold the inner bucket suspended, a circular tube is fixed at the top of the inner bucket in one of the grooves, which in turn would hold it suspended from the outer bucket. The size (diameter) of the pipe used may vary based on the gap with the outer bucket.
The picture below will make this aspect clear.
The inner bucket of type 2 filter has filter mesh pasted on the sides, in addition to the bottom. This is done to easily filter out large quantity of rainwater from bigger roof area. These filters can also filter rainwater through the sides in case of more impurities. Thus, the outer container (bucket) needs to be accordingly bigger. The clearance at the bottom should be about 2 inches (minimum 1”) and at the sides, about half to one inch each.
Because of these constraints, the inner mesh bucket would naturally settle at the bottom of the outer bucket, defeating the requirement of about 2 inches gap at the bottom. To achieve this gap and also to hold the inner bucket suspended, a circular tube is fixed at the top of the inner bucket in one of the grooves, which in turn would hold it suspended from the outer bucket. The size (diameter) of the pipe used may vary based on the gap with the outer bucket.
The picture below will make this aspect clear.
- Suspended inner bucket
- Inner bucket suspended using tube.jpg (214.17 KiB) Viewed 21907 times
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Connecting the last stage of the filter to the pipe leading to storage tank:
As we had seen earlier that the second/last stage of both Type 1 and Type 2 Filters finally leads to the storage tank by appropriate routing pipe.
We are pasting 75 mm PVC collar to the bucket. This collar needs to be connected to the routing pipe by a mechanism which would allow easy dismantling (without applying force) of the bucket for cleaning purposes and to place it back without difficulty. At the same time we need to ensure that the PVC collar does not get detached from the bucket, since that would defeat the very purpose of making the filter.
In my model (as seen in the above picture), a short piece of 75 mm pipe is pushed into the PVC collar (it is not pasted) of the filter bucket, ensuring a minimum projection of about 1.5 inch (it may be more depending upon the site conditions) from the collar. This pipe is made to fall freely into a 75 mm PVC elbow/bend below. This elbow is of gasket/washer type. This gasket is removed so as to allow the projection pipe to fall freely. This ensures that the bucket can be easily dismantled for cleaning purposes and put back effortlessly. The narrow gap resulting out of removing the gasket does not in any way allow water leakage (as the flow of water is ensured by gravity) and this has been practically confirmed by me.
In my model, the above picture shows the pipe leading to the storage tank. In my opinion, it would be better to have an offset of at least 6 inch to 1 foot (if it is more, no issue) between the plumb line of the PVC collar of the filter bucket and the projecting pipe from ground, which leads to the storage. This would ensure fixing the 75 mm elbow. Please also ensure that the elbow has a clearance of at least 6 inches from the ground, to avoid entry of raw water resulting out of flooding. In case your filter placement area is prone to flooding, please increase the height accordingly.
As we had seen earlier that the second/last stage of both Type 1 and Type 2 Filters finally leads to the storage tank by appropriate routing pipe.
We are pasting 75 mm PVC collar to the bucket. This collar needs to be connected to the routing pipe by a mechanism which would allow easy dismantling (without applying force) of the bucket for cleaning purposes and to place it back without difficulty. At the same time we need to ensure that the PVC collar does not get detached from the bucket, since that would defeat the very purpose of making the filter.
- Filter output to storage
- Filter output to storage.jpg (27.41 KiB) Viewed 21566 times
In my model (as seen in the above picture), a short piece of 75 mm pipe is pushed into the PVC collar (it is not pasted) of the filter bucket, ensuring a minimum projection of about 1.5 inch (it may be more depending upon the site conditions) from the collar. This pipe is made to fall freely into a 75 mm PVC elbow/bend below. This elbow is of gasket/washer type. This gasket is removed so as to allow the projection pipe to fall freely. This ensures that the bucket can be easily dismantled for cleaning purposes and put back effortlessly. The narrow gap resulting out of removing the gasket does not in any way allow water leakage (as the flow of water is ensured by gravity) and this has been practically confirmed by me.
- Pipe from storage
- Pipe from storage.jpg (68.41 KiB) Viewed 21566 times
Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Positioning of pipe in sump (routed from filter):
Last week, details of routing the pipe carrying the filtered rainwater to the sump were mentioned.
As the filtered rainwater falls into the sump, due to the force of falling water, it is likely to stir/mix the earlier stored water. The stored water may contain some settled down dust, which is likely to get mixed up again.
To avoid/minimize this possibility, it is suggested that the pipe inside the sump be carried close to the sump wall, due to which the incoming filtered water would hit the wall and flow down softly, nearly eliminating the chance of mixing up the settled impurities, if any.
Last week, details of routing the pipe carrying the filtered rainwater to the sump were mentioned.
As the filtered rainwater falls into the sump, due to the force of falling water, it is likely to stir/mix the earlier stored water. The stored water may contain some settled down dust, which is likely to get mixed up again.
To avoid/minimize this possibility, it is suggested that the pipe inside the sump be carried close to the sump wall, due to which the incoming filtered water would hit the wall and flow down softly, nearly eliminating the chance of mixing up the settled impurities, if any.