Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Eco friendly ideas & concepts
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SAMPATH S
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Joined: October 28th, 2014, 1:00 pm

Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Post by SAMPATH S »

ardesarchitects wrote:
May 24th, 2022, 7:10 pm
Hi Sampath,
Your knowledge sharing about rainwater storage and filtration is amazing. This summer rains gave enough water in most of my projects to be dependent completely on rain water for all their daily needs.
Data from old projects with average family size of 5-6 people and 8k liter rainwater sump brought down the BWSSB water consumption down by half during rainy seasons and summer by 1/4th .

Regards,
Ar.Praveen.N
Ardes Architects and Interior designers
ardesarchitects@gmail.com
www.ardesarchitects.com
https://www.instagram.com/ardesarchitects

Hi Praveen,

Thank you so much for your complements. I am just sharing my little knowledge on the subject and my personal experience gained out of my experimenting in the nature’s lab.

It is indeed gratifying to know that you are an ardent promoter of rainwater harvesting in your projects and the residents are richly reaping the benefits.

Initially at the time of construction of my house, everyone discouraged my thought of harvesting rainwater for storage and was even laughed upon. It was this attitude that made me to put in my heart and soul to showcase its success.

People always prefer BWSSB water supply as water is supplied at a highly subsidized cost and made available at the turn of the tap. Rooftop rainwater is still considered as contaminated water.

Apartments are ready to buy tanker water throughout the year to meet their requirements, but rainwater harvesting is not considered. Majority of the apartment owners are completely against harvesting rainwater for storage despite their complete dependency on tanker water.

Probably we are waiting for a catastrophe.
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SAMPATH S
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Joined: October 28th, 2014, 1:00 pm

Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Post by SAMPATH S »

How fine is the filter mesh in EFFECTIVE RWH Filters?

You might have noticed that Effective RWH filter makes use of the finest (smallest) filter hole possible for Rooftop Rainwater. Rooftop rainwater for an average roof size of about 1500 sq. ft. can reach an intensity of well over 5000 liters per hour during heavy rains.

The Effective RWH filters with its 75 micron hole Stainless Steel Filter mesh is designed to handle this heavy inflow. Commercially available RWH filters have mesh size of 250 microns or more. Thus, Effective RWH filters offer the best filtration purity (more than 1100% fine filter); and all this at a fraction of the cost of the commercial filters.

Now, how to relate this 75 micron with any real size object? An average sized human hair has a diameter of around 75 microns (though the minimum and maximum can vary considerably).

A filter mesh of the next smaller size is of 50 microns. This mesh cannot handle rains of even light intensity, as the holes get blocked swiftly. In fact, even after filtration through 75 micron mesh, the 50 micron mesh gets blocked in no time. This has been tested and confirmed by me.

Now what are you waiting for? With the monsoon just round the corner, harvest the pure rooftop rainwater with the best DIY filters at negligible cost.
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SAMPATH S
Posts: 139
Joined: October 28th, 2014, 1:00 pm

Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Post by SAMPATH S »

Rainwater, even after sufficient first rain separation and fine filtration, contains some amount of extremely fine dust (consistency like wheat flour), which makes the water somewhat turbid. Ultimately this fine dust settles down at the bottom of the sump, but it takes some time to settle on its own. This fine dust is inorganic and inert, i.e. it neither reacts with water nor dissolves in it (hence the TDS of rainwater remains extremely low), nor gives any foul smell.

Even after ensuring the incoming rainwater flows down into the sump softly, the turbidity of the incoming rainwater makes the stored clear water also somewhat turbid, i.e. even the clear water in the sump (after settling down of the dust) becomes turbid again.

To reduce the effect of the mix up of incoming and settled water, the incoming rain water can be made to flow directly to the bottom of the sump, without the mixing up with the already settled water.

This can be achieved by attaching a pipe to the rainwater sump inlet. A picture of the attachment pipe is below:

Attachment to rainwater inlet in the sump
Attachment to rainwater inlet in the sump
Attachment to rainwater inlet to sump.jpg (37.37 KiB) Viewed 1147 times

With this, the incoming rainwater will cause very little disturbance to the already settled water. Since the incoming water is made to flow in the upward direction, the already settled sediment would also be disturbed least. The pressure of water level above the incoming rain water will calm it down and slowly distribute the fresh rain water at the bottom itself.

This needs to be attempted when the sump is empty or has sufficiently low level of water. I have adopted this model and find that it works fine.
Last edited by SAMPATH S on June 14th, 2022, 2:08 pm, edited 1 time in total.
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SAMPATH S
Posts: 139
Joined: October 28th, 2014, 1:00 pm

Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Post by SAMPATH S »

SAMPATH S wrote:
June 6th, 2022, 7:32 pm
Rainwater, even after sufficient first rain separation and fine filtration, contains some amount of extremely fine dust (consistency like wheat floor), which makes the water somewhat turbid. Ultimately this fine dust settles down at the bottom of the sump, but it takes some time to settle on its own. This fine dust is inorganic and inert, i.e. it neither reacts with water nor dissolves in it (hence the TDS of rainwater remains extremely low), nor gives any foul smell.

Even after ensuring the incoming rainwater flows down into the sump softly, the turbidity of the incoming rainwater makes the stored clear water also somewhat turbid, i.e. even the clear water in the sump (after settling down of the dust) becomes turbid again.

To reduce the effect of the mix up of incoming and settled water, the incoming rain water can be made to flow directly to the bottom of the sump, without the mixing up with the already settled water.

This can be achieved by attaching a pipe to the rainwater sump inlet. A picture of the attachment pipe is below:


Attachment to rainwater inlet to sump.jpg


With this, the incoming rainwater will cause very little disturbance to the already settled water. Since the incoming water is made to flow in the upward direction, the already settled sediment would also be disturbed least. The pressure of water level above the incoming rain water will calm it down and slowly distribute the fresh rain water at the bottom itself.

This needs to be attempted when the sump is empty or has sufficiently low level of water. I have adopted this model and find that it works fine.

This, along with the one to follow, represents a QUANTUM LEAP IN RAINWATER HARVESTING.
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SAMPATH S
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Joined: October 28th, 2014, 1:00 pm

Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Post by SAMPATH S »

Floating suction to pump clear rainwater from top layer of sump:

With the attachment to the sump inlet pipe already detailed, the settled clear water remains at the top of sump and the incoming mild turbid water settles at the bottom, the turbidity in which settles down much faster.

Nowadays pumping from sump to the overhead tank is done using submersible pumps (also called open well submersible pump). This pump / motor is placed at the bottom of the sump under water. The suction generally takes place at a height of less than one foot from the bottom of the sump.

The bottom of the sump has settled down sediments and the incoming turbid water. Even though the water above is clear (after settlement), the pump tends to suck the somewhat turbid water and may be some sediments settled at the bottom.

To overcome this situation, a simple suction float helps in pumping the clear settled down water from the top layer of the sump. I have successfully designed a suction float costing very less and with materials available from local shop. Same is pictured below:

Suction pipe with float
Suction pipe with float
Suction pipe with float.jpg (139.27 KiB) Viewed 698 times

The suction float is connected to the suction inlet of the pump. A union is used to facilitate removal of the float for any possible repairs and re-fixing. The floating effect is achieved using an empty plastic bottle, preferably about two liters or more (sufficiently strong with a good cap). The attachment is done using cable tie. I have used a 1.5 inch flexible hose pipe. Also use hose clamps at both ends of the pipe so that the hose remains airtight. (Only one clamp is shown, but use hose clamp at both ends, also use 304 stainless steel or aluminum clamps so that they stay rust free). Please ensure that the connections are air tight for a good suction effect. If the hose pipe is heavy, it might need a bigger sized bottle as float. A transparent bottle will enable you to confirm whether the bottle remains empty always; any leakage would be visible.

This floating suction has been tested by me and is working extremely well.

The exercise has to be carried out when the sump is empty or when the water level is sufficiently low.
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SAMPATH S
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Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Post by SAMPATH S »

FIRST IN - FIRST OUT

The sump inlet piping, together with the suction float arrangement given above, also ensures the "First in - First out" principle, i.e. the water collected first is pumped out first, without any special effort.
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SAMPATH S
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Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters

Post by SAMPATH S »

Notification
Notification
Notification.jpeg (137.29 KiB) Viewed 255 times

Not sure about the applicability to different regions of the country.

But the writing on the wall is clear. Ground water is limited. It is already over exploited in the country. Restrictions are likely to be applied very soon and may be even metered and charged.

A golden opportunity to switch over to collection of pure rooftop rainwater, atleast during the monsoon days.

Maximum removal of impurities using EFFECTIVE Rainwater Harvesting FILTERS.
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