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

[SAMPATH S]

EFFECTIVE Rainwater Harvesting FILTERS and bore well and ground water recharge:

The rapid and steady decline of ground water all over the country due to over exploitation in urban as well as rural areas for potable water requirements and irrigation is well known.

In urban areas, a number of bore wells have dried up due to this and in most others, the yield has been coming down steadily. New bore wells are dug in massive numbers every day and in many places in the city ground water is not struck even beyond 1000 feet. It is a different issue whether ground water at such depths would remain potable.

Side by side, flooding of roads and low lying areas even during light rains is not uncommon. Traffic coming to a standstill for hours and houses and cellars getting inundated is regular news. Drains filled with silt and garbage block movement of rainwater. Yet, the lakes are getting dried up and ground water level is rapidly declining. Ground water recharge, which used to take place due to thick vegetation and porous soil, has become a thing of the past.

Can we, as citizens, in any way contribute to reduce this menace? Rooftop of all buildings contribute to substantial collection of rainwater, which in most cases flows to the storm water drains and sometimes to the sewage pipes (illegal). Percolation pits and wells in most cases have got filled up with silt over the years and naturally have lost their efficiency.

Since most of the residential and commercial units have bore wells, functional or otherwise, efficient ground water recharge would help them immensely in reviving the bore wells and / or increase the yield. It can also reduce/help dilute the ill effects of water sourced from deep borewells.

A high efficiency rooftop rainwater harvesting filter like the EFFECTIVE RWH FILTER would be of immense help in channelizing rooftop rainwater for increasing the groundwater level in such situations.

[riturajmnit]

hi Sampath

As i am still going through the details you have accumulated in this thread, thanks to your selfless effort. I am doing RWH again in my second house and i have taken an ambitious goal of making rainwater as drinkable. I still have 4 months to get this solution. Would really help if you can suggest some leads.

[SAMPATH S]

hi Sampath

As i am still going through the details you have accumulated in this thread, thanks to your selfless effort. I am doing RWH again in my second house and i have taken an ambitious goal of making rainwater as drinkable. I still have 4 months to get this solution. Would really help if you can suggest some leads.

Hi riturajmnit

Glad that you are following this thread and you intend doing RWH again in your second house and to make the rainwater as drinkable.

If you can narrate your requirement of the specific leads you expect, I would try to furnish them to the best of my ability.

Learning is not a one-way process. I do keep learning from the queries raised by RWH enthusiasts and try to improve the system to the extent possible.

[riturajmnit]

Thank you for your reply.
So we have done 2 sumps of 10k ltr each storage and now will be putting 2 Overhead tank of 5000 and 1000 ltr each.

1000 ltr is feeding the kitchen line and all wash basin line. I will be adding sediment and carbon filter, and finally routing water through UV filter.

This is brute force solution, not sure if there is any ready solution for same ?

Thanks

[SAMPATH S]

Thank you for your reply.
So we have done 2 sumps of 10k ltr each storage and now will be putting 2 Overhead tank of 5000 and 1000 ltr each.

1000 ltr is feeding the kitchen line and all wash basin line. I will be adding sediment and carbon filter, and finally routing water through UV filter.

This is brute force solution, not sure if there is any ready solution for same ?

Thanks

You have mentioned that you have done 2 sumps of 10k ltr each. Believe one for rainwater and the other for Cauvery water/borewell water. In any case it would be better to interlink the two tanks, both at top and bottom through valves. The valve for the bottom connector may be placed inside the sump from which maximum water will be pumped. It would also be preferable if you can make a device to operate this valve from the top/lid (bottom linking will be about 1 foot from the sump floor). The top link may be made by pipe connecting from outside and the valve placed in this pipe can be easily operated from outside itself. This is only a suggestion as this arrangement would permit easy transfer of water from one sump to the other.

You have mentioned two overhead tanks. It is not clear whether the distribution lines are interconnected by valves to facilitate easy switch over in case of necessity.

Regarding water purifier, UV purifier would be sufficient. Generally purifier would have a sediment filter in the package, either external or internal. UV purifiers invariably have a carbon filter built in. It is not clear whether you are referring to these or you intend providing additional one. In case you are planning for additional filters, the servicing/maintenance and replacement costs would be additional.

There are many ways of doing anything and it is for you to take a call.

[SAMPATH S]

Monsoon – Use rain water now and save the excess by recharging ground water – Preserve the ground water for summer.

It is easy and cheap to harvest rooftop rainwater - Using Effective RWH Filters

[SAMPATH S]

Below is the link to a short video of my rainwater collection sump and the water from the topmost layer being pumped (you can hear the background pump noise) using a self designed simple suction float. You may also notice the special piping arrangement in the sump for the inlet (filtered) rainwater. Do observe the clarity of rainwater being pumped. Daily rainwater is being collected in this sump. The sump has not been cleaned for the last three months.
Apart from the EFFECTIVE rainwater harvesting filter, a few other arrangements together makes this possible.
I do have pristine water stored in other sumps which is a few months old.

https://drive.google.com/file/d/1CV25nSFciBxDoQRXVWKeKdy18AAA9S6u/view?usp=sharing

[SAMPATH S]

Where are we heading?

https://timesofindia.indiatimes.com/spotlight/india-and-water-how-is-the-worlds-largest-groundwater-user-tackling-its-looming-water-crisis/articleshow/93637697.cms

About 70 per cent of our water sources are contaminated and country's major rivers are dying because of pollution. In June 2019, a report suggested that 65 per cent of all reservoirs in India reported below-normal water levels, and 12 per cent were completely dry.

As regards our Groundwater Extraction, India extracts more groundwater than US and China combined.

The country captures only 8 per cent of its annual rainfall, which is amongst the lowest in the world.

A NITI Aayog report of 2018 clearly stated that nearly half of India's population is all set to face extreme water stress in coming years. NITI Aayog also estimated that 21 major cities, including Delhi, would run out of groundwater by 2030.

Jal Shakti Mantralay advocates Mission - Catch the Rain, Where it falls, When it falls.

Additionally, the Central Ground Water Board has prepared its ‘Master Plan for Artificial Recharge to Groundwater – 2020’ that involves the construction of about 1.4 crore rainwater harvesting and artificial recharge structures in the country to harness 185 billion cubic metres (BCM) of water.

However the big question is which agencies are going to implement such schemes? Even in major cities less than 30% of apartments have implemented such systems to recharge groundwater table. Very little progress on buildings owned by Govt., Public, Educational Institutions and Religious places of worship. Unless all possible rooftops are utilised to catch rainwater for recharging groundwater table, water crisis is likely to become unmanageable.

[SAMPATH S]

Does stored rainwater needs to be chlorinated?

Rainwater harvesters generally take precautions like keeping the rooftop fairly clean, allowing for first rain separation, usage of high efficiency filters like the Effective RWH Filters and proper care of storage sump/s. These greatly reduce the chances of bacterial contamination.

One aspect which may not be predicted / effectively controlled is the bird droppings. It is well known that excreta of birds contain coli form bacteria, particularly e-coli. The excreta of all warm blooded animals (birds belong to this category) contain coli form bacteria. While a negligible amount of bird droppings can be ignored, it is better to take precautionary steps in case the bird droppings become substantial.

Now-a-days households generally use some kind of water purifier like the UV filter for making water potable and this effectively neutralizes the bacterial content, including coli form bacteria.

However, new comers to rainwater harvesting have a lot of apprehensions and insist on chlorination of the entire stored rainwater. The following information is for them.

Chlorine is a highly unstable gas. Hence it cannot be procured and stored. This is overcome by the use of bleaching powder, which contains chlorine. It is preferable to use a bleaching powder with the highest percentage of chlorine. The powders that contain about 33% chlorine can serve the purpose. Here it is to be noted that even though at the time of preparation and packing the bleaching powder may contain 33% chlorine, with the passage of time the level of chlorine reduces drastically. Hence one has to not only choose the bleaching powder with highest chlorine percentage, but also ensure that the stock is reasonably new, say about 3 months from the date of packing.

Generally, in case of good bleaching powder, approximately 5 grams per 1000 liters of water may be used. Since bleaching powder does not dissolve in water and needs to be spread on the water stored in sump, mix the desired quantity of bleach in about half a bucket of water, stir well and spread on the stored water as evenly as possible. Allow a minimum of 24 hours for the bleach to react with water.

While chlorination is good, what needs to be ensured is that excess chlorine is also not good for drinking water. The bleach used should neutralize the bacteria and there could be slight excess chlorine to take care of future storage and use. This excess chlorine is called RESIDUAL CHLORINE. This residual chlorine might be in the range of 2 ppm (parts per million). There are low priced kits available on online shopping sites to check this residual chlorine ON SITE. In any case, the maximum residual chlorine should be well below 5 ppm. In case the desired effect of chlorination is not achieved in the first attempt, try using a little more bleaching powder to achieve the desired effect.

As I have stated elsewhere, I initially used to chlorinate the stored water occasionally, but over the last more than 3 years have given up this and as such no treatment whatsoever is being done and water stored over several months and beyond continues to be of good quality.

[SAMPATH S]

One more report on the alarming depletion of groundwater levels and the story of unregulated mushrooming growth of borewells in Bengaluru.

Alternative is to recharge groundwater at every available opportunity and harvest rooftop rainwater for all domestic applications, besides other water conservation measures. Consider the low cost DIY Effective RWH Filters.

https://timesofindia.indiatimes.com/city/bengaluru/bengaluru-groundwater-levels-critical/articleshow/93603472.cms?utm_source=whatsapp&utm_medium=social&utm_campaign=AmpArticleshowicon