Re: Effective Rainwater Filter – For rooftop rainwater harvesting – Very low-cost, do-it-yourself filters
Posted: February 11th, 2023, 9:09 pm
RRWHASIMS – Rooftop Rainwater Harvesting & Storage Integrated Management System
Piping:
Downpipe from roof carries the rainwater. This simple downpipe can be modified so as to serve various purposes to help in collecting rainwater.
Normally, the rainwater is routed to groundwater recharge pit through the downpipe from terrace. In some cases, it is sent to storm water drain. In this downpipe, for harvesting rainwater (for storage), a valve is fixed at about 3 or 4 feet above the ground level. This is called first rain separator valve. When this valve is kept open (which is generally done for allowing initial impure rainwater to escape and also when the storage becomes full), the rainwater flows out.
A couple of feet above the valve, a T joint is fixed, to route the rainwater to the RWH Filter. Additional tapping/s may be made as per individual requirements for various purposes. Also for sampling the quality of water, a tapping can be made above the first rain separation valve using a service saddle. Here are some pictures:
First rain separation valve & just above it a tapping for water sampling using a service saddle:
First rain separation: There are many interpretations regarding first rain separation. Some say that the first couple of rains should not be collected as the impurities would be large; others say that the valve has to be kept open for 5 minutes, other say 15 minutes.
To avoid all speculations and to know for how long the valve has to be kept open, the sampling outlet would be of great help. It is also known that those who have no other source of water and are in dire need of water, even the rainwater with some impurities would be of immense help. There are others who have other sources like groundwater, but here also when the groundwater level goes down precariously, some amount of impurities in rainwater (particularly during occasional rains in summer), would be tolerable. There are others who have access to multiple sources like tap water supply, tanker water, ground water, etc., for them clean water is the prime criteria.
The tapping above the first rain separation valve using the service saddle would be of immense help in such situations. Once the first rain separation valve is closed and the tap in the service saddle is opened, water flows out through it. This water may be collected in a bucket preferably with white interior and the water quality analyzed. Till one gets water of satisfactory quality to meet their requirements, the first rain separation valve may be kept open.
With this arrangement, one may decide the quality of rainwater they wish to collect, without any speculation.
Tapping for RWH filter; also for collection of unfiltered water for watering plants, cleaning, etc.
Above the first rain separation valve, one may make a tapping using a T junction for collecting impure / pure water in a separate storage which can be used for watering plants, cleaning vehicles, floor and such other non-potable purposes. This is purely optional.
A little above this, the T junction tapping is used to route the water to the all important rainwater harvesting filter. I have used two elbows/bends to make the water rise and then connected to the RWH filter. This has been done deliberately so as to avoid any possibility of impure rainwater getting splashed through the pipe to the filter. One may also use a Y joint or any other suitable piping to achieve this objective.
In my installation, almost all the PVC pipes and fittings have not been pasted, but just push-fitted. I do not find any significant water leakage due to this. This arrangement, however, enables me to make changes whenever I wish to experiment, by pulling out the pipes and joints which can be reused. This is purely optional.
Piping:
Downpipe from roof carries the rainwater. This simple downpipe can be modified so as to serve various purposes to help in collecting rainwater.
Normally, the rainwater is routed to groundwater recharge pit through the downpipe from terrace. In some cases, it is sent to storm water drain. In this downpipe, for harvesting rainwater (for storage), a valve is fixed at about 3 or 4 feet above the ground level. This is called first rain separator valve. When this valve is kept open (which is generally done for allowing initial impure rainwater to escape and also when the storage becomes full), the rainwater flows out.
A couple of feet above the valve, a T joint is fixed, to route the rainwater to the RWH Filter. Additional tapping/s may be made as per individual requirements for various purposes. Also for sampling the quality of water, a tapping can be made above the first rain separation valve using a service saddle. Here are some pictures:
First rain separation valve & just above it a tapping for water sampling using a service saddle:
First rain separation: There are many interpretations regarding first rain separation. Some say that the first couple of rains should not be collected as the impurities would be large; others say that the valve has to be kept open for 5 minutes, other say 15 minutes.
To avoid all speculations and to know for how long the valve has to be kept open, the sampling outlet would be of great help. It is also known that those who have no other source of water and are in dire need of water, even the rainwater with some impurities would be of immense help. There are others who have other sources like groundwater, but here also when the groundwater level goes down precariously, some amount of impurities in rainwater (particularly during occasional rains in summer), would be tolerable. There are others who have access to multiple sources like tap water supply, tanker water, ground water, etc., for them clean water is the prime criteria.
The tapping above the first rain separation valve using the service saddle would be of immense help in such situations. Once the first rain separation valve is closed and the tap in the service saddle is opened, water flows out through it. This water may be collected in a bucket preferably with white interior and the water quality analyzed. Till one gets water of satisfactory quality to meet their requirements, the first rain separation valve may be kept open.
With this arrangement, one may decide the quality of rainwater they wish to collect, without any speculation.
Tapping for RWH filter; also for collection of unfiltered water for watering plants, cleaning, etc.
Above the first rain separation valve, one may make a tapping using a T junction for collecting impure / pure water in a separate storage which can be used for watering plants, cleaning vehicles, floor and such other non-potable purposes. This is purely optional.
A little above this, the T junction tapping is used to route the water to the all important rainwater harvesting filter. I have used two elbows/bends to make the water rise and then connected to the RWH filter. This has been done deliberately so as to avoid any possibility of impure rainwater getting splashed through the pipe to the filter. One may also use a Y joint or any other suitable piping to achieve this objective.
In my installation, almost all the PVC pipes and fittings have not been pasted, but just push-fitted. I do not find any significant water leakage due to this. This arrangement, however, enables me to make changes whenever I wish to experiment, by pulling out the pipes and joints which can be reused. This is purely optional.