Our Deluxe rainwater harvesting and water purification process

Our Deluxe system is recognized as the world standard for treatment of rainwater for the use as drinking water. It has a 3 step rainwater treatment and water purification process. These 3 steps ensure that the water coming from a rainwater system system is clear, contains no visible particles, no chemicals and has been sanitized of all possible bacteria and harmful micro-organisms. 

The treatment steps are:

Step 1 – Flushing and cleaning.

Filtration begins with the collection of rainwater. Using our system all debris, leaves and small particles are removed before it enters the system. A primary rainwater filter - like an inline collector or a vortex filter screen out the debris before it enters the tank. The vortex filter also acts as a first flush allowing the first amount of roof water to pass before it starts collecting rainwater for the tank. This ensures that the storage system remains clean and oxygenated. Any small amount of debris that goes into the storage tank becomes part of the bio-layer that settles to the bottom. Supplying it with fresh oxygenated water (special inflow system) ensures that it is broken down effectively without leaving any taste in the water. Our inflow system ensures that the bio-layer is not disturbed and that it works effectively.

Wisy Downpipe filterSmoothing Inlet2

Step two - Filtration of the water under pressure.

Our pump floating suction system ensures that the bio-layer is not disturbed and pumps clear fresh water to the the filtration system. The floating suction draws the rainwater from just below the surface of the water in the tank. This is the cleanest rainwater and by doing this it also ensures proper rotation of rainwater through the tank. As a precaution the floating suction has a course filter-element.

Filter cartridges remove all particles bigger than 1-5 microns  from the water so the water is completely clear and there are no visible particles in the water. After filtration the water is passed over an activated carbon filter which removes all tastes and chemicals from the water. These molecules and chemicals are absorbed by the activated carbon leaving the water clean and pure.

Waterpurification with Grundfos Frame

Step 3 – Sanitization.

After the water has been purified it can still contain bacteria or harmful micro organisms. Our sanitation process uses a process called ultraviolet sterilization. The water is passed through a system where it is exposed to a high dose of ultraviolet light. The UV light kills off any other harmful micro organism, bacteria, viruses in the water ensuring that the rainwater that you drink are safe for human consumption. 

Due to the unreliable supply of water in the smaller towns in South Africa we have designed a Hybrid rainwater harvesting system.

We change the municipal supply to connect into the rainwater tanks. We set it that that the tanks will always be a quarter full - topped up by the municipal supply. Should there be a breakdown in the municipal water supply the household or business is guaranteed that there is at least a quarter tank of water supply in the house.

If it rains and the tank level passes the set level the valve to the municipal supply will close and thus no municipal water will be used until the rainwater water drops below the set level. 

This system is complex and purifies harvested rainwater for potable use. It combines with  a municipal backup water system to ensure that the building has potable water at all times - even during municipal water interruption. This system is designed to be integrated into a new building and it is designed together with the architects and constructed during a construction of a new building

 

In his example the system will harvest water off a 350sqm roof. Water is treated to potable standard and simply replaces the municipal water when there is rainwater in the tanks. It also contains a switch-over backup system if the municipal supply is interrupted or if the rainwater tanks are empty.

 

Key components:

 

  1. Four round 5000l interconnected rainwater tanks or two 10000 liter low profile tanks Generally the building is designed to place the tanks in a basement or deck covered area which is at the lowest point in the building or property .

  2. Integrated gutter and down-pipes that direct all the water from the roof via a network of pipes and gutters to a single 160mm header pipe. The header pipe direct the water to a primary vortex filter mounted near the tanks.

  3. One WFF 150 vortex filter . All the water from the roof gutters will be directed to the WISY. The WISY WFF150 primary vortex filter is self-cleaning and screens  out any organic material greater than 280 microns. It can manage rainwater falling on roof surfaces of up to 500sqm. It ensures that the rainwater tank is kept clean with minimal sludge buildup in the tank, thus improving the water quality and reducing the cleaning frequency of the tank (you would only have to clean the tank once every 5 years).

  4. One multi syphon overflow with vermin and insect protection. You want to protect the water quality in your tank. The multi syphon overflow prevent any insect or vermin from getting into the rainwater tanks - especially where the overflow is connected directly to the underground stormwater pipe.

  5. One calming inlet that will allow fresh rainwater from the vortex filter to enter the bottom of the tank and not disturb the sediment and microbiological layer on the bottom of the tank

  6. One wireless tank level gauge so you can see the water level in the tank at any location of the building

  7. One floating suction connected to the suction of the pump. The floating suction draws water from just under the water surface ensuring that the old water in the tank is used first - keeping water fresh at all times in the tank.

  8. A frame mounted pressurized filtration pre-built and factory tested and  consisting  of the following:

  • Sturdy 304 stainless steel frame.

  • Grundfos multistage horizontal centrifugal pump.

    • The pump is a high quality unit that runs very efficiently and very quietly. It is as loud as an air conditioner when running.

  • Global Water Solutions PressureWave Pressure tank

    • The tank increases the longevity of the pump and reduces energy consumption by reducing the number of pump starts required.

    • The pressure tank uses an EPDM diaphragm instead of a bladder.

  • Global Water Solutions PumpWave pump controller.

    • The pump controller is designed to work in conjunction with the pressure tank.

    • The controller automatically starts the pump when the pressure drops to a preset setting, and stops the pump when it senses that water has stopped flowing

    • The controller protects the pump from dry running.

  • 20" 20 micron pleated cartridge filter.

    • The filter removes all suspended particulates larger than 20 microns from the water.

  • 20" 1 micron pleated cartridge filter.

    • The filter removes all suspended particulates larger than 1 microns from the water.

  • Activated Carbon and KDF55 cartridge filter.

    • The filter treats the water for any color and odor that might be present, resulting in fresher tasting water.

    • The KDF media also removes any metals from the water as well as kill some bacteria in the water

  • High intensity UV Sterilizer

    • The UV light kills 99.9% of all microbes that might be present in the water, resulting in water that is safe for human consumption.

 

  1. Once municipal top up solenoid valve and float switch  system. By setting the a minimum water level in the tanks an electrical solenoid valve will always top an minimum amount of water to the tank.  Thus if there is no rainwater or if the tanks are starting to empty,  the system will automatically add some water to ensure you always have potable standard water in the building. When it rains and the tanks fill up it will stop and the system will only use rainwater.

  2. One municipal switch-over system and bypass valve system. If anything goes wrong or if the system need to be maintained you can bypass it and simply use municipal water for a while.

  3. Backflow preventer valve and assembly. This is a critical element of the installation. When there is a risk that you can pump any water, but municipal water back into the municipal supply, you have to install a backflow preventer. It is not a non return valve, but a specialized valve built and designed for these applications. It also has to be inspected  by a specialist plumber every year

 

Positive aspects.

  • This is the ultimate “green” water solution for a new building and adds significant value to the property for re-sale.

  • The system is developed and designed at conceptual stage - reducing cost and focusing on maximizing rainwater recovery.

  • When you design a system like this it delivers the greatest return on your capital investment.

  • All the roof surface of the building is being used to harvest rainwater as efficiently as possible.

  • There are no dual plumbing and piping system. The purified municipal water simply replace the municipal water.

  • If the municipal supply is interrupted the building will still have pressurized potable water

  • Installation time is about 7-10 days.  

 

Negative aspects

  • These system can be expensive but it has a good return on investment.

  • It is best designed  by the Engineers and Architect involved in the building design.

Costs - Installed on site

 

Two  1000l interconnected  tanks - R30000

One Wisy WFF150 vortex filter  R9000

One multi-siphon overflow R2600

One floating suction R1000

PVC Down-pipe and fitting  R2000

Tank Base with R4000

Tank Gauge - R1400

Pressurized water filtration system - complete unit R22000

One Solenoid make-up valve system with level switch R3500

One Municipal switch-over system R1000

One Backflow preventer assembly R2100

Valve, brackets,  and accessories R3000

Design, Installation and commissioning -  R18000

Total R 99000


Potential amount of rainwater that can be recovered in a coastal zone with 1040 mm of rain per year is 347 000 liters per year,

5000l Raincell Rainwater Harvesting system

Use-rainwater.com is offering a 5000l Raincell® Rainwater harvesting system and municipal back-up system with water purification. The configuration is perfect for estates where aesthetics must comply with estate specifications and space is limited.

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