FilteringThe filtration system in any rainwater harvesting system is dependent on what the water will be used for. If potable uses are intended then more rigorous filtration is needed as opposed if water was only intended to be used for landscaping and irrigation purposes (11). The purpose of filtering the water is so it doesn’t smell or become contaminated by extraneous debris which could contaminate the storage tank. These are typically installed near the storage tank. The filtration system usually consists of filter, gutters, and downspouts. (5) A summary of types of filtration systems and their cost is shown in the table below:
There is no best option for the filtration system as it all depends on what the use of the water will be. Some are great for irrigation uses but not potable uses while others are great for both. A figure showing a filtration system is show below (12):
Storage TankThe storage tank houses the water until its ready to be used and is the single most expensive component when building a rainwater harvesting system. (11) After all the water is filtered through the gutters, downspouts and filters, the water is kept in this tank. Storage tanks vary in building materials, and some of the more popular materials, their costs and sizing are highlighted in the table below.
As we can see the rain barrel is only an option for those looking to build rainwater harvesting for residential areas. On the other hand the wood and the polypropylene can be used for industrial and even commercial purposes (8). The storage tank is all dependent on the owner’s choice and available funds. The storage tank can be left above the surface or in the ground. (11) Examples of both are shown in Figures 6 and 7.
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Because either of the two pumps are great choices and their price differential is minimal, it’s all personal preference (13). Figures 9 and 10 show the differences between the two pumps (14,15):
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