Back in mid Dec 2019, I expressed interest to have an experimental filter installed before having the piping laid. My dad made one and we installed it by early Jan 2020. He wanted to try out his idea so I thought why not. Unfortunately, it only lasted ONE day with a moderate performance at the expense of flow rate, before a heavy downpour on one particular day rendered it useless. Sad but there was indeed much to be learnt from this experience.
The concept for the innovative filter is pretty simple: a double filtration system that channels clean water out into the intake pipe at the dam, made up of both external fabric and internal used mattress protector. We soon learnt much later on that the biggest mistake was to try filtering water at the capture point (water source) where pressure was non-existent. More on this later.
We repurposed a large green barrel by drilling holes to its side at the mid point. A couple layers of used bedsheet cover is then wrapped around the numerous tiny holes drilled on the barrel. This is fastened tightly by two bicycle tyre tubes. Inside the centre of this large barrel is placed a 4″ pipe, which also has tiny holes drilled into it. Both the outside barrel and this internal 4″ pipe is connected by a 1/2″ pipe.
Water would seep through the external bedsheet cover into the green barrel before being filtered a second time through a double layer of towels (white and blue). This filtered water would enter the 4″ pipe which leads to the outgoing 1/2″ pipe jutting from the filter unit. This outgoing pipe will be connected to the intake pipe of the dam, after which the water will be sent to the farm via plastic transparent hoses.
Unfortunately, during a heavy downpour, it appears that the water level rose unexpectedly high resulting in silt and debris entering the filter unit. The entire filter was thus compromised. A thick layer of silt wrapped around the external fabric. Despite some cleaning thereafter, we soon realised that the filter was blocking just too much water to be sent into the hoses. The intake rate was severely affected.
After some troubleshooting, the team at Soilogy advised against having a filter at the capture point of the water source. Because pressure was almost non-existent, there was not enough force to push water consistently through the filter to generate a reasonable outflow of water into the hoses. A number of other implemented designs at the trail of water hose also negatively impacted water flow; namely, the installation of release valves thought to help release air bubbles, but instead, contributed to air bubbles.
I guess at the end of the day, my dad was satisfied that his ideas were put to the test. Fail it did, but learnt even much more we did. In the end, it was a simple used oil can riddled with many holes that saved the day. The Soilogy team, led by Mike remarked that while the filter was truly one of an innovative kind; his experience led him to reckon it would not last a single day. Truly he was right. Reason being, we can never fight nature. The immense force of incoming water and silt after a downpour – thus, clogging the filter – can never be underestimated.
More importantly, filtration should always be done with pressure. That means, filtration should be implemented at the point of usage. For example, once all water has been channeled and stored in a tank, the tank itself would hold immense pressure. Filtration then can be done when water is released from the tank to be used.
In short, this is simply the nature of a natural dam. It requires periodical maintenance. The dam has to be inspected from time to time. Silt, debris and sand have to be occasionally removed. That’s a given. They can never be filtered at the source, not at least for this setup of ground water source where pressure is zero. Had it been a voluminous source, the resulting pressure may have probably made a filter work.
Perhaps once a year, the dam has to be drained and cleaned up. Until then, it’s about saving and using water wisely while appreciating and respecting the force of nature.
