Remediation of filtration systems is tough work at best. The use of manual labor, with conveyors, sump pumps while fluidizing media and vacuum trucks are all current methods utilized to remove media. Our company specializes in filtration system rehabs and we have completed hundreds of filtration plants across the US. The methodologies of removal and replacement often are determined based on the filtration system design, physical location and type of media, support gravel or underdrain to be removed.
New technology has been developed to provide "in situ" cleaning of all portions of the filtration system to include underdrains, media and support gravel. This technology has provide untold savings on filtration rehab by cleaning existing media and topping off with new media. Contact me at the email provided or see our website at www.s4water.net to listing of our past projects, current projects and an explanation of our media cleaning abilities.
How the process is treated depends on what type of sand filtration is being used. Are we talking a rapid sand filter here? Semi-rapid? Or is it a slow sand filter?
If it's a rapid filter, then instead of a removal of the media involved, cleaning it by backwashing will generally solve the issues being faced – even if you've got severe slowing of water movement.
If it's a semi-rapid filter, then replacing the materials is pretty straightforward. You just pull out the sand and gravel that has become ripe and replace it with fresh materials of the same quantity and quality. It's a lot like what homeowners in rural areas need to do with their sand filters for their septic pumps.
For slow sand filters, the level of micro-organism contamination kind of dictates whether you try to replace the materials or you try backwashing.
It can be a lengthy process – depending on the temperature and the quality of the water in question, it could take several months. If you've got chlorinated water, then you've got an even bigger headache.
And if you've just decided to replace the media, keep in mind that some areas have specific disposal protocols which must be followed because the ripe media is sometimes classified as a hazardous material.