Media removal, replacement and filter inspection in a rapid gravity sand filter

Lessons learnt the hard way

What is the most effective way to replace 37 tonnes of filter media?

Three things to consider

Removal of

old media

Inspect and repairthe empty filter

Re-instatingThe filter

2007 – The Hard Way

Media stored in sacks!!

Re-sorting media after sacks rotted

What we found!Damage to filter 2 in 2007

Media is removed by Richardson’s Drilling using an air vacuum pump system, then sorted and stored in big yellow metal shipping containers

onsite.

2010 - Getting Better

Richardson's Drilling staff members are a committed bunch!The only way he could get the suction line primed

Above and beyond the call of duty

Note the clean undies

Filter floor before baffle walls put in and levelled channel plate.

Media replacement because of poor performance on Filter #2 due to re-using

old media

2012 – We’ve Nailed It

Washing workers boots in sodium hypochlorite

Hygiene procedures are followed to help minimise any possible contamination.

Davies staff removing the media one layer at a time then storing it all separately onsite for re-use within other council

jobs.

Filter Inspection

Check all

nozzles

Inspect conditionOf walls and filter

floor Watch theair scourpattern

Turitea’s #1 Process Technician inspecting filter nozzles.

That’s me!!

Once repairs are made it is important to inspect air scour and up wash patterns before the media is replaced to

check the repairs were successful.

Two important people inspecting the air scour patterns after the repairs are completed.

Re-instating

Mark the filte

r

walls for th

e different

media grades

Back wash in between layersto wash the media, and

remove the thin layer of ‘fines’ between

each layer Soak in Sodium hypo overnight.

Putting brand new media into the filter using a hiab truck.

1 Bag at a time

What is the most effective way to replace 37 tonnes of filter media?

Conclusion

From 3 weeks To 3 hours

Ask this guy!