Chlorine experiment

[Chris Bates]

Hi Fraser,
Quite impressive figures - I guess the Chlorplus does what it says in the spec quite well.
Can you clarify the configuration of these 2 different types of filter ? i.e which ones were in series or parallel ?
Also if you changed the filters at sample 8 how did you get the following 8 samples ?
Or am I being thick ?
Chris

[Ian Wilde]

Nice work Fraser.

So that's 1,500,000 litres of water

What does the BB stand for in the filter description?  Just trying to visualize the setup.

[fraser gilmour]

We have two parallel streams, each with a standard 20" housing first then a 20" "big blue" housing in series. Ian, the BB housing   is able to accept a 4" wide cartridge so double the capacity compared to the standard.
Chris, I plotted the graph over six months from Autumn to show how the filters perform as the chlorine level increase to our normal peak of around 0.5 mg/l. We normally swap out at around three months and you can see that corresponds with the dip in the post level after sample eight even though the incoming level is still rising. We used to run with EP filters but our local water company switched to chloramine a few years ago so we upgraded to the chlorplus. We also have the smallest plant room in the world so no space for GAC columns.
I'm going to try running with just the two big blues in parallel, will post the results.

[Ian Wilde]

Judging from your experience, what would you recommend for our home setup Fraser judging on the chlorine levels you have seen from my spreadsheets for the incoming water to be able to change the filters every 6 months rather than monthly?  
Our water supplier doesn't use chloramines for pipework disinfection.
A 20" carbon block or perhaps a "big blue"?

[fraser gilmour]

I don't have any experience of running filters for that long, I've always been a bit wary of the amount of slime that builds up on them over that amount of time. However if others are doing it there can't be much of a problem and I would prefer to change the HHD filters ourselves to coincide with the six monthly water testing, may try it myself. If I were in your position I might try out the Pentair CFB plus or Spectrum SCB range, not sure what your water is like for sediment but I've never bothered with pre filtering our carbons at home. You could just try two standard 10" carbons in series.

[Ian Wilde]

OK I know its been a while but I've got my hands on some 10" granulated carbon filters so I thought lets test them and post the results!




I believe granulated filters take some rinsing so we'll take a look at that element too.

[Chris Bates]

Hi,
We have been running 2x 20" CFB-Plus filters in series for 11 months now at a home patient. The patient dialyses 2.5hrs 6 times a week. We are measuring monthly with a Chlorosense - no sign of breakthrough yet.
The spec is 75,700 litres each and the patient's water consumption is roughly 100000 litres/yr.
We visit twice a year but I am probably going to change these filters only once a year on a filter change and sampling visit.

Filter changes every 12 months !!!  I can hear the sharp intakes of breath around the country but so far these figures look good enough to me.

Chris

[Ivor D]

We are also considering a similar set-up and are in the early stages of a trial to determine the effectiveness of switching to 1 micron carbon block in chlorinated areas as well a previously chlorominated areas.
Pre-filtering is critical here as although we have soft water it is high in organic matter.
The figures look good, we just need to avoid blinding.

[Ian Wilde]

Excellent work chaps!

I'm with you there Chris, if the figures stack up plus you have redundancy from the RO too you should be fine - shouldn't you!?

I'm trying 10" filters to start with purely because we already have the 10" filters bowls installed in the homes.

I would think you'd definitely need prefiltering with a 1 micron filter Ivor - don't think it would take long for us to block that up here in the north west.

[Ivor D]

We do Ian.
Having historically used 5 micron carbon block filters, 10" like yourselves, we have been using 1 micron sedimet pre-filtering for some time. True depth filters dropped our already low water pressures too far so we use pleated filters.
What we're trying to establish right now is whether we will need to drop to 0.5 micron sediment pre-filters.

[Chris Bates]

Hi again,
As a result of this thread I calculated worst case annual water usage by each home patient.
One home patient's consumption was approx 50% more than the average. As a result I am now fitting 3 of the CFB-PLUS20 filters annually at all patients. This will provide more than enough chlorine removal at all patients. This will be a total extra annual cost of less than £500 but will give me a little peace of mind.
I also expect few problems with blockage as they are a 5u depth filter rather than a surface filter like most carbon block types. Pressure drops seem pretty low too.
For a year or two we will test the chlorine levels before and after changing the filters to confirm their effectiveness.
Regards
Chris

[Ian Wilde]

Nice work Chris.

Just to update everyone on why this thread has not progressed recently - I'm just waiting for a delivery of chlorosense test strips so if anyone from Palintest is viewing this see if you can get a wriggle on with our order ;-)  

Cheers

[Ian Wilde]

So I have now loaded up my granulated carbon filter - 10" into my filter housing!

Knowing that some rinsing is required of this type of filter I thought I'd rinse it into a white bucket and see just how bad it may be.  

And here are the results:



Not sure if you can see on the picture but that is 3.5 litres of rinsing.  As I wasn't sure if it was still pumping contaminated water out I then rinsed another 2 litres or so into a measuring cylinder and it looks like this:



As you can see it is clear which tells me 3.5 litres of rinsing is plenty before letting the water get through to your RO with this particular brand of filter.