Unsatisfactory sediment removal

[Warren P]

I use city water, which is sourced from surface water and heavy rains can load it with a lot of sediment. Right now it has so much sediment that washing clothes gets them dirtier, as I inadvertently discovered to my wife's annoyance (thanks for nothing, Hurricane Eta). So I installed an inline filter upstream from the washing machine with a pleated 50 micron filter. Seeing no improvement, I tried 5 micron and 1 micron polypropylene filters. Still no improvement. I'm stumped, because all online resources I have found say that this is the range of filters that should work for different kinds of sediment.

What does reduce the level of sediment, although not enough for my purpose, is to reduce the flow rate. If I mostly close the shutoff valve just upstream from the filter so that only a trickle comes out, the water is less muddy. It is still too dirty to to wash clothes with, and the pressure is too low for the washing machine to use, but it is a data point.

Ideally I would call in a professional at this point, or at least get the water tested to determine the diameter and composition of the sediment, but those are not options here. I'm in a small town in a developing country and will have to make do myself with what I can find in the hardware store.

What might I be doing wrong, and what might I try to get water clean enough for the washing machine?

 

[LLigetfa]

How do you heat your water and is the hot water just as bad?

 

[Sponsor]

 

[Reach4]

Put tinted water into a glass jar or drinking glass. Let it sit undisturbed. What does it look like initially? How different does it look an hour later? 24 hours later?

Also, it it possible that the filters you used are a different size than that filter housing is made for?

 

[Warren P]

How do you heat your water and is the hot water just as bad?

The average temperature here is about 30 C = 86 F, so all we have or need is a tankless heater for the shower. There's never been any filter upstream from them, so the heater and shower head do need to be cleaned out periodically, and what comes out of the shower head today is pretty dirty. Ideally I'd filter all the water entering the property, but it's just as well that I didn't try to do that because I would have used the same inline filter that isn't working for me now.

 

[LLigetfa]

I wonder if the particulate would settle out if the water was first fed into a large storage tank which was why I was asking about the water heater.

 

[Warren P]

Put tinted water into a glass jar or drinking glass. Let it sit undisturbed. What does it look like initially? How different does it look an hour later? 24 hours later?

Also, it it possible that the filters you used are a different size than that filter housing is made for?

Using a bucket as in the photo, initially I can see faint swirls in the suspended sediment as water enters the bucket. After just a few minutes fine silt-like sediment begins to settle. After 24 hours the water appears to the naked eye to be just as dirty as ever though there is more sediment at the bottom of the bucket.

I too suspected that I might be using the wrong size filter, so I measured them and compared them to the manufacturers' specifications. The 50 micron filter came with the Rotoplas inline filter I purchased. It was 9 3/8" tall, just as the manufacturer specifies, and when I removed it I could see that it had bulged very slightly in the center by being compressed while in use. Ditto the 5 micron filter came with the Foset inline filter I bought to replace the Rotoplas, because I wanted to eliminate the possibility of a defective inline filter. That filter, and the 1 micron filter I later used, were both 10" tall, just as the manufacturer specifies.

I also wondered if I had mis-installed them, so I opened and reinstalled each several times, and confirmed that there was no leakage between inline filter top and jar.

 

[Warren P]

I wonder if the particulate would settle out if the water was first fed into a large storage tank which was why I was asking about the water heater.

That's a good thought and I wish the plumbing of this house wasn't such an undocumented mess. Street water goes to a ground level storage tank, is pumped to an elevated tank, and is gravity fed to the house. If that was all, I could probably rely on much of the sediment settling out in the two tanks before getting to the house. Unfortunately there is also a direct connection from the street to the house that predates the pump and tank. Not even the owner (I'm a renter) knows where I might dig to find that connection and cut it, but it may well be under any of several concrete slabs. The house itself is on a slab foundation, so there is no crawlspace underneath to investigate.

There is a parallel universe where things are easy. In it, alternate-me had no trouble doing the following to solve all my problems:

1. Find and cut the direct connection from the street to the house. With that cut, all water must sit in both tanks and settle a bit before getting to the house.
2. Move the inline filter (which now magically works great) to between the pump and the elevated tank. That way, the water not only sits twice in two tanks but is filtered as well.

 

[Reach4]

It might be good if somebody could suck out the sediment accumulated at the bottom of the ground level tank.

You seem to be trying the right things.

when I removed it I could see that it had bulged very slightly in the center by being compressed while in use.

A cartridge filter should feed the unfiltered water into the space around the filter cartridge, and remove water from the inside. Getting that backwards would not cause your symptoms, but it would reduce the filter capacity before clogging.

 

[Warren P]

It might be good if somebody could suck out the sediment accumulated at the bottom of the ground level tank.

You seem to be trying the right things.

A cartridge filter should feed the unfiltered water into the space around the filter cartridge, and remove water from the inside. Getting that backwards would not cause your symptoms, but it would reduce the filter capacity.

I actually did drain, clean, and refill the ground level tank with clean water before the hurricane came, knowing that the city water was going to be dirty for a while.

I did confirm during installation, and again afterward, that I got the inlet and outlets set up right. I see what you mean and can certainly imagine someone getting that backward.

Good to know that I'm not obviously on the wrong track. So far the worst of all this is the nagging feeling that I must be doing something laughably, stupidly wrong.

 

[Bannerman]

Is there a lab test report for the raw water?

Since the turbidity is comprised of fine suspended particles which are not settling out on their own or removed by filtration, one possible option will be to utilize a coagulant and flocculation. These processes will cause fine particles to combine to form larger particles which will become heavy enough to settle out within a subsequent settling tank which is then followed by sediment filtration.

 

[Warren P]

Is there a lab test report for the raw water?

Since the turbidity is comprised of fine suspended particles which are not settling out on their own or removed by filtration, one possible option will be to utilize a coagulant and flocculation. These processes will cause fine particles to combine to form larger particles which will become heavy enough to settle out within a subsequent settling tank which is then followed by sediment filtration.

Flocculation, that's a good idea! I'll visit the local well service company Monday and see if they sell flocculant, provide testing, and/or can give any advice. I had hoped to do some initial experimentation with grocery store alum but sadly the local store doesn't carry it.

In the meantime the city water began running reasonably clear again this afternoon, but I'll follow up as possible now in order to be better prepared for the next time. Many thanks for the good lead.

 

[Bannerman]

Each municipality operating a water system will usually post an annual water test report on their web site. If not posted, it should be provided to you on request. Perhaps standard practices within the US and Canada, may not be standard in Honduras?

 

[Warren P]

Hi, I'm back with a follow-up report. For hurricane Iota (two hurricanes in three weeks, yikes) what I did was flocculate the incoming turbid water in the first, ground level tank, and let it clarify before pumping it to the elevated tank for distribution to the house. Works great! One of these days the city water will become reasonably clear, and when that happens I'll clean out the sediment at the bottom of the tanks. Thanks again, folks.

 

[Water Pro]

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