In a post way back here, I was talking about the sewer system on Plum Island and I invited reader Bubba, in the comments, to think some more about water freezing and how the sewer people are saying the water in the pits is freezing from the top down.
I wrote a story that kind of addresses this but it did not make it into the paper because there was so much more newsy stuff that went on last week.
I would have made the same decision.
So ... has anyone thought about it?
The people here are saying it's freezing from the top down, which is what a body of standing water does.
The guy in Michigan is saying OK, technically if you're pumping out the pits in the fall, the water freezes from the bottom up because you get an inch of water accumulation at the bottom and it freezes; and an inch or two on top of that, which then freezes - and so forth until the most recent water is freezing at the same level as the works.
If you get that much rain during the winter.
To be fair, it did rain a lot this winter. But I don't know if it rained enough before Jan. 14 or 15 to fill up a pit - and aren't roads canted slightly so rainwater runs off the road?Not sure if that's true out here because there are no storm drains.
I don't know how much space there is between the top or the bottom of the pits and the controllers, but it seems to me if they're breaking solid ice from the top of the pit, there must have been a hell of a lot of water in them babies before the temps dropped.
I do know the sump, or bottom part of the pit, holds 10 gallons. But I also know the pits come in different sizes, and the sewer people are saying the freezing is happening mostly in the most shallow pits.
I'm assuming that by "shallow" they mean the works are closer to the top.
Which is why if you pump out the pits, the man in Mich. meant, there is never enough water accumulation in there to freeze from the top down - not meaning the actual freezing process, but that you shouldn't let that much water accumulate in the pit.
But - if you can believe it - I had a hard time believing it - the system should work, even if frozen in a block of ice, according to this guy in Provincetown (a Mr. Bill Burke, WWTF plant manager and collections manager),where they also use a vacuum sewer system.
Interesting how he recalled speaking to someone from here but did not recall recommending drilling holes between the two parts of the pit ... I do believe that the same someone from here who spoke to him said that "Provincetown" did recommend it ... told six city councillors that, a week ago last Thursday ...
But then, either one or both of these guys may have an agenda.
Mr. Burke wasn't too happy about references to Provincetown being warmer than here and that's why they don't have the same problems.
As Bubba pointed out, I believe, water freezes at the same temperature everywhere. And it's not like it's Tropical in Provincetown during the winter.
10 comments:
Without knowing how much water was originally in the pit and/or the rate of seepage during a rain event one can only speculate about how the ice is accumulating. Ideally, one would not only drill the hole but also pitch the bottom of the valve pit towards the drain hole. Hopefully the pits have settled out of level whereby drilling the hole on the low side would drain the water towards the hole.
Well no ... they have said repeatedly that it's freezing from the top down, which as you pointed out is how standing water ices up. That says to me the pits were full, or nearly full, of water by the time the temps dipped below freezing.
And heaven forbid the holes should get clogged up by random bits of grass, pine needles, gravel or you know, sand. You say you live out here - you know the sand gets everywhere and how many people have gravel driveways.
I wonder if anyone has thought about the impact of sand/gravel accumulating in the bottom, sealed part of the pit - or being sucked into the sewer system.
Just a thought ...
Well, technically water freezes from whichever direction(s) the coldness is applied - if you've ever removed a tray of ice cubes from the freezer before the completely frozen it's the center that freezes last.
As for the valve pits, it's quite possible that they were pumped and that several subsequent rain events caused the ice to form in layers.
Certainly debris would be a concern but fortunately they have several months to analyze the pit debris.
Yes, the sand does get everywhere with quite a bit of it making its way down my shower drain after a day at the beach. One would hope that the system is tolerant of small amounts of sand.
No system is perfect - all one can do is minimize unwanted conditions. They have several months to decide which is the preferred solution.
Oh Bubba - are you on retainer for the sewer dept.? Or are you just trying to provoke me?
Neither, I thought we were having a civil discussion regarding the finer points of sewer pit remedies.
OK ... well ... moving on from how water freezes since I've been told the system should (and does, if people are to be believed) work underwater and in a block of ice ... how about the smell?
I haven't really noticed any smell.
More fun with science. The lowest plumbing fixture in my home is about 12 ft above the ground. My candycane is about 3 ft. Now we know that water will seek it's own level, so where do you suppose the sewerage will flow should my sewer pit malfunction ?
I think I chose wisely when I instructed my contractor to place my candycane adjacent to the roadway.
I meant after they drill the holes! geesh
Sadly, the plumbing here I fear is below the top of the candy cane. But I think this is the only house on the pit and the plumbing is all on the other side of the house from the vent (closer to where the well was), so I hope I'd be alerted to a problem before 'it' ends up on the floor.
Oh, well if the smell isn't working its way up the candycane, I don't see it making it's way through the valve pit and manhole. That said, there's talk of plugging the hole except for the winter when of course, I'm not out in the yard.
PS I do find it ironic that I was the one who chose the location for my candycane - I guess that's how they ended up too close to the pits. Would it be rude of me to blast "The Candyman" across the neighborhood as sewer workers search for frozen valve pits ?
Hey, it sounds like someone talked to the guy in Michigan ... or maybe not. He said they had to plug all their holes back up - permanently. Per the order of their version of the DEP.
Huh, you chose? So did a lot of my neighbors (some have them under their decks).
And if the smell doesn't come out the candy cane, how do you suppose "freezing ambient air" going down them could be responsible for the freezing? Not only was that in the now famous memo, but that's what sewer crews are telling people, I hear.
I also hear that the system doesn't suck in the "ambient air" unless it's evacuating the pit ...
"That said, there's talk of plugging the hole except for the winter when of course, I'm not out in the yard."
Been talking to Pedro, have you? Tell him "hi" from me ...
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