Calcite clogging septic tank outlet filter?

MJS Posted By MJS, Oct 31, 2013 at 11:46 AM

  1. MJS

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    I have acid well water (5.5 pH) with sediment, so I have a main line water filter, an acid neutralizer and a water softener. I add about 40 lbs of calcite to the neutralizer tank twice a year to keep the level between 50 and 75%, and 40 lbs of salt to the water softener every 3 weeks or so. Both tanks backwash into the house drain pipe. There's a Zoeller(?) filter in the septic tank outlet pipe which clearly does its job. The filter routinely gets clogged with white-ish pebble-sized pieces. Is that from the calcite? If it is, what can I do about it? We're very careful about what goes into the septic tank. The filter first clogged about 10 months after the house was built in '03. Since then I'm lucky if I can go 3 weeks without cleaning the filter, all year round. I check it at least once every 2 weeks. It's been this way for years. Thanks for any insight and suggestions.
     
  2. semipro

    semipro
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    What type of salt are you using for the water softener?(CaCl, NaCl, etc.)
    What is the flow order of the neutralizer and softener systems? That is, which one flows into the other? I suspect neutralization occurs first but wanted to check.
     
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  3. MJS

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    Thanks for the quick reply. I use straight NaCl (typically from Home Depot - blue bag, either Morton Salt or Diamond Crystal), and fine calcite for the neutralizer. And yes, the neutralizer flows into the softener.
     
  4. burnham

    burnham
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    I don't know anything about this, but my buddy that owns a septic service hates water softeners and powdered Tide detergent. I know he said Tide would clog the baffle, not sure about what his beef with the water softener was.
     
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  5. semipro

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    I have enough knowledge of aquatic chemistry to know that its complicated.
    I asked about the salt type and treatment order thinking it would give some idea of the reactions occurring. It didn't really so I've read a bit on the web.
    A couple things I read stand out.
    The first is that calcite alone is seldom recommended with pH below 6.0. With more acidic water (lower pH) it is recommended that magnesium oxide (Corosex) be mixed with calcite for proper neutralization.
    The 2nd is that the issue of salt laden water softener backwash effects on septic are controversial. Some contend that the introduction of high density salt water into the tank displaces sunken solids allowing them to flow out, clogging the drainfield, or in your case, the outlet filter. This seems reasonable to me.
    I also can't help but wonder if your softener is not over regenerating the column in that its washing much more salt water through it than is needed for regeneration.
    No sure answers here but maybe this will bump your post and someone that know's something will chime in.
    Good luck.
     
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  6. Highbeam

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    I am all set up to install my water treatment equipment. I have a septic and the LAST thing I would want to do is run all of that backwash and regen water into the septic system. Flush that junk out into the grass somewhere. These things backwash every so often for 14 minutes at 5-10 gpm. That's a lot of water not to mention the funk being backwashed. A normal house uses about 200 gallons per day so the extra 140 per device is like dumping another house into your system.

    I doubt that the treated water is your problem, it's that nasty backwash with all the funk plus the high loading of waste into your septic during a backwash.

    Can you divert the backwash waste? Even for a few months to see what happens?
     
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  7. MJS

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    I would have to poke a hole through my outside wall or dump the backwash into my sump pit.

    Update on the pH- I used a test strip I bought today from Home Depot: untreated: <5, treated ~6. Also, the whitish pebble-sized pieces that clog the septic tank outlet filter turn to powder when dried and crushed.
     
  8. Highbeam

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    Poke a hole or use your sump pit. It is silly to run this concentrated nasty stuff into your septic system.

    Why can't you get your pH up to neutral? Even at 6 it is quite acidic and will dissolve copper. I've had to fix city water systems that were making 6.5 water and causing pinholes in the plumbing along with excessive discharges of dissolved copper from the sewage treatment plant. I used caustic soda injection (NaOH, aka lye or sodium hydroxide) to raise pH.
     
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  9. semipro

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    Agreed, 6 is too low. The pH scale is logarithmic so pH 5 water is 10 times as acidic as pH 6.
    As I mentioned above it seems you could easily add some magnesium oxide (Corosex) to your system to raise you pH to 7.
    Neutralization processes creates "salt" as a byproduct. You're also adding salt to your system when you regenerate your softener column. That's a lot of salt for a septic system to handle.
     
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  10. homebrewz

    homebrewz
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    Interesting problem. There are some places where the geology can't buffer out the acidic rainwater that recharges the groundwater.
    How deep is your well, and do you know what its completed in? Sand and gravel, or bedrock? If bedrock, do you know what type?

    I don't have much to add, except that the whitish stuff is probably one of the byproduct salts from neutralization.
    In your case, its either calcium chloride or calcium sulfate.

    Calcite is a slightly weaker base compared to magnesium oxide, so magnesium oxide should do a better job of mopping up the extra acidity.
    If you can neutralize the acidity more efficiently, you may see less byproducts clogging the filter.
     
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  11. TradEddie

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    The Corosex (also called NS Mix when pre-mixed with Calcite) has other advantages too, it adds less hardness to the water, much less gets consumed so you need to refill less often. It does cost more, but I think in the long run it works out less expensive. Finding a retail supplier is the only problem. Do not use pure Mag Oxide, it will cake up and clog.

    A properly operating neutralizer should not be adding salt to the backwash water, the "salts" (not sodium chloride) it produces stay in solution (adding hardness), only the softener regeneration would add salts, the neutralizer backwash is really only to flush out particles because it acts as a depth filter too.

    TE
     
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  12. MJS

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    Update- the water treatment company man came out and tested my water. From the well it's 5.5 pH, at the faucet it's 7, as it was when they installed the system 10 years ago. (So, don't blindly trust the $10 water test kit you can buy, it said both numbers were lower.) Like everyone else I've talked to, he hasn't seen this problem before. I'll have those whitish pieces from the septic tank tested at a lab to see what they are. I poured vinegar on some dried ones and nothing happened - didn't bubble (bubbles would indicate calcium) or dissolve. They turn to powder when crushed.

    My acid neutralizer back washes every 6 days, about 50 gals per cycle. The water softener back washes every 1500 gallons, also about 50 gals per.
     
  13. velvetfoot

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    Do you know the hardness of the water? It seems like a lot to me, but our water isn't that hard.
    Not that it has anything to do with it but do you use the crystals? In the softener brine tank I've had better luck with crystals rather than pellets, as far as clumping. I've heard that the pellets are formed as the byproduct of some other product, not sure what.
     
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  14. Highbeam

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    Interested to see what the lab comes up with. Calcium, magnesium, etc. what makes you think that it would bubble with vinegar? By the time those minerals precipitate out and form that white junk they are a salt and at equilibrium If the calcium was pure and unbonded it might fizz. Vinegar is an acid and since your water is so acidic, I doubt that additional acid would create a reaction. Septic tanks are quite acidic as well due to the stuff you add to the water before dumping it. Put something basic on there and you might see a reaction. Got any lye?
     
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  15. homebrewz

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    Effervescence is the classic reaction of a carbonate with acid, and usually hydrochloric acid is used. I'm not sure if vinegar if strong enough to promote a reaction. Maybe if its heated. I'm guessing you have some kind of sulfate product showing up, maybe CaSO4 or MgSO4.
     
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  16. sjb2015

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    I know this is an old thread but was hoping someone could help. Did you ever find out what was causing the white-ish pebble sized pieces in the effluent filter?
     
  17. onetime_poster

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    This is an old thread, but I have 4 years of constant experience with this problem now.
    The issue is that you cannot put and kind of salt in a septic tank that has an effluent filter.
    During the backwash cycle, enough salt brine goes into the tank and it keeps the finer particles from settling correctly, and they stay suspended in the graywater middle area of the tank. The suspended particles get washed into the filter and plug it frequently. The white particles you see on the filter is the salt residue. I even switched to potassium chloride to see if it helped, and it still had the same problem. You have to send your backwash somewhere else, not into the septic tank. I ended up switching to potassium chloride and I dump it outside on the ground, since potassium is good for our plants. That made my issue a lot better, and my filter lasted longer. I still have some early clog ups due to washing machine lint if my wife washes a large blanket. etc.
     
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  18. MJS

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    I think I've figured out what those pieces are. By chance, our kitchen sink drain became clogged the other day, after running slowly for some weeks. When I snaked the drain pipe, I pulled out a few pieces that look and feel a lot like the pieces in the septic tank. My wife is a voracious baker, especially chocolate chip cookies. I expect that those pieces are cookie dough and cake batter, not to mention icing, that went down the kitchen sink drain and solidified in the drain pipe. The plumber agrees with my assessment (I had to call a plumber to clear the clog).

    From now on, we won't put cookie dough, batter and similar things down the drain. My plan for the septic tank is to clean or replace the effluent filter and have the tank pumped to get rid of what's in there now. I hope and expect that that will prevent another occurrence of both problems.
     
  19. Highbeam

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    Good thing you have the filter or all of that clogging would be occurring in your drain field!
     
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  20. AlbergSteve

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    Flour and grease are deadly in drain pipes, and those backwashes should be routed outside the septic system.
     
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  21. blades

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    Unfortunately in many area it is against code to run your softner backwash out over your land - ( pure bullxxxx to me but that's the rule ) In my area I am also not allowed to run my basement ground water collection any where else except the septic -- Now I do not know where they find these morons but they sure seem to be breeding at an exceptionally high rate. This is farm country and my land is ag2 ( my limited knowledge says salt and concrete do not play well together)
     
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  22. Highbeam

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    Those rules are not normal. Especially sump water to septic! Taken out of context though I can see how it might happen, you’ve got to ask the right question.

    Floor drains in a basement need to go to sewer , not storm. If the guy you ask doesn’t know the difference then that’s your problem. I let people hook sump pumps to storm all the time. I require it since I don’t want tons of groundwater in the sewer.

    Usually if you’re in close enough for these people to care where your backwash water goes then you are on municipal water and sewer.

    Sometimes it’s better not to ask. They don’t even want you washing your car and letting the water make it to a storm system.
     
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  23. semipro

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    The main problem with salt and concrete is either corrosion of reinforcement metals or spalling that occurs during freezing. I don't think either of these are an issue in septic tanks. Besides, most of what's going into a septic tank contains a lot of salt anyway - kitchen waste, urine, etc.
    Most softener systems use a salt solution to regenerate the softening tank. The backwash is salty and not the kind of thing you want to put out on your land. At least if you put it in the septic tank it ultimately discharges below the surface (hopefully) where the salt won't damage vegetation - still not a great thing for the groundwater but the lesser of evils.
     
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  24. Sodbuster

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    I have run my softener water into my sump pit for years, I don't even know If I'm supposed to or not, and don't care, it all ends up in the same place anyway. Also live in the on acreage, so no nosy neighbors to bust me.
     
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  25. Swamp_Yankee

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    I'm glad I caught this thread. We moved into our new house with a brand new septic last year-we have plenty of experience with septic, but not with water softening/pH balancing. We never needed it in the past. Right now the water treatment backwashes to the septic. Previous to the new septic the former owner was discharging his laundry machine, dishwasher, and kitchen sink to daylight off the side of the house but as per code that system was abandoned and the outfall was buried. I had been contemplating digging it up to reconnect the laundry, dishwasher, and sink to it, but I'll definitely be hooking up the water treatment as well. We've had no issues with the effluent filter yet, but better safe than sorry.
     

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