Treatment plant

aoifski

We have a treatment plant (rather than plain) septic tank in our garden and have had issues with it since it's installation.

Issues mainly to do with drain smells which sort of leads me to believe that it's not working correctly.

There is a vent pipe coming out of it as with all tanks, which is not blocked and on specific days (cant figure out whether it's when it's raining more or drier) the smell around the tank is horrendous! God help our neighbours, or us when they eventually decide to kick up stink (no pun intended!) about it!

My understanding of a treatment plant is that the sewage is "treated" and it shouldn't smell. Lots of people who have come to empty/service have said it shouldn't but noone has any suggestions as to why it does and what we can do to get rid of it.

Last guys suggestion was let a hunk of meat go rancid and throw it in?!!

Anyone got any knowledge or experience of these, how would we know it's not working, if it is and this is the norm, what we can do? Is there a special vent or something?

ART6

aoifski wrote: »

We have a treatment plant (rather than plain) septic tank in our garden and have had issues with it since it's installation.

Issues mainly to do with drain smells which sort of leads me to believe that it's not working correctly.

There is a vent pipe coming out of it as with all tanks, which is not blocked and on specific days (cant figure out whether it's when it's raining more or drier) the smell around the tank is horrendous! God help our neighbours, or us when they eventually decide to kick up stink (no pun intended!) about it!

My understanding of a treatment plant is that the sewage is "treated" and it shouldn't smell. Lots of people who have come to empty/service have said it shouldn't but noone has any suggestions as to why it does and what we can do to get rid of it.

Last guys suggestion was let a hunk of meat go rancid and throw it in?!!

Anyone got any knowledge or experience of these, how would we know it's not working, if it is and this is the norm, what we can do? Is there a special vent or something?

Septic tanks work on anaerobic digestion -- ie the bacteria work on the sludge in the basence of oxygen. In doing so they produce methane and hydrogen sulphide gases, the latter having a really foul smell. For that reason the tanks are not ventilated by the percolation pipes are. A sewage plant, however, normally works on aerobic digestion -- the bugs need oxygen. That is normally provided by either rotating disks dipped in the surface or aerating blowers delivering air in bubbles beneath it.

In the aerobic type, if you don't supply the air, the bacteria colony will change to anaerobic and the hydrogen sulphide gas will escape from the vent that only aerobic tanks have.

If yours is indeed a sewage plant (Klargester or similar) then there should be an electrical connection to it to drive either the disks or the blower. There should be a green (or other colour) box on the ground close by the unit, where the electical connections go. That's where you need to start looking I suspect. The power supply might be disconnected, turned off, or tripped in some way. Best guess I'm afraid:o

3dsteel

I had this problem too, I fitted a carbon filter to the treatment unit and a valve to the vent stack coming out of the house. It worked a treat, you just need to replace the filter every summer, they're about 20€ a go?

This is where I got them:
http://humm-busters.com/

3dsteel

I forgot to mention, I also fitted a 90° bend to the inlet pipe. This should go down below the water level and will stop odours going back up the inlet pipe and coming out through the manhole covers in your yard!

mrbig

ART6 wrote: »

Septic tanks work on anaerobic digestion -- ie the bacteria work on the sludge in the basence of oxygen. In doing so they produce methane and hydrogen sulphide gases, the latter having a really foul smell. For that reason the tanks are not ventilated by the percolation pipes are. A sewage plant, however, normally works on aerobic digestion -- the bugs need oxygen. That is normally provided by either rotating disks dipped in the surface or aerating blowers delivering air in bubbles beneath it.

In the aerobic type, if you don't supply the air, the bacteria colony will change to anaerobic and the hydrogen sulphide gas will escape from the vent that only aerobic tanks have.

If yours is indeed a sewage plant (Klargester or similar) then there should be an electrical connection to it to drive either the disks or the blower. There should be a green (or other colour) box on the ground close by the unit, where the electical connections go. That's where you need to start looking I suspect. The power supply might be disconnected, turned off, or tripped in some way. Best guess I'm afraid:o

ART6 is correct about how your system works and a possible problem,
but it is also possible you are misusing or overloading the unit.
These units are designed based on size of household, (ussually 5) and the watse generated by this number but you can overload the system by using a garbage disposal,putting a large quantity of organic liquids ie.milk down the drain, do you have any drains other than sewage going to the system?
Also putting alot of bleach in your toilets or using drain cleaner can kill the microbes and stop the Aeoribic digestion.
do not put rancid meat or a dead cat in your plant unless you want to introduce a new foul smell.

aoifski

Thanks a million everyone.

Art6 I will have a hunt for the electrics, but we think it's running as we can hear the pump churning...is that a good indication?

3dsteel sounds like just what I am looking for - the maxi filtra is what you are referring to as the carbon filter is it? I'll give it a whirl, and try and 90 degree bend also, as we did have this issue and I believe have already fitted the special valve to the air-in pipe (which the cowboy of a plumber originally vented into the ATTIC!)....so our pipes look like this (attached pictures if I can)...(the one in the attic is just capped off and sealed)...any issue with that?

MrBig, we are only a household of 4, and wouldn't go mad on the water or bleach. But I presume all our drains (ie sinks, dishwasher etc) go into it.

3dsteel

aoifski wrote: »

the maxi filtra is what you are referring to as the carbon filter is it?

That's the one!

ART6

aoifski wrote: »

Thanks a million everyone.

Art6 I will have a hunt for the electrics, but we think it's running as we can hear the pump churning...is that a good indication?

The diagramme you post shows a septic tank, but in your OP you referred to a "sewage plant" and there is a great deal of difference. A septic tank is an anaerobic system and doesn't normally have pumps -- just a percolation drain and vent as your picture shows. A domestic sewage plant can have either an aerator blower or a rotating disk or drum since it is an aerobic system and needs to be kept aerated to work. Aerobic systems don't create odours if they are working correctly.

Normally you wouldn't hear the blower or drum of an aerobic system running, particularly the latter as it is under ground. If you can hear something running then I would guess it is a blower and is either faulty or in some way blocked. You would need to find it and check it out. Normally it would be under something like a green plastic cover in the ground close to or on the tank.

What you have done with the main drain vent pipe in your attic is fine provided that the horizontal section has a fall to ensure that it doesn't fill with water.

aoifski

Sorry Art6 - that was just a modification of the previous diagram to show the attic piping. It is a treatment plant....or at least it was installed as one.

ART6

aoifski wrote: »

Sorry Art6 - that was just a modification of the previous diagram to show the attic piping. It is a treatment plant....or at least it was installed as one.

That's a relief -- I began to think I was talking through my a**e:D

Thinking about it further, I wonder if what you have is a Klargester disk aerator. I have no experience of them and have never seen one, but I think the disk shaft is belt driven or something. If the drive belt broke then the motor would be running flat out and not doing anything, which could account for the sound you hear. Have a look at the Klargester web site http://www.klargester.ie That might give you some ideas, even if yours isn't a Klargester.

youtheman

Might be worth calling out the service guy. My auld man had his unit serviced and it turns out that rodents had chewed through the plastic pipe between the pump and the tank. So it could be something simple.

mrbig

I think all of the replies say the same thing, more or less stating the obvious its not working, but this type of system works very well and does not usualy smell so there is almost definitly a fault, but I would rather be told my system is faulty than that they all smell or it isnt suitable etc.
Good Luck with sorting this out I'm sure when you find and rectify the fault you will have a smell free system.