Drainfield

[Hester]

I had a new fosse system installed last summer viz. all domestic water to a small holding tank with a pump, this then pumped up the slope to the fosse toutes eaux and then released into the tranchees which run horizontally across sloping land. Recently the ground around the bottom trench has begun to smell which I didn't really expect.  Could anyone tell me whether this indicates a problem or is there always going to be some odour in the water that is passed into the drainage trenches?  There has been a lot of rain could this make a difference? Thanks Hester.

[mint]

Your system sounds like ours which was installed in early 2007.  We, too, have a pump and everything else as you have described.  But, the difference is that our filter beds do not smell at all. 

We do get the odd whiff but it definitely does not come from the top of the plot where the filter beds are.  In fact, we think the whiff is from the neighbour's fosse which hasn't been emptied for years.

[Gluestick]

The Discharge Field should only be processing treated and effectively odourless waste fluid; not effluent.

Sounds as if summat is wrong!

Call back the original installer.

 

[Hester]

 Oh dear.  Thanks for your replies, I have looked into a regard in the bottom left hand corner, it is half full of quite smelly water.  After reading other threads I think that I will check that the filter rock has been put in place and maybe add something other than the Eparcyl which I use weekly; didn't add anything special to it when it was installed.  Otherwise I guess I should try a get the builder back.  Regards Hester.

P.S. Do you clean out your tank that holds the pump?  

 

[Gluestick]

Hester:

Normally, the pump is there only because the Discharge Field is at a higher level than the septic tank itself. The pumps sit in a small tank with a float device, which turns on the pump when the catch tank fills sufficiently.

Barring accidents is should rarely need cleaning out as ought only to be pumping relatively inactive fluids.

If any water sits stagnant, it will begin to smell, as bacteria from decaying plant life around it and aerobic bacteria will infest it.

Call back the installer: I fear something is not correct.

 

[mint]

As Gluey says, have not had the pump cleaned out.  But then we've only been using it a year.  And, yes, you can hear the pump going when the "stuff" needs to be flushed up to the filter beds.

Oh for good old mains drains.  Who'd have thought one of the (very few) things I'd miss about the UK would be mains sewerage!

[Clair]

We have had a similar system since 2003.

We have never cleaned the holding tank.

We have a filter between the septic tank and the filter bed which we should clean every 6 months or so. There has been no smell when it has not been cleaned.

We have a small venting pipe at the exit of the septic tank and it lets out a faint smell, but nothing noticeably unpleasant unless you happen to be very close to it and in the wind.

[tracteurtom]

Has the system not been used for a while or has it had a sudden increase in load (Guests maybe?).  The bacteria populate the Fosse according to the amount of effuent they have to deal with.  So if the house is say a holiday home with infrequent visits, the bacteria will die off and then will ned restarting when the house is occupied again.  Or, if say the Fosse is normally dealing with a load of 2 people then all of a sudden its expected to deal with 8 people, the bacteria will struggle for a while and this will cause a smell.  This is very common in Gites were the load changes on a weekly basis with big swings from 0 people to 6 ++, always smelly !!!

The drainage field should not smell, in fact it should be clean water that comes out of these pipes.  If it does, it suggests a problem up-line somewhere and as you have a pump, it could be that the pump is over flowing the fosse and forcing effuent out into the drainage field somehow ???  What ever, open the tops and have a look !!

[bejay]

The effluent from a septic tank is far from fully treated. It is a highly complex and variable mix of organic decay products and bacteria, some of which are pathogens. It is in the drain field in the presence of oxygen and aerobic bacteria that the decomposition is completed.  It seems a reasonable  possibility that if this drain field is saturated after heavy rain then  this secondary process is not occurring at the moment. Whether this is just a temporary problem or is a flaw in the design of the drainage system can only be determined locally. Back to the installers I think.

bj

[Hester]

Thanks everyone for the replies.  I have looked into the regards and in the second one there is some rock filter, however this is in a string bag, should it have been left in the bag or should the bag be cut away.  Thanks Hester.