Smelly septic tank update

At last the terrible smell from the septic tank coming into the house has been solved.

To recap – The septic tank system, with pump and sand filter bed was installed almost a year ago but never really used until we moved into the house in August. Within a few days there was quite a strong smell in the laundry room. The laundry room houses the electric meter, water supply and the main drain to the tank. Fortunately shutting the door kept most of the smell in. Talking to friends they suggested that it just needs a little time to settle and get a crust on the surface of the water in the tank.

Anyway after a few weeks the smell was getting stronger and permeating into the rest of the house. There was definitely something wrong with my plumbing. As a temporary measure I even put a small extractor fan on the outlet for the tumble dryer to suck the bad smell out.

Things didn’t really improve and I spent lots head scratching and pondering trying to work out how the smell was getting back into the house. I checked all the obvious things, like all the traps had water in them, the primary and secondary vents were clear, the soil pipe entered the tank below the water line etc. I just couldn’t understand how the gas was getting in. Maybe there was a pressure build up and the gas was forcing it’s way past the trap for the washing machine. I started imagining the nightmare scenario that somehow I must have cracked or broken a soil pipe under the floor. But even that didn’t really make sense as the smell was isolated to the laundry room and the pipes were buried under the concrete floor.

Anyway to buy some thinking time I decided to leave the lid off the pumping chamber that pumps the waste water from the tank up the garden to the sand filter bed. The pumping chamber has a small electric pump with a float that kicks when the water level rises. It is also vented using the same pipework as the vent for the septic tank. It worked as a temporary solution but sitting outside was not very pleasant.

I was on the point of calling out either the installers of the system or a drain company to send cameras down the soil pipes to find the problem when some friends turned up. After a standing over the pumping chamber bathing in the aroma for a few minutes telling them about the problem, one of them pointed to the red conduit in the side of the pumping chamber containing the electric cable for the pump and asked, ‘where does that go?’

Bing – light bulb goes on. The conduit goes to the fuse box in the laundry room and it was open both ends. All the waste gas was travelling up the electrical conduit straight into the house.

Stuffing a plastic bag into the end of the conduit and sealing the end up with silicon solved the problem. Lid back on, no smell anywhere; fantastic

Sometimes you just get so fixed on one thing (e.g. the soil pipes or my incompetence as a plumber) and just can’t see the wood for the trees!

Smelly septic tank

Septic tank

Stinky

With the bathrooms operational and having been moved in for nearly a week there has been quite a strong smell coming from the septic tank back up into the house. The septic tank does have a ventilation pipe running from the output side of the tank and before the filter bed that vents up through the roof. However first impressions seem to be that this is not working correctly and the smelly gases are somehow coming back through the input side and the gas escaping through a trap. Fortunately the trap the gas has chosen is the washing machine trap in the laundry cupboard. Keeping the door to the laundry room shut helps, but it’s still seeping into the house.

As a temporary measure we’ve fitted a small fan to the tumble drier pipe to suck out the gas and relegated the tumbler to the garage. Blocking the washing machine trap might well shift the gas escape to a more sensitive part of the house !

Speaking to some friends they said that their new septic system also smelt a bit at first but settled down quickly. It does seem a bit strange to me that the gas isn’t taking the easy route via the vent.

I guess we’ll just have to wait and see.

UPDATE: Problem solved.

Septic tank inspection

The guy came to inspect the septic tanks this morning. He was pretty thorough, checking the depth of sand and gravel in the filter beds, various levels of pipework, the levels for the septic tanks, the pumping stations, ventilation out to the roof, etc. Everything passed although he did recommend a grill on the outflow pipe in the gulley to prevent vermin coming up the pipe.

Once he had left the guys starting backfilling everything and leveling out the garden. It rained really heavily all weekend so the ground was very wet which didn't make it that easy, but even though they haven't quite finished it's starting to return to normality. Hopefully they should be finished by lunchtime tomorrow.

No grass left but at least I've got a nice blank canvas for new garden design.

Fosse septique photos

As promised some photos of the septic tanks and filter beds.

Everything has gone really well and both sand filter beds (bac-a-sable) are now complete with the guys just finishing the outflow pipe from the two filter beds out to the gulley in the lane.

The only slight delay was the suspected presence of an underground PTT cable in the garden. My neighbour mentioned it and gave me a copy of the plan showing the 'approximate' position of the cable. It was a very old hand drawn plan. The guys from the digger company also had a plan from the PTT which was slightly different! No problem, they say, the boss is coming to find the cable. I expected someone to arrive with a metal detector, ground radar or something, but he turned up with a couple of rusty bent welding rods. A bit of divining and some comical and sceptical remarks from me and the 'known' position of the cable was marked out and everything positioned to avoid the cable.

Well as it turned out, the diviner was just about bang on and as you can see the cable was uncovered without plunging Northern Brittany into silence. Apparently it's a fairly major national trunk cable.

Once the authority's inspector has been and checked everything conforms it will all be backfilled, covered over and the garden should be ready for planting. It's certainly going to need some work as it's a very muddy mess at the moment.

Hole for septic tank
Hole for first septic tank
Septic tank
Tank lowered into place
Septic tank installed
Pipework connected and pump (green top) fitted
Gravel delivery
Gravel delivery rescued from mud
Sand filter bed
Hole for sand filter
Sand Filter bed construction
Plastic liner, gravel and pipework
Filling sand filter bed
Filling with sand
Complete sand filter bed
Completed filter with input pipework and gravel
Waste water exit
Filter bed outflow pipe
Telephone cable
Buried national PTT cable

Septic tanks started

The digger men turned up this morning to start installing the two septic tanks and filter beds. The bad news is I took loads of photos but left the camera behind at work. I'll update tomorrow with photos. Pictures speak a thousand words.

After a some minor discussion and planning about placement the guys got straight on with the job digging two very large deep holes for each tank at the front of each house. Each tank is 3000 litres, that's 3 cubic meters, so lots of spoil. Most of the spoil was clay.

The only hiccup during the day was that the lorry delivering gravel for the filter beds got stuck driving across the garden. The digger soon managed to pull him clear. I suspect it's quite a regular occurrence as they were not fazed at all and just hooked up a chain to pull him free. I also lost a couple of concrete gate posts and a garden wall which got pulled out by the digger to give the lorry access. I was going to pull them out and remove the wall for a better view anyway, so they saved me a huge job.

By the end of the day both tanks were buried, two thirds filled with water, and all the soil and ventilation pipes connected up. Interestingly they are not allowed to use 90 degree bends and have to layout the pipework to avoid sharp turns. I guess it's to avoid blockages.

Septic tanks emptied

There was an article in the local paper a week or so ago about septic tank inspections taking place in Les Champs Geraux. We knew some friends of ours in neighbouring Evran had been inspected to ensure their tanks were functioning properly and not polluting, so Caroline arranged for a firm to come and pump out our septic tanks and get them cleaned and checked beforehand.

Well this afternoon a large tanker covered in tubes arrived to remove our 'effulent'.

We have got four fosse septique around the back of the house. The new one installed last year and three existing tanks for our house and the existing gites.

It was a fairly simple process with the tanker driver dipping his suction tube into each fosse and then pressure washing the tanks and various pipes and inspection chambers for each tank. In total he sucked out about 9000 litres of 'waste'.

Once finished we had to refill to about halfway the two concrete tanks and fully fill the plastic tank with a garden hose. I believe that the plastic ones can 'float' out of the ground if they are not refilled and because they are not as strong could deform if left empty.

Oh the joys of living in the countryside.