Vent problem, ejector pump

[Qwertyjjj]

There used to be a sewage smell coming from the ejector pump.
To solve this, I put a vacuum on reverse on the vent pipe and then sprayed a soapy solution onto the top of the pump.
I watched some air bubbles come out of certain areas where the lid has either cracked or broken over the years.
That seemed to solve the problem in the short term although if you leave it for a week or so, the smell would come back but usage on a day to day basis was fine.
Now that the colder weather has appeared again with temps down to near zero overnight, the smell has come back on a daily basis in the morning, ie the water sits in the tank overnight and as soon as the pump goes in the morning, some air comes out of the leaks.
I cannot find any more air seepage holes with the vacuum method but it seems odd that the symptom has come back with the colder weather.
Could there be a negative pressure problem with the vent? Is there anyway to solve this?
I have attached a picture of the pump:
(a) lots of silicone as you can see my attempts to seal it.
(b) the vent pipe runs about 6ft the right of the pump, then 10ft to the outside, then you'll see an outside picture, where it runs 25ft up to the roof.
(c) The vent pipe looks like a 2inch pipe (6cm diameter)
(d) There is no central stack venting in this house as all wastewater runs into the ejector pump in the basement and the only venting is this pipe from the ejector pump
Pictures:
https://drive.google.com/folder/d/0BwSNadx1dbgxdWsySXRjaXctX2c/edit

 

[Qwertyjjj]

could the horizontal vent be an issue?

 

[Sponsor]

 

[Reach4]

Is there a floor drain 0r other drain whose trap may have dried up?

 

[Cacher_Chick]

Given the condition of he lid and fittings, the basin could be leaking also. I would saw cut the floor and replace the basin and lid. The vent pipe should be pitched so that any condensation or rainwater in the vent flows to the basin.

 

[Qwertyjjj]

The smell definitely comes from the basin area, there are no other drains in the area and the smell never comes up from elsewhere.
I poured some water down the vent pipe from the roof and it drained into the basin correctly so there must be enough slope.
It doesn't seem like it is venting properly though, the vent pipe should take any smell away even if there is a small leak in the lid? The lid is not a standard size as it is 25 years old and the basin is set in concrete so is difficult to pull out and replace.

 

[hj]

If this is the ONLY vent for the entire house, you have a much worse problem, because that vent CANNOT prevent trap siphonage on any sink that is higher than the basin.

 

[Qwertyjjj]

If this is the ONLY vent for the entire house, you have a much worse problem, because that vent CANNOT prevent trap siphonage on any sink that is higher than the basin.

I haven't checked but I assume all the other fixtures etc have an AAV (maybe not as it's all hidden). There doesn't seem to be any trap siphonage, which considering the pump must pull some air in means it works ok for pulling air in through the vent, just that it is not drawing air outwards.
Everything in the house is higher than the waste basin: Floor 1: 1 washing machine, kitchen sink, toilet, bathroom sink. Floor 2: shower, bathroom sink, toilet.

 

[Terry]

Each trap should be vented "above" the trap arm and trap.
Without "proper" venting, traps will siphon, and sewage smells will enter the home.

 

[hj]

Unless there is some "force" applied to it, the air in the pit will go wherever it wants to and not necessarily up the vent. The air, and odor, will flow from a high pressure area into a low pressure point.

 

[Qwertyjjj]

The smell only comes out when the pump turns on and only after waste water has been left for a few days in the pit (ie it is not venting out).
I have smelt at every trap whilst the pump is going. The smell ONLY comes from the pit area.

 

[hj]

Why WOUL D it vent out? Your house and the outside atmosphere are probably at the same pressure so the odor is just going to stay in the pit and leak out. When the pump runs it is sucking air IN from the vent.

 

[Qwertyjjj]

So, how do I find the leak?
Blow a smoke machine in through the vent?
I tried putting soapy liquid on the outside and sealed up what I could.
Someone suggested pouring soap in the sink and then running water continuously to make it bubble up from the inside out.

 

[Cacher_Chick]

The piping system can be sealed and pressure tested, just like all new installations are done.

 

[Qwertyjjj]

deleted post

 

[Qwertyjjj]

Found the problem doing a DIY smoke test.
There is smoke coming out from between the basin and the concrete - perhaps there is a crack just below the surface.
How can I seal this off? Presumably, running sealant at the join of basin and concrete will not seal it off properly?

Given the condition of he lid and fittings, the basin could be leaking also. I would saw cut the floor and replace the basin and lid. The vent pipe should be pitched so that any condensation or rainwater in the vent flows to the basin.

The floor is concrete, the basin is set into it or do you mean saw cut off the basin that sticks above it? Also, it's a very tight space to work in...

 

[Cacher_Chick]

If a basin is damaged, it needs to be removed and replaced. The concrete needs to be cut and/or jack-hammered so that the basin can be freed from the floor. The drain inlet enters the side of the basin under the floor. Sometimes some demo and re-build is part of doing a job right.

 

[Qwertyjjj]

I'm not sure how I'd get a jack hammer in there, it's a tight space, you cannot even stand in there, you have to sit or crouch down.
Any other options or would something like a mini jack hammer work? It's difficult to get round the back.

 

[Cacher_Chick]

They make electric hammers that are smaller than the common pneumatic ones. Many rental places will have them. We cannot see what you are dealing with. If it's framed walls, it can be removed and replaced. You need about a foot around the basin to dig and pour new concrete.

 

[Qwertyjjj]

They make electric hammers that are smaller than the common pneumatic ones. Many rental places will have them. We cannot see what you are dealing with. If it's framed walls, it can be removed and replaced. You need about a foot around the basin to dig and pour new concrete.

How much concrete will I need to go through? ie the basin is probably 3ft deep but presumably it's all concrete sitting on foundation of more concrete?

 

[Reach4]

Probably about 4 to 6 inches. There may be reinforcing mesh in the concrete. Then there will be gravel under the concrete. There will probably be gravel around the sewage pit. Use a bolt cutter to cut if needed. What you can fold back, fold back and put back in place as best you can. I used fiber-filled concrete for putting in a ground water sump.

I dug a lot less than a foot around the perimeter, but I was starting fresh. If your hole fills with water, that complicates things. Best to do that work when the water level is lower.

Consider hiring a plumber to do the work. It is going to take you a lot longer than it would take a pro.