Falcon sewage treatment plant smell

[Lmnop77]

We have recently had a Falcon sewage treatment plant installed in our garden, and are being plagued with the smell of sewage. We had the tank emptied and de-sludged a few days ago, but the smell is back.

There are two soil vents on the system, one for each of the houses connected, so we are assuming, and are assured by the installer, that this is not the problem. However, we are having a great deal of difficulty understanding why the gasses from the primary tank would vent out of the soil vent, when they can so easily vent out of the lid. Have we been sold an inappropriate system? We're totally devastated as it is ruining our home. We can't even open windows, because the smell blows in.

Could the problem be that our garden is in a windy position? Is the wind blowing over the lid sucking the gasses out of the lid, which would otherwise go through the vents?

Any suggestions, or reassurance that this system is appropriate for gardens, would be greatly appreciated.

 

[coopersim]

How recently was it installed? I was under the impression (currently researching the options) that the biomass had to build up and there would be a time before that there might be some smells.

 

[Lmnop77]

Only 2 months ago. We think the smell is coming from the raw sewage in the primary tank, rather than digestion process. We had it emptied on the suggestion of the installer, who thought it had been flooded. However, it became obvious that he was trying to fob us off, and we still have smells, albeit not so strong now that it's mainly filled with water again. We are anticipating that the smell will again increase to unbearable levels as it fills up.

 

[coopersim]

How far is it from your property? Are you able to change the lid for a sealed one (if that is possible) or could you re route the vent down wind? Have you spoken to the manufacturer to see if there is any advice they could give you?

 

[Lmnop77]

It's about 6 metres from the house. The smell is definitely from the tank lid rather than the soil vent pipe. We asked the manufacturer about it, but they were adamant that no smell should come from the lid, even though it is not sealed. However, they were unable the explain how this works! They did offer to send us a smoke bomb to test our vents.

I'm planning to write to them, to see if I can get a reply from an engineer. If we can understand what it is that is supposed to happen, why the gas is supposed to go up through the vents instead of the lid, perhaps we can work out what is going wrong in our case.

I was hoping someone would reply that they have the same system, in their garden, and there is no smell. Then I would know we've not bought the wrong system.

 

[Nige F]

Are the vent on the houses open vent pipes - there is a craze for fitting air admittance valve @ the moment

 

[Lmnop77]

Thanks for all the responses.

There are two open soil vent pipes, installed in the 50s when the house was built. According to the manufacturer and the installer, this should be enough, however, we had a couple of engineers visiting (family), who were sure it was not enough in our situation. Our house has had two extensions, both of which added toilets without vents. In theory, these should vent through the original pipe, however, they are closer to the tank than to the vent. We're getting a quote to add new vents, and also have got some smoke bombs to test the venting.

I will give an update when we have one.

 

[Hugh Jaleak]

I'm not familiar with that particular unit, however, 6 metres from the house is very close for any septic tank arrangement! (Was there no alternative site for it?) Normally installations such as the Klargester Biodisc/Biotec only require an annual desludge and any odour is negligible.

It may be a combination of factors, the dry weather wont help, it's been emptied (unnecessarily IMO!) far too soon, and possible the incoming effluent hasn't helped the bacteria to establish. Ideally the use of detergents and chemicals in the property (ies) being drained wants to be kept to an absolute minimum, washout from water softeners is an absolute NO, and try and avoid anything that hasn't been through you (other than tissue) finding it's way in. Wipes, sanitary products, condoms etc wreak havoc in these plants!

I suspect it's unlikely the manufacturer will admit to any potential problems with odours, (or anything else that may cost them money!). A smoke test may prove inconclusive, whilst it may show where air (and odour) could escape, under normal circumstances I would expect a slight negative pressure in the system, with air being drawn in at the tank and vented off by the stack(s).....

It needs to be left, undisturbed for a few weeks possibly to allow the bacteria to establish and the plant to begin to operate as designed. These do rely on an element of natural processes, and wont be hurried! Once a sludge blanket has built up though in the primary chamber, then the majority of the breakdown should be happening anaerobically under that blanket, in effect sealed in. The semi clarified effluent will be drawn off from under the blanket for the next stage of treatment, by which time it should have little odour to it.....

Out of curiosity, what were the previous arrangements for sewage treatment?

 

[Lmnop77]

Thanks for your response.

It certainly will be left for a few weeks at the very least before we spend any money on it. We're being very careful about what goes in, as are our neighbours. It should only require an annual desludge, but there was a suspicion that the tank had been flooded due to emptying a cold water tank. I think it had been flooded, but this shouldn't have caused the problems we had. Emptying it was the best way to eliminate that as the cause if the smell.

It's in our garden and there was no alternative site for it, although I may have underestimated the distance from the house (I haven't actually measured it, but it obviously is very close). It is a pair of semi-detached ex council houses, so maybe the plot is smaller than the average rural property. Next door have a smaller garden than us, so there was no chance of moving it there.

The old system was a failing septic that had been there since the 50s and was pushing raw sewage out into a nearby woodland. It was way too small for 2 modern houses, especially our house which has been extended. The new tank was put in adjacent to the old one, further from the original part of the house, but still close to our extension.

 

[Hugh Jaleak]

That must have been some cold water tank! The plant should be capable of dealing with some peaks in flow, e.g. if a bath was discharged and a couple of W.C.'s were flushed in quick succession, without it stirring matter up to cause a problem.

The Klargesters (Biodisc and Biotec), in fact most treatment plants I have come across do not have an airtight lid, (the 'bottle' type septic tanks sometimes have a rubber seal in the frame onto which the lid sits to seal), but simply because they do not appear to need it. There is sometimes odour when the contents are stirred up when being emptied, but under normal usage this shouldn't present a problem. It may be a case of waiting, if things settle down fair enough but if odour problems persist over the colder months then something isn't right IMHO.

Looking at the working diagram for the plant, it is is basically a variation on a theme, combining elements of the traditional settlement method and use of compressed air to treat the effluent, nothing outstandingly different that would indicate a new method that may not have been tried and tested....

 

[Agile]

I have just been reading the sales blurb.

One feature is that it blows oxygen into the liquid.

So what goes in must come out.

Could this air volume be the cause of air coming out of the tanks together with smell?

I think that its possible to buy bacteria to add to these tanks to start the operation?

Tony

 

[Hugh Jaleak]

Some plants do use the aeration system to help treat the effluent, the Klargester Biotec being one other I know of, but this doesn't usually cause a problem. (I think if it did the idea would have been abandoned a long time ago!)

The primary section (where the worst of the sludge would be), once a sludge blanket has established, should have the majority of the bacterial breakdown taking place anaerobically under the blanket anyway. Unless the blanket is disturbed any odours should be negligible by this stage.

The best thing to kick start this type of process is some active sludge from another plant, hence when a septic tank is emptied a small amount of sludge should always be left in the bottom to allow the bacteria to re-establish very quickly.

 

[sooey]

Hey Huge...you certainly know your sh*t.

 

[Hugh Jaleak]

Spent too long around the stuff, and certainly have listened to enough in the past! Now often the case, Same day, different sh*t.....

 

[IanCD]

Hi Lmnop,
I don't see an update? We have a Falcon 6 with pumped discharge into a stream which runs by the house... it seems the discharge pump in ours might just have packed up, but I was just wondering if you'd got yours working ok?
Ian