h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Septic Tanks - A835599
Author: Dr Montague Trout - U188966

Is there a place in the guide for this? I am not competent in the biological processes that go on - just the practical fundamentals.

If you've already done a search and found no Edited Entry on this subject, then there most certainly *is* a place for it

No need to worry about the biologicals - that could be considered for an entry of its own, if indeed it hasn't aleady been covered in any entry there may be about sewage treatment.

I must admit that I got a little lost toward the end in amongst the description of the structure of the tank, but it is rather early in the day for me right now. I'll have another run-up at it later when I'm a little more compos.

No you're right. But it's hard without diagrams.

If you can find a site on the internet with a decent diagram, link to it. Other than that I say tart the entry up with a bit of GuideML and go stick it in Peer Review.

I know

It's making a little more sense now, and I've got a clearer picture in my head of the tank compartments, but I'm still blanking out on that stuff about invert levels.

Right.

The invert level is the bottom of the pipe ... the lowest point where the water runs.

The level of the invert of the outlet pipe fixes the twl (top water level). When the water is that high, it will overflow. right?

So the level of the outlet pipe fixes the twl of the tank.

And the invert level of the inlet pipe should be, say 75mm (what 5 inches?) higher than that. But at the opposite end of the tank.

So there would be a slight 'cascade' of water into the tank at the inlet. But not.

Because it's better to have the inlet coming into a tee-shaped pipe turned so that one arm of the tee is vertically upwards, and one is vertically downwards.

Maybe I should put all this in?

Right.

The invert level is the bottom of the pipe ... the lowest point where the water runs.

The level of the invert of the outlet pipe fixes the twl (top water level). When the water is that high, it will overflow. right?

So the level of the outlet pipe fixes the twl of the tank.

And the invert level of the inlet pipe should be, say 75mm (what 5 inches?) higher than that. But at the opposite end of the tank.

So there would be a slight 'cascade' of water into the tank at the inlet. But not.

Because it's better to have the inlet coming into a tee-shaped pipe turned so that one arm of the tee is vertically upwards, and one is vertically downwards.

Maybe I should put all this in?

Why not put it in twice

That makes much more sense now

Updated. Ready for PR?

Oh aye.

It looks OK, but there are a few things I'm not 100% happy with.

1. You still need to add that explanation of the difference between sewerage and sewage before putting it in PR.

2. It doesn't seem to mention that it is bacteria that do the sewage treatment. Do these enter the tank naturally or is a "starter pack" required?

3. There are a lot of technical words like influent and effluent, which are somewhat offputting. I understand that you have to be euphemistic at times, but you could say "sewage coming in" instead of "influent" and it would be more explanatory. And people are used to thinking of effluent as waste, so the process whereby the effluent is cleaner than the influent makes the use of the word effluent not recommended.

U.S.A. --> USA

Sorry, I didn't spot that this is no longer in Writing Workshop. I'll trot on over to Peer Review now.

Anyone care to add an opinion:- a small old tank say 50 years with a small brick construction, would have had a simple soakaway at its tail pipe / outlet .... my thoughts are that this would be the norm. Anyone care to contradict. The environment is small house in a remote rural background. However there is a small river some distance away - downhill but accessable and an open pipe could have been constructed to reach it. The thing is - even 50 year ago would it be in an individuals mind to create a responsible soakaway or allow the ouflow to discharge into a river. The soakaway seems easiest but the river is much more long term. What's the opinions??

Many thanks for any input (forgive the pun) it does have a serious side.