On 22/04/2020 10:17, NY wrote:
"Commander Kinsey" wrote in message
newsp.0jfq8biwwdg98l@glass...
I suppose we use what you would call a two pipe system. There is talk
here of introducing a new third pipe for greywater. That is, water that
comes from baths, sinks, showers, etc. as opposed to sewerage from
toilets. Difficult to retrofit of course but new estates are likely to
be plumbed this way in the near future.

My parents have a holiday cottage in a tiny village that has no mains
drainage. All the houses have their own septic tank (two-chamber sewage
treatment unit that does more than just store the sewage, as happens
with a cesspit). However to reduce the amount of water that goes into
the septic tank, all the grey water is piped to a communal "land drain"
that discharges into a nearby stream. I'm sure that arrangement
contravenes almost every health and safety and environmental law known
to man!

Do many houses have a rainwater drain in the street? I thought that
usual arrangement was for there to be a soakaway under the lawn for
rainwater, so the rainwater and grey/sewage water never mixed. As far as
I know, our house doesn't put rainwater into the septic tank, but pipes
it into the same soakaway under the lawn that is used for the outflow of
treated sewage water from the septic tank.

The replacement of all in one drain systems by 'rain into local
buffering via soakaways or flood ponds' and 'all grey water and sewage
to be treated', has been gradually implemented over the last 50 years or
more.

There is a massive benefit in terms of flood and hygiene control from
buffering rainwater as near to where it falls as possible. or, failing
that, to get it into the natural ditch/stream/river/sea drainage systems
as fast as possible. The last thing you want to do with it is mix it
with sewage needing treatment and risk raw sewage mixing with flood
water or overwhelming treatment plants.

There is an argument that grey water might be treated separately, but in
the end a three way system is a bit too complex, and there is no telling
how many people pee in the shower, or flush rotting food down the sink.


--
The theory of Communism may be summed up in one sentence: Abolish all
private property.

Karl Marx