Treatment plant capacity

[Russell griffiths]

Leading on from another question I asked, I am wondering if I am oversizing our treatment plant

the new house is three bed all with En-Suite bathrooms, and another downstairs cloakroom 

we also have an outside toilet in a shed for fisherman’s usage, 

however there are only two of us going to live in the house, with the occasional guest couple, as for the outside toilet it may get used once per day. 

So I have gone for a 2-8 person unit rather than the 1-6. The capacity for each unit I’ve listed below, how have you sized yours, and thoughts on mine. 

The 1-6 person unit has a recommended design flow rate of 900 litre a day and a tank size of 1485 litre 

the 2-8 person unit has a recommended design flow rate of 1200 litre a day and a tank size of 1934 litre 

Cheers russ. 

[Onoff]

Is there any way to reduce the capacity of an installed treatment plant in the future? Say there's 4 people in the house and the kids leave. 

 

Thinking some way to reduce the volume.

[Jeremy Harris]

I'd be inclined to fit the smaller one.  It seems unlikely that you would overload it, and even if you did it would probably only be for a very short period of time, which wouldn't be that likely to cause a significant problem.  Better to have too much nutrient available than too little, IMHO.

[ProDave]

Building regs normally stipulate the size of tank depending on the number of bedrooms. Is is a forula something like 2 people for the first bedroom then one person for each additional bedroom (but check that is the correct formula)

In any event for our 3 bedroom house the "correct" size was the 1-6 person treatment plant, so I would not be fitting anything bigger than that.

[recoveringbuilder]

Yes it’s 1.5 people per bedroom 

[joe90]

Our treatment plant which we installed recently had to be a 6 person ( three bedrooms, two persons per bedroom) we chose a 6 person plant called vortex because it can be turned down to match the actual persons living in it. We had it commissioned by a local firm and the guy has a Vortex himself and said if you don’t feed it enough ( poo) it won’t work properly unless you can turn it down. Ours is now set for two of us and the guy told us we would only need to turn it back up if we had a lot of guests fir 4 weeks or more ( ain’t going to happen). But if 6 persons bought the place it could be turned up to suit.

[dpmiller]

what type of timer/controller does the Vortex use, @joe90?

[joe90]

1 minute ago, dpmiller said:

what type of timer/controller does the Vortex use, @joe90?

 

It’s built into the pump housing, because the Vortex has two types of bubbles ( large ones to break up solids and small ones to feed bacteria) the timer switches between the two, it is shown here.  https://www.suppliesforfarmers.co.uk/vortex-eco-treatment-plant-i-11.html. The adjustment for numbers of people is done by valves which control the air pressure which controls the amount of bubbles.

[dpmiller]

The Solido Smart that we're going with has a programmable controller which uses variable timings for the aeration/ settling/ discharge, and has standard, commissioning, and holiday modes as well as preconfigured setups for different sizes of occupation.

I believe the same controller is used by a couple of different brands of plant.

Solido SMART OM Rev 3.pdf