Septic tank Running Costs

knittingnanny1102

I am trying to source running costs for a particular model or ascertain how the Treatment plants actually operate.  
In the property I am looking to buy there is a Bio Pure 3 Gravity 5 --13 person treatment unit.  My research tells me that is a 92w power usage.  Do these systems use the same power 24 hours a day or does it kick in and out.  
I thought my calculation would be  92w x 24 hours x 365 days of the year x electricity cost (approx 27p) plus 5% vat.  which comes in around £230 a year.  Is this an accurate calculation of running costs. 
I am being advised be my sellers who provide the electricity that the cost is "nominal" and so have still yet to provide details of how it is split between them and the other property who shares the unit.  I think they believe it runs almost for free and don't bother either checking or charging the other property.  there is a meter on the side so it can be calculated.  I just wanted to be clear how it all works.    I know it is not mega bucks but i just wanted to check my understanding of the system before  wading in with my suggested numbers. 

The_Unready

For info/comparison,  my treatment plant has a 60w pump that is on 24 hours a day, so the calculation is 60 × my unit price per hour x 24 for the daily rate. I don't bother charging the neighbour who also uses the plant, although I probably should.

Lorian

Don't forget you will probably want to pay for annual maintenance and breakdown cover, and periodic pumping out of solids.

WIAWSNB

Hi KG.
The manufacturer should be able to tell you whether the pump, or any other part, is operated continuously. A quick Google suggests not, but I personally do not know.
If it does, however, then your calcs appear correct. Do bear in mind, tho', that your water bill should be a lot less as they don't have to include sewage. 
Swings and whatsits.
Do check the deeds carefully, tho', that they represent the current setup, and all of this isn't done on a gentleman's agreement. ALL the running g costs should, of course, be shared equally (or perhaps in proportion to house size).
If this TP replaced a ST, then possibly the deeds only refer to sharing maintenance costs, and not 'running'. 
Obviously some tact may be required too... I'd suggest, if it's clear the vendor is handling all the elec costs, and you wish this to change, perhaps I sist they inform their neighbour that this is what 'buyers' are asking about and expecting?