house self build

Septic Cesspit Bio waist tanks Sewage treatment plant.

Septic Cesspit Bio waist tanks Sewage treatment plant.

Cesspits.
These were about way back in history & were really just a large covered hole in the ground. The cesspits of today are not much different, but come in the form of a large tank buried  in the ground. British Water sizing criteria should be used when calculating the capacity of a cesspool/pit based on a loading of 200 litres per person per day in residential applications. The tank should be of a sufficient capacity to hold 45 days worth of effluent. For a single dwelling 18,000 litres (4,000 gallons) is the minimum allowable capacity. This capacity is suitable for two residents only. A tank of 45,000lt for a family of 5.
The disadvantage is that they are usually larger than most other tanks & have to be pumped out to a lorry on a regular basis.



Septic Tanks
These are the more recent types of tank that are very common in the UK flat land area's. These rely on the heavy waste settling to the bottom of the tank & the light fluids  running off into a soak away's in the form of ether lower half perforated 4" pipes or a soak away pit, or a combination of both. This can only happen if the ground conditions are ok & the local authority's except it. These also need to be pumped out, but on a far less frequent basses depending on tank size & usage. You can see that a 45'000LT cesspit tank is only ok for a family of 5, where as a 3800Lt septic tank will cope with a family of 10.





Sewage treatment plant
These are being requested more & more as the local authority's get greener in there ways. 
A treatment plant is a mechanical system that treats the sewage from your property and allows the final effluent to be discharged into a watercourse. Somewhere usually close to the system will be an electric supply to power either the pump or motor that will cost around 50 a year to run. Again a Treatment Plant will need periodic emptying on average once per year, but this can increase or decrease depending on the size of Plant & number of people in the property. A Treatment Plant will also need regular servicing by the manufacturer or a qualified service agent.
45,000lt cesspool/pit
Size w 2500mm L9600mm
3,800Lt septic tank
Size w 2000mm H1795mm