Page 74 - David Burr Rooftops Magazine Winter 2017/2018

Would you believe this idyllic scene disguises a micro sewage treatment plant?
Let the drain take the strain
William Pewter, senior partner at the Pewter Partnership Surveyors, shares his expertise and knowledge about private drainage systems
If you are looking to buy a house in a rural area, maybe with its own land or far away from other houses, you may well find that it comes with its own private
drainage system.
This could be in the form of a micro
sewage treatment system, a septic tank or even a cesspool.
Private drainage systems are necessary for any property that is unable to connect to the public sewer. Connections to the public sewer will depend on the location of the sewer and how far you would need to excavate within any highway to get to that sewer. You will also need permission from the local water authority to connect to such and your local council to excavate on their land, which is usually only carried out by a recommended highways company,
authorised and recommended by the relevant council, which can be very expensive.
Having your own
private drainage system
means that you are
responsible for
maintaining it. If you
neglect to keep it
serviced and emptied,
this can result in
discharging untreated effluent into the ground or a watercourse. If this occurs then you could be liable for a fine from the Environment Agency.
However, if you find a property with its own private drainage system, these are not an area of concern as long as they are managed and maintained in the correct manner and will work for years without any problems.
A cesspit or cesspool are the same thing, in that they are purely a holding tank for liquid and solid sewage only and not designed to either treat or discharge such. These are emptied by licensed waste disposal contractors on a regular basis. We always advise our clients to obtain the records for such, in order they are aware how often these need to be emptied. However, this does of course depend upon the demands being made on the system, i.e. how many occupiers are present.
Septic tanks are designed to connect into soakaways, otherwise known as “finger drains”, which basically stretch out away from the tank where the solid waste settles to the bottom and the liquids rise to the top. Whilst this liquid still contains sewage, it is in small enough particles to carry through the discharge outlet and into the soakaway or finger drains. This liquid then drains into the soil for further anaerobic treatment.
Whilst a septic tank contains no moving parts and does not require regular servicing, it will still need to be emptied by a licensed waste disposal company.
A micro sewage treatment plant is really what it says on the tin, in that the system provides full treatment of sewage to such a degree that the effluent is suitable to drain directly into a local ditch or stream.
There are different types of treatment systems although generally the sewage is treated by micro-organisms within the tank. Solid waste that is not broken down settles into sludge at the bottom of
the tank and the liquids are discharged from the system. The sludge will of course, build up over a period of time and need to be emptied, again by a licensed waste disposal company.
Many systems need power, a motor or an air blower that will aerate the sewage. This obviously means there are working parts within the system which will need to be annually serviced and checked by a qualified engineer.
n Pewter Partnership Surveyors are period property specialists, whose area encompasses Essex, Suffolk, Cambridgeshire, Hertfordshire and Central London. Tel 01787 460964.
74
“Many systems need power, a motor or an air blower that will aerate the sewage.”