Frequently Asked Questions about Treatment Plants
Are the plants noisy?
The modern plants are a lot quieter than they were years ago - most are virtually silent in
operation. In some cases the splashing water is all that can be heard and only then when
standing on the cover.
Are treatment plants below ground?
Some plants are designed to be entirely below ground, and some need a slightly raised lid for
access. In the larger and more complex versions of the SBR range they can either be underground
or on the surface or a combination of both.
Are there any moving parts in a treatment plant?
The majority of treatment plants are driven by remote air blowers and have no moving parts within
the main unit, but some have submersible pumps. Where there are geared mechanisms within the
plant they are precision made and have a proven track record in the field.
Do treatment plants use much electricity?
The modern plants are very economical to run, and when the plant is shared by two or more
households the costs per household are relatively low.
Are they guaranteed?
Yes. The manufacturers offer a twelve month guarantee on the plant, usually from date of
delivery, and a similar period for the electrical components. S&B Services also offers
a twelve month guarantee from the date of installation.
How long will they last?
The plants are in the main constructed of glass fibre, plastic and stainless steel and
have an indefinite life. However, as with all working machines they require regular maintenance
and in the case of treatment plants and septic tanks they need periodic de-sludging to remove
excess material, which can cause blockages and failure to the soakaway or discharge quality.
Regular servicing and maintenance of the plant will prolong its effective working life.
Can you drink the discharge?
No. Although the fluid is clear and odourless and low in BOD etc., it is not recommended that
it be consumed. The majority of treatment plants do not remove all bacteria that can be harmful
to health. The discharging to a high flow water course dilutes the material and the natural
UV breaks down the residual bacteria. Discharge to the ground allows the soil to remove the
bacteria and render it harmless to health, although there is a remote possibility that an
adjacent pond or well may be contaminated, so the soakaway should be located at least 10 metres
away from any possible water source. Specialist treatment plants are available that can discharge to a
pond.
Can you drive over a plant?
Usually not. However, if the surface is protected by a reinforced concrete or steel apron, then
an appropriate loading is possible.
How frequently do treatment plants need de-sludging?
Most plants need only an annual de-sludge but some require a more frequent interval; you should
always consult the manufacturer’s instructions.
Is any maintenance required?
Yes. As with any working machine the regular attention and cleaning is essential for
continued trouble free operation and, of course, continued clean discharge to conform with the
‘Consent to Discharge’ issued by the Environment Agency. S&B Services offer service
contracts for most plants within the South West of England.
Are treatment plants one or three phase?
Generally single phase (240 volts) but some larger ones may be three phase (415 volts). Pumps
for small installations are usually single phase, but if a high loading is required a three
phase pump will give a better and longer service.
Can two or more houses share a treatment plant?
Yes, but it is advisable for a formal agreement to be entered into by all parties. The
formation of a Management Committee, with a regular subscription by all members, is a useful
method of administering the finances. The power supply can be either from a single house with a
credit meter to record the electrical usage or a separate supply can be arranged through the
local utility company.
Does storm water have to be separated from foul drains?
The majority of smaller package sewage treatment plants are not designed to cater for
additional flows other than foul waste. However, some SBR and larger plants can cater for up
to three times the dry flow figure. (The dry flow figure is the calculated figure for foul
discharges – nominally 200 litres per person per day) The input of sudden surges of storm water
will flush the plant out, reduce the retention time for treatment, and disturb the settlement
and cause untreated and suspended solids to be discharged.