Sewage plant leaflet - Coastline Housing

Living with a sewage plant
Many outlying rural properties do not have the facility of being connected to a public
sewerage network provided by South West Water.
Coastline Housing manages and maintains a number of sewage treatment plants to
which your property is connected. In order for these plants to function correctly within
the operating parameters we would ask you to read this leaflet in full.
Effective sewerage treatment plant must meet four requirements:
• Remove risks to public health, that is, to prevent disease
• Avoid unpleasant smells and sights, both on and off the sewerage works
• Enable the receiving streams and rivers to fulfil all their varying uses
• Meet legally required conditions of discharge (Environment Agency permit)
Sewerage contains a wide variety of waste products of human, animal, vegetable or
mineral origin, some of which are in solution and others in suspended solid state.
Part of the treatment process requires biological oxidation to remove sewerage
polluting substances. Biological oxidation requires close contact between sewerage,
living organisms and oxygen to allow the full treatment process to function. Sewage
treatment plants use all the live natural micro-organisms to break down the
pollutants, allowing the plant to discharge to a permitted receiving watercourse
(known as Environment Agency consented discharge).
Many chemicals found in the household can inhibit or kill these micro-organisms,
particularly if used in excessive amounts. As a result of killing the organisms the
whole treatment plant would have to be removed and disposed at the nearest South
West Water reception centre. Reseeding a plant after failure requires live sewerage
which is called activated sludge. This sludge has to be transported from a South
West Water treatment plant to our plant. This operation of reseeding costs in the
region of £4000 to £6000 depending on plant size.
If the micro-organisms are damaged, they will eventually recover in time but still
require a small amount of activated sludge. In the meanwhile, one of the more
obvious symptoms is an unpleasant smell from the plant. It is therefore in your
interest to avoid this.
In the normal course of events all common household cleaning fluids are acceptable,
provided they are used in accordance with the maker's instructions and stated
concentrations.
Version: CHL SEW/V1 Copyright Coastline Housing Ltd 2013

Common chemicals
Washing machine and dishwasher detergents - perfectly alright in normal
concentrations and usage. Problems can occur if for instance you are washing the
jerseys of the local rugby club.
Floor cleaners, disinfectant and bleaches - again these are safe to use in
accordance with the maker's recommendations. What you should refrain from doing
is pouring neat disinfectant and bleach down the sink or outside gully. If these smell
it is likely there is a build-up of decaying material or a plumbing problem that should
be dealt with accordingly.
Nappy disinfectant and bottle sterilizing fluids like Milton - when disposing the used
fluid ensure that it is well diluted with water. The easiest way of doing this is to flush
it away down the toilet.
Drain and pipe cleaning solutions like Mr Muscle - these must not be used where a
property is connected to a septic tank or treatment plant. One sachet is strong
enough to kill all the bacteria in a plant that serves around 20 properties.
Waste disposal units - these do not inhibit the micro-organisms but they can present
the plant with a considerable extra load. It is much better and more environmentally
friendly to compost your vegetable peelings.
Home beer and wine making - this presents a similar problem to waste disposal
units. A treatment plant works as hard to treat one pint of beer as it does to treat the
normal waste of one person in 24 hours. Therefore when disposing ensure it is well
diluted with water.
Out of sight, out of mind
The average family produces 600 litres of waste water a day, equivalent to eight
dustbins.
Here are the top ten harmful substances and items that must not be discharged to
the drains:
• Cooking oil and fat – bag and bin
• Cotton buds, condoms and disposable contact lenses – bag and bin
• Disposable razors and hypodermic needles – talk to Cornwall Council or your
health care provider to arrange safe disposal of hypodermic needles
• Disposable nappies, sanitary towels, backing strips, tampons and panty liners
– bag and bin
• Weed killers, insecticides, fungicides and other gardening chemicals - take to
a local authority collection point
• Wet wipes and facial wipes – bag and bin
Version: CHL SEW/V1 Copyright Coastline Housing Ltd 2013

• Paint, thinners, white spirit, turpentine, creosote - take to a local authority
collection point
• Medicines - these should be taken to a pharmacist for disposal
• Motor oil, grease, anti-freeze, brake fluid - take to a local authority collection
point
• Photographic developing fluids - take to a local authority collection point
Non-organic waste
Sewage plants are designed to treat organic waste. Non-organic waste will cause
harm to the plant, especially those that contain mechanical parts such as inlet
screens and pumps.
The foul drain leaving your house is only four inches in diameter. This is only
designed for dirty water and human waste. Blockages are caused by sanitary towels,
tampons, panty liners congealed cooking fat, cotton buds and condoms. Although
such items do not directly damage the micro-organisms they can however cause
problems such as blockages and damage to moving parts and unnecessary call outs
to the plant. Even so-called disposable nappies and sanitary towels often do not
degrade fully in the treatment plant and can lead to malfunctions, and then need to
be disposed of by other means.
Please remember that the costs of running the sewage plants are shared equally
between the all the connected properties, and breakdowns caused by the
inappropriate use of chemicals and the blockages by non-organic material will be
recharged to each property under the recharge policy, as this would be considered
deliberate damage or abuse.
Contact us
For any help or advice please call Coastline on 08082 027728 or 01209 200200, or
email customer.service@coastlinehousing.co.uk
Version: CHL SEW/V1 Copyright Coastline Housing Ltd 2013