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Foul drains (sewer system) - carry contaminated
water, trade effluent and domestic sewage to treatment
works prior to discharge into controlled waters
Under the conditions of the Water
Industry Act (1991) a consent is required from the
relevant water service company (United
Utilities) to discharge trade effluent to the
sewers.
The Water company are legally required to take your
effluent as long as it conforms to certain standards
and levy a charge for the services required and may
well impose restrictions (including pre-treatment and
monitoring) on the effluent before discharge.
It is the Water Companies duty to secure copies of
consents given under part III of the Water Industry
Act 1991 in a Trade Effluents Register.
How is the charge levied by the Water Company calculated?
The charge is calculated using the modified Mogden formula
which takes into account the volume, average COD or
BOD* concentration and average suspended solids concentration.
*COD - Chemical Oxygen Demand
BOD - Biochemical Oxygen Demand, measure of oxygen use
by bacteria in breaking down the organic (biodegradable)
fraction of effluent discharge.
What can I do to reduce my charge?
Effluent volume is often not measured but is assumed
to be the same as the volume of water used (based on
water meter readings). Therefore
improving water efficiency will reduce cost of effluent
discharge to the sewers.
If the BOD, COD and suspended solids concentration
of your effluent is high you should consider (if practical
and cost-effective) on-site separation or biological
treatment which would result in as reduction in the
trade effluent charge.
Are discharges of special waste under the control of
the water company?
If the water company classifies the effluent as special
waste the application for consent to discharge is
passed to The Environment Agency and assessed under
special waste regulations.
Do I need to obtain consent if the process that I operate
is under the remit of IPC/IPPC regulations?
If the process you operate falls within the remit of
IPC/IPPC regulations
the discharges made to the sewer are covered by these
regulations but your interface with the water company
remains the same.
If no mains drainage is available what disposal options
do I have?
If after consultation with your local water company
it is decided that a sewer connection is not possible
you could consider (either alone or in combination)
the following options:
1) Septic Tank
2) Package Treatment Plant
3) Reed Bed System
4) Waterless Toilet
Links to Further Information
Netregs
Management Guidelines: Trade Effluent
Environment
Agency (PPG1) General Guide to the Prevention of Water
Pollution
Environment
Agency (PPG4) Disposal of sewage where no mains drainage
is available
Environment
Agency (PPG11) Preventing Pollution on Industrial Sites
Envirowise
Ref. Note 006 Effluent Discharge to Sewers
Envirowise
Ref. Note 190 Water Industry Act
United
Utilities
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