ENVIRONMENTAL CODE OF PRACTICE
Waste Water Management
Overview
The discharge of sewage can affect water quality by locally
increasing the biochemical oxygen demand (BOD) and therefore
reducing the available oxygen required by aquatic species for their
survival. Although the quantity of material discharged from boats
is small, it is untreated. Raw sewage introduces microbial
pathogens into the environment and can pose a health hazard for
swimmers and those consuming shell fish from the area. In addition,
excessive quantities will raise the nutrient levels of the water
which can trigger algal ‘blooms’. Portable toilet effluent and some
holding tank systems contain chemical additives such as chlorine,
formaldehyde, ammonium and zinc compounds. In sufficient quantities
all these chemicals are toxic to marine life. The most immediate
impacts of boat sewage are those which are visual and
odour-related, both of which are unwelcome to boaters and
non-boaters alike.
The discharge of sewage can affect water quality by locally
increasing the biochemical oxygen demand (BOD) and therefore
reducing the available oxygen required by aquatic species for their
survival. Although the quantity of material discharged from boats
is small, it is untreated. Raw sewage introduces microbial
pathogens into the environment and can pose a health hazard for
swimmers and those consuming shell fish from the area. In addition,
excessive quantities will raise the nutrient levels of the water
which can trigger algal ‘blooms’. Portable toilet effluent and some
holding tank systems contain chemical additives such as chlorine,
formaldehyde, ammonium and zinc compounds. In sufficient quantities
all these chemicals are toxic to marine life. The most immediate
impacts of boat sewage are those which are visual and
odour-related, both of which are unwelcome to boaters and
non-boaters alike.
However, overboard discharge is prohibited on most inland
waterways. For tidal and coastal waters reference should be made to
local harbour authority by-laws.
Statutory regulations
Ports waste management covers sewage disposal. Please
review our ports waste management
guidance for more information.
Freshwater Navigations
Vessels with sanitation systems discharging sewage overboard
must be sealed (or rendered inoperable) when entering freshwater
navigations, so that no toilet waste is discharged overboard or
onto land. “Grey water” from sinks and showers may be discharged
but strong cleaning agents and cooking oil should be avoided from
being discharged. Holding tanks must be pumped out at a sanitary
station.
Tidal waters
Discharges from sea toilets are not prohibited. However it is
good practice not to discharge a sea toilet where doing so would
affect the water quality or harm the amenity value of local waters.
It is therefore necessary to provide adequate facilities for both
resident and visiting boats to ensure that the good practice is
adhered to. The fitting of holding tanks for boats regularly using
inshore waters is encouraged. These should then be discharged well
offshore (3 miles) or to the shore through pump out facilities.
For specific cases, there may be by-laws covering waters in the
control of local harbour or port authorities. For example, the
proximity of shellfish beds for human consumption and potable water
abstraction point may have led to the creation of a by-law
prohibiting the direct discharge of sea toilets within a certain
area. Marina operators can impose conditions of contract on their
customers which disallows the use of sea toilets when in their
marina.
On-shore toilet facilities
Marinas and boatyards should provide clean, accessible shore
side toilet facilities and washrooms and encourage berth holders to
use these facilities whenever possible. If a charge is deemed to be
necessary for the use of the facilities, it should be small or
included within the mooring fees. Properly managed, these
facilities can become a valued asset.
Where possible, and with prior permissions of the local sewer
provider, these facilities should be connected to the public foul
sewer. Discharges to sewer are controlled by the Water Industry Act
1991 and Trade Effluents (Prescribed Processes & Substances)
Regulations 1989. Owners of trade premises may not discharge
effluent into the foul water sewer unless a trade effluent consent
has first been agreed with the relevant sewerage undertaker. In
England and Wales, this will probably be one of the water
companies. The undertaker will review the details of the effluent,
its quantity and likely peak discharge when assessing the consent
application. In remote situations, it may not be possible to
discharge to a sewer and an alternative method of sewage disposal,
such as a septic tank or package sewage treatment plant will have
to be considered. These options require careful attention and
consultation with your local Agency office is recommended as you
will require a discharge consent prior to making any discharge to
controlled waters. Any sewage disposal facilities will need
adequate maintenance to ensure correct operation and to prevent
overflows to a watercourse.
Providing sewage pump-out facilities
The inland waterways generally have a well established network
of pump-out facilities and most if not all residential hire craft
have holding tanks. Conversely, on coastal waters, pump-out
facilities are limited mainly due to the limited demand, however
there is often a political benefit to installing pump outs.
As boat users become more environmentally educated, demand for
such facilities is likely to rise and coastal marinas and boatyards
should be ready to respond to this rise in demand. The European
Recreational Craft Directive, which will be implemented into UK
legislation in 2005, specifies that all new craft containing
sea-toilets must make provision for the easy installation of
holding tanks, this is stimulating such demand.
Whilst installation may be seen as prohibitively expensive, some
operators make charges to pump sewage ashore which enables them to
recoup some of the costs. You should also be aware that some local
planning authorities are striving to make the provision of pump-out
facilities mandatory for new boating facilities or where existing
facilities are to be significantly expanded.
If pump-out stations are being fitted, they should be connected
to the main public foul sewer where possible. In remote situations,
the advice from the regulatory agencies suggests that alternative
methods of sewage disposal, such as septic tanks or package sewage
treatment plant will have to be considered, but that chemical
toilets should not be emptied into these facilities.
When planning the installation of a sewage pump-out facility the
following issues should be considered:
- The location and accessibility for yachts
- The promotion of the service and guide to its use
- How to charge for the use of the facilities so that people are
not put off using them. Options include charging each time they are
used, charging as part of the harbour dues or mooring/berthing
fees, charging by volume, or charging different rates at different
times of the year
- Arrangement of a maintenance/inspection contract with a
competent servicing and repair contractor
- The availability of foul sewers for connection. You should
obtain advanced permission from the sewerage undertaker to
discharge sewage into their foul sewers
- When the effluent will be treated on site (through the use of
septic tanks or package sewage treatment plants) prior to being
discharged to land or a controlled water. You should obtain
advanced permission from the environment agencies to discharge
sewage from pump out facilities into controlled waters
The Green Blue has produced a directory of UK pumpout facilities
which can be found at www.thegreenblue.org.uk
Disposal of chemical toilet waste
Chemical toilets are self contained systems which rely on
biocides, in one form or another, to control the production of foul
odours. It is recommended that either the foul sewer or a
centralised waste collection/disposal facility (such as a chemical
toilet disposal point) is used as a means of disposing of any
collected chemical toilet wastes. If a collection point is used,
bulk sewage can then be collected by road tankers belonging to
suitable waste disposal contractors.
Do not allow chemical toilet waste to be accepted at stations
served by septic tanks and package sewage treatment plants as the
chemicals can harm the micro-organisms responsible for treating the
sewage. For further guidance on sewage disposal see the environment
agencies Pollution Prevention Guidelines PPG4.