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ALBATROSS
PUBLICATIONS
PO Box 523
Horsham
West Sussex
RH12 4WL
Tel:
01293 871201
Fax:
01293 871301
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KENNEL DESIGN - SITE
DRAINAGE AND DISPOSAL SYSTEMS
David Key
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The subject
of adequate and efficient drainage and disposal of foul water
is often an area that tends to get overlooked, particularly
for properties that have been constructed in stages over a
number of years. The problems often relate to the fact that
the business has grown in small stages at any one time and
the infrastructure has not grown in proportion to keep up-to-date
with the increasing use of water for washing down and greater
use of washing machines for laundry.
I have visited several sites where
the owners have adopted all sorts of engineering methods to
overcome the problems associated with systems for the disposal
of foul water. These range from foul water isolating valves
that have to be closed shut when it rains to prevent clean
rain water entering the system and overloading it; this is
particularly relevant to owners with septic tanks and cesspools,
to small electric pumped systems that have to be manually
switched on when a holding chamber is full - through to more
illegal methods that the Environment Agency would have a field
day with!
The most noticeable area of problem
lies with the older style of brick/concrete septic tanks that
were installed to service a house only. Generally the systems
were never designed to cope with any form of business and
not one which by its nature uses larger volumes of water.
The end result is that the septic does not work as it was
intended to do; therefore there is no or little purification
of the foul water. In addition to the physical construction
of the tank itself there is the problem with inadequate final
soakaway systems from the final discharge point of the tank.
This often results in the area around the tank being a swamp
of foul smelling and stagnant sewage water.
The problems often come to a head when
either a neighbour complains of the smell or the owner applies
for Planning Permission to construct new kennels/cattery.
Once an application is submitted to the local authority for
planning permission it is automatically passed to the Environment
Agency for their comments and approval.
The Environment Agency is responsible
for the protection of "controlled waters" from pollution
and for the prevention of pollution of the environment, harm
to human health and detriment to local amenity. Generally,
any planning submission for kennel/catteries and stables will
attract more attention from the EA.
All waste produced from breeding, boarding
and stabling is defined as industrial waste (under the Environmental
Protection Act 1990 and the Control of Waste Regulations 1992).
Once a Planning Application has been
submitted, the EA will state what level of purification and
system they wish to be used for your particular location.
Sometimes this is a matter of negotiation and compromise.
However, at the end of the day, you will need to comply with
their requirements in order to secure your planning application.
The cost of this legal requirement should be taken into consideration
when you are putting together your financial cost plan for
any development or upgrading works.
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The main methods available
for the efficient disposal of foul water are:
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SEWER
A sewer can be either public or private.
Generally I would always advise that wherever possible you
endeavour to connect onto a mains sewer. This is also the
most preferred disposal method for the EA.
Animal establishments by their nature
tend to be in more isolated areas, away from mains drainage.
However, it is always worth investigating how far away the
nearest mains sewer is to you. Often, and in the long run,
the costs of connecting onto a main sewer will be cheaper
than some of the other methods mentioned below.
The Blue Cross has a site that is
some 500m away from a main sewer. The initial costings gave
a payback period of some 5-6 years to recoup the cost of
paying the farmer to cross his land and installing a macerator
pumped system.
Once installed the system is the
easier to maintain, manage and does not have the problems
associated with constant changing of discharge consents
that some of the other systems have.
Under normal circumstances the preferred
method to connect onto a mains sewer is by use of gravity,
eg your site is higher than the sewer. However, the other
option is to install a pumped system. This generally involves
a holding chamber; on electric macerator pump and a small
bore pipe, usually 50mm. There are plenty of packaged systems
available that will provide a cost-effective solution.
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CESSPOOL
A cesspool is an underground
watertight tank that acts as a storage reservoir for all
foul water entering it. This is then collected by tanker.
Modern cesspools are manufactured out of GRP, although brick,
concrete and steel systems are sometimes used.
A cesspool is to be
considered the least desirable method of sewage disposal
for the kennel owner. Building Regulations state that the
minimum size of the tank must be 18000 litres with a minimum
of 45 days of storage sited at least 15m away from any dwelling
and at least 10m away from any watercourse.
The cost of emptying
the tank is an ever-increasing one. At present this is highly
dependent on where in the country you live and the proximity
of suitable sewage treatment facilities. A sum in the region
of £200 - £400 per 12000 - 20000 litres seems
to be an average. However, there will be great fluctuations
on this for the reasons stated above.
The Environment Agency
give guidelines for sewage per person for the following
locations, these are:
Domestic = 180 litres
per day
Hotels = 200 litres per day
Hospitals = 450 litres per day
A Blue Cross centre
with approximately 40 dogs, 25 cats, staff, W.C.s etc will
average approximately 3000 - 4500 litres per day of water
for cleaning etc.
It is clear to see that
the emptying cycles for a cesspool are regular and expensive.
NB - in Scotland, the
Building Regulations do not permit the use of cesspools.
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SEPTIC
TANK
A modern septic tank
is manufactured from GRP, however, its operation differs
little from that of concrete and brick systems over 100
years old.
The tank is normally
divided into two or three chambers. The first chamber holds
all of the solids; from this the effluent rises into smaller
chambers where the sedimentation of the finer solids takes
place. From the final chamber the effluent is discharged
into a soakaway system. This is normally into shallow land
drains, however it could be into a river or stream.
The main considerations
to remember when installing a septic tank are:
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Ensure that the
land surrounding the discharge point has suitable porosity.
This is ascertained by the use of a percolation test.
The onus will be on you to ensure that the land is suitable
for your requirements. Ground conditions will vary for
each location; generally clay, very steep sites and sites
which have a high water table, create the most difficulties
for the owner. The amount of underground pipework for
the final soakaway required would depend on how porous
the subsoil is.
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The tank will require
to be emptied at least once a year. Suitable vehicular
access will be required within 20m of the tank.
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In areas with bore
wells, the distance required from the discharge point
will be not less than 50m away. The EA will advise on
this.
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Surface water should
not be alowed to enter the tank as this greatly overloads
it and prevents it working efficiently.
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Generally, the EA
will require notification of any underground discharge.
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SEWAGE
TREATMENT PLANT
WIn cases where the
standard of effluent has to be a higher standard than that
produced by a septic tank, this is normally when a sewage
treatment plant is installed.
A sewage treatment plant
is a self-contained unit and, providing it is working correctly,
can produce an extremely high quality of effluent. Again,
the final discharge is normally into an underground soakaway
system, although in some cases it can be straight into a
watercourse. Any discharge into a watercourse will require
the consent of the EA.
Most packaged units
require single-phase electricity supply to power either
the pumps or compressors. They also require regular maintenance
to ensure that they are working to the required standard.
This is often best carried out by either the manufacturer
or a pump engineer.
If you have to go to
the expense of installing a sewage treatment plant careful
consideration should be given to the type, its efficiency:
some are not as efficient when dealing with animal waste,
disinfectants and the amount of maintenance it requires.
The other point often
overlooked is that septic tanks and sewage treatment plants
have living organisms in them to help reduce the animal
waste. The use of disinfectants and washing powders in excessive
amounts will kill these useful organisms, thus rendering
the system ineffective for a period of time until they recover.
In addition to the above
systems the two other methods employed to produce higher
qualities of effluent are reed beds and filtration mounds.
These tend to be used as polishing or tertiary treatment
to existing systems.
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David Key is author
of "Essential Kennel Design", available from Kennel
& Cattery Management. For more information on kennel
design, visit www.kenneldesign.com.
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