Featured Editorial

PIG WORLD SLURRY
He’s got the problem covered
As he farms near an urban area,
Philip Cornforth has introduced
‘clay marbles’ to prevent smell
escaping when slurry is stirred
Philip Cornforth has always been keen to avoid
complaints from neighbours when he spreads
slurry, so all the slurry goes through a separator before being pumped into his 15-year-old slurry silo.
And recently he decided to go one step further and
cover the silo with Aerocover polymer-coated aggregates, from Biotec.
These look like small clay marbles. They stop
any smells emerging when the slurry is stirred before being pumping underground to a new deep
lagoon some distance away.
When the tank is being stirred, the particles
can be thrown to the sides but they return to cover
the whole area immediately the stirring stops.
As the content of the tank lowers, the aggregate lowers with it, and because the silo is a
straight, slippery-sided construction, they do not
stick to the sides as they would in earth-walled lagoon.
In that type of lagoon — as at Robert Hirst’s,
which we reported on in July — the particles are
picked up again as the lagoon is filled and cover the
whole area, so none are lost.
At the Cornforth’s Scalibur Farm, which is near
Knaresborough, the large lagoon has a thick slippery-sided lining supplied by Tanlake, and none of
the particles stick to the side as it empties.
Philip thinks that over time there will be a need
to top up the aggregate, but perhaps not much.
ESCAPE ROUTE FOR RATS
He has jumped through hoops to comply with regulations. The fencing round it the lagoon is excellent. At each corner of the lagoon, he has a line of
old tyres fastened together in a long line which is
secured to the top of the lagoon.
I asked why they were there and he said he
had been told it would provide an escape route for
any vermin that got into the lagoon, rather than
them trying to gnaw through the lining to get out.
I suspect the only vermin that would be able to get
in would be rats and they indeed could cause damage.
Philip has an underground pipe leading to offlying land, some of which is across the other side
of a busy road. They grew potatoes years ago and
had an underground pipe for irrigation. This has
now been connected to the slurry pipe and works
a treat.
There was no smell whatsoever when I visited. He has an automatic connection for the slurry
tanker so the driver simply pulls alongside the discharge connection, fills up and is then on his way.
Next to the lagoon he has made a concrete
standing with concrete panel walling for solid manure and these panels have been painted green’
Above: Philip Cornforth with his slurry siloDPWFSFEJOTNFMMTVQSFTTJOHhNBSCMFTh
Below: His concrete pad with kind-to-the-eyes green-painted walls for solid manure.
52 PIG WORLD September 2011
and what a difference that makes.
It is the sort of attention to
detail that is typical of Philip. It is
a really neat and tidy set-up and a
pleasure to look at, as well as do
ing everything he has asked of it.
It is an example of what can
be achieved. Apparently the En
vironment Agency is very happy
with it.
• More information:
Biotec 01827 715544.
September 2011 PIG WORLD 53
PIG WORLD SLURRY MANAGEMENT
Stirring Robert Hirst’s aggregate-covered lagoon.
I cannot count on both hands
the number of products we have
looked at over the years for reducing the smell from slurry. Some,
it has to be said, have not come
quite come up to scratch, whilst
others have shown promise.
Most recently I have been to
look at expanded clay aggregate,
which floats on the surface of lagoons and tanks, to prevent the
release of ammonia and to control smell.
Robert Hirst farms at Swillington, near Leeds. The Hirst family are indeed progressive farmers,
with an immaculate, extremely
22 PIG WORLD July 2011
NO MORE SMELL
On the day of my visit I saw the lagoon being stirred and slurry being spread. There
was no smell at all. As the level of slurry subsides, the aggregate remains on the side
of the lagoon and when it fills again it is simply picked up by the rising liquid and
again forms a seal. Sam Walton reports from Robert Hirst’s farm
productive unit.
They are committed to environment schemes, which means
footpaths alongside hedges next
to the unit. They have tried vari-
As a first step, they installed
ous products to reduce smell but
a Bauer separator to take out
when the lagoon was either filled,
solids. They were so surprised by
emptied or stirred, they still reCall Hugh Crabtree
the amount they were taking out,
ceived complaints from people
Tel 0118 988 9093 Email hugh@farmex.co.uk Fax 0118 988 9658
with sensitive noses. Farmex, Unit 4, Wyvols Court Farm, Basingstoke Road, Swallowfield,
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PIG WORLD NEWS
No more smell
• FROM PAGE 22
they lifted the separator up another tier of concrete panels and
widened the reception area by 50
percent.
The second step, which they
took almost a year ago now, was
to have Aerocover aggregate applied to the surface of the lagoon
at a depth 20-25mm. It was blown
on by a blower bulk lorry.
So has it worked? Complaints have all but disappeared
and the Environment Agency
is delighted and endorses what
they have done.
On the day of my visit I saw
the lagoon being stirred and
slurry being spread. There was no
smell whatsoever. The aggregate
remains on top. It doesn’t get into
the pump.
As the level of slurry subsides, the aggregate remains on
the side of the lagoon and when it
fills again it is simply picked up by
the rising liquid and again forms
a seal.
Above: Close-up of the clay aggregate. Below: Dry matter from the Bauer separator..
GALES
During some very strong gales
the week before my visit, the aggregate had been blown towards
one end of the one- acre lagoon
but as soon as the wind subsided
it levelled itself out again.
Aerocover has been developed by Biotec Ltd. The product
contains two polymers, one of
which, in the presence of ultra violet light, decomposes ammonia
into nitrogen gas and water.
The second has a longerterm action, capturing and absorbing ammonia and other volatile organic compounds.
The product is said to be selfsustaining and maintenance-free,
with the minimal top-up required.
Independent tests have shown
removal of 100 percent of ammonia and hydrogen sulphide and
an average removal of 45 percent
carbon dioxide.
Similarly Philip Cornforth,
who farms near Knaresborough,
with 560 sows through to finish,
wanted to comply with IPPC regulations, and three months ago
he covered his 12-year-old steel
tanks with Aerocover. Again, this
ticked all the boxes for the Environmental Agency.
Since then Philip has built
a large lagoon which gives him
extra storage should anything
happen to his tanks or should he
24 PIG WORLD July 2011
Below: Expanded clay aggregate on the lagoon surface.
decide to expand production.
This too has been covered
with Aerocover. Like Robert Hirst
he separates his slurry and this
has helped with odour emissions.
He is well pleased with the
combined results from separation
and the application of aggregate,
as are his neighbours. He says the
only thing the aggregate doesn’t
do is to keep water out.
He wouldn’t categorically
say there is no odour at all, but it
is negligible and is currently keeping the various authorities happy.