Date of visit: 28 July 2008
Hidden away in the picturesque countryside of Suffolk is a farm
owned and managed by forward thinking people. A farm that is
working hard to ensure any negative impact on the environment is as
low as possible and that it enhances nature where possible. The
specific features are:
- All refurbishments have been done using reclaimed non plastic
materials where possible, insulated
with Warmcel (new window) and painted
using eco-friendly paints (new window) from the
Green Shop.
- The majority of lights are energy efficient.
- All agricultural vehicles are run on 100% biodiesel from oil
seed rape grown locally and processed on site. Oil seed rape has
been chosen as it has a much higher yield than other seed heads
like linseed or sunflower. The downside is that it requires more
treatment.
- Two experiments to grow the oil seed without use of pesticides
or, herbicides or added fertilisers have been carried out on site.
Interestingly there was a higher yield where pigs had previously
been kept and fertilised the ground. The future aim is to use as
little as possible while maintaining yield - weeds and pollen
beetle are a particular problem.
- A 100% biodiesel boiler has recently been installed to give the
staff area and stables hot water, but also used as a pre-heater for
the bio production.
- The back up generator (currently used as a top up in winter)
runs on 100% oil seed rape biodiesel.
- Producing animal feed from the husks left after rapeseed oil
extracted.
- An effective rainwater harvesting system (new window) is in
place.
- About 12 -15 people are on site on average and once waste has
been separated in a septic tank the effluent is added to water
which the percolates through a rather beautiful pool of reeds for
‘polishing’ before being released into a ditch.
17 members of the Greenprint Forum were given the opportunity to
have an informative and inspiring guided tour led by the owner of
the farm, the farm hand and Jeff Tebbutt from Bio Integrated
Organics. In the interest of fuel security the owner of the farm
has asked that we do not disclose the name or location of the
farm.
Thanks go to Jeff Tubbutt from Bio Integrated Organics for his
information on biodiesel:
Key notes from the tour
The vision is to create low impact, low carbon, self sufficient
working farm.
Bio Integrated Organics were hired to identify the best
equipment for producing biodiesel - the specification given
was:
- To produce a biodiesel to a high quality.
- To produce a quantity to cover each months usage with as little
man hours as possible, and the scope to double production if
required without further investment.
- To produce a fuel that would work well at lower ambient
temperatures.
- To produce a minimum by-product waste on site.
- To use a dry filter rather than the traditional water wash as
this uses a lot of water and cannot be released into a reed bed
system.
Biodiesel was chosen because as there is sufficient land locally
to grow food and fuel crops for the farms need it is in this
instance a sustainable fuel with the following key benefits:
- Negligible net carbon emissions in comparison to fossil fuels
and because as the cost of fossil fuels rises it has become more
economically attractive.
- It can be stored anywhere that petroleum diesel fuel is stored.
All diesel fuelling infrastructure including pumps, tanks and
transport trucks can use biodiesel without modifications.
- Biodiesel is more lubricating than diesel fuel, it increases
the engine life and it can be used to replace sulphur, a
lubricating agent that, when burned, produces sulphur dioxide - the
primary component in acid rain
- Biodiesel is safe to handle because it is biodegradable and
non-toxic. According to the National Biodiesel Board, 'neat
biodiesel is as biodegradable as sugar and less toxic than
salt.'
- Biodiesel is safe to transport. Biodiesel has a high flash
point, or ignition temperature, of about 300ºF compared to
petroleum diesel fuel, which has a flash point of 125ºF.
- Engines running on biodiesel run normally and have similar fuel
mileage to engines running on diesel fuel. Auto ignition, fuel
consumption, power output, and engine torque are relatively
unaffected by biodiesel.
- Biodiesel has a pleasant aroma similar to popcorn popping in
comparison to the all-too-familiar stench of petroleum diesel
fuel.
- As under 2,500 litres are produced per year the fuel is tax
exempt.
Biodiesel production process
Chemical production chosen uses a process called
trans-esterification. Once extracted from seeds oil is heated,
filtered and methanol is added, together with a small amount of
sodium hydroxide catalyst (in this case caustic soda). The mixture
separates in a settling tank and the by-product glycerol is
removed.
The raw material used - oil seed rape
Oil seed rape is the most popular European fuel base due to its
characteristics when used in colder climates. This will produce a
fuel that will need a lower cold weather blending, which again fits
well with reducing the carbon foot print. When ambient temperatures
are over 10ºC this can be used at 100%.
Seed press
The seed press was chosen for its long term reliability and ease to
add further presses to the frame as and when production increases.
This unit produces approx 10 litres per hour and approx 300 litres
to 350 litres of oil per ton of seed. The press was also chosen due
to the by-product being delivered in pellet form offering the
advantage of using the by-product as fuel for a multi-burner or a
high protein animal feed. Used on this farm for both purposes. The
protein being approx 36%.
Processor
The production of oil in small quantities is fundamentally a
simple process; the art is in calculating the correct mixture of
methanol and caustic soda, and the use of a good quality base
product. The processor was identified due to value for money with
an easy to use design.
Filtration
This area was more important to identify due to the conventional
way of washing the fuel. Normal production would require approx 50
- 75 litres of water which becomes contaminated with soaps and
by-products that can not be disposed of through the reed bed
filtration on the site. The farm has installed a dry filtration
system that uses no water to wash and polish the finished fuel.
Waste
The only waste this production will produce is:
Glycerine - approx 20% of batch size. This
by-product is no longer a dead waste as there is now a market for
this product and if collected to a suitable quantity, firms will
take this away free of charge.
Filtration by-product - approx 350 - 500 grams
per batch. This product would be disposed of through normal
domestic waste, and would find its way to land fill.
Further information on biodiesel
Reed bed waste water treatment
The key was to make an attractive natural looking pond system
utilising water flow from the natural artesian well which coupled
with the use of a sceptic tank would be sufficient to treat the
waste water and grey water from the 12 -15 people who use the farm
house and for the run off from the stables. This has been
successful with minimal maintenance required and the Environment
Agency have to date been satisfied with the quality of water being
released into the overflow.
Reed beds are an established method for treating waste water/sewage
and can also be used to treat grey water. Biological systems use
reed beds to add oxygen to waste water and allow naturally
occurring bacteria to remove organic matter. Waste water can be
passed through the soil/gravel in which the reeds are growing and
the bacteria fed by oxygen from the reeds and nutrients from the
waste water decompose the waste.
Further information on reed beds and grey water
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