Sprayer filling Biobed

	A pit excavated to a depth of 60 cm. Plinths are set and fixed in place. The bottom is filled with a 10 cm layer of clay.
	Depending on available material and spryer size, a load bearing frame is suitably constructed on which to place the ramps.
	The biobed is filled with a mixture of chopped straw, peat mould and top soil rich in humus but with a low clay content. Finally grass is covered the biobed.

Excavate a 60 cm deep pit with both length and breadth set in proportion to the sprayers size.
Place 10 plinths according to the drawing.
Adjust and secure in place using crushed gravel.
Place 3 U-grinders upside down over the plinths as shown in the diagram.
Weld I-grinders (I 14), railway rails or similar according to the diagram below. Guaranteed strength should be 1,8-2 tons per grinder with approximately 4 m span. Finally adjust the grinders to a ramp made from meshed steel or similar.
Remove the ramps and fill the pit with 10 cm clay. Fill the pit with a mixture of 50% chopped straw, 25% peat-mould and 25% topsoil. Proportions are calculated as percent in volume. Finally set the ramps in place

-Ready for use-

The biobed has now been in use for a number of years on several Odling i Balans´ pilot farms. Introduced at first as an interesting idea, the biobed has shown itself to work extremely well with regard to illuminating risks occurring with filling and cleaning of spraying equipment. Several of the biobeds have been tested by Dr Lennart Torstensson from the Institution of Microbiology at SUAS (Swedish University of Agricultural Sciences).

Soil samples have been taken from different levels in the bed and different time intervals. Using analysis, can the occurrence of pesticides be identified. As expected the presence of pesticides can be found in the top layer as a result of either filling or cleaning of spraying equipment. Later testing of the bottom layers shown no indication of pesticides which demonstrates the biobed functioning as expected. Spill occurring while filling and cleaning is broken down by the presence of microorganisms with high microbial activity in mixture of soil, straw and peat-mould.

According to Lennart Torstensson, the following points are special importance:

-When the biobed has sunk approx. 10 cm it should be topped up using a mixture of straw / peat-mould / soil. This is best done before the beginning of the new spraying season in spring.

-If the grass layer has been damaged as a result of spillage, new turf should be used to replace the damaged areas. The biobed functions best when the grass layer isn´t suffering from too much damage.

-When the sprayer is not in use it should be parked on the biobed unless it can be stored inside. When it rains pesticide is washed from the underneath of the sprayer and this should end up in the biobed.

An alternative to the biobed, is to have filling and cleaning done on a hard nonpouros surface where any spill and wastewater can be easily collected for treatment. One method is to lead the wastewter to a slrry tank. It is imprtant that the inflow of wastewater be to the surface where the aerobic environment favours the breakdown of pesticides.

One other possible method is to after having collacted the wastewater on a hard nonporous surface, spread it on a grass area or other ground having high microbial activity.