The decrease in number of farmers and the increase in farm sizes will continue. The milk quota in the EU will be abolished and this will give a further increase in the size of heards of milking cows. In the Netherlands the stables for milking cows have been enlarged. Even in the period of recession in the building sector, companies building stables were very busy in the Netherlands. The next bottle necks for farmers will be to get rid of the manure.

This is already a problem for pig farmers in the Netherlands, who pays up to € 20,- euro a ton. The norm for putting the nitrogen part has also decreased in the last week to 230 kg a hectare for grassland (derogation). For phosphate the Dutch government has introduced legislation to limit the amount of
phosphate for the Dutch agriculture. Farmers could get additional revenues when export it.

The solution of the problem of phosphate surplus could be the decrease of phosphate import. The second problem is the feeding of the cows. Protein rich feed is needed to get the a highly productive milking cow. Soya is important for this. It would be good to replace this by locally produced feed. This means less import of Soya beans for feeding the cows and pigs and less imported phosphate for using fertilizer. To a lesser extent, but concentration processes in the farming sector takes place also in Poland and the UK.

This Eranet-proposal gives a solution on farm scale. The manure is digested and further refined to fertilizer. This will be done by making struvite and ammonium sulphate of the digested manure. The struvite can be used by the fertilizer industry and the ammonium sulphate is recognized as
fertilizer and will replace the present artificial fertilizer. By digestion of the manure it will be better treated and the energy is generated for this treatment process. Only part of the nitrogen and phosphate is captured in this way. The part which cannot be used directly on his fields. The new element in this already existing innovation project is the use of the excess nitrogen and phosphate to a duckweed pond. Duckweed provides high amount of proteins and it can replace the soya import. In this project we will look under what conditions an optimal duckweed production can be obtained in combination with the biogas installation providing heat and the struvite reactor and ammonium stripper providing the

The objective of this proposal is to developed and test the duckweed lake in the new configuration. Research will be held which minerals feed is the best for the duckweed production from a technical and economical viewpoint. Different species of duck weeds will be tested an also the harvesting method. The scientific objective is to proof we can have a sustainable farm, which generates its own electricity (in reality it will be three times more), fertilizer and feed. No proteins import is needed anymore, which will lead to an balance of nutrients, like phosphate and nitrogen on the farm. The technological objective is to demonstrate that it is economical and technical feasible to realise such a sustainable farm.