The Use of Fermentation Sludge as a Fertilizer in Agriculture

Abstract

Novo Nordisk is one of the world's largest producers of enzymes, insulin and biopharmaceuticals. This production is based mainly on biotechnology and fermentation processes. The waste from the fermentation process is non-toxic, but due to the high content of nitrogen and phosphorus the waste can cause eutrophication if it is discharged in the marine environment. Novo Nordisk has developed a process in which the fermentation sludge, which constitutes a large part of the waste, is used as an organic fertilizer - NOVOsludge - in agriculture. The total amount of sludge is 500,000 m3/year, corresponding to 800,000 kg of nitrogen and 300,000 kg of phosphorus. Around 10,000 hectares of farmland benefit from this. Since a great proportion of the raw materials used in fermentation are based on agricultural products, this use is an example of re-cycling of nutrients. Investigations of the uptake of the nutrients in different types of crops are made in order to develop still more efficient uses. The system which has been developed has also contributed to new rules for the utilization of organic waste material.