In the right form and in the right place, the manure of domesticated animals is a valuable source of nutrients. However, manure is often a burden. More efficient processing and utilization of manure could make it a source of income, helping bind nutrients in crops instead of the environment. Why, then, is manure not recycled?
"In Finland, animal husbandry and crop farms are concentrated in different parts of the country," said Juha Gronroos, a principal research scientist at the Finnish Environment Institute. "In some parts of the country, too many nutrients are accumulated, while in other parts of the country, nutrient needs are supplemented by purchasing fertilizers. Manure should be spread over a larger area, but transporting manure ... is not sensible."
The bulk of manure ends up where it should: in an unprocessed form in the field.
"However, producers need to restrict the use of manure and increase the area over which manure is spread due to regulations becoming more stringent and on account of the fact that the phosphate levels of the soil are high following large volumes of manure having been spread in large volumes in the past," said Sari Luostarinen, principal research scientist at the Natural Resources Institute Finland.
According to Gronroos, there is a need for processing. "The proportion of nutrients contained in manure is not optimal from the perspective of plants. This challenge is coupled with the fact that the nitrogen in manure easily evaporates in the form of ammonia," Gronroos said.
Producers are interested in the subject and obtaining a new source of income from the processing of manure.
"The problem lies in substantial investments and in the uncertainty of the methods that would be suitable for a particular farm," Luostarinen added.
According to researchers, an individual producer should not necessarily invest in manure processing but, instead, should develop processing in collaboration with other producers in the same area.
"The profitability of processing greatly depends on the characteristics of manure. For example, when testing the (spreading) of liquid swine manure, we noticed that the method is only cost effective with concentrated liquid manure."
Furthermore, processing is not necessarily the best solution.
"For example, when planning a biogas plant, one of the issues to take into account are the questions of how and where nutrients could be used most efficiently," Luostarinen said.
"The spreading of manure in fields can also be made more effective if animal husbandry and crop farms could collaborate more closely and if solutions could be found for sensible transport of manure," Gronroos added.
Every link in the chain of manure handling — with or without processing — must be thought out thoroughly. All of the pieces of the jigsaw puzzle must fit together in order to ensure that the whole will be functional and sustainable, from both an environmental and economic perspective.
"The producer should not be left alone to deal with these questions. For this reason, for example, under our 'Teholanta' ('Power manure' project), we are in a process of creating uniform instructions for poultry producers for the utilization of manure," Luostarinen said.
The Teholanta project seeks solutions for recycling poultry manure that are directly applicable to farms. In the same context, water protection can be intensified.
"The Teholanta project was born at the initiative of producers (in Finland). Interest in the efficient use of poultry manure exists, and producers would like to see more appreciation for manure," said Reetta Palva, project manager at TTS. "The target is to create sample solutions that can be duplicated and be readily applied at farms to the recycling of valuable nutrients."
The Teholanta project focuses on the overall sustainability of manure processing, taking both the ecological and economic perspective.
Tests involve manure incineration, its thermal gasification and biogasification and utilization of the end products generated as fertilizers.
"We have already noticed that the manure of commercial layer chicken generates more biogas per fresh weight unit than the manure of other poultry. We have plans to demonstrate the biogasificaton of various manures under real farm conditions," Luostarinen said.
"In a suitable form, poultry manure is an excellent nutritional supplement for the fields of our contract producers. On the other hand, at the moment, phosphorus contained in poultry manure is a problem, and its recovery should absolutely be examined. Developments in the sector will benefit all parties," Jarmo Seikola, procurement manager at HKScan, said in justifying the company's participation in the project.
Teholanta is a joint project of TTS, Natural Resources Institute Finland, Finnish Environmental Institute, Suomen Siipikarjaliitto Oy (Finnish Poultry Assn.) and JAMK University of Applied Sciences.
The operators receive support provided by separate funding for water protection and nutrient recycling under the Rural Development Program. Atria Suomi, HKScan, MTK, Maa- ja vesitekniikan tuki ry and Siipikarjasaatio (the Finnish Poultry Foundation) also participate in the project.