Manure separation in dairy barns phase II

This project aims to reduce greenhouse gas and ammonia emissions in existing stables through faster (primary) separation and removal of faeces and urine. By upgrading these separate components and offering them through practical integrated solutions, the research contributes to making the dairy sector more sustainable.

This project proposal is closely related to the PPP and Climate Envelope on Manureseparation in dairy barns. Primary manure separation systems were identified and described at the end of 2019. The three most promising ones have been selected for use in existing dairy barns.

Expected results

New applicable knowledge about:

  • Emission measurements in the barn
  • NPKC balances of barn and storage
  • Separation Yield
  • Permeability and walkability of the "Tile floor".

Knowledge and experiences are exchanged with predecessor companies that are actively involved in manure separation and separate storage.

What are we researching?

The choice of the most promising principles of primary manure separation on the basis of three selection rounds with researchers, advisers in barn construction, dairyfarmers who are interested in manure separation and in consultation with the PPS supervisory committee are:

1. Cow toiletDirect separation of faeces and urine under the tail gives the best separationof NPKC (nitrogen, phosphorus, potassium, carbon); NK is mainly in urine and PCmainly in faeces. The faeces in the manure cellar still contains urine but less.

2. Rubber floor with manure separation

The material ensures good walkability. There are also indications that the urease activity can be lower than on a concrete surface. Ammonia is formed from urea present in urine. This process is accelerated by the enzyme urease, present in manure. There are different types of rubber floors. The floor to be examined is characterized by the rapid drainage of urine via gutters.

3. Permeable synthetic floor ("Tile floor")

The ZeraFlex is a permeable floor in the form of tiles or elements that drain urine. These can be placed screwless on a grid floor or solid surface. This offers perspective for limiting the emission of ammonia, because the urine is quickly drained via the permeable tile to the manure cellar. The principle of quick separation and therefore little urine on the top layer offers opportunities to limit emissions in thehouse. The disposal of faeces with a folding trap developed for this floor offers possibilities to limit the emission of methane, provided that it is stored correctly and, if necessary, treated. The faeces are mixed with straw to make it stackable.

4. Combinations

In order to achieve a far-reaching reduction of ammonia emissions in the barn(guideline less than 5 kg per animal place per year and ambition less than 3kg), a combination of the cow toilet with a rubber floor or "tiledfloor" may be useful. This can possibly be combined with other management.

Importance to dairy farming

  • Innovative and affordable solutions to adapt existing barns or possibly build new ones, aimed at reducing emissions of nitrogen and greenhouse gases at the level of the entire fertilizer chain from barn to land. The systems to be investigated will help to meet future standards.
  • Saving on fertilizer, this will partly depend on the extent to which the urine fraction can be upgraded to a fertilizer substitute.
  • Specific opportunities for nature-inclusive agriculture and sales to arable farming through the use of faeces (with or without the addition of straw).
  • Increasing the yield of digestion by using fresh manure / faeces.
  • Lower manure disposal costs of manure, by saving transport costs when selling faeces and by supplying manure quality that matches the customer.
  • Better utilization of the nutrients in manure both on land-based dairy farms and when sold to arable farming.
  • Important preconditions are that the floors are easier to walk on and that it is not at the expense of claw health.

How do we research?

The emission measurements in the barn and the preparation of an NPKC balance in the barn take place in the measurement units on Dairy Campus. All floors are compared with a conventional free stall barn with slatted floor (case-control study).The urine that drains through the floor is stored in the manure cellar under the grids. The faeces are removed from the barn with a folding scraper and stored separately with cover. It is important that ammonia and methane emissions from urine and faeces are also limited during storage. That is why the different fractions are also processed in special vessels by adding acid, among other things. The following measurements are taken:

  1. Emission measurements in the house (continuous): Ammonia and greenhouse gases (methane and nitrous oxide).
  2. Establish NPK balance in barn and storage based on measurements: - quantity and composition of feed and manure fractions - milk production.
  3. Emission measurements during storage of faeces and urine The emission measurements are made by extracting the air from the storage.
  4. Determining separation efficiency; which part of NPKC and DS ends up in different fractions.
  5. Determine permeability, walkability and barn comfort of the floor according to fixed protocols. The ZeraFlex has been installed on a number of dairy farms and may be installed on more farms in the course of 2020.

In 2020, measurements will also be taken at four farms in terms of permeability andwalkability. User experiences are inventoried in terms of economy, fertilization and animal welfare. The knowledge gained is shared with the dairy farmers and advisers who were involved in the inventory phase in 2019. A go / no-go evaluation will take place at the end of 2020. If the three separation principles have perspective, the emission measurements in the barn, the NPK balances in the barn and storage and emission measurements of ammonia and greenhouse gases during the storage of faeces will be continued at Dairy Campus.

At the end of 2021, another evaluation will take place based on measurements and experiences in practice, together with an evaluation of PPP Manure Separation and Climate Envelope.


The approach to emissions from barn and storage aims to develop and implement innovative techniques and measures in barn, manure and processing for emission reduction in practice. The goal is to achieve the reduction targets by 2030. The Agriculture Stable and Storage research program consists of Measuring and monitoring (E) research (F), pilots and demos (G) and communication (H). Research must show which reduction techniques work and how much emission reduction this yields. In addition to research aimed at new stables, cost-effective modifications to existing stables are also being examined. The effects of the reduction options will be tested and demonstrated in practice atpilot companies and demo companies. In order to implement reduction measures,knowledge about new and existing measures is disseminated among the targetgroup of livestock farmers and farm visitors. The approach provides actionperspectives for livestock farmers to reduce emissions and encourage them toapply. This study (F) will show whether manure separation at source underpractical conditions results in good manure separation with a reduction in NH3and CH4 emissions.