WP 5: Environmental and Economic Implications
WP 5 aimed to increase the knowledge concerning the environmental and economic impacts of slurry acidification technologies (SATs) to help understand and justify the risks involved with investing in these innovative technologies.
A careful analysis with local parameters and future prices should be performed before deciding on SAT use on the farm. Financial studies of SAT implementation done within the frames of WP5 provide end-users with the tools necessary for making their own calculations and estimates on the feasibility and potential profitability of implementing SATs. The economic analysis of SAT implementation that combines both the environmental and financial analysis is also intended increase the understanding of authorities and policy-makers concerning the value of supporting SAT implementation in relation to other measures for meeting the ammonia emission reduction targets. Models, calculation data, methods and results are presented in the report “Economic aspects of slurry acidification”.
Some highlights from the economic and environmental impact assessments:
- SATs decrease ammonia emissions by 49–64%. Reduced emissions mean that farmers save nitrogen in slurry, thereby reducing the need of mineral nitrogen fertiliser. By using SATs, farmers can reduce the need for mineral nitrogen fertilizer, saving 0.77–2.10 € for each cubic meter of slurry used.
- Slurry pH is lowered using sulphuric acid. One litre of sulphuric acid contains 0.56 kg of sulphur and consequently 1.5–2.5 kg of sulphur is applied with a cubic meter of acidified slurry. It decreases the need for mineral sulphur fertiliser saving an estimated 0.8–1.4€ /m3, if slurry is applied according to the crop’s need.
- The investment cost of an acidification system depends on the chosen SAT.
- The main cost factor is the price of sulphuric acid. Here a reference price of 128 € per 1000 kg of acid (including tank truck delivery) is used. Additionally, it is calculated that the use of acidified slurry raises liming cost by 0,11 €/m3
- The farm level savings do not always cover cost of acidification, so society should compensate farmers for reduced ammonia emissions.
- Acidification decreases the environmental burden, largely due to reductions in ammonia emissions. SATs also reduce greenhouse gas emissions and have been found to reduce leaching of total organic carbon.
- The main risk associated with slurry acidification is nutrient and pathogen leaching and higher survival rates of some pathogens due to the lower slurry pH. Since the highest risk of pathogen leaching is immediately after slurry application, slurry application should be avoided when rainfall is expected.
- To reduce risk of plant root and groundwater contamination with E. coli bacteria, surface application of slurry is recommended. As acidified slurry can be applied on the surface without the risk of ammonia losses, acidification can be also a good method of reducing the risk of contamination by E. coli.
Reports produced by WP 5
The report below considers the environmental aspects of slurry acidification. The economic assessment report will be published on the reports page.
WP 5 contacts
WP leader: Estonian Crop Research Institute, Kalvi Tamm
email: firstname.lastname@example.org Tel. +3723223886
Assisting project partner: JTI – Swedish Institute of Agricultural and Environmental Engineering, Sweden
Andras Baky, email: email@example.com
tel: +46 (0) 730-66 94 94