ManuREsource 2017 – focus on circular economy on manure management and valorization
The third ManuREsource conference was held in 27th-29th November in Eindhoven, Netherlands. The core concept was in exchanging experiences and knowledge between European regions on effective policy measures dealing with manure surplus and innovations in manure treatment technologies. This time the special focus was on showing which possibilities there are to create value out of animal manure, and to change m anure excesses in some European regions onto chances for other regions.
Ammonia emission from manure and use and processing of manure and/or digestates were in the focus on several of the presentations and posters in the conference. Here are some short notices from the presentations
- Use of acidified slurry or acidified biogas digestate was studied in order to find out whether it can increase the nitrogen fertilizer value of the products. The study indicated that it did not result in higher yield with growing lettuce compared to non-acidified counterparts. It was suggested that acidified bio-based fertilizers might be less suitable for crops with short growing period like lettuce. (Can acidification increase the nitrogen fertilizer value of bio-based fertilizers? I.Sigurnjak, E. Michaels, S. Crappe, S. Buysens, F.M.G. Tack, S. De Neve, E. Meers)
- The processing of manure at a biogas plant can reduce environmental impacts comparing with other manure management practices, while generating renewable energy. Nevertheless, the anaerobic digestion of manure at a biogas plant also produces undesired gaseous emissions, which should be taken into account in the environmental evaluation of this activity. Comparing the biogas plant performance with the reference situation, total NH3-N, N2O and CH4 were lower in the current situation than total emissions in the reference situation of not processing the manure in a biogas plant, demonstrating the efficiency of anaerobic digestion of manure. (Gaseous emission measurement and environmental assessment at a biogas plant. Torrellas, A. Anton L. Burgos, L. Tey, J. Noguerol, V. Riau, A. Bonmati)
- In winter wheat production system, use of digestate and acidified digestate, alone and together with nitrogen inhibitor, was tested. NH3 emissions were reduced significantly when using acidified products, and there were also yield increases observed though not statistically significant. The knowledge obtained will help to understand how digestate use could be improved in terms of enhances NUE, through minimizing environmental risks for crop production. (Enhancing nitrogen use efficiency of anaerobic digestate in a winter wheat cropping system. A.R. Sanches-Rodriguez, A. Carswell, R. Shaw, J. Cotton, J Hunt, K. Saunders, T. Misselbrook, D.L. Jones, D.R. Chadwick)
- Thermal drying is an increasingly common post-treatment for digestate-solids (DS). However, relatively high N losses via NH3 volatilization will commonly occur from the solids during the drying process. Acidification and zeolite addition can significantly increase NH4-N in processed DS. (Thermal drying of digestate solids with acidification and zeolite addition to increase available nitrogen retention J. Liu, A. de Neergaard, L. Stoumann Jensen)
The last day of the conference, a visit was made to a manure processing plant Green Mineral Mining Center in Groot Zevert. The plant, established by Nijhuis & GEA, produces phosphate, nitrogen and potassium fertilisers. From the original volume of pig slurry, 10-20 % is turned into phosphate rich solid fraction with 3-6 % phosphate; 5-10% is turned into liquid nitrogen fertilizer with 7-8% ammonium sulphate; 5-10 % is turned into organic potassium liquid fertilizer with 7-10 % of potassium, and 60-80% of the volume is turned into clean water.