RL5: Novel animal feeds produced from agro-residue
Responsible partner: Inagro & University of Ghent,
Country: Ghent & Rumbeke-Beitem BELGIUM
This demo is considered at TRL 6 with an outdoor academic setup of cultivation area of 1 m² and consists of three identical units to allow statistical analysis. Meanwhile, the pilot-scale is used at a large scale, with a cultivation area of 140 m².
This demo solution is linked to Nutri2Cycle research line 5 (RL-5: Novel animal feeds produced from agro-residue) and is one of the shortlist priority solutions i.e. sub-research line 12 (Floating wetland plants grown on liquid agro-residues as a new source of proteins).
The potential of Lemna minor to valorise agricultural wastewater into a protein-rich feed component is investigated within this demo case to meet the growing demand for animal feed protein and reduce the excess of nutrients in certain European regions. Therefore, different cultivation units are executed within Nutri2Cycle. First, a cultivation pond of 140 m² is supplied with biological effluent and liquid fraction of the pig manure treatment facility of IVACO (Eernegem, Belgium). Secondly, a raceway pond with a cultivation area of 32 m² is supplied with effluent from the pikeperch production. These two pilots provide a production capacity of several kilograms per week, which allows using the duckweed for several experiments. First, duckweed from the raceway pond was supplied for a broiler feeding test at Hochschule Onsebrück. Then, the same was done at the pilot of Ivaco. The third set-up is at a semi-pilot scale and is designed to execute academic-grade outdoor experiments. This consists of three identical systems of each 1 m² of cultivation area. The systems are fed with a mixture of the liquid fraction and the biological effluent of a swine manure treatment system diluted with rainwater that the weekly N and P addition was equal to the N and P removal by the system. The design tests the accumulation of elements in a continuous recirculation system. Potassium, Cl, S, Ca, and Mg are abundantly available in the swine manure wastewaters and tended to accumulate, being a possible cause of concern for long-operating recirculation systems. The harvested duckweed is characterized for its mineral composition and protein content. In animal husbandry, trace elements are specifically added to animal feed as micronutrients and, thus, feedstuffs biofortified with essential trace elements can provide added value. Duckweed grown on the tested mixture of swine manure waste streams could be considered as a source of Mn, Zn, and Fe for swine feed, while it is not a source of Cu for swine feed. Moreover, it is observed that As, Cd, and Pb content were below the limits of the feed Directive 2002/32/EC in the duckweed grown on the tested medium. Overall, these results demonstrate that duckweed can effectively remove nutrients from agriculture wastewaters in a recirculated system while producing a feed source with a protein content of 35% DM.
In this demo, a liquid fraction and biological effluent from the pig manure treatment facility which is rich in N and P was used as a nutrient source for duckweed. During this process, N is removed from the medium due to (de-)nitrification and plant uptake, while P is removed by sedimentation and plant uptake. Also, other nutrients are taken up by the plant. These are potentially recovered within the livestock sector if the plant biomass is harvested and supplied as a feed ingredient for animals. Even more, the harvested plant can be considered a protein rich ingredient.
RL5: Novel animal feeds produced from agro-residue
Responsible partner: Ghent University
Country: Ghent, BELGIUM
TRL and Scale of set up: This demo is considered at TRL 5 with two types of algal reactors set up: one commercial horizontal reactor (600L) and one custom-made vertical reactor (2000L). The reactors used are already at their full-scale. Commercial applications would only use a higher number of the tested reactors.
This demo solution is linked to Nutri2Cycle research line 5 (RL-5: Novel animal feeds produced from agro-residue) and is one of the shortlist priority solutions i.e. sub-research line 12 (Floating wetland plants grown on liquid agro-residues as a new source of proteins).
The current demonstration study investigates microalgae-based valorisation of nutrient-rich digestate, a liquid agro-residue and co-product of the anaerobic digestion (AD) process, for production of protein-rich biomass and as an alternative treatment pathway to land application of digestate. More specifically, regions of North-West Europe which are characterized by local surplus of nitrogen fertilizers are in need of such alternative processing strategies. Microalgae can actively recycle nutrients present in digestate to cultivate microalgae in the presence of (sun)light and without the need of arable land. However, the challenging raw digestate characteristics – high concentrations of nutrients (ammonium), dark colour (turbidity) and high viscosity – may cause microalgal growth inhibition due to toxicity, limited light penetration and non-homogenous distribution of algal cells within the medium respectively. A series of physico-chemical pre-treatment techniques including centrifugation-dissolved air floatation (within AD facility), paper-filtration, dilution and acidification (with inorganic phosphorus solution) are applied to improve the properties of digestate. A mixed consortium of Desmodesmus sp. and Chlorella vulgaris are cultivated on the paper filtered digestate (PFD) under non-axenic conditions in a 3-litre lab-scale photobioreactor and 3000-litre pilot-scale facility. In lab-scale studies, under 10% (v/v) PFD without acidification condition, a biomass productivity of 0.1 g/L/day DW at nitrogen (N) and phosphorus (P) uptake of 16.5 mg N/day and 0.24 mg P/day are observed, respectively. The additional acidification step enhances the N-uptake and P-uptake to 28.5 mg N/day and 1.2 mg P/day yielding a final biomass productivity of 0.09 mg/L/day DW with protein content of 67% (w/w). Furthermore, preliminary pilot-scale trials performed in two batches under varying digestate loading conditions (2% and 5% v/v) presents a similar biomass productivity of 0.08 mg/L/day but higher N-uptake rate of 3600 mg N/day and P-uptake of 180 mg P/day.
In this demonstration study, both lab- and pilot-scale investigations are performed to exhibit the microalgae-AD technology. A factory-processed liquid fraction of digestate of plant and food-waste origin, rich in N and P content, are pre-treated with a paper (bag) filter to improve its properties for microalgae cultivation – reduction of viscosity, turbidity and increasing the light penetration capacity. These improvements enable active and maximal recycling of soluble nutrients (especially N and P) from digestate to produce protein-rich biomass. During this process, C is sequestered by utilizing carbon dioxide as an inorganic carbon source for promoting algae growth and for pH stabilization in a 3-litre lab-scale photobioreactor and 3000-litre pilot-scale facility.
This project has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement nº 101135708. The dissemination of results herein reflects only the author’s view, and the European Commission is not responsible for any use that may be made of the information it contains.
Copyrights © 2024 | Jarvis-project.eu Cookie & Privacy Policy Webdesign & Development by ALYS
