17 th International Conference on Environmental Science and Technology Athens, Greece, 1 to 4 September 2021 CEST2021_00036 Improving Innovation Capacities of Private and Public Actors for Sustainable and Profitable Recycling of Livestock Waste. ANTONIOU M.G. 1,* , KALLIKAZAROU, N. 1 , KOUTSOKERAS, L. 2 , CONSTANTINIDES, G. 2 , and CONSTANTINIDE, E. 3 1 Department of Chemical Engineering, Cyprus University of Technology, P.C 3036, Limassol, Cyprus 2 Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, P.C 3036, Limassol, Cyprus 3 Department of Environment, Ministry of Agriculture, Rural Development and Environment, P.C 2025, Strovolos, Nicosia, Cyprus *corresponding author: e-mail: maria.antoniou@cut.ac.cy Abstract The Mediterranean region is known for its intensive livestock farming, especially for the breeding of pigs and cattle. These activities result in vast amounts of waste that necessitate proper treatment. Inadequate manure treatment can cause eutrophication of surface waters, enrichment of nitrates and pathogens into groundwater, detection of excess nutrients and heavy metals in soil, and increase GHGs emissions. RE-LIVE WASTE is an Interreg MED project (2/2018-4/2021) that focused on testing innovative solutions for livestock waste management in Cyprus, Italy, Spain, and the Federation of Bosnia and Herzegovina. The proposed route to address the environmental and financial problems associated with livestock waste was through nutrient recovery and the precipitation of an organo- metallic fertilizer known as struvite. Each participating region constructed and operated a struvite precipitation plant that transformed anaerobically treated and untreated livestock waste from cattle, pig, and mixed waste into struvite. Different treatment trains were followed in each demonstrative pilot to record the effects of treatment and source of waste on the final product. In Cyprus struvite was produced by a mixed effluent that was anaerobically digested and filtered with filter bags and UF ceramic membranes. The struvite produced had a purity between 90-99% based on the applied conditions. Keywords: struvite, livestock waste, anaerobic digestion, nutrients. 1. Introduction The Mediterranean region is characterized by intensive cattle and pig livestock farming, that in return results into high volumes of waste. Release of greenhouse gases (GHGs) into the atmosphere, nitrates and pathogens leaching into surface and groundwater, buildups of excess nutrients and heavy metals in soil, and destruction of fragile ecosystems through eutrophication are the major problems associated with poor waste management (Casasús et. al., 2012). It has been reported that agricultural production is expected to increase by 60% by 2050 to address word- hunger, which means if we still use conventional agriculture practices phosphorus-mining demand will also increase, since it is an important nutrient for plant growth and a vital component of fertilizers. However, P-resources are constantly declining, and predictive models indicated that they may be extinct within the next 100 years, it becomes a necessity to find alternatives to industrially produced P-fertilizers so that food availability and security are sustained. Nutrient recovery (N and P) from livestock wastewater through struvite crystallization/precipitation could be a sustainable solution to alleviate this problem. Struvite is a crystalline organo-mineral, known for its insect repellent properties and slow nutrient releasing properties that make it a high-value organic fertilizer. It contains equal molar concentrations (1:1:1) of magnesium, ammonium, and phosphate (struvite MgNH4PO4·6H2O), that can be recovered from nutrient-rich wastewater streams including livestock, dairy, agro-industrial, and industrial (Le Corre et al., 2009). The Interreg MED project RE-LIVE WASTE that was completed in April 2021 (total duration 39 months) applied this innovative nutrient recovery solution for livestock waste in demonstrative struvite precipitation pilot plants located in nitrogen vulnerable regions of Cyprus, Italy, Spain, and the Federation of Bosnia and Herzegovina. The project aimed to alleviate all the previously mention environmental and financial problems associated with livestock waste management, that are of particular concern to small scale farmers, through strong cooperation among the 4-helix actors (academia, government, industry, and public). Herein, the treatment processes applied along with the outcomes of the Cypriot pilot are presented and discussed. 2. Materials and Methods