Complex processing of brewery waste for obtaining feed additives

One of the key directions in the development of the modern brewing industry in Ukraine is the rational utilisation of organic waste generated during beer and malt production. The article aimed to investigate the composition, physicochemical properties, and utilisation methods of the main brewing wastes, using Mykulynetsky Brewery as a case study. Quantitative and qualitative characteristics of solid (brewer’s spent grain, malt sprouts, barley screenings, trub) and liquid (transport water suspensions of spent grain, protein sediment, residual yeast, lager sediments, wastewater) wastes were determined. It was established that brewer’s spent grain accounts for up to 85% of all solid production residues and represents a valuable raw material for feed production due to its high content of protein, fibre, and minerals. Experimental studies were conducted on the processes of spent grain dewatering and drying, malt sprout and barley screenings grinding, and filtration of concentrated suspensions from the fermentation-brewing workshop. Optimal conditions for phase separation of suspensions were determined, yielding a concentrated protein fraction with 73% moisture content and a filtrate with a low concentration of suspended solids (0.1-0.45 g/dm³). A technology for the comprehensive processing of all major brewing wastes was proposed, resulting in two types of feed products: dewatered brewer’s spent grain and granulated protein-vitamin feed containing 35% crude protein, 5-7% fibre, and 8-10% moisture. The developed technology also provides for the neutralisation of acidic and alkaline wastewater to standard parameters and their reuse in the production cycle. Practical implementation of the proposed technology significantly reduces environmental impact, decreases waste generation, increases resource efficiency of production, and creates a closed-loop system for the utilisation of secondary resources in the brewing industry