In response to the environmental challenges posed by livestock waste, a comprehensive project was initiated to explore the feasibility of implementing the H2OPE(1) system in the pig and dairy industry. The primary goal was to assess how this innovative system could efficiently manage slurry waste, separating solid and liquid phases to produce a natural fertiliser. The key objectives included reducing environmental impact, minimising ammonia loss and runoff, complying with legislation, and enhancing the overall sustainability of livestock farming.
A thorough consultation with 22 farms across England and Scotland revealed common challenges related to organic waste management, including waste volume, storage management, legislative compliance, pollution mitigation, value addition, and carbon reduction. The subsequent feasibility study demonstrated the suitability of the H2OPE system for treating liquified agricultural slurries. Engineering analysis and lab research provided the foundation for conceptual designs and a basis of design. Testing and sampling of slurry samples indicated promising results, with the H2OPE system consistently achieving moisture contents of less than 20%. Furthermore, the system enhanced macro nutrients (N, P, K) in both cow and pig slurries, showcasing its potential benefits for the agricultural sector.
A comparative study on carbon emissions associated with traditional slurry export versus on-site processing with H2OPE revealed significant environmental advantages. The baseline case, without separation of slurry fractions and extended storage, resulted in substantial fugitive greenhouse gas emissions. In contrast, the proposed model, incorporating the H2OPE system, demonstrated a 75% reduction in slurry storage time and a 74% reduction in associated greenhouse gas emissions. This reduction was attributed to quicker on-site processing, eliminating the need for carbon-intensive shipping of synthetic fertilisers.
The project also assessed the economic viability of implementing the H2OPE system. The average cost of handling slurry, including spreading, was £5.50 per m3 across participating farms. Notably, these costs did not cover additional storage expenses or potential fines associated with environmental violations. However, these results were encouraging, showcasing a potential saving of 23% on the handling costs alone.
Additionally, two approaches for handling the fertilised end product were considered. Based on the volumes of fertiliser purchased by the 22 diary and pig farms within the feasibility assessment, SEM could return 58% and 132% of the require volumes respectively.
The feasibility study confirmed the H2OPE system’s suitability for transforming livestock waste management, offering environmental and economic benefits. The carbon assessment, conducted independently by Carbon Zero, underscored the potential for significant emissions reduction. The next steps involve real-world testing to validate the solution’s suitability and establish detailed costs and benefits.
The successful implementation of the H2OPE system holds the promise of not only enhancing the environmental performance of individual farms but also positively impacting the broader supply chain and meeting the expectations of environmentally-conscious consumers. This case study serves as a blueprint for sustainable practices in the livestock industry, showcasing the potential of technology-driven solutions to address pressing environmental challenges.