Improving Life Cycle Economic and Environmental Sustainability of Animal Manure Management in Marginalized Farming Communities Through Resource Recovery

Abstract

A growing world population with increasing levels of food consumption will lead to more dairy and swine production and increasing amount of manure that requires treatment. Discharge of excessive nutrients and carbon in untreated animal manure can lead to greenhouse gas emissions and eutrophication concerns, and treatment efforts can be expensive for small scale farmers in marginalized communities. The overall goal of this study was to determine the environmental and economic sustainability of four animal manure management scenarios in Costa Rica: (1) no treatment, (2) biodigesters, (3) biodigesters and struvite precipitation, and (4) biodigesters, struvite precipitation, and lagoons. Life cycle assessment was used to assess the carbon footprint and eutrophication potential, whereas life cycle cost analysis was used to evaluate the equivalent uniform annual worth over the construction and operation and maintenance life stages. Recovery of biogas as a cooking fuel and recovery of nutrients from the struvite reactor reduced the carbon footprint, leading to carbon offsets of up to 2,500 kg CO 2 eq/year. Offsets were primarily due to avoiding methane emissions during energy recovery. Eutrophication potential decreased as resource recovery processes were integrated, primarily due to improved removal of phosphorus in effluent waters. Resource recovery efforts led to equivalent uniform annual benefits of $825 to $1,056/year, which could provide a helpful revenue source for lower-income farmers. This research can provide clarity on how small-scale farmers in marginalized settings can utilize resource recovery technologies to better manage animal manure, while improving economic and environmental sustainability outcomes.

A Critical Review of Data Science Applications in Resource Recovery and Carbon Capture from Organic Waste

“…In addition to quantifying the environmental impacts of anaerobic digestion of wet feedstocks integrated with treatment of liquid (via struvite precipitation or ammonia stripping) and solid digestate (via composting or gasification), studies in Spain, Italy, Belgium, and United Kingdom used CML, ReCiPe, and IPCC to conduct LCA for treating the liquid effluent via constructed wetlands, ,, reverse osmosis, , or sequencing batch reactor for water reuse. Studies in Costa Rica and China assessed anaerobic digestion integrated with struvite precipitation and composting, respectively, for nutrient recovery and lagoon for liquid effluent treatment where animal waste was the feedstock. , A study in the USA utilized municipal sewage sludge to assess the integration of anaerobic digestion, pyrolysis, hydrothermal liquefaction, ammonia stripping, and tertiary treatment of effluent using ReCiPe for LCA and NPV for LCCA/TEA . Generally, fewer LCA and LCCA/TEA studies on the treatment of solid and liquid digestates for RRCC have been completed compared to assessing the environmental and economic impacts of just producing biogas.…”

“…However, considering the large number of studies in the past two decades, a need exists for unified reporting and comparison of such relevant information to appropriately inform practitioners about the effective utilization of data science tools for sustainable RRCC from organic waste streams. Further, although recent studies have demonstrated the potential of integrating multiple technologies to maximally utilize organic waste and recover a variety of resources, [13][14][15]47,48 a literature review of data science applications in such integrated RRCC technologies has yet to be conducted. The overall goal of this study is to conduct a critical literature review covering the wide umbrella of data science applications that includes data-driven process modeling along with the environmental and economic impact assessments in RRCC from multiple organic waste streams through single or multiple-treatment technologies.…”

“…However, considering the large number of studies in the past two decades, a need exists for unified reporting and comparison of such relevant information to appropriately inform practitioners about the effective utilization of data science tools for sustainable RRCC from organic waste streams. Further, although recent studies have demonstrated the potential of integrating multiple technologies to maximally utilize organic waste and recover a variety of resources, − ,, a literature review of data science applications in such integrated RRCC technologies has yet to be conducted.…”

“…Fortunately, these organic waste streams, rich in nutrients (e.g., nitrogen, phosphorus, potassium) and carbon, can be valorized utilizing RRCC technologies while also mitigating risks to the environment and human health. ,− On a global scale, a fully functional circular economy between agriculture and wastewater treatment utilizing RRCC could have reduced 140 Tg of CO 2 emissions in addition to sequestering 104 Tg of CO 2 in 2022 . RRCC from organic waste streams also addresses two of the 14 grand challenges for engineering in the 21st century: managing the nitrogen cycle and developing carbon sequestration methods .…”

Integrating chemical precipitation and membrane separation for phosphorus and ammonia recovery from anaerobic digestate

“…The production processes of these critical substances are however, energy‐intensive and account for significant CO 2 emission 1,3 . In particular, ammonia production via the conventional Haber‐Bosch process accounts for ~1.4% global CO 2 emission, 3,4 whereas approximately 1 ton of CO 2 is generated for a kilogram of phosphorus fertilizer production 5 . In addition, excessive nutrient loads discharged to the environment from waste streams can result in harmful algal blooms, causing impacts on aquatic ecosystems, fisheries, recreation, water supplies, and public health, 6 via a process called eutrophication.…”