Horacio Andres Aguirre-Villegas

• Ph.D.
• Researcher at University of Wisconsin–Madison

Manure is the second largest source of greenhouse gas (GHG) emissions from dairy farms. Detailed data for representative manure systems are needed to guide climate change mitigation strategies. This study uses surveys sent to WI dairies to identify current farm and manure management practices, collect inventory data on manure handling and energy co...

Four manure processing pathways are evaluated to provide a system-level understanding of their impacts on different sustainability indicators. In particular we look at how solid-liquid separation (SLS), anaerobic digestion (AD), and AD + SLS affect depletion of fossil fuels (DFF), nutrient balances, global warming potential (GWP), and ammonia emiss...

This study applies life cycle assessment (LCA) techniques to evaluate the processes controling the environmental impacts of anaerobic digestion (AD) pathways on a modeled dairy farm setting representative of Wisconsin. Seven electricity-producing AD pathways are compared against a base-case (BC) pathway to understand the effect of management practi...

The objective of this study was to evaluate the effect of integrating dairy and bioenergy systems on land use, net energy intensity (NEI), and greenhouse gas (GHG) emissions. A reference dairy farm system representative of Wisconsin was compared with a system that produces dairy and bioenergy products. This integrated system investigates the effect...

In this study, life cycle assessment (LCA) methods are used to develop life cycle inventory (LCI) and life cycle impact assessment (LCIA) data to estimate the global warming potential (GWP) and energy intensity (EI) of cheese and dry whey manufacturing in Wisconsin using a farm gate to plant gate approach. All of the environmental burdens and benef...

Objetivos: actualmente, la técnica estándar de detección de virus qRT-PCR, requiere personal capacitado, equipos especializados y reactivos relativamente costosos. La técnica de amplificación isotérmica mediada por bucle, LAMP, ha resurgido como una alternativa prometedora previamente y durante la pandemia de COVID-19 y su estudio tiene potencial p...

Modern mechanical recycling infrastructure for plastic is capable of processing only a small subset of waste plastics, reinforcing the need for parallel disposal methods such as landfilling and incineration. Emerging pyrolysis-based chemical technologies can �upcycle� plastic waste into high-value polymer and chemical products and process a broader...

Livestock manure wastewater, containing high level of ammonia, is a major source of water contamination, posing serious threats to aquatic ecosystems. Because ammonia is an important nitrogen fertilizer, efficiently recovering ammonia from manure wastewater would have multiple sustainability gains from both the pollution control and the resource re...

Existing plastic recycling infrastructure largely relies on mechanical recycling technologies, which are capable of processing only a small subset of waste plastics. Emerging chemical technologies can “upcycle” plastic waste by producing high-value products (e.g., olefins that can be used to produce virgin-grade polymers) and are more scalable, as...

Nearly 60% of all ammonia (NH3) emissions are from livestock manure. Understanding the sources and magnitude of NH3 emissions from manure systems is critical to implement mitigation strategies. This study models 13 archetypical conventional (5 farms), organic (5 farms), and grazing (3 farms) dairy farms to estimate NH3 emissions from manure at the...

Material Recovery Facilities (MRFs) are crucial players in achieving a circular economy. MRFs receive complex waste streams and separate valuable recyclables from these mixtures. This study conducts techno-economic analysis (TEA) to estimate the net present value (NPV) and life cycle assessment (LCA) to estimate different environmental impacts of a...

Correction for ‘Expanding plastics recycling technologies: chemical aspects, technology status and challenges’ by Houqian Li et al. , Green Chem. , 2022, 24 , 8899–9002, https://doi.org/10.1039/D2GC02588D.

Food packaging often appears in the form of multilayer (ML) plastic films, which leverage the functional properties of different polymers to achieve specific food protection goals (e.g., oxygen, water, and...

Food packaging often appears in the form of multilayer (ML) plastic films, which leverage the functional properties of different polymers to achieve specific food protection goals (e.g., oxygen, water, and temperature barriers). These properties are essential to enable long shelf lives, reduce refrigeration usage, mitigate food waste, and increase...

Thermochemical technologies, such as pyrolysis, offer a potentially scalable pathway for upcycling diverse types of plastic waste (PW) into value-added chemicals. However, deploying these technologies in waste management infrastructures is not straightforward because such systems involve a wide range of interdependent stakeholders, processing facil...

In many developing countries, milk and meat produced from dual-purpose cattle systems contribute substantially to the national supply of animal-derived human-edible protein (HEP). Defining a main product and a co-product may be difficult in these diversified systems because of the large spatial variation and possibly rapid temporal variation in the...

Less than 10% of the plastics generated globally are recycled, while the rest are incinerated, accumulated in landfills, or leach into the environment. New technologies are emerging to chemically recycle waste plastics that are receiving tremendous interest from academia and industry. Chemists and chemical engineers need to understand the fundament...

Increasing awareness of climate change has induced demand for action most notably. As public demand for action on climate change increases, conversion to energy sources with lower greenhouse gas (GHG) intensity will accelerate. Experience during the COVID-19 pandemic provided insight into how atmospheric conditions will respond to lower GHG emissio...

A farm scale life cycle assessment (LCA) was conducted to estimate environmental indicators of organic dairy systems in the U.S. and evaluate alternative management practices and methodological decisions. Fourteen farm layouts (including Amish and grass intensive) are evaluated over four U.S. regions. Carbon (C) sequestration from pasture and cropp...

Less than 10% of the plastics generated globally are recycled, while the rest are incinerated, accumulated in landfills, or leach into the environment. New technologies are emerging to chemically recycle waste plastics that are receiving tremendous interest from academia and industry. Chemists and chemical engineers need to understand the fundament...

Dairy farms are challenged to increase productivity while achieving environmental sustainability, where greenhouse gas (GHG) emissions are at the center of the discussion. The U.S. dairy industry leadership has committed to a Net Zero Initiative to achieve GHG neutrality, but the specifics on how to achieve this are still uncertain. Life cycle asse...

airy farming is a multi-billion {USD} industry that provides essential food products. At the same time, the millions of animals that this industry oversees generate a massive environmental footprint (affecting air, land, and water quality). Specifically, livestock manure is a carbon- and nutrient-rich waste stream that is routinely used as fertiliz...

Less than 10% of the plastics generated globally are recycled, while the rest are incinerated, accumulated in landfills, or leach into the environment. New technologies are emerging to chemically recycle...

Correction for ‘Expanding plastics recycling technologies: chemical aspects, technology status and challenges’ by Houqian Li et al. , Green Chem. , 2022, https://doi.org/10.1039/d2gc02588d.

Thermochemical technologies, such as pyrolysis, offer a potentially scalable pathway for upcycling diverse types of plastic waste (PW) into value-added chemicals. However, deploying these technologies in waste management infrastructures is...

Our objective was to determine the cradle-to-farmgate carbon footprint of fat-and-protein corrected milk (FPCM) for four diets fed to two breeds using measured enteric methane and greenhouse gas emissions during manure storage and after field application. The diets were formulated as 2×2 factorial with forage neutral detergent fiber at two levels (...

p>We apply systems engineering principals and life cycle analysis (LCA) to municipal waste supply chains to elucidate sustainability incentives. Environmental impacts are quantified using LCA for waste management technologies available in the supply chain, and included as products. The supply chain is modeled as a coordinated market and resolved us...

We determined the partial carbon footprint (CF) of milk for 4 diets fed to 2 breed using measured enteric methane and greenhouse gas emissions during manure storage and after field application. Emissions and animal performances were collected in companion studies with diets containing forage neutral detergent fiber at 2 levels (NDF; 19 and 24% of d...

Model Multilayered Website for Varied Audiences: Dairy Sustainability "Virtual Farm" v58-3tt6 Fabian-Wheeler, Eileen; Hofstetter, Daniel; Larson, Rebecca; Aguirre-Villegas, Horacio; Betz, Carolyn R. A "virtual farm" website with science-based information about dairy sustainability topics was created for a variety of audiences. A key structure of th...

Pork producers can have difficulty operating or expanding existing facilities or establishing new facilities based on perceived negative impacts to the environment and surrounding community. It is critical to understand the characteristics and practices adopted in swine facilities to evaluate the extend of these impacts. A survey, completed by 69 p...

A "virtual farm" website with science-based information about dairy sustainability topics was created for a variety of audiences. A key structure of the website is layering of information. At the most frequently used entry level, a site visitor explores by looking and learning. As interest evolves, the visitor finds links to technical levels, and t...

The influence of farm-specific beneficial management practices (BMPs) on a set of comprehensive environmental impacts was characterized and quantified for two representative dairy farms in the Great Lakes region (a large 1500-cow farm in New York (NY) and a smaller 150-cow farm in Wisconsin (WI)). Comparative benefits or drawbacks of the effect of...

Anaerobic digestion (AD) and solid-liquid separation (SLS) can increase operational flexibility at livestock facilities, but they can also affect environmental impacts during downstream manure handling. In this study, manure was characterized before and after AD, SLS, and drying. The measured data were used as inputs to models to estimate greenhous...

Manure characteristics change through processing, including anaerobic digestion (AD). These changes can alter handling of manure during downstream operations. This study analyzed the density, total solids (TS) content, and volatile solids (VS) content of pre-digested and anaerobically digested dairy manure from seven dairy farms in Wisconsin. The d...

We propose a coordination framework for managing urban and rural organic waste in a scalable manner by orchestrating waste exchange, transportation, and transformation into value added products. The framework is inspired by coordinated management systems that are currently used to operate power grids across the world and that have been instrumental...

We present a supply chain optimization framework to analyze economic and environmental benefits of recovering biogas, caproic acid (C6), and caprylic acid (C8) from different sources of organic waste. The framework makes simultaneous decisions on technology selection, sizing and placement, and transportation logistics. We consider livestock manure,...

The nutrient profile in stored manure can be highly variable due to the solids building up at the bottom of the storage over time as unagitated manure is removed. This variability can lead to under- or over-application of nutrients potentially reducing crop yields or increasing nutrient losses, respectively. Agitation of stored manure is a common p...

Dairy products are major components of the human diet but are also important contributors to global environmental impacts. This study evaluated greenhouse gas (GHG) emissions, net energy intensity (NEI), and land use of confined dairy systems with increasing levels of pasture in the diet. A Wisconsin farm was modeled to represent practices adopted...

Manure management at dairy production facilities, including anaerobic digestion (AD) and solid-liquid separation (SLS), has shown strong potential for the abatement of greenhouse gas (GHG) and ammonia (NH3) emissions. However, previous study results are inconsistent and the combined effect of AD + SLS remains to be quantified. This study evaluated...

This bulletin explains CO2 and other greenhouse gas (GHG) emissions from the cheese production chain, from farm to cheese plant along with general concepts of calculating GHG emissions, allocation methods, and life cycle assessment.

Life Cycle Assessment (LCA) methods were used to quantify the Global Warming Potential (GWP) and Energy Intensity (EI) of cheese and dried whey manufacture in Wisconsin. Several allocation methods to assign environmental impacts to cheese and dried whey were compared: Economic, total solids, and nutritional value were each applied to the entire pro...

The objective of this study was to estimate the effects of dairy diets, manure-handling methods, and interactions with the bio-fuels industry on the net energy intensity, greenhouse gas (GHG) emissions, and land use for milk production in Wisconsin. Five dairy diets supplemented with varying amounts of co-products from corn ethanol and soybean biod...