Gerardo Ruiz-Mercado | United States Environmental Protection Agency (original) (raw)

Papers by Gerardo Ruiz-Mercado

Research paper thumbnail of A graph-based modeling framework for tracing hydrological pollutant transport in surface waters

Computers & Chemical Engineering

Research paper thumbnail of Promoting phosphorus recovery at livestock facilities in the Great Lakes region: Analysis of incentive policies

Computer Aided Chemical Engineering

Research paper thumbnail of Embedded Control for Optimizing Flexible Dynamic Process Performance

Industrial & Engineering Chemistry Research, 2011

Research paper thumbnail of ADAM: A web platform for graph-based modeling and optimization of supply chains

Computers & Chemical Engineering

Research paper thumbnail of MOL2NET-07 (Call For Papers), International Conference on Multidisciplinary Sciences, ISSN: 2624-5078, MDPI SciForum, Basel, Switzerland, 2021

Research paper thumbnail of Data-Driven Framework for Tracking Chemical Flows at End-of-Life Stage

Research paper thumbnail of Resilience of aquatic ecosystems in farming areas: implementing nutrient recovery systems in concentrated animal feeding operations

Research paper thumbnail of Tracking Chemicals in Waste Streams - An Approach Towards Resilience at End-of-Use Scenarios

Research paper thumbnail of Rapid Estimation of Release Inventories and Evaluation - A Metal Coating Industry Case Study

Research paper thumbnail of Anaerobic digestate management, environmental impacts, and techno-economic challenges

Waste Management, 2022

Digestate is a nutrient-rich by-product from organic waste anaerobic digestion but can contribute... more Digestate is a nutrient-rich by-product from organic waste anaerobic digestion but can contribute to nutrient pollution without comprehensive management strategies. Some nutrient pollution impacts include harmful algal blooms, hypoxia, and eutrophication. This contribution explores current productive uses of digestate by analyzing its feedstocks, processing technologies, economics, product quality, impurities, incentive policies, and regulations. The analyzed studies found that feedstock, processing technology, and process operating conditions highly influence the digestate product characteristics. Also, incentive policies and regulations for managing organic waste by anaerobic digestion and producing digestate as a valuable product promote economic benefits. However, there are not many governmental and industry-led quality assurance certification systems for supporting commercializing digestate products. The sustainable and safe use of digestate in different applications needs further development of technologies and processes. Also, incentives for digestate use, quality regulation, and social awareness are essential to promote digestate product commercialization as part of the organic waste circular economy paradigm. Therefore, future studies about circular business models and standardized international regulations for digestate products are needed.

Research paper thumbnail of A data engineering approach for sustainable chemical end-of-life management

Resources, Conservation and Recycling, 2022

Research paper thumbnail of Special Issue on “Bioenergy Systems, Material Management, and Sustainability”

The growing worldwide demand for energy and resources, combined with the stringent environmental ... more The growing worldwide demand for energy and resources, combined with the stringent environmental challenges and regulations, means that the efficient, cost-effective, and sustainable use of energy and material sources, including bio-based, has become increasingly important [...]

Research paper thumbnail of A Thermodynamic Feasibility Evaluation Model for the Efficient Struvite Production from Livestock Waste

Computer Aided Chemical Engineering, 2019

Abstract Inefficient management of anthropogenic organic waste from agricultural sources (e.g., a... more Abstract Inefficient management of anthropogenic organic waste from agricultural sources (e.g., animal manure) results in nutrient pollution and can negatively affect public health and increase human impact on the environment. Therefore, an effective management strategy for livestock waste processing is necessary. In this contribution, a thermodynamic model is developed to design feasible and efficient struvite production as a technology for nutrients recovery from cattle digestate. Cattle digestate presents a high concentration of calcium ions which compete with magnesium for the struvite precursor ions, being able to inhibit struvite formation. An additional hindrance is the variability in the composition of cattle manure, which largely affects the formation of struvite due to the changes in the distribution of the reagent compounds. This feedstock composition variability is studied through a probabilistic framework. Struvite formation is found as a suitable method to recover nutrients from digestate, achieving efficiencies up to 80%, although an individual analysis of raw material for each case is desirable to adjust the operational parameters and optimize the nutrients recovery process from livestock waste.

Research paper thumbnail of A data engineering framework for on-site end-of-life industrial operations

Journal of Cleaner Production, 2021

Sustainable initiatives for converting end-of-life (EoL) material flows into feedstocks would mak... more Sustainable initiatives for converting end-of-life (EoL) material flows into feedstocks would make a crucial contribution towards protecting our environment and mitigating the negative impacts of anthropogenic activities. Chemical flow analysis enables decision-makers to identify potential environmental releases and exposure pathways at the EoL stage and, therefore, improves the estimation of chemical exposure. Certain industrial facilities apply on-site pollution abatement operations, thereby constituting nodes of the chemical EoL management chain that can be evaluated and improved to enable greater circularity of materials. This work enhances and extends a recently published EoL data engineering framework by using publicly-available databases, data- driven models, and analytic hierarchy approaches to track chemicals, estimate releases, and potential exposure pathways at on-site industrial pollution management operations. The extended framework develops pollution abatement unit (PAU) technologies and estimates their efficiencies, chemical releases, exposure media, operating expenses, and capital expenditures. Relevant case studies based on the food and pharmaceutical industry sectors illustrate the application of the framework for chemical flow allocation and analysis of a chemical of concern and the benefits of integrating and extending the framework with data-driven and multi-criteria decision-making models. The results show how the enhanced framework designs and evaluates PAU technology systems for managing EoL chemical flows and provides release inventories and pathways for conducting chemical risk evaluation and exposure assessment of potential on-site EoL scenarios.

Research paper thumbnail of Spatio-Temporal Control of Nutrient Pollution from Organic Waste

Computer Aided Chemical Engineering, 2019

Recent work has shown that adaptive CSMA algorithms can achieve throughput optimality. However, t... more Recent work has shown that adaptive CSMA algorithms can achieve throughput optimality. However, these adaptive CSMA algorithms assume a rather simplistic model for the wireless medium. Specifically, the interference is typically modelled by a conflict graph, and the channels are assumed to be static. In this work, we propose a distributed and adaptive CSMA algorithm under a more realistic signal-to-interference ratio (SIR) based interference model, with time-varying channels. We prove that our algorithm is throughput optimal under this generalized model. Further, we augment our proposed algorithm by using a parallel update technique. Numerical results show that our algorithm outperforms the conflict graph based algorithms, in terms of supportable throughput and the rate of convergence to steady-state.

Research paper thumbnail of Analysis of incentive policies for phosphorus recovery at livestock facilities in the Great Lakes area

Resources, Conservation and Recycling, 2022

Research paper thumbnail of A Logistics Analysis for Advancing Carbon and Nutrient Recovery from Organic Waste

Advances in Carbon Management Technologies, 2021

Research paper thumbnail of A geospatial environmental and techno-economic framework for sustainable phosphorus management at livestock facilities

Resources, Conservation and Recycling, 2021

Evaluating the amount of information obtained from non-orthogonal quantum states is an important ... more Evaluating the amount of information obtained from non-orthogonal quantum states is an important topic in the field of quantum information. The commonly used evaluation method is Holevo bound, which only provides a loose upper bound for quantum measurement. In this paper, we provide a theoretical study of the positive operator-valued measure (POVM) for discriminating nonorthogonal states. We construct a generalized POVM measurement operation, and derive the optimal one for state discrimination by Lagrange multiplier method. With simulation, we find that the optimal POVM measurement provides a tight upper bound for state discrimination, which is significantly lower than that predicted by Holevo bound. The derivation of optimal POVM measurement will play an important role in the security research of quantum key distribution.

Research paper thumbnail of Model-driven spatial evaluation of nutrient recovery from livestock leachate for struvite production

Journal of Environmental Management, 2020

Nutrient pollution is one of the major worldwide water quality problems, resulting in environment... more Nutrient pollution is one of the major worldwide water quality problems, resulting in environmental and public health issues. Agricultural activities are a main source of nutrient releases emissions, and livestock industry has been proven to be directly related to the presence of high concentrations of phosphorus in the soil, which potentially can reach waterbodies by runoff. To mitigate the phosphorus pollution of aquatic systems, the implementation of nutrient recovery processes allows the capture of phosphorus, preventing its release into the environment. Particularly, the use of struvite precipitation produces a phosphorous-based mineral that is easy to transport, enabling redistribution of phosphorus to deficient locations. However, livestock leachate presents some characteristics that hin

Research paper thumbnail of Data engineering for tracking chemicals and releases at industrial end-of-life activities

Journal of Hazardous Materials, 2021

Performing risk evaluation is necessary to determine whether a chemical substance presents an unr... more Performing risk evaluation is necessary to determine whether a chemical substance presents an unreasonable risk of injury to human health or the environment across its life cycle stages. Data gathering, reconciliation, and management for supporting risk evaluation are time-consuming and challenging, especially for end-of-life (EoL) activities due to the need for proper reporting and traceability. A data engineering framework using publicly-available databases to track chemicals in waste streams generated by industrial activities and transferred to other facilities across different U.S. locations for waste management is implemented. The analysis tracks chemicals in waste streams generated at industrial processes and handling at off-site facilities and then estimates releases from EoL activities. The final product of this effort is a framework that identifies a set of chemical, activity, and industry sector categories as well as hazardous waste flows, emission factors, and uncertainty indicators to describe EoL activities. This framework helps to identify EoL exposure scenarios that would otherwise not be evaluated. As a case study, methylene chloride, one of the first ten chemicals to undergo risk evaluation under the amended U.S. Toxic Substances Control Act, was evaluated with results highlighting potential additional exposure scenarios.

Research paper thumbnail of A graph-based modeling framework for tracing hydrological pollutant transport in surface waters

Computers & Chemical Engineering

Research paper thumbnail of Promoting phosphorus recovery at livestock facilities in the Great Lakes region: Analysis of incentive policies

Computer Aided Chemical Engineering

Research paper thumbnail of Embedded Control for Optimizing Flexible Dynamic Process Performance

Industrial & Engineering Chemistry Research, 2011

Research paper thumbnail of ADAM: A web platform for graph-based modeling and optimization of supply chains

Computers & Chemical Engineering

Research paper thumbnail of MOL2NET-07 (Call For Papers), International Conference on Multidisciplinary Sciences, ISSN: 2624-5078, MDPI SciForum, Basel, Switzerland, 2021

Research paper thumbnail of Data-Driven Framework for Tracking Chemical Flows at End-of-Life Stage

Research paper thumbnail of Resilience of aquatic ecosystems in farming areas: implementing nutrient recovery systems in concentrated animal feeding operations

Research paper thumbnail of Tracking Chemicals in Waste Streams - An Approach Towards Resilience at End-of-Use Scenarios

Research paper thumbnail of Rapid Estimation of Release Inventories and Evaluation - A Metal Coating Industry Case Study

Research paper thumbnail of Anaerobic digestate management, environmental impacts, and techno-economic challenges

Waste Management, 2022

Digestate is a nutrient-rich by-product from organic waste anaerobic digestion but can contribute... more Digestate is a nutrient-rich by-product from organic waste anaerobic digestion but can contribute to nutrient pollution without comprehensive management strategies. Some nutrient pollution impacts include harmful algal blooms, hypoxia, and eutrophication. This contribution explores current productive uses of digestate by analyzing its feedstocks, processing technologies, economics, product quality, impurities, incentive policies, and regulations. The analyzed studies found that feedstock, processing technology, and process operating conditions highly influence the digestate product characteristics. Also, incentive policies and regulations for managing organic waste by anaerobic digestion and producing digestate as a valuable product promote economic benefits. However, there are not many governmental and industry-led quality assurance certification systems for supporting commercializing digestate products. The sustainable and safe use of digestate in different applications needs further development of technologies and processes. Also, incentives for digestate use, quality regulation, and social awareness are essential to promote digestate product commercialization as part of the organic waste circular economy paradigm. Therefore, future studies about circular business models and standardized international regulations for digestate products are needed.

Research paper thumbnail of A data engineering approach for sustainable chemical end-of-life management

Resources, Conservation and Recycling, 2022

Research paper thumbnail of Special Issue on “Bioenergy Systems, Material Management, and Sustainability”

The growing worldwide demand for energy and resources, combined with the stringent environmental ... more The growing worldwide demand for energy and resources, combined with the stringent environmental challenges and regulations, means that the efficient, cost-effective, and sustainable use of energy and material sources, including bio-based, has become increasingly important [...]

Research paper thumbnail of A Thermodynamic Feasibility Evaluation Model for the Efficient Struvite Production from Livestock Waste

Computer Aided Chemical Engineering, 2019

Abstract Inefficient management of anthropogenic organic waste from agricultural sources (e.g., a... more Abstract Inefficient management of anthropogenic organic waste from agricultural sources (e.g., animal manure) results in nutrient pollution and can negatively affect public health and increase human impact on the environment. Therefore, an effective management strategy for livestock waste processing is necessary. In this contribution, a thermodynamic model is developed to design feasible and efficient struvite production as a technology for nutrients recovery from cattle digestate. Cattle digestate presents a high concentration of calcium ions which compete with magnesium for the struvite precursor ions, being able to inhibit struvite formation. An additional hindrance is the variability in the composition of cattle manure, which largely affects the formation of struvite due to the changes in the distribution of the reagent compounds. This feedstock composition variability is studied through a probabilistic framework. Struvite formation is found as a suitable method to recover nutrients from digestate, achieving efficiencies up to 80%, although an individual analysis of raw material for each case is desirable to adjust the operational parameters and optimize the nutrients recovery process from livestock waste.

Research paper thumbnail of A data engineering framework for on-site end-of-life industrial operations

Journal of Cleaner Production, 2021

Sustainable initiatives for converting end-of-life (EoL) material flows into feedstocks would mak... more Sustainable initiatives for converting end-of-life (EoL) material flows into feedstocks would make a crucial contribution towards protecting our environment and mitigating the negative impacts of anthropogenic activities. Chemical flow analysis enables decision-makers to identify potential environmental releases and exposure pathways at the EoL stage and, therefore, improves the estimation of chemical exposure. Certain industrial facilities apply on-site pollution abatement operations, thereby constituting nodes of the chemical EoL management chain that can be evaluated and improved to enable greater circularity of materials. This work enhances and extends a recently published EoL data engineering framework by using publicly-available databases, data- driven models, and analytic hierarchy approaches to track chemicals, estimate releases, and potential exposure pathways at on-site industrial pollution management operations. The extended framework develops pollution abatement unit (PAU) technologies and estimates their efficiencies, chemical releases, exposure media, operating expenses, and capital expenditures. Relevant case studies based on the food and pharmaceutical industry sectors illustrate the application of the framework for chemical flow allocation and analysis of a chemical of concern and the benefits of integrating and extending the framework with data-driven and multi-criteria decision-making models. The results show how the enhanced framework designs and evaluates PAU technology systems for managing EoL chemical flows and provides release inventories and pathways for conducting chemical risk evaluation and exposure assessment of potential on-site EoL scenarios.

Research paper thumbnail of Spatio-Temporal Control of Nutrient Pollution from Organic Waste

Computer Aided Chemical Engineering, 2019

Recent work has shown that adaptive CSMA algorithms can achieve throughput optimality. However, t... more Recent work has shown that adaptive CSMA algorithms can achieve throughput optimality. However, these adaptive CSMA algorithms assume a rather simplistic model for the wireless medium. Specifically, the interference is typically modelled by a conflict graph, and the channels are assumed to be static. In this work, we propose a distributed and adaptive CSMA algorithm under a more realistic signal-to-interference ratio (SIR) based interference model, with time-varying channels. We prove that our algorithm is throughput optimal under this generalized model. Further, we augment our proposed algorithm by using a parallel update technique. Numerical results show that our algorithm outperforms the conflict graph based algorithms, in terms of supportable throughput and the rate of convergence to steady-state.

Research paper thumbnail of Analysis of incentive policies for phosphorus recovery at livestock facilities in the Great Lakes area

Resources, Conservation and Recycling, 2022

Research paper thumbnail of A Logistics Analysis for Advancing Carbon and Nutrient Recovery from Organic Waste

Advances in Carbon Management Technologies, 2021

Research paper thumbnail of A geospatial environmental and techno-economic framework for sustainable phosphorus management at livestock facilities

Resources, Conservation and Recycling, 2021

Evaluating the amount of information obtained from non-orthogonal quantum states is an important ... more Evaluating the amount of information obtained from non-orthogonal quantum states is an important topic in the field of quantum information. The commonly used evaluation method is Holevo bound, which only provides a loose upper bound for quantum measurement. In this paper, we provide a theoretical study of the positive operator-valued measure (POVM) for discriminating nonorthogonal states. We construct a generalized POVM measurement operation, and derive the optimal one for state discrimination by Lagrange multiplier method. With simulation, we find that the optimal POVM measurement provides a tight upper bound for state discrimination, which is significantly lower than that predicted by Holevo bound. The derivation of optimal POVM measurement will play an important role in the security research of quantum key distribution.

Research paper thumbnail of Model-driven spatial evaluation of nutrient recovery from livestock leachate for struvite production

Journal of Environmental Management, 2020

Nutrient pollution is one of the major worldwide water quality problems, resulting in environment... more Nutrient pollution is one of the major worldwide water quality problems, resulting in environmental and public health issues. Agricultural activities are a main source of nutrient releases emissions, and livestock industry has been proven to be directly related to the presence of high concentrations of phosphorus in the soil, which potentially can reach waterbodies by runoff. To mitigate the phosphorus pollution of aquatic systems, the implementation of nutrient recovery processes allows the capture of phosphorus, preventing its release into the environment. Particularly, the use of struvite precipitation produces a phosphorous-based mineral that is easy to transport, enabling redistribution of phosphorus to deficient locations. However, livestock leachate presents some characteristics that hin

Research paper thumbnail of Data engineering for tracking chemicals and releases at industrial end-of-life activities

Journal of Hazardous Materials, 2021

Performing risk evaluation is necessary to determine whether a chemical substance presents an unr... more Performing risk evaluation is necessary to determine whether a chemical substance presents an unreasonable risk of injury to human health or the environment across its life cycle stages. Data gathering, reconciliation, and management for supporting risk evaluation are time-consuming and challenging, especially for end-of-life (EoL) activities due to the need for proper reporting and traceability. A data engineering framework using publicly-available databases to track chemicals in waste streams generated by industrial activities and transferred to other facilities across different U.S. locations for waste management is implemented. The analysis tracks chemicals in waste streams generated at industrial processes and handling at off-site facilities and then estimates releases from EoL activities. The final product of this effort is a framework that identifies a set of chemical, activity, and industry sector categories as well as hazardous waste flows, emission factors, and uncertainty indicators to describe EoL activities. This framework helps to identify EoL exposure scenarios that would otherwise not be evaluated. As a case study, methylene chloride, one of the first ten chemicals to undergo risk evaluation under the amended U.S. Toxic Substances Control Act, was evaluated with results highlighting potential additional exposure scenarios.