Per-and polyfluoroalkyl substances(PFASs)represent an increasingly global challenge for keeping water and soil“non-toxic”.100 of millions of people are exposed to PFAS levels of concern,in particular,around PFAS pro...Per-and polyfluoroalkyl substances(PFASs)represent an increasingly global challenge for keeping water and soil“non-toxic”.100 of millions of people are exposed to PFAS levels of concern,in particular,around PFAS production sites and sites where PFASs are/were used and released or disposed.The Stockholm Convention established recommendations to systematically assess PFOS pollution which can be transposed to all PFASs considering that PFASs are an issue of concern under The Strategic Approach to International Chemical Management(SAICM).One major wide-spread source of environmental pollution is the long-term use of PFAS-containing fire extinguishing agents.Strategies for the reduction of human exposure need to reduce and were feasible eliminate the current uses of PFASs and reduce and eliminate the human exposure from the contamination of the environment from past uses including contaminated drinking water.The current study shows that well-known methods of water treatment,especially the use of materials for adsorption and ion exchange,can often neither guarantee satisfactory cleaning results nor economically justifiable filter running times at high PFAS concentrations and complex matrix conditions.Their combination with a pre-precipitation stage using specialized precipitants can significantly optimize treatment successes.PFAS is still being released into the environment in considerable quantities by e.g.the use of so-called aqueous film forming foams(AFFF).Fire departments are increasingly trying to reduce the risks associated with the use of AFFF agents for the health of firefighting personnel and the environment by replacing AFFF foaming agents with fluorine-free foaming agents.If the fluorine-containing foaming agents are simply replaced,considerable residual PFAS loads often remain in the fire extinguishing systems contaminated with PFAS(fire engines,fire boats,stationary fire extinguishing systems,etc.),which are then discharged further into the environment during renewed operations-normally at a reduced c展开更多
Accuracy in predictions leads to better planning with a minimum of opportunity lost. In open pit mining,the complexity of operations, coupled with a highly uncertain and dynamic production environment,limit the accura...Accuracy in predictions leads to better planning with a minimum of opportunity lost. In open pit mining,the complexity of operations, coupled with a highly uncertain and dynamic production environment,limit the accuracy of predictions and force a reactive planning approach to mitigate deviations from original plans. A simulation optimization framework/tool is presented in this paper to account for uncertainties in mining operations for robust short-term production planning and proactive decision making. This framework/tool uses a discrete event simulation model of mine operations, which interacts with a goalprogramming based mine operational optimization tool to develop an uncertainty based short-term schedule. Using scenario analysis, this framework allows the planner to make proactive decisions to achieve the mine's operational and long-term objectives. This paper details the development of simulation and optimization models and presents the implementation of the framework on an iron ore mine case study for verification through scenario analysis.展开更多
文摘Per-and polyfluoroalkyl substances(PFASs)represent an increasingly global challenge for keeping water and soil“non-toxic”.100 of millions of people are exposed to PFAS levels of concern,in particular,around PFAS production sites and sites where PFASs are/were used and released or disposed.The Stockholm Convention established recommendations to systematically assess PFOS pollution which can be transposed to all PFASs considering that PFASs are an issue of concern under The Strategic Approach to International Chemical Management(SAICM).One major wide-spread source of environmental pollution is the long-term use of PFAS-containing fire extinguishing agents.Strategies for the reduction of human exposure need to reduce and were feasible eliminate the current uses of PFASs and reduce and eliminate the human exposure from the contamination of the environment from past uses including contaminated drinking water.The current study shows that well-known methods of water treatment,especially the use of materials for adsorption and ion exchange,can often neither guarantee satisfactory cleaning results nor economically justifiable filter running times at high PFAS concentrations and complex matrix conditions.Their combination with a pre-precipitation stage using specialized precipitants can significantly optimize treatment successes.PFAS is still being released into the environment in considerable quantities by e.g.the use of so-called aqueous film forming foams(AFFF).Fire departments are increasingly trying to reduce the risks associated with the use of AFFF agents for the health of firefighting personnel and the environment by replacing AFFF foaming agents with fluorine-free foaming agents.If the fluorine-containing foaming agents are simply replaced,considerable residual PFAS loads often remain in the fire extinguishing systems contaminated with PFAS(fire engines,fire boats,stationary fire extinguishing systems,etc.),which are then discharged further into the environment during renewed operations-normally at a reduced c
基金part of a PhD research, which was supported by Mine Optimization Laboratory, University of Alberta-Canada
文摘Accuracy in predictions leads to better planning with a minimum of opportunity lost. In open pit mining,the complexity of operations, coupled with a highly uncertain and dynamic production environment,limit the accuracy of predictions and force a reactive planning approach to mitigate deviations from original plans. A simulation optimization framework/tool is presented in this paper to account for uncertainties in mining operations for robust short-term production planning and proactive decision making. This framework/tool uses a discrete event simulation model of mine operations, which interacts with a goalprogramming based mine operational optimization tool to develop an uncertainty based short-term schedule. Using scenario analysis, this framework allows the planner to make proactive decisions to achieve the mine's operational and long-term objectives. This paper details the development of simulation and optimization models and presents the implementation of the framework on an iron ore mine case study for verification through scenario analysis.
