Optimizing an in Situ Bioremediation Technology to Manage Perchlorate-Contaminated Groundwater

Combining horizontal flow treatment wells (HFTWs) with in situ biodegradation is an innovative approach with the potential to remediate perchlorate-contaminated groundwater. A technology model was recently developed that combines the groundwater flow induced by HFTWs with in situ biodegration processes that result from using the HFTWs to mix electron donor into perchlorate-contaminated groundwater. A field demonstration of this approach is planned to begin this year. In order to apply the technology in the field, project managers need to understand how contaminated site conditions and technology design parameters impact technology performance. One way to gain this understanding is to use the technology model to select engineering design parameters that optimize performance under given site conditions. In particular, a project manager desires to design a system that: 1) maximizes perchlorate destruction; 2) minimizes treatment expense; and 3) attains regulatory limits on down gradient contaminant concentrations. Unfortunately, for a relatively complex technology with a number of engineering design parameters to determine, as well as multiple objectives, system optimization is not straight forward. In this study, a multi-objective genetic algorithm (MOGA) is used to determine design parameter values (flow rate, well spacing, concentration of injection electron donor, and injection schedule) that optimize the first two objectives noted; to maximize perchlorate destruction while minimizing cost. Four optimization runs are performed, using two different remediation time spans (300 and 600 days) for two different sets of site conditions. Results from all four optimization runs indicate that the relationship between perchlorate mass removal and operating cost is positively correlated and nonlinear

The 23rd Annual International Conference on Soils, Sediments and Water

Conference at a Glance Monday, October 15, 2007 (workshop #1-2: 9:00am – 5:00pm, workshop #3: 10am – 5:00pm, workshop #3, 10:00am – 5:00pm, workshops #4, 5, & 6, 1:00pm – 5:00pm, workshop #7 & 8, 2-5pm) 1) Compliant Analysis of Water, Wastes and Related Solid Environmental Samples Using Inductively Coupled Plasma Atomic Emission and Mass Spectrometry 2) In-Situ Chemical Oxidation Workshop 3) Theory and Use of Field Portable X-ray Fluorescence for Soil Analysis 4) The 2007 MCP Audit – A Case Study Approach 5) “Lies, Damned Lies, and Statistics”: Avoiding Pitfalls in Environmental Sampling 6) Evaluating Monitored Natural Attenuation of MTBE and TBA 7) Environmental Forensic Techniques for Classic and Emerging Contaminants 8) Environmental Fate of Hydrocarbons in Soils and Groundwater Tuesday, October 17, 2007 Morning 8:30am – 9:00am Conference Welcome and Overview 9:00am – Noon, Sessions are concurrent Session 1: Ethics in Environmental Practice: Responsibilities, Benefits & Case Examples Session 2a: Pesticides Session 2b: Vapor Intrusion Session 3a: Brownfields Session 3b: Fisherville Mill - Assessment and Cleanup of a Brownfields Site on the Blackstone River Session 4a: Environmental Fate Session 4b: Sediments Afternoon 1:30 to 5:30pm, Sessions are concurrent Session 1: Phytoremediation Session 2: Biotechnology Session 3: Tungsten Session 4: Combining Chemical and Biological Technologies for Soil and Groundwater Remediation Session 5: Environmental Forensics Poster Sessions 4:00 – 6:00pm Arsenic Environmental Fate Environmental Forensics Pesticides Phytoremediation Remediation Sediments Tungsten Vapor Instrusion Social 4:30 – 6:00pm, exhibit area, 1st floor Workshops (Evening, 7:00 – 10:00pm) 9) In-Situ Thermal Remediation 10) Applied Chemical Fingerprinting in Environmental Forensics 11) Utilization of Stable Isotopes in Environmental and Forensic Geochemistry Studies 12) Professional Ethics, Professional Conduct, and Environmental Professionals Wednesday, October 17, 2007 Morning 8:30am – Noon, Sessions are concurrent Session 1: Gasoline Oxygenates I Session 2: Remediation I Session 3: Regulatory Session 4: Coated and Uncoated Microbubble Ozone Remediation Projects Afternoon 1:30 – 5:30pm, Sessions are concurrent Session 1: Gasoline Oxygenates II Session 2: Perchlorate/MECs Session 3: Analysis Session 4: Chemical Oxidation Poster Sessions 4:00 – 6:00pm Acid Mine Drainage Analysis Bioremediation Brownfields Chemical Oxidation Emerging Issues with Energy in the Environment Heavy Metals MECs Miscellaneous MTBE Radionuclides Site Assessment Social 4:30 – 6:00pm, exhibit area, 1st floor Workshops (Evening, 7:00 – 10:00pm) 13) Critical Exposure Pathways 14) Characterizing PAH Bioavailability in Sediments for Remedial Decision-Making 15) Theory and Application of Molecular Biological Tools (“MBTs”) and Biogeochemistry to Bioremediation Process Monitoring and Monitored Natural Attenuation Programs 16) Geochemical Evaluations of Metals in Environmental Media: How to Distinguish Naturally Elevated Metals Concentrations from Site-Related Contamination Thursday, October 18, 2007 Morning 8:30am – Noon Sessions are concurrent Session 1: Bioremediation Session 2: Remediation II Session 3: Modeling Session 4: Risk Assessment Afternoon 1:30pm – 5:00pm Sessions are concurrent Session 1: Heavy Metals Session 2: Innovative Technologies Session 3: Site Assessmen

The 21st Annual International Conference on Soils, Sediments and Water

Conference at a Glance Monday, October 17, 2005 Workshops (Workshops #1 and #2: 10:00am - 5:00pm; Workshop #3: 1:00 - 5:00pm; Workshop #4: 1:00 - 3:00pm, Workshop #5: 2:00 - 5:00pm) 1) Theory and Use of Field Portable X-ray Fluorescence for Soil Analysis 2) In-Situ Chemical Oxidation Workshop 3) The Role of Anaerobic Biodegradation Processes in Passive and Enhanced Monitored Natural Attenuation Programs 4) Application of Classic and Emerging Techniques in Environmental Forensics 5) Environmental Fate of Hydrocarbons in Soils and Groundwater Tuesday, October 18, 2005 Platform Presentations 8:30am – Noon Session 1: Environmental Biotechnology Session 2: Ecological Restoration and Natural Treatment Systems Session 3: Pesticides (10:30am – Noon) Session 4: Heavy Metals 1:30 – 5:30pm Session 1: Arsenic Session 2: Bioremediation Session 3: Bioremediation Strategies for Contaminated Soils and Sediments Session 4: Ozone Poster Session 4:00 – 6:00pm, Exhibit Area, First Floor, Campus Center Social 4:30-6:00pm, Exhibit Area, First Floor, Campus Center Workshops 7:00 - 10:00pm 6) Applied Environmental Forensics Workshop 7) Massachusetts Contingency Plan Method 2 Risk Characterizations Wednesday, October 19, 2005 Platform Presentations 8:30am – Noon Session 1: Perchlorate: Emerging Issues and Innovative Remedial Approaches Session 2: Soil Geochemical Background on a Continental Scale Session 3a: Environmental Fate Session 3b: Risk Assessment Session 4: Environmental Stewardship and Proactive Management at Small Arms Ranges 1:30 – 5:30pm Session 1: Ecoterrorism: Research Issues Session 2: Environmental Forensics Session 3a: Legal/Regulatory Session 3b: MTBE Session 4: Bioremediation of Acid Mine Drainage Wastes Poster Session 4:00 – 6:00pm Exhibit Area, First Floor, Campus Center Social 4:30-6:00pm, Exhibit Area, First Floor, Campus Center Workshops 7:00 - 10:00pm 8) In-Situ Thermal Remediation 9) Perchlorate: The Path to Regulatory Standards Setting and Future Assessment & Cleanup Implications 10) NIMS (National Incident Management System) and the Environment Thursday, October 20, 2005 Platform Presentations 8:30am – Noon Session 1: Evolving Strategies for Dealing with Contaminated Sediments Session 2: Pay-for-Performance Remediation Technologies - Methods & Case Studies of Science & Economics Session 3: Phytoremediation Session 4: Site Assessment 1:30 – 5:30pm Session 1: Remediation Session 2: Chemical Oxidation Session 3a: Analysis Session 3b: Indoor Ai

Optimization and enhancement of soil bioremediation by composting using the experimental design technique

The objective of this study was the application of the experimental design technique to optimize the conditions for the bioremediation of contaminated soil by means of composting. A low-cost material such as compost from the Organic Fraction of Municipal Solid Waste as amendment and pyrene as model pollutant were used. The effect of three factors was considered: pollutant concentration (0.1-2 g/kg), soil:compost mixing ratio (1:0.5-1:2 w/w) and compost stability measured as respiration index (0.78, 2.69 and 4.52 mg O2 g⁻¹ Organic Matter h⁻¹). Stable compost permitted to achieve an almost complete degradation of pyrene in a short time (10 days). Results indicated that compost stability is a key parameter to optimize PAHs biodegradation. A factor analysis indicated that the optimal conditions for bioremediation after 10, 20 and 30 days of process were (1.4, 0.78, 1:1.4), (1.4, 2.18. 1:1.3) and (1.3, 2.18, 1:1.3) for concentration (g/kg), compost stability (mg O₂ g−1 Organic Matter h−1) and soil:compost mixing ratio, respectively

Optimization of Palladium-Catalyzed in Situ Destruction of Trichloroethylene-Contaminated Groundwater Using a Genetic Algorithm

Conventional technologies for the treatment of groundwater contaminated with chlorinated solvents have limitations that have motivated development of innovative technologies. One such technology currently under development involves using palladium-on-alumina (Pd/Al) as a catalyst to promote dechlorination. Pd/Al catalyst may be used in-well as part of a re-circulating horizontal flow treatment well (HFTW) system. An HFTW system involves two or more dual-screened wells, with in-well reactors, to capture and treat contaminated groundwater without the need to pump the water to the surface. In this study, objective and fitness functions, based on system costs and TCE concentration requirements, were developed to optimize a dual-well HFTW system with in-well Pd/Al reactors in a two-aquifer remediation scenario. A genetic algorithm (GA) was coupled with a three dimensional numerical model of contaminant fate and transport to determine optimized HFTW control parameters (well location, pumping rate, and reactor size). The GA obtained a solution within the specified constraints, but the solution was an artificial solution, as contaminated groundwater in one of the two aquifers received no treatment. Based on these results, new objective and fitness functions were developed in an effort to determine the most cost effective solution to remove contaminant mass from the aquifer. The solution arrived at using this approach, while resulting in minimized values of cost per contaminant mass destroyed, produced unacceptably high downgradient contaminant concentration levels. We conclude that by specifying that only two wells could be used in the HFTW system, we overconstrained the problem and that a multi-well HFTW solution is required

AI and OR in management of operations: history and trends

The last decade has seen a considerable growth in the use of Artificial Intelligence (AI) for operations management with the aim of finding solutions to problems that are increasing in complexity and scale. This paper begins by setting the context for the survey through a historical perspective of OR and AI. An extensive survey of applications of AI techniques for operations management, covering a total of over 1200 papers published from 1995 to 2004 is then presented. The survey utilizes Elsevier's ScienceDirect database as a source. Hence, the survey may not cover all the relevant journals but includes a sufficiently wide range of publications to make it representative of the research in the field. The papers are categorized into four areas of operations management: (a) design, (b) scheduling, (c) process planning and control and (d) quality, maintenance and fault diagnosis. Each of the four areas is categorized in terms of the AI techniques used: genetic algorithms, case-based reasoning, knowledge-based systems, fuzzy logic and hybrid techniques. The trends over the last decade are identified, discussed with respect to expected trends and directions for future work suggested

In-situ bioremediation of TCE-contaminated groundwater

This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). A barrier to wider use of in situ bioremediation technology is that results are often variable and difficult to predict. In situ bioremediation has shown some very notable and well publicized successes, but implementation of the technology is complex. An incomplete understanding of the effects of variable site characteristics and the lack of adequate tools to predict and measure success have made the design, control and validation of bioremediation more empirical than desired. The long-term objective of this project is to improve computational tools used to assess and optimize the expected performance of bioremediation at a site. An important component of the approach is the explicit inclusion of uncertainties and their effect on the end result. The authors have extended their biokinetics model to include microbial competition and predation processes. Predator species can feed on the microbial species that degrade contaminants, and the simulation studies show that species interactions must be considered when designing in situ bioremediation systems. In particular, the results for TCE indicate that protozoan grazing could reduce the amount of biodegradation by about 20%. These studies also indicate that the behavior of barrier systems can become complex due to predator grazing

Evaluating Sustainable Aspects of Hazardous Waste Remediation

The main objective of the research presented herein is to be a major contributor to the current international initiative to advance sustainability assessments for remediation projects by integrating methodologies from the environmental economics and social science disciplines. More specifically, the study aims to address some of the knowledge gaps related to conducting a comprehensive sustainability assessment for a remediation project. These knowledge gaps include: (1) there are few studies that include sustainability assessments of the variety of techniques and technologies implemented during site characterization; (2) the majority of sustainable remediation publications and assessment tools focus on evaluating the environmental impact of a contaminated site’s life cycle and minimally, if at all, on related socio-economic impacts; and (3) the role of risk perception in stakeholder engagement has not been explored in existing sustainable remediation frameworks. Chapters 2 through 4 presents a societal cost analysis methodology to quantify global socio-economic impacts arising from cleanup activity by monetizing the emissions and energy consumption through the integration of the social cost of environmental metrics. The results of environmental footprint and life cycle assessment evaluations conducted at various stages throughout the project life cycle were used as the basis for the societal cost analysis. Chapter 5 presents a survey developed and implemented to identify risk perception factors that influenced residents’ level of participation in risk management activities conducted by the local health department. Based on the case study evaluations presented herein, it can be concluded that the integration of methodologies from the environmental economics and social science disciplines into existing sustainable remediation frameworks results in a more comprehensive evaluation of triple bottom line impacts, a reduction in emissions and resources consumed during site activities, efficient use of financial resources, and a maximization of benefits to stakeholders, in particular the community