SBIR-STTR Award

Hexavalent chromium, or Cr(VI), is among the most widespread contaminants in water resources in the U.S. and around the world. Cr(VI) has been found in at least 1,127 of the 1,699 current or former National Priority List (NPL) sites, which have been identified by the U.S. Environmental Protection Agency (EPA) as the most serious hazardous waste sites in the nation and are the highest priority targets for long-term federal cleanup activities. Toxicological research has found that high concentrations of Cr(VI) can contribute to stomach cancers, kidney and liver damage, and reproductive harm. As a result, there is significant demand among water providers and managers of Superfund sites for innovative technologies to address Cr(VI) contamination in a cost-effective and environmentally sustainable manner. The lack of cost-effective technologies to reduce Cr(VI) levels in water are due to technical challenges associated with existing physical/chemical approaches, including high cost, the need for disposal of secondary waste streams, and performance that can be vulnerable to influent water geochemistry. Specifically, there is a need for new technologies to reliably reduce Cr(VI) to very low parts-per-billion levels with lower costs and less waste than existing physical or chemical treatment technologies. This project seeks to address this need through a novel combination of materials science and bacterial reductive immobilization. In contrast to conventional physical or chemical technologies, this new technology does not produce a hazardous secondary waste stream. Moreover, the proposed technology offers unique redox flexibility, which allows it to remain effective even while hydrogeological characteristics may change. These and other advantages help position the proposed technology as a highly effective ex-situ or in-situ treatment approach to achieve low concentrations of Cr(VI) in water. In the proposed project, a prototype of the proposed technology is developed through comprehensive kinetic studies under various operating conditions supported by whole-genome transcriptional studies. In addition to developing optimum parameters for the treatment system, the project will also provide insights into the unique physiology employed to achieve reductive immobilization of Cr(VI). Development of material composites to deploy a high density of the targeted culture proceeds in an iterative manner to ultimately select one composite to evaluate in a continuous-flow reactor study using both synthetic and actual contaminated groundwater. The outcome of this project will be the proof-of-concept of a new technology for efficient, environmentally friendly, and cost-effective Cr(VI) treatment. As a result, this project holds significant promise to provide a critically necessary tool for protecting and remediating drinking water supplies from chromium contamination, thus promoting public safety and environmental health.

Public Health Relevance Statement:
Project Narrative Hexavalent chromium is a widespread and highly toxic water contaminant which threatens human health and public safety. The lack of low-cost remediation technologies for hexavalent chromium removal has led to the shutdown of drinking water wells and significant delays in clean-up efforts. This project develops a new, low-cost biological treatment technology to safety and effectively remove hexavalent chromium from water.

Project Terms:
Acetates; Bacteria; Biological Response Modifier Therapy; Biologic Therapy; Biological Therapy; biological therapeutic; biological treatment; biotherapeutics; biotherapy; Biomass; Biotechnology; Biotech; Carcinogens; Cancer Causing Agents; Oncogens; oncogenic agent; Chromium; Cr element; Communities; Engineering; Environment; Environmental Health; Environmental Health Science; Gene Expression; Goals; Health; Human; Modern Man; Immobilization; orthopedic freezing; Kinetics; Laboratories; malignant stomach neoplasm; Gastric Body Cancer; Gastric Cancer; Gastric Cardia Cancer; Gastric Fundus Cancer; Gastric Pylorus Cancer; Malignant Gastric Neoplasm; Malignant Gastric Tumor; Stomach Cancer; gastric malignancy; malignant stomach tumor; stomach fundus cancer; stomach pylorus cancer; Metals; Mutagens; Genotoxins; genotoxic agent; Nitrates; NO3-; oxidation; Oxidation-Reduction; Redox; oxidation reduction reaction; Oxidoreductase; Dehydrogenases; Oxidoreductase Gene; Reductases; Phenotype; Physiology; Pilot Projects; pilot study; Polymers; Production; Research; Resources; Research Resources; Safety; Surveys; Survey Instrument; Technology; Testing; Toxicology; Genetic Transcription; Gene Transcription; RNA Expression; Transcription; United States Environmental Protection Agency; Environmental Protection Agency; Water; Hydrogen Oxide; Water Supply; Work; Oxidants; Oxidizing Agents; electron acceptor; Hazardous Waste Sites; Cr(VI); chromium(VI); hexavalent chromium; chromium hexavalent ion; base; density; Site; Phase; Variation; Variant; Biological; Chemicals; insight; wasting; Sludges; Environmental sludge; Letters; Metabolic; P stutzeri; P. stutzeri; Pseudomonas stutzeri; tool; Stream; In Situ; microorganism; Source; System; interest; innovative technologies; groundwater; ground water; Performance; water treatment; Bioremediations; axenic culture; denitrification; drinking water; pollutant; toxicant; electron donor; Structure; novel; novel technologies; new technology; Abscission; Extirpation; Removal; Surgical Removal; resection; Excision; Position; Positioning Attribute; reproductive; Regulation; Sampling; response; superfund site; Bioavailable; Provider; Metabolic Pathway; Address; Aerobic; technology implementation; technology validation; Characteristics; Process; developmental; Development; cost; designing; design; remediation; Outcome; cost effective; Prevalence; Microbe; combinatorial; prototype; Superfund; flexible; flexibility; operation; Injury to Liver; hepatic damage; hepatic injury; liver damage; liver injury; materials science; Industry Standard; entire genome; full genome; whole genome; experiment; experimental research; experimental study; Expression Profiling; damage to kidney; kidney damage; renal damage; well water

Hexavalent chromium, or Cr(VI), is a highly prevalent contaminant in water resources in the U.S. and worldwide. Research has found that high concentrations of Cr(VI) can be carcinogenic and dangerous for public health. As a result, there is significant demand among water providers and Superfund sites for innovative technologies to reduce Cr(VI) concentrations in water resources in a cost-effective and environmentally sustainable manner. Current technical challenges posed by existing technologies for Cr(VI) remediation include high costs, limited capabilities to achieve low parts-per-billion (ppb) concentrations, and the outsized effects of influent water geochemistry on system performance. Specifically, there is a need for new technologies to reliably reduce Cr(VI) to low parts-per-billion (ppb) levels with lower costs and better performance than existing technologies. This proposed Phase II project builds on successful outcomes from Phase I in which a new biological process technology was developed. The new technology is based on enhanced biological reductive immobilization in which microorganisms reduce soluble, mobile, and highly toxic forms of specific metals to oxidation states at which the metals are very poorly soluble and easily removed from water. In this new technology, specifically chosen natural microorganisms are incorporated inside proprietary polymer composites called biocatalysts. The biocatalysts are designed to retain, control, and maintain a highly active population of the chosen microorganisms inside a bioreactor as part of a compact, high-performance water treatment system. In Phase I support, the Cr(VI)-removal biocatalysts were developed, and a prototype bioreactor was designed, built, and operated. Under continuous flow conditions, the removal of various influent concentrations of Cr(VI) was consistently demonstrated, including more than 99% removal to levels below 1 μg/L, which is well below the target concentration of five (5) μg/L. The technology was validated using actual contaminated groundwater with co-contaminants and a technoeconomic analysis was conducted. In Phase II, this new technology is further optimized and then scaled-up for demonstration at a contaminated site. The Phase II project seeks to further establishes the performance and operational parameters for this new technology. In addition, the proposed project positions the new technology for immediate implementation through documenting the technology's long-term operation, conducting stress testing and recovery studies, and assessing detailed maintenance, cost and operation parameters. This new technology addresses a critical need: the reliable treatment of Cr(VI) that cannot be removed cost- effectively using existing technologies. This project's success holds significant promise to become a commercial technology-of-choice for water managers and providers to address Cr(VI) contamination, enhance water security, and promote public health for thousands of communities in the U.S. and around the world.

Public Health Relevance Statement:
PROJECT NARRATIVE Hexavalent chromium is a widespread and highly toxic water contaminant which threatens human health and public safety. The lack of low-cost remediation technologies for hexavalent chromium removal has led to the shutdown of drinking water wells and significant impacts on clean-up efforts. This Phase II project further develops and demonstrates a new, low-cost biological treatment technology to remove hexavalent chromium safely and effectively from water.

Project Terms:
Bacteria; Biological Response Modifier Therapy; Biological Therapy; biological therapeutic; biological treatment; biologically based therapeutics; biotherapeutics; biotherapy; Biotechnology; Biotech; California; Capital; Carbon; Carcinogens; Cancer Causing Agents; Oncogens; oncogenic agent; Chromium; Cr element; Client; Communities; Connecticut; Cost Analysis; Cost Analyses; assess cost; cost assessment; cost effectiveness; Dangerousness; Engineering; Environmental Health; Environmental Health Science; Equilibrium; balance; balance function; Feasibility Studies; Goals; Health; Human; Modern Man; Immobilization; orthopedic freezing; Investments; Laboratories; Life Cycle Stages; Life Cycle; life course; Maintenance; Metals; Mutagens; Genotoxins; genotoxic agent; oxidation; Micrococcus denitrificans; P denitrificans; P. denitrificans; Paracoccus denitrificans; Polymers; Public Health; Research; Research Resources; Resources; Safety; Technology; Testing; Time; Universities; Water; Hydrogen Oxide; Water Pollutants; water contaminant; Work; chromium hexavalent ion; Cr(VI); chromium(VI); hexavalent chromium; base; Procedures; Site; Phase; Biological; biologic; Series; Recovery; Biological Function; Biological Process; Letters; Metabolic; microbioreactor; Bioreactors; Life; Hour; microorganism; Source; System; innovative technologies; field based data; field learning; field test; field study; groundwater; ground water; Performance; success; water treatment; drinking water; pollutant; toxicant; novel; novel technologies; new technology; Abscission; Extirpation; Removal; Surgical Removal; resection; Excision; Position; Positioning Attribute; Regulation; carcinogenicity; Modeling; Sampling; superfund site; Provider; Effectiveness; Address; Dose; Aerobic; Data; Interruption; Security; Process; Development; developmental; cost; design; designing; remediation; Outcome; scale up; cost effective; Population; Stress Tests; prototype; Superfund; flexibility; flexible; operation; health goals; well water; geochemistry; geochemical