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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

In silico evaluation of a targeted metaproteomics strategy for broad screening of cellulolytic enzyme capacities in anaerobic microbiome bioreactors

Microbial-driven solubilization of lignocellulosic material is a natural mechanism that is exploited in anaerobic digesters (ADs) to produce biogas and other valuable bioproducts. Glycoside hydrolases (GHs) are the main enzymes that bacterial and archaeal populations use to break down complex polysaccharides in these reactors. Methodologies for rapidly screening the physical presence and types of GHs can provide information about their functional activities as well as the taxonomical diversity within AD systems but are largely unavailable. Targeted proteomic methods could potentially be used to provide snapshots of the GHs expressed by microbial consortia in ADs, giving valuable insights into the functional lignocellulolytic degradation diversity of a community. Such observations would be essential to evaluate the hydrolytic performance of a reactor or potential issues with it.

09 BIOMASS FUELS↗
DOE OSTI2024

Utilization of microalgae for agricultural runoff remediation and sustainable biofuel production through an integrated biorefinery approach

Generally wastewater such agricultural runoff is considered a nuisance; however, it could be harnessed as a potential source of nutrients like nitrates and phosphates in integrated biorefinery context. In the current study, microalgae Chlorella sp. S5 was used for bioremediation of agricultural runoff and the leftover algal biomass was used as a potential source for production of biofuels in an integrated biorefinery context. The microalgae Chlorella sp. S5 was cultivated on Blue Green (BG 11) medium and a comprehensive optimization of different parameters including phosphates, nitrates, and pH was carried out to acquire maximum algal biomass enriched with high lipids content. Dry biomass was quantified using the solvent extraction technique, while the identification of nitrates and phosphates in agricultural runoff was carried out using commercial kits. The algal extracted lipids (oils) were employed in enzymatic trans-esterification for biodiesel production using whole-cell biomass of Bacillus subtilis Q4 MZ841642. The resultant fatty acid methyl esters (FAMEs) were analyzed using Fourier transform infrared (FTIR) spectroscopy and gas chromatography coupled with mass spectrometry (GC–MS). Subsequently, both the intact algal biomass and its lipid-depleted algal biomass were used for biogas production within a batch anaerobic digestion setup. Interestingly, Chlorella sp. S5 demonstrated a substantial reduction of 95% in nitrate and 91% in phosphate from agricultural runoff. The biodiesel derived from algal biomass exhibited a noteworthy total FAME content of 98.2%, meeting the quality standards set by American Society for Testing and Materials (ASTM) and European union (EU) standards. Furthermore, the biomethane yields obtained from whole biomass and lipid-depleted biomass were 330.34 NmL/g VS added and 364.34 NmL/g VS added , respectively. In conclusion, the findings underscore the potent utility of Chlorella sp. S5 as a multi-faceted resource, proficiently employed in a sequential cascade for treating agricultural runoff, producing biodiesel, and generating biogas within the integrated biorefinery concept.

09 BIOMASS FUELS↗
DOE OSTI2011

Biomass in Multifunction Crop Plants: Cooperative Research and Development Final Report, CRADA Number CRD-05-163

An array of cellulase, hemicellulase, and accessory enzymes were tested for their ability to increase the conversion levels and rates of biomass to sugar after being subjected to thermochemical pretreatment. The genes were cloned by Oklahoma State University and expressed, purified, and tested at NREL. Several enzymes were noted to be effective in increasing conversion levels, however expressionlevels were typically very low. The overall plan was to express these enzymes in corn as a possible mechanism towards decreased recalcitrance. One enzyme, cel5A endoglucanase from Acidothermus cellulolyticus, was transformed into both tobacco and corn. The transgenic corn stover and tobacco were examined for their susceptibility to thermochemical pretreatment followed by enzymatic digestion.

09 BIOMASS FUELS↗
DOE OSTI2012

DECREASE: Development of a Commercial Ready Enzyme Application System for Ethanol (Final Technical Report)

Conversion of biomass to sugars plays a central in reducing our dependence on petroleum, as it allows production of a wide range of biobased fuels and chemicals, through fermentation of those sugars. The DECREASE project delivers an effective enzyme cocktail for this conversion, enabling reduced costs for producing advanced biofuels such as cellulosic ethanol. Benefits to the public contributed by growth of the advanced biofuels industry include job creation, economic growth, and energy security. The DECREASE primary project objective was to develop a two-fold improved enzyme cocktail, relative to an advanced cocktail (CZP00005) that had been developed previously (from 2000- 2007). While the final milestone was delivery of all enzyme components as an experimental mixture, a secondary objective was to deploy an improved cocktail within 3 years following the close of the project. In February 2012, Novozymes launched Cellic® CTec3, a multi-enzyme cocktail derived in part from components developed under DECREASE. The externally validated performance of CTec3 and an additional component under project benchmarking conditions indicated a 1.8-fold dose reduction in enzyme dose required for 90% conversion (based on all available glucose and xylose sources) of NREL dilute acid pretreated PCS, relative to the starting advanced enzyme cocktail. While the ability to achieve 90% conversion is impressive, targeting such high levels of biomass digestion is likely not the most cost effective strategy. Novozymes techno economic modeling showed that for NREL's dilute acid pretreated corn stover (PCS), 80% target conversion enables a lower total production cost for cellulosic ethanol than for 90% conversion, and this was also found to be the case when cost assumptions were based on the NREL 2002 Design Report. A 1.8X dose-reduction was observed for 80% conversion in the small scale (50 g) DECREASE benchmark assay for CTec3 and an additional component. An upscaled experiment (in 0.5 kg kettle reactors) was performed to compare the starting enzyme mixture CZP00005 with CTec3 alone; these results indicated a 1.9X dose- reduction for 80% conversion. The CTec3 composition does not include the best available enzyme components from the DECREASE effort. While these components are not yet available in a commercial product, experimental mixtures were assayed in a smaller scale assay using DECREASE PCS, at high solids loadings (21.5% TS). The results indicated that the newer mixtures required 2.9X-less enzyme for 90% conversion, and 3.2X-less enzyme for 80% conversion, relative to the starting enzyme cocktail. In conclusion, CTec3 delivers a 1.8-1.9X dose reduction on NREL PCS at high solids loadings, and the next generation enzyme from Novozymes will continue to show dramatically improved biochemical performance. CTec3 allows reduced costs today, and the experimental cocktails point to continued biotechnological improvements that will further drive down costs for biorefineries of tomorrow.

02 PETROLEUM↗
DOE OSTI2012

Uncertainty Measurement for Trace Element Analysis of Uranium and Plutonium Samples by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

The measurement uncertainty estimation associated with trace element analysis of impurities in U and Pu was evaluated using the Guide to the Expression of Uncertainty Measurement (GUM). I this evaluation the uncertainty sources were identified and standard uncertainties for the components were categorized as either Type A or B. The combined standard uncertainty was calculated and a coverage factor k = 2 was applied to obtain the expanded uncertainty, U. The ICP-AES and ICP-MS methods used were developed for the multi-element analysis of U and Pu samples. A typical analytical run consists of standards, process blanks, samples, matrix spiked samples, post digestion spiked samples and independent calibration verification standards. The uncertainty estimation was performed on U and Pu samples that have been analyzed previously as part of the U and Pu Sample Exchange Programs. Control chart results and data from the U and Pu metal exchange programs were combined with the GUM into a concentration dependent estimate of the expanded uncertainty. Comparison of trace element uncertainties obtained using this model was compared to those obtained for trace element results as part of the Exchange programs. This process was completed for all trace elements that were determined to be above the detection limit for the U and Pu samples.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Analytical Capability of Plasma Spectrometry Team [Slides]

Samples analyzed were: (1) Pu and U metal; (2) Pu oxide for nuclear fuel; (3) 23 8Pu oxide for heat source; and (4) Nuclear forensic samples - filters, swipes. Sample preparations that we did were: metal dissolution, marple filter dissolution, Pu oxide closed vessel acid digestion, and column separation to remove Pu.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

California Hydrogen Infrastructure Project

Air Products and Chemicals, Inc. has completed a comprehensive, multiyear project to demonstrate a hydrogen infrastructure in California. The specific primary objective of the project was to demonstrate a model of a real-world retail hydrogen infrastructure and acquire sufficient data within the project to assess the feasibility of achieving the nation's hydrogen infrastructure goals. The project helped to advance hydrogen station technology, including the vehicle-to-station fueling interface, through consumer experiences and feedback. By encompassing a variety of fuel cell vehicles, customer profiles and fueling experiences, this project was able to obtain a complete portrait of real market needs. The project also opened its stations to other qualified vehicle providers at the appropriate time to promote widespread use and gain even broader public understanding of a hydrogen infrastructure. The project engaged major energy companies to provide a fueling experience similar to traditional gasoline station sites to foster public acceptance of hydrogen. Work over the course of the project was focused in multiple areas. With respect to the equipment needed, technical design specifications (including both safety and operational considerations) were written, reviewed, and finalized. After finalizing individual equipment designs, complete station designs were started including process flow diagrams and systems safety reviews. Material quotes were obtained, and in some cases, depending on the project status and the lead time, equipment was placed on order and fabrication began. Consideration was given for expected vehicle usage and station capacity, standard features needed, and the ability to upgrade the station at a later date. In parallel with work on the equipment, discussions were started with various vehicle manufacturers to identify vehicle demand (short- and long-term needs). Discussions included identifying potential areas most suited for hydrogen fueling stations with a focus on safe, convenient, fast-fills. These potential areas were then compared to and overlaid with suitable sites from various energy companies and other potential station operators. Work continues to match vehicle needs with suitable fueling station locations. Once a specific site was identified, the necessary agreements could be completed with the station operator and expected station users. Detailed work could then begin on the site drawings, permits, safety procedures and training needs. Permanent stations were successfully installed in Irvine (delivered liquid hydrogen), Torrance (delivered pipeline hydrogen) and Fountain Valley (renewable hydrogen from anaerobic digester gas). Mobile fueling stations were also deployed to meet short-term fueling needs in Long Beach and Placerville. Once these stations were brought online, infrastructure data was collected and reported to DOE using Air Products Enterprise Remote Access Monitoring system. Feedback from station operators was incorporated to improve the station user's fueling experience.

08 HYDROGEN↗
DOE OSTI2014

Haiti: Feasibility of Waste-to-Energy Options at the Trutier Waste Site

This report provides further analysis of the feasibility of a waste-to-energy (WTE) facility in the area near Port-au-Prince, Haiti. NREL's previous analysis and reports identified anaerobic digestion (AD) as the optimal WTE technology at the facility. Building on the prior analyses, this report evaluates the conceptual financial and technical viability of implementing a combined waste management and electrical power production strategy by constructing a WTE facility at the existing Trutier waste site north of Port-au-Prince.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Testing of the Defense Waste Processing Facility Cold Chemical Dissolution Method in Sludge Batch 9 Qualification

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) tests the applicability of the digestion methods used by the DWPF Laboratory for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) Receipt samples and SRAT Product process control samples. DWPF SRAT samples are typically dissolved using a method referred to as the DWPF Cold Chemical or Cold Chem Method (CC), (see DWPF Procedure SW4- 15.201). Testing indicates that the CC method produced mixed results. The CC method did not result in complete dissolution of either the SRAT Receipt or SRAT Product with some fine, dark solids remaining. However, elemental analyses did not reveal extreme biases for the major elements in the sludge when compared with analyses obtained following dissolution by hot aqua regia (AR) or sodium peroxide fusion (PF) methods. The CC elemental analyses agreed with the AR and PF methods well enough that it should be adequate for routine process control analyses in the DWPF after much more extensive side-by-side tests of the CC method and the PF method are performed on the first 10 SRAT cycles of the Sludge Batch 9 (SB9) campaign. The DWPF Laboratory should continue with their plans for further tests of the CC method during these 10 SRAT cycles.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Well-to-Wheels Analysis of Compressed Natural Gas and Ethanol from Municipal Solid Waste

The amount of municipal solid waste (MSW) generated in the United States was estimated at 254 million wet tons in 2013, and around half of that generated waste was landfilled. There is a huge potential in recovering energy from that waste, since around 60% of landfilled material is biomass-derived waste that has high energy content. In addition, diverting waste for fuel production avoids huge fugitive emissions from landfills, especially uncontrolled CH 4 emissions, which are the third largest anthropogenic CH 4 source in the United States. Lifecycle analysis (LCA) is typically used to evaluate the environmental impact of alternative fuel production pathways. LCA of transportation fuels is called well-to-wheels (WTW) and covers all stages of the fuel production pathways, from feedstock recovery (well) to vehicle operation (wheels). In this study, the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET ® ) model developed by Argonne National Laboratory is used to evaluate WTW greenhouse gas (GHG) emissions and fossil fuel consumption of waste-derived fuels. Two waste-to-energy (WTE) pathways have been evaluated – one for compressed natural gas (CNG) production using food waste via anaerobic digestion, and the other for ethanol production from yard trimmings via fermentation processes. Because the fuel production pathways displace current waste management practices (i.e., landfilling waste), we use a marginal approach that considers only the differences in emissions between the counterfactual case and the alternative fuel production case.

03 NATURAL GAS↗
DOE OSTI2018

Economical and Environmentally Benign Extraction of Rare Earth Elements (REES) from Coal & Coal Byproducts

This final report provides a complete summary of the activities, results, analytical discussion, and overall evaluation of the project titled “Economical and Environmentally Benign Extraction of Rare Earth Elements (REES) from Coal & Coal Byproducts” under DOE Award Number DE-FE-0027155 that started in March 2016 and ended December 2017. Fly ash was selected as the coal-byproduct source material due to fact that it is readily available with no need for extensive methods to obtain the material, it is produced in large quantities (>50 million tons per year) and had REE concentrations similar to other coal-byproducts. The selected fly ash used throughout this project was from the Mill Creek power generating facility operated by Louisville Gas and Electric located in Louisville, KY and was subjected to a variety of physical and chemical characterization tests. Results from fusion extractions showed that the selected fly-ash had a TREE+Y concentration of 480 ppm with critical REEs concentration of 200 ppm. The fly ash had an outlook ratio of 1.25 and an estimated value of $16-$18 worth of salable REEs per 1-tonne of fly ash. Additional characterizations by optical evaluation, QEMSCAN, XRD, size fractionation, and SEM analysis showed the fly ash consisted of small glassy spherules with a size range between 1 to 110 µm (ave. diam. of 13 um), was heterogeneous in chemical composition (main crystalline phases: aluminum oxides and iron oxides) and was primarily an amorphous material (75 to 80%). A simple stepped approach was completed to estimate the total REE resource quantity. The approach included REE characterization of the representative samples, evaluation of fly-ash availability, and final determination estimated resource availability with regards to REE grade on a regional and national scale. This data represents the best available information and is based upon the assumptions that the power generating facility where the fly-ash was obtained will use the same coal sources (actual mines were identified), the coal materials will have relatively consistent REE concentrations, and the REE extraction process developed during this project can achieve 42% REE recovery (validated and confirmed). Calculations indicated that the estimated REE resource is approximately 175,000 tonnes with a current estimated value of $3,330MM. The proposed REE extraction and production process developed during this project used four fundamental steps; 1) fly-ash pretreatment to enhance REE extraction, 2) REE extraction by acid digestion, 3) REE separation/concentration by carbon adsorption and column chromatography, and 4) REE oxide production. Secondary processing steps to manage process residuals and additional processing techniques to produce value-added products were incorporated into the process during the project. These secondary steps were not only necessary to manage residuals, but also provided additional revenue streams that offset operational and capital expenditures. The process produces one value product stream (production of zeolite Na-P1), a solids waste stream, and one liquid stream that met RCRA discharge requirements. Based upon final design criteria and operational parameters, the proposed system could produce approximately 200 grams of REOs from 1-tonne of fly-ash, thereby representing a TREE+Y recovery of 42% (project target of > 25%). A detailed economic model was developed to evaluate both CAPEX and OPEX estimates for systems with varying capacities between 100 kg to 200 tonnes of fly ash processed per day. Using a standard system capacity of 10 tonne/day system, capital costs were estimated at $88/kg fly ash while operating costs were estimated at approximately $450/kg fly ash. This operating cost estimate includes a revenue of $495/tonne of fly ash processed from the value-added product produced from the system (zeolite Na-P1). Although operating cost savings due to zeolite production were significant, the capital + operating cost for a 10 tonne system was more expensive than the total dollar value of REEs present in the fly ash material. Specifically, the estimated cost per 1-tonne of fly ash treated is approximately $540 while the estimated value of REEs in the fly ash is $18-$20/tonne. This is an excessive difference showing that the proposed process is not economically feasible strictly on the basis of REE revenue compared to extraction costs. Although the current proposed system does not produce sufficient quantities of REEs or additional revenue sources to offset operational and capital costs, supplementary factors including US strategic concerns, commercial demands, and defense department requirements must be factored. At this time, the process developed during this project provides foundational information for future development of simple processes that require low capital investment and one that will extract a valuable quality and quantity of REE oxides from industrial waste.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2020

An Overview of the Waste-to-Energy System Simulation (WESyS) Model

The leveraging of waste streams for energy and chemical production could add revenue to waste disposal operations, and it presents opportunities for addressing a variety of economic and environmental objectives at the local, state, and national levels. The Waste-to-Energy System Simulation (WESyS) model is a system dynamics model that was created to simulate the development of the U.S. waste-to-energy industry over time. For each of the three primary waste resources modeled (landfills, concentrated animal feeding operations, and publicly owned treatment works), WESyS simulates technically feasible scenarios for use of the waste, including direct conversion to fuels, and anaerobic digestion followed by flaring, electricity generation, combined heat and power, cleanup and compression to compressed natural gas, and cleanup and injection into an existing pipeline. The model allows users to explore numerous plausible future scenarios for the development of the U.S. waste-to-energy industry. This report provides an overview of the WESyS model and documents the key assumptions, equations, and data sources used to create the model.

09 BIOMASS FUELS↗
DOE OSTI2021

Improved Hydrogen Utilization and Carbon Recovery for Higher Efficiency Thermochemical Bio-oil Pathways

The goal of this project was to develop a novel integrated direct biomass liquefaction process with improved hydrogen utilization and better carbon efficiency compared to other thermochemical conversion technologies for advanced biofuels production. Reactive catalytic fast pyrolysis, or RCFP, combines a robust hydrodeoxygenation catalyst for in situ pyrolysis in an excess of hydrogen at atmospheric (low) pressure. RCFP was developed to leverage advantages from catalytic fast pyrolysis (process simplicity and improved bio-crude quality) and biomass hydropyrolysis (enhanced hydrodeoxygenation) to produce a thermally-stable, low oxygen containing bio-crude intermediate that can be upgraded in a single conventional hydroprocessing step to produce gasoline- and diesel-range hydrocarbons. In parallel, carbon lost to the aqueous phase was recovered as renewable methane from anaerobic digestion to offset fossil carbon required to meet the hydrogen demand of the integrated process.

09 BIOMASS FUELS↗
DOE OSTI2022

Opportunities for Utilization of Low-Cost Algae Resources: Techno-Economic Analysis Screening for Near-Term Deployment (Parts 1 and 2)

This report presents a comprehensive techno-economic analysis (TEA) for the production, collection, or procurement of several low-cost algae resources that may otherwise be considered "waste" biomass materials today, as well as the utilization of these materials through exemplary conversion processes to produce renewable fuels and chemicals. In contrast to conventional TEA models attributed to large-scale algae "farming" approaches, which may be able to produce substantially more biomass and thus fuels/products at a national scale in the future, this assessment focuses on understanding opportunities and costs for such "waste" algal biomass resources as may be available at considerably lower cost today. Economics for base case assumptions and a range of sensitivity scenarios are presented, employing conversion technologies that are simple and well understood, and thus may be deployed at smaller community scale in the near term, as a means to support and expand a nascent algae industry on the way to employing a larger commercial algae farm approach for commodity-scale production. Specifically, three algal biomass resources are considered in this assessment, as may be sourced from (1) municipal wastewater treatment (WWT) utilizing algae in place of more conventional technologies for nitrogen/phosphorus removal, (2) collection and removal of harmful algal bloom (HAB) biomass as proliferates in certain inland water bodies, and (3) procurement of residual biomass following commercial lipid extraction (EXT) operations performed at smaller scale by industry today focused on higher-value nutraceutical applications. These three resources are evaluated through two conversion pathways: (1) combined algal biomass processing (CAP) through a simple/low-complexity configuration, and (2) anaerobic digestion (AD). The CAP pathway produces liquid fuels and chemical coproducts (polymer for off-site upgrading to bioplastics), whereas the AD pathway produces biogas (specifically renewable natural gas [RNG]) and crop fertilizer coproducts. To streamline the discussion, this report is broken into two sections: Part 1 focuses on WWT-derived biomass, and Part 2 on HAB and EXT biomass.

09 BIOMASS FUELS↗
DOE OSTI2022

Membrane Carbonation for 100% Efficient Delivery of Industrial CO 2 Gases

Industrial processes generate about one quarter of all greenhouse gases emissions in the US, about 80% of which is carbon dioxide (CO 2 ). Biological processes are one of the largest natural sinks for atmospheric CO 2 , but the rate of capture is limited by the low concentration in air (~0.04%). Industrial emissions have significantly higher CO 2 concentrations, ranging from 5–80% CO 2 , which can significantly increase the rate of biological CO 2 capture, including many-fold improvements for cultivating microalgae to produce food, fertilizer, and renewable fuel. However, traditional methods for delivering CO 2 to microalgae using bubbling is < 40% efficient, leading to significant residual CO 2 emissions and increased cost. This project developed the Membrane Carbonation (MC) technology to significantly improve the CO 2 delivery efficiency to microalgae from power plant flue gas, wastewater treatment plant anaerobic digesters biogas (Figure 1), and other CO 2 -containing industrial sources.

09 BIOMASS FUELS↗
DOE OSTI2024

Synthetic Feces for Arctic Research [Slides]

Synthetic feces can be utilized to study waste treatment systems while minimizing human risk through exposure to fecal pathogens. This presentation compares properties of synthetic waste to human waste and showcases the utility of synthetic feces for a pilot study on anaerobic digestion taking place in Fairbanks, AK. This workshop also demonstrates how to create synthetic feces and engages participants in a hands-on experience.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Biohydrogen: prospects for industrial utilization and energy resiliency in rural communities

Biohydrogen (bioH 2 ) production in rural regions of the United States leveraged from existing biomass waste streams serves two extant needs: rural energy resiliency and decarbonization of heavy industry, including the production of ammonia and other H 2 -dependent nitrogenous products. We consider bioH 2 production using two different strategies: (1) dark fermentation (DF) and (2) anaerobic digestion followed by steam methane reforming of the biogas (AD-SMR). Production of bioH 2 from biomass waste streams is a potentially ‘greener’ pathway in comparison to natural gas-steam methane reforming (NG-SMR), especially as fugitive emissions from these wastes are avoided. It also provides a decarbonizing potential not found in water-splitting technologies. Based on literature on DF and AD of crop residues, woody biomass residues from forestry wastes, and wastewaters containing fats, oils, and grease (FOG), we outline scenarios for bioH 2 production and displacement of fossil fuel derived methane. Finally, we compare the costs and carbon intensity (CI) of bioH 2 production with those of other H 2 production pathways.

08 HYDROGEN↗
DOE OSTI2025

In anaerobic reactors the microbial community structure depends on feed type, with no “keystone” species tied to COD removal

Two-stage anaerobic digestion (AD) systems provide treatment for high strength wastewater with high stability and performance. Encapsulation technology can intensify AD to facilitate the separation of the solids retention time from the hydraulic retention time (HRT), offering lower HRTs, smaller reactors, and high effluent quality. To support successful deployment, however, the encapsulated community must contain all the needed microorganisms for successful treatment and be flexible enough to treat a variety of wastewaters. Here, a two-stage system was investigated in which microbial cultures were enriched on various high-strength wastewaters in suspended flow-through systems to determine how feed type influenced performance and microbial community structure. The hypothesis was that specific genera, or so-called “keystone species” would positively correlate to organic carbon degradation for a given feed, enabling construction of a well-functioning community for encapsulation. Results showed that the number of total bacteria (as 16S rRNA gene copies) did not correlate to soluble chemical oxygen demand (sCOD) removal, indicating that the community structure and/or members were important for good performance. Results also showed that feed type strongly influenced carbon removal and microbial community structure for 1st-stage fermenting communities, but not 2nd-stage methanogenic communities. In this study, the “core” community members were defined as organisms common to all of either the 1st- or 2nd-stage reactors irrespective of the feed they received and were present in at least 50% of the samples throughout the entire experiment. “Unique” community members were specific to a single feed, and hence, only present in either the 1st- or 2nd-stage reactors receiving that feed. In both 1st- and 2nd-stage communities, only one core genera and no unique genera were positively and significantly correlated to sCOD removal. Verification experiments performed with encapsulated communities showed that organisms identified in flow-through system and correlated with carbon degradation, though not significantly, seemed to be important for performance. Our results suggest that one cannot construct a community containing specific populations in lieu of enrichment. Nevertheless, a single diverse encapsulated anaerobic community should provide good (>80%) carbon removal when fed a variety of influents, if time is provided for enrichment after deployment.

54 ENVIRONMENTAL SCIENCES↗