Controlled Release Electron Donors: Hydrogen Release Compound (HRC)—An Overview of a Decade of Case Studies

Koenigsberg, Stephen S.; Willett, A.; Sutherland, Michelle

doi:10.1080/10889860600842837

Cited by 11 publications

(4 citation statements)

References 3 publications

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“…Results of various filed applications and laboratory-scale studies have revealed the significance of several factors affecting HRC-based bioremediation processes, such as application types and locations, kinds of contaminants treated, injection and mixing methods, oxygen supply, and system design [46][47][48]. Typically, HRC is applied to in situ environments using direct injection techniques to deliver it into the zone of contamination.…”

Section: Significance Of Pla Usementioning

confidence: 99%

“…Also, low molecular liquid types of PLA have greater appeal in application for anaerobic bioremediation of contaminated solid matrices and subsurface environments [2]. The ability of PLA to serve as such a long-term source of the organic acid makes it possible to use for engineered bioremediation processes in which the microbial redox process involved requires much time and constant supply of electron donor to reduce target contaminants.…”

Section: Introductionmentioning

confidence: 99%

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Environmental Applications

Hiraishi

2010

Poly(Lactic Acid)

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Section: Significance Of Pla Usementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Environmental Applications

Hiraishi

2010

Poly(Lactic Acid)

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“…A variety of substrates including pentanol, ethanol, lactate, propionate, butyrate, and oleate have been shown to produce suitable electron donors (e.g., acetate, hydrogen) to support chlororespiring populations ( Carr and Hughes 1998 ; Fennell and Gossett 1998 ; He et al 2002 ; Yang and McCarty 1998 , 2002 ). Alternative amendment strategies that supply slow-release, nonsoluble substrates for example, olive oil, chitin, polylactate esters [e.g., Hydrogen Release Compound (HRC; Regenesis Bioremediation Products, San Clemente, CA)], have also been successfully, used ( Koenigsberg and Farone 1999 ; Yang and MacCarty 2002). Chlororespiring populations are highly competitive hydrogen users and outcompete methanogens, acetogens, and sulfate-reducing populations for this electron donor ( Löffler et al 1999 ).…”

Section: Chlorinated Ethene Biodegradationmentioning

confidence: 99%

Coupling Aggressive Mass Removal with Microbial Reductive Dechlorination for Remediation of DNAPL Source Zones: A Review and Assessment

Christ

Ramsburg

Abriola

et al. 2005

Environ Health Perspect

103

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The infiltration of dense non-aqueous-phase liquids (DNAPLs) into the saturated subsurface typically produces a highly contaminated zone that serves as a long-term source of dissolved-phase groundwater contamination. Applications of aggressive physical–chemical technologies to such source zones may remove > 90% of the contaminant mass under favorable conditions. The remaining contaminant mass, however, can create a rebounding of aqueous-phase concentrations within the treated zone. Stimulation of microbial reductive dechlorination within the source zone after aggressive mass removal has recently been proposed as a promising staged-treatment remediation technology for transforming the remaining contaminant mass. This article reviews available laboratory and field evidence that supports the development of a treatment strategy that combines aggressive source-zone removal technologies with subsequent promotion of sustained microbial reductive dechlorination. Physical–chemical source-zone treatment technologies compatible with posttreatment stimulation of microbial activity are identified, and studies examining the requirements and controls (i.e., limits) of reductive dechlorination of chlorinated ethenes are investigated. Illustrative calculations are presented to explore the potential effects of source-zone management alternatives. Results suggest that, for the favorable conditions assumed in these calculations (i.e., statistical homogeneity of aquifer properties, known source-zone DNAPL distribution, and successful bioenhancement in the source zone), source longevity may be reduced by as much as an order of magnitude when physical–chemical source-zone treatment is coupled with reductive dechlorination.

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“…Poly(lactic acid), or PLA, which belongs to the family of linear polyesters, is industrially produced via Ring Opening Polymerization (ROP) of the cyclic dimer of lactic acid (lactide), which is made from the fermentation of dextrose, a renewable feedstock available from sugar or corn, among others [1,2]. Processing, crystallization, final properties and degradation behaviour of PLA are all strongly influenced by the structure and composition of the polymer chains, specifically the ratio of the L-and D-isomer of lactic acid [3][4][5][6][7]. This stereochemical structure of PLA can be tuned by copolymerization of mixtures of L-lactide and meso-, D-, or rac-lactide resulting in high molecular weight amorphous or semicrystalline polymers with a melting temperature from 130 to 185°C [8,9].…”

Section: Introductionmentioning

confidence: 99%

Influence of temperature on high molecular weight poly(lactic acid) stereocomplex formation

Hortós¹,

Vinas²,

Espino³

et al. 2019

Express Polym. Lett.

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The influence of temperature on the formation of high molecular weight poly(lactic acid) (PLA) stereocomplex was studied by evaluation of the precipitates from dioxane solutions of PLA enantiomers (PLLA and PDLA). The racemic mixtures were characterized by Gel Permeation Chromatography, Infrared Spectroscopy, Differential Scanning Calorimetry, Scanning Electronic Microscopy, Wide-Angle X-ray Scattering and Vicat Softening Temperature. Precipitation was carried out under different solution temperatures, keeping constant the mixing ratio (X D), the molecular weight, the optical purity of both PLA enantiomers and the stirring rate. It was found that the precipitates contained only pure stereocomplex crystallites (racemic crystallites), without observing crystal phase separation between both homocrystals. The kinetics of the insoluble phase formation could be adjusted with the Avrami model, classically used for polymer crystallization in molten state. It was observed that the maximum PLA stereocomplex production rate was at about 40°C. However, more thermally stable racemic crystallites were formed at high solution temperatures. It was found that all the precipitates were sphere-like at 10 g•dl-1 at the solution temperature of 25, 40, 60 and 80°C.

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Controlled Release Electron Donors: Hydrogen Release Compound (HRC)—An Overview of a Decade of Case Studies

Cited by 11 publications

References 3 publications

Environmental Applications

Environmental Applications

Coupling Aggressive Mass Removal with Microbial Reductive Dechlorination for Remediation of DNAPL Source Zones: A Review and Assessment

Influence of temperature on high molecular weight poly(lactic acid) stereocomplex formation

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