Bioremediation of trichloroethylene-contaminated groundwater using green carbon-releasing substrate with pH control capability.

In this research, a sustainable substrate, termed green and long-lasting substrate (GLS), featuring a blend of emulsified substrate (ES) and modified rice husk ash (m-RHA) was devised. The primary objective was to facilitate the bioremediation of groundwater contaminated with trichloroethylene (TCE) using innovative GLS for slow carbon release and pH control. The GLS was concocted by homogenizing a mixture of soybean oil, surfactants (Simple Green™ and soya lecithin), and m-RHA, ensuring a gradual release of carbon sources.

An innovative permeable reactive bio-barrier to remediate trichloroethene-contaminated groundwater: A field study.

Permeable reactive bio-barrier (PRBB), an innovative technology, could treat many contaminants via the natural gradient flow of groundwater based on immobilization or transformation of pollutants into less toxic and harmful forms. In this field study, we developed an innovative PRBB system comprising immobilized Dehalococcoides mccartyi (Dhc) and Clostridium butyricum embedded into the silica gel for long-term treatment of trichloroethene (TCE) polluted groundwater. Four injection wells and two monitoring wells were installed at the downstream of the TCE plume.

Draft genome sequence of Pseudomonas sp. A46 isolated from mercury-contaminated wastewater.

Pseudomonas sp. A46 was first isolated from mercury-contaminated groundwater in Taiwan. This study is the first to report the draft whole-genome sequence of Pseudomonas sp.

Cleanup chlorinated ethene-polluted groundwater using an innovative immobilized Clostridium butyricum column scheme: A pilot-scale study.

In this study, the developed innovative immobilized Clostridium butyricum (ICB) (hydrogen-producing bacteria) column scheme was applied to cleanup chlorinated-ethene [mainly cis-1,2-dichloroethene (cis-DCE)] polluted groundwater in situ via the anaerobic reductive dechlorinating processes. The objectives were to assess the effectiveness of the field application of ICB scheme on the cleanup of cis-DCE polluted groundwater, and characterize changes of microbial communities after ICB application. Three remediation wells and two monitor wells were installed within the cis-DCE plume.

Growth inhibition of sulfate-reducing bacteria for trichloroethylene dechlorination enhancement.

Trichloroethylene (TCE) is a frequently found organic contaminant in polluted-groundwater. In this microcosm study, effects of hydrogen-producing bacteria [Clostridium butyricum (Clostridium sp.)] and inhibitor of sulfate-reducing bacteria (SRB) addition on the enhancement of TCE dechlorination were evaluated.

Application of enhanced bioreduction for hexavalent chromium-polluted groundwater cleanup: Microcosm and microbial diversity studies.

Hexavalent chromium (Cr) is a commonly found heavy metal at polluted groundwater sites. In this study, the effectiveness of Cr bioreduction by the chromium-reducing bacteria was evaluated to remediate Cr-contaminated groundwater. Microcosms were constructed using indigenous microbial consortia from a Cr-contaminated aquifer as the inocula, and slow-releasing emulsified polycolloid-substrate (ES), cane molasses (CM), and nutrient broth (NB) as the primary substrates.

Enhanced reductive dechlorination of trichloroethene with immobilized Clostridium butyricum in silica gel.

Deteriorated environmental conditions during the bioremediation of trichloroethene (TCE)-polluted groundwater cause decreased treatment efficiencies. This study assessed the effect of applying immobilized Clostridium butyricum (a hydrogen-producing bacterium) in silica gel on enhancing the reductive dechlorination efficiency of TCE with the slow polycolloid-releasing substrate (SPRS) supplement in groundwater. The responses of microbial communities with the immobilized system (immobilized Clostridium butyricum and SPRS amendments) were also characterized by the metagenomics assay.

Numerical study of ultrashort-optical-feedback-enhanced photonic microwave generation using optically injected semiconductor lasers at period-one nonlinear dynamics.

This study numerically investigates the enhancement of photonic microwave generation using an optically injected semiconductor laser operating at period-one (P1) nonlinear dynamics through ultrashort optical feedback. For the purpose of practical applications where system miniaturization is generally preferred, a feedback delay time that is one to two orders of magnitude shorter than the relaxation resonance period of a typical laser is emphasized. Various dynamical states that are more complicated than the P1 dynamics can be excited under a number of ultrashort optical feedback conditions.

Optical feedback stabilization of photonic microwave generation using period-one nonlinear dynamics of semiconductor lasers.

Effects of optical feedback on period-one nonlinear dynamics of an optically injected semiconductor laser are numerically investigated. The optical feedback can suppress the period-one dynamics and excite other more complex dynamics if the feedback level is high except for extremely short feedback delay times. Within the range of the period-one dynamics, however, the optical feedback can stabilize the period-one dynamics in such a manner that significant reduction of microwave linewidth and phase noise is achieved, up to more than two orders of magnitude.