scholarly journals Bioremediation of toluene by bioaugmentation, biostimulation and natural attenuation

2021 ◽  
Vol 280 ◽  
pp. 11014
Author(s):  
Cevat Yaman ◽  
Ismail Anil ◽  
Omer Aga ◽  
Ayse B. Yaman ◽  
Aleem Qureshi
Keyword(s):  
Removal Efficiency ◽  
Natural Attenuation ◽  
Permeable Reactive Barriers ◽  
Toluene Degradation ◽  
Oil Refineries ◽  
Toluene Removal ◽  
Subsurface Environment ◽  
Underground Storage Tanks ◽  
The Impact

Contamination in subsurface environment is a serious environmental hazard. Main sources of the contamination are petrol, diesel fuel, gasoline at oil refineries, underground storage tanks, transmission pipelines and different industries. Permeable reactive barriers (PRBs), which is a promising technology to remediate groundwater in-situ, are filled with reactive materials for the removal of the contaminants present in groundwater. In this study, groundwater contaminated with toluene is treated in reactor columns by biological processes. This study was conducted to assess the impact of bioaugmentation (BA) and biostimulation (BS) on toluene degradation efficiency. After 44 days of treatment, toluene concentrations were decreased from 5 mg/l to 4.304 mg/l by the natural attenuation treatment (Reactor 2), which represents a 13.9% removal efficiency. Toluene was reduced to 0.0239 mg/l in the biostimulation and bioaugmentation treatment (Reactor 1), which represents a toluene removal efficiency of 99.5%. This study showed that the toluene removal efficiency in the combined BA and BS process was much higher than in natural attenuation (NA) process tested.

Toxicity Evaluation with the Microtox® Test to Assess the Impact of In Situ Oiled Shoreline Treatment Options: Natural Attenuation and Sediment Relocation

2003 ◽  
Vol 8 (3) ◽  
pp. 273-284 ◽  
Author(s):  
Kenneth Lee ◽  
Gary Wohlgeschaffen ◽  
Gilles H Tremblay ◽  
B Thomas Johnson ◽  
Gary A Sergy ◽  
...  
Keyword(s):  
Natural Attenuation ◽  
Treatment Options ◽  
Toxicity Evaluation ◽  
The Impact

scholarly journals In situ treatment technologies for pit latrines to mitigate groundwater contamination by fecal pathogens: a review of recent technical advances

2021 ◽  
Author(s):  
Shray Saxena ◽  
Walter Den
Keyword(s):  
Early Stage ◽  
Appropriate Technology ◽  
Permeable Reactive Barriers ◽  
Fecal Sludge ◽  
Technical Advances ◽  
Fecal Pathogens ◽  
Treatment Technologies ◽  
Sanitation Systems ◽  
The Impact

Abstract On-site sanitation systems such as pit latrines are extensively used around the world, while there is a growing number of evidence documenting the impact of pit latrines on groundwater quality that may affect human health. Hence, this paper summarizes the various safe-sanitation technologies by broadly categorizing them into fecal pathogen disinfection methods (anaerobic digestion, chemical disinfection, biological additives, solar pasteurization and vermicomposting) and capturing methods (pit lining and permeable reactive barriers, the latter of which simultaneously capture and sanitize fecal sludge in pit latrines). While some of the reviewed technologies have been widely practiced for mitigating microbial contamination of the groundwater, others are still in the early stage of commercialization and field validation. Though there are challenges to the selection and adoption of the most appropriate technology, this paper discusses the readiness of each technology as a stand-alone fecal sludge management solution.

scholarly journals Investigation of ZrMnFe/Sepiolite Catalysts on Toluene Degradation in a One-Stage Plasma-Catalysis System

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 828
Author(s):  
Jianqi Liu ◽  
Xin Liu ◽  
Jiayao Chen ◽  
Xianying Li ◽  
Tianpeng Ma ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Carbon Balance ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Toluene Degradation ◽  
Plasma Catalysis ◽  
Efficient Catalyst ◽  
Toluene Removal ◽  
Co2 Selectivity ◽  
Constant Energy Density

Toluene removal by double dielectric barrier charge (DDBD) plasma combined with a ZrMnFe/Sepiolite (SEP) catalyst was investigated and compared with the results from Fe/SEP, Mn/SEP and MnFe/SEP ones. All the catalysts were prepared by the impregnation method and characterized by XRD, BET, ICP, SEM, TEM, H2-TPR and XPS. The effect of catalysts on toluene degradation efficiency, carbon balance, CO2 selectivity and residual O3 concentration was studied. The experimental results indicated that the ZrMnFe/SEP catalyst presented the best catalytic performance. This is because of the high content of lattice oxygen contained in its surface, owing to the addition of Zr. When the SIE was 740 J/L, the highest toluene removal efficiency (87%), carbon balance (93%) and CO2 selectivity (51%) were obtained. The ZrMnFe/SEP catalyst had a better ozone inhibition effect than other catalysts. The catalyst has good stability, which the toluene removal efficiency, carbon balance and CO2 selectivity did not decrease significantly after 36 h of work at a constant energy density. The results indicated that the ZrMnFe/SEP catalyst is an efficient catalyst for degradation of toluene by plasma-catalyst measures.

scholarly journals Performance and Kinetics of Bioaugmentation, Biostimulation, and Natural Attenuation Processes for Bioremediation of Crude Oil-Contaminated Soils

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 883
Author(s):  
Cevat Yaman
Keyword(s):  
Removal Efficiency ◽  
Natural Attenuation ◽  
Contaminated Soils ◽  
Petroleum Hydrocarbon ◽  
Reaction Rate ◽  
Contaminated Sites ◽  
Microbiological Analysis ◽  
Monod Kinetic ◽  
The Impact ◽  
Kinetics Of

Bioremediation of contaminated sites is usually limited due to the inadequate availability of nutrients and microorganisms. This study was conducted to assess the impact of bioaugmentation (BA) and biostimulation (BS) on petroleum hydrocarbon degradation efficiency. In addition, treatment performance and kinetics of different remediation processes were investigated. For this purpose, four tanks containing oil-contaminated soils were tested. Tank 1 was operated as the natural attenuation process. Then, a microbial inoculum and nutrients were added to tank 2 to promote BA and BS. In tank 3, only the BA process was adopted, whereas in tank 4, only the BS process was adopted. After 63 days of operation, the total petroleum hydrocarbon (TPH) in tank 2 was reduced from 1674 to 430 mg/kg, with 74% reduction. Tank 1, tank 3, and tank 4 indicated TPH reductions of 35%, 41%, and 66%, respectively. Microbiological analysis of the inoculum indicated that Alcanivorax was the dominant bacterium. The population of TPH degrader bacteria in tank 2 soil was two orders of magnitude higher than in the control tank. Reaction rate data were fitted with a first-order reaction rate model. The Monod kinetic constants, maximum specific growth rate (µmax), and substrate concentration at half-velocity constant (Ks) were also estimated. This study showed that the TPH removal efficiency in the combined BA and BS process was higher than in other processes tested. The populations of TPH degrading microorganisms in soil tanks were positively related to TPH removal efficiency during bioremediation of petroleum-contaminated soils.

scholarly journals Toluene Bioremediation by Using Geotextile-Layered Permeable Reactive Barriers (PRBs)

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 906
Author(s):  
Cevat Yaman ◽  
Ismail Anil ◽  
Omar Alagha ◽  
Nawaf I. Blaisi ◽  
Ayse Burcu Yaman ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Permeable Reactive Barriers ◽  
Permeable Reactive Barrier ◽  
World Health ◽  
Order Kinetic ◽  
Oil Refineries ◽  
Fabric Filter ◽  
Guideline Value ◽  
Sand And Gravel ◽  
The Impact

Sources of contamination in a subsurface environment are petrol, diesel fuel, gasoline at oil refineries, underground storage tanks, transmission pipelines, and different industries. The permeable reactive barrier (PRB) is a promising technology to remediate groundwater in-situ. In this study, synthetic groundwater samples containing toluene are treated in three reactor columns by biological processes. PRB-1 consisted of sand and gravel as reactor media, microbial inoculum (bioaugmentation—BA), and nutrients (biostimulation—BS); PRB-2 consisted of sand and gravel as reactor media, microbial inoculum, nutrients, and 12 layers of nonwoven geotextile fabrics; and PRB-3 consisted of only sand and gravel as reactor media (natural attenuation—NA). This study was conducted to assess the impact of geotextile fabric filter, bioaugmentation, and biostimulation on toluene degradation efficiency. After 167 days of treatment, toluene biodegradation efficiencies varied between 88.2% and 93.8% for PRB 1, between 98.0% and 99.3% for PRB 2, and between 14.2% and 68.6% for PRB 3. The effluent toluene concentrations for PRB-2 were less than the guideline value (0.7 mg/L) of the World Health Organization. Reaction rate data were fitted with a first-order kinetic reaction rate model. This study showed that the toluene removal efficiency in the geotextile layered PRB combined with BA and BS process was significantly higher compared to the other processes tested. This lab-scale study introduced a new PRB configuration suitable for the remediation of sites contaminated with toluene.

In situ Quantification of the Impact of Episodic Enhanced Turbulent Events in Large Phytoplankton

2011 ◽  
Author(s):  
Percy L. Donaghay ◽  
Jan Rines ◽  
James Sullivan
Keyword(s):  
The Impact

PFAS removal from wastewater by in-situ formed ferric nanoparticles: Solid phase loading and removal efficiency

2021 ◽  
Vol 9 (4) ◽  
pp. 105452
Author(s):  
Jianhua Zhang ◽  
Hongjiao Pang ◽  
Stephen Gray ◽  
Shaoheng Ma ◽  
Zongli Xie ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Solid Phase

Bayesian analysis reveals the impact of load partitioning on microstructural evolution in Ti-6Al-4V during in-situ tensile loading

Materialia ◽  
2021 ◽  
Vol 15 ◽  
pp. 100993
Author(s):  
N. Armstrong ◽  
P.A. Lynch ◽  
P. Cizek ◽  
S.R. Kada ◽  
S. Slater ◽  
...  
Keyword(s):  
Bayesian Analysis ◽  
Microstructural Evolution ◽  
Tensile Loading ◽  
The Impact

scholarly journals Association of temporary Environmental Protection Agency regulation suspension with industrial economic viability and local air quality in California, United States

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Emily Chang ◽  
Kenneth Zhang ◽  
Margaret Paczkowski ◽  
Sara Kohler ◽  
Marco Ribeiro
Keyword(s):  
United States ◽  
Air Quality ◽  
Environmental Protection ◽  
Environmental Protection Agency ◽  
Manufacturing Industry ◽  
Economic Viability ◽  
Treatment Control ◽  
Oil Refineries ◽  
Pollution Levels ◽  
The Impact

Abstract Background This study seeks to answer two questions about the impacts of the 2020 Environmental Protection Agency’s enforcement regulation rollbacks: is this suspension bolstering the economic viability of industries as oil and manufacturing executives claim they will and are these regulations upholding the agency’s mission of protecting the environment? Results To answer the former question, we utilized 6 months of state employment level data from California, United States, as a method of gauging the economic health of agency-regulated industries. We implemented a machine learning model to predict weekly employment data and a t-test to indicate any significant changes in employment. We found that, following California's state-issued stay-at-home order and the agency’s regulation suspension, oil and certain manufacturing industries had statistically significant lower employment values. To answer the latter question, we used 10 years of PM2.5 levels in California, United States, as a metric for local air quality and treatment–control county pairs to isolate the impact of regulation rollbacks from the impacts of the state lockdown. Using the agency’s data, we performed a t-test to determine whether treatment–control county pairs experienced a significant change in PM2.5 levels. Even with the statewide lockdown—a measure we hypothesized would correlate with decreased mobility and pollution levels—in place, counties with oil refineries experienced the same air pollution levels when compared to historical data averaged from the years 2009 to 2019. Conclusions In contrast to the expectation that the suspension would improve the financial health of the oil and manufacturing industry, we can conclude that these industries are not witnessing economic growth with the suspension and state shutdown in place. Additionally, counties with oil refineries could be taking advantage of these rollbacks to continue emitting the same amount of PM2.5, in spite of state lockdowns. For these reasons, we ask international policymakers to reconsider the suspension of enforcement regulations as these actions do not fulfill their initial expectations. We recommend the creation and maintenance of pollution control and prevention programs that develop emission baselines, mandate the construction of pollution databases, and update records of pollution emissions.

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