scholarly journals Pilot Scale Feasibility Test of In-situ Soil Flushing by using 'Tween 80' Solution at Low Concentration for the Xylene Contaminated Site

2013 ◽  
Vol 18 (6) ◽  
pp. 38-47 ◽  
Author(s):  
Jae-Yeon Um ◽  
Gyusang Lee ◽  
Sung-Ho Song ◽  
Sunwook Hong ◽  
Minhee Lee
Keyword(s):  
Tween 80 ◽  
Pilot Scale ◽  
Contaminated Site ◽  
Soil Flushing ◽  
Low Concentration ◽  
Feasibility Test

Pilot-scale injection of colloidal activated carbon for PFAS immobilization at a contaminated field site

2020 ◽  
Author(s):  
Fritjof Fagerlund ◽  
Georgios Niarchos ◽  
Lutz Ahrens ◽  
Dan Berggren Kleja ◽  
Jonny Bergman ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Seasonal Changes ◽  
Preferential Flow ◽  
Pilot Scale ◽  
Contaminated Site ◽  
Flow Paths ◽  
Groundwater Levels ◽  
Geological Setting ◽  
Scale Test

<p>Per- and polyfluorinated alkyl substances (PFASs) are extremely recalcitrant contaminants that pose a challenge for remediation in soil and groundwater due to their chemical stability and resistance to degradation. They are used in numerous consumer products and their use in firefighting aqueous-film-forming foams has led to worldwide contamination of groundwater resources associated with airports and firefighting training areas. One of the currently most promising in-situ treatment techniques is stabilization using activated carbon (AC) sorbents that can immobilize PFASs in the soil and prevent further spreading from a contaminated site. However, few documented field studies exist.</p><p>In this study we investigated in-situ stabilization of PFASs by injection of colloidal activated carbon (CAC, PlumeStop®) at a PFAS contaminated site in Arboga, Sweden. Prior to the design of the pilot-scale test and CAC injection, the geology and state of contamination were carefully characterized and PFAS concentrations and groundwater levels were monitored continuously for almost one year. CAC was injected to create a defined zone of PFAS-sorption where PFASs from the contaminant plume would be sorbed to CAC and removed from the flowing groundwater, similar to a permeable reactive barrier. The effect of the injected CAC was studied by monitoring PFAS concentrations in the groundwater up- and down-gradient as well as within the CAC barrier both before and after injection. General water chemistry and groundwater levels were also monitored.</p><p>The site characterization showed that there are two distinct source zones of PFAS contamination with different contamination signatures. Continuous baseline monitoring prior to CAC injection did not show any major changes in PFAS concentrations, but revealed seasonal variations in the groundwater levels and flow patterns, leading to seasonal changes also in the direction of contaminant transport. The CAC injection pilot-scale test was therefore designed to shield the down-gradient evaluation wells in small part of the plume accounting for seasonal changes. The geological setting of the site mainly is clayey till soil of relatively low hydraulic conductivity on top of crystalline bedrock, but there are also high permeability flow paths. The low-pressure CAC injections were hence designed and adapted to avoid excessive preferential flow of CAC and achieve a good distribution of CAC in the intended treatment zone (barrier).</p><p>Preliminary results from the monitoring showed strong reduction of all measured PFASs within and directly down-gradient of the CAC barrier. These results indicate that the installation of the CAC barrier was successful despite a relatively complex geological setting where fast preferential flow paths exist. The continuing monitoring will show how the CAC performs over time.</p>

scholarly journals In situ oxalic acid injection to accelerate arsenic remediation at a superfund site in New Jersey

2014 ◽  
Vol 11 (5) ◽  
pp. 525 ◽  
Author(s):  
Karen Wovkulich ◽  
Martin Stute ◽  
Brian J. Mailloux ◽  
Alison R. Keimowitz ◽  
James Ross ◽  
...  
Keyword(s):  
New Jersey ◽  
Oxalic Acid ◽  
Solid Phase ◽  
Sediment Cores ◽  
Pilot Scale ◽  
Contaminated Site ◽  
Superfund Site ◽  
Superfund Sites ◽  
Pump And Treat

Environmental context Arsenic is one of the most common contaminants at US Superfund sites; therefore, establishing techniques to accelerate As remediation could benefit many sites. In a pilot scale study, we determined that addition of oxalic acid to the subsurface has the potential to increase arsenic release from sediments and possibly improve remediation efficiency by pump and treat techniques. Because pump and treat remediation can require many decades to sufficiently decrease contaminant levels, methods for improving remediation could lead to substantial savings in time and resources. Abstract Arsenic is a prevalent contaminant at a large number of US Superfund sites; establishing techniques that accelerate As remediation could benefit many sites. Hundreds of tonnes of As were released into the environment by the Vineland Chemical Co. in southern New Jersey during its manufacturing lifetime (1949–1994), resulting in extensive contamination of surface and subsurface soils and sediments, groundwater, and the downstream watershed. Despite substantial intervention at this Superfund site, sufficient aquifer clean up could require many decades if based on traditional pump and treat technologies only. Laboratory column experiments have suggested that oxalic acid addition to contaminated aquifer solids could promote significant As release from the solid phase. To evaluate the potential of chemical additions to increase As release in situ and boost treatment efficiency, a forced gradient pilot scale study was conducted on the Vineland site. During spring and summer 2009, oxalic acid and bromide tracer were injected into a small portion (~50m2) of the site for 3 months. Groundwater samples indicate that introduction of oxalic acid led to increased As release. Between 2.9 and 3.6kg of As were removed from the sampled wells as a result of the oxalic acid treatment during the 3-month injection. A comparison of As concentrations on sediment cores collected before and after treatment and analysed using X-ray fluorescence spectroscopy suggested reduction in As concentrations of ~36% (median difference) to 48% (mean difference). Although further study is necessary, the addition of oxalic acid shows potential for accelerating treatment of a highly contaminated site and decreasing the As remediation time-scale.

Long-term evaluation of a spectral sensor for nitrite and nitrate

2008 ◽  
Vol 57 (10) ◽  
pp. 1563-1569 ◽  
Author(s):  
L. Rieger ◽  
P. A. Vanrolleghem ◽  
G. Langergraber ◽  
D. Kaelin ◽  
H. Siegrist
Keyword(s):  
Prediction Interval ◽  
Nitrate Concentration ◽  
Pilot Scale ◽  
Low Concentration ◽  
Uv Sensor ◽  
Alarm Systems ◽  
Nitrate Concentrations ◽  
Term Evaluation

A spectral in-situ UV sensor was investigated to measure nitrite and nitrate concentrations in the effluent of the EAWAG pilot-scale plant. The sensor was used with a calibration that was based on data from another WWTP and was operated over a period of 1.5 years. The results showed constant accuracy although the sensor was operated with minimal maintenance (manual cleaning once a month). It could be shown that the sensor was able to accurately predict the nitrite and nitrate concentration with a precision of 0.32 mg N/l (95% prediction interval at mean lab value of 1.15 mg N/l) and 1.08 mg N/l (at 5.55 mg N/l) for nitrite and nitrate, respectively. The UV sensor showed good results for nitrite in the low concentration range and very accurate results for higher concentrations (up to 10 mg N/l). This allows using the sensor for alarm systems as well as for control concepts at WWTPs.

Sequential Soil Flushing for Remediation of Complex Contaminated Soils: A Pilot-Scale Test

2014 ◽  
Vol 1073-1076 ◽  
pp. 704-707
Author(s):  
Kim Gillan ◽  
Sung Mi Yun ◽  
Han Seung Kim
Keyword(s):  
Heavy Metals ◽  
Contaminated Soils ◽  
Soil Surface ◽  
Pilot Scale ◽  
Ex Situ ◽  
Heavy Petroleum ◽  
Soil Flushing ◽  
Industrial Sites ◽  
Soil Complex

In this study, an efficient soil flushing process was developed for the remediation of soil complex contaminated with heavy petroleum oils (HPOs) and heavy metals. In most cases, remediation of contaminated soil is carried out after all industrial activity is suspended and removal of facilities. Therefore, in-situ remediation becomes more favored over ex-situ technologies albeit relatively long remediation periods are needed. In particular, soil flushing has been employed as an efficient in-situ technology most frequently in many railroad and industrial sites still in business. The objective of this study was to develop an in-situ soil flushing method using horizontal injection/suction channels. A pilot-scale box reactor (1 m × 0.6 m × 0.7 m) was employed to evaluate desorption of complex contaminants from complex contaminated soils by flushing agents. Since HPOs and heavy metals can be removed by different mechanisms, various flushing agents were required for the treatment of HPOs and heavy metals. Hydrogen peroxide (H2O2) and citric acid were selected and injected sequentially as flushing agents for HPOs and heavy metals, respectively. Soils complex contaminated with HPOs, Zn, and Pb were collected from a railroad site, Seoul, Korea, and they were packed into the pilot-scaled reactor. Two horizontal channels were installed: injection channel was placed 10 cm below the top of soil surface and suction channel was placed 10 cm above the bottom of the reactor. Flushing agents were injected at a flow rate of 3.86 mL/min for 1 month. After flushing, soil samples were collected separately from various points of the reactor (divided into 5 vertical layers and 15 horizontal sections), and then each soil sample was analyzed for the soil flushing efficiency. The initial concentrations of HPOs, Zn and Pb were 4685.5±374.4 mg/kg, 204.9±60 mg/kg, and 139.8 mg/kg (n = 3). After soil flushing, the concentrations were decreased to 1448.4±166.7 mg/kg, 143.4 mg/kg, and 99.5 mg/kg (total removal rates = 69%, 30% and 28.9%, for HPOs, Zn, and Pb, respectively). Hence, it was confirmed in this pilot-scale study that sequential soil flushing by combination of flushing agents was effective for soils complex contaminated with HPOs and heavy metals. These results must be useful for field-scale application of soil flushing remediation for the complex contaminated soils.

IN SITU SOIL FLUSHING - STUDIES ON REMEDIATION EFFICIENCY OF POLLUTED SANDY SOILS WITH ORGANIC ACIDS

2012 ◽  
Vol 11 (12) ◽  
pp. 2163-2168
Author(s):  
Alexandra-Dana Chitimus ◽  
Valentin Nedeff ◽  
Emilian Florin Mosnegutu ◽  
Mirela Panainte
Keyword(s):  
Organic Acids ◽  
Sandy Soils ◽  
Soil Flushing ◽  
Remediation Efficiency

On-site and in situ bioremediation of wood-preservative contaminated groundwater

2000 ◽  
Vol 42 (5-6) ◽  
pp. 371-376 ◽  
Author(s):  
J.A. Puhakka ◽  
K.T. Järvinen ◽  
J.H. Langwaldt ◽  
E.S. Melin ◽  
M.K. Männistö ◽  
...  
Keyword(s):  
Iron Oxidation ◽  
Wood Preservative ◽  
Pilot Scale ◽  
High Rate ◽  
Contaminated Groundwater ◽  
Groundwater Temperature ◽  
In Situ Bioremediation ◽  
Contaminated Aquifer ◽  
Fluidized Bed Process

This paper reviews ten years of research on on-site and in situ bioremediation of chlorophenol contaminated groundwater. Laboratory experiments on the development of a high-rate, fluidized-bed process resulted in a full-scale, pump-and-treat application which has operated for several years. The system operates at ambient groundwater temperature of 7 to 9°C at 2.7 d hydraulic retention time and chlorophenol removal efficiencies of 98.5 to 99.9%. The microbial ecology studies of the contaminated aquifer revealed a diverse chlorophenol-degrading community. In situ biodegradation of chlorophenols is controlled by oxygen availability, only. Laboratory and pilot-scale experiments showed the potential for in situ aquifer bioremediation with iron oxidation and precipitation as a potential problem.

scholarly journals Air Concentrations of Gaseous Elemental Mercury and Vegetation–Air Fluxes within Saltmarshes of the Tagus Estuary, Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 228
Author(s):  
Rute Cesário ◽  
Nelson J. O’Driscoll ◽  
Sara Justino ◽  
Claire E. Wilson ◽  
Carlos E. Monteiro ◽  
...  
Keyword(s):  
Leaf Area ◽  
Elemental Mercury ◽  
Ambient Air ◽  
Tagus Estuary ◽  
Contaminated Site ◽  
Gaseous Elemental Mercury ◽  
Mercury Flux ◽  
Sarcocornia Fruticosa ◽  
Air Concentrations

In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged between 1.08–18.15 ng m−3 in CN and 1.18–3.53 ng m−3 in ALC. In CN, most of the high Hg(0) levels occurred during nighttime, while the opposite was observed at ALC, suggesting that photoreduction was not driving the air Hg(0) concentrations at the contaminated site. Vegetation–air Hg(0) fluxes were low in ALC and ranged from −0.76 to 1.52 ng m−2 (leaf area) h−1 for Hp and from −0.40 to 1.28 ng m−2 (leaf area) h−1 for Sf. In CN, higher Hg fluxes were observed for both plants, ranging from −9.90 to 15.45 ng m−2 (leaf area) h−1 for Hp and from −8.93 to 12.58 ng m−2 (leaf area) h−1 for Sf. Mercury flux results at CN were considered less reliable due to large and fast variations in the ambient air concentrations of Hg(0), which may have been influenced by emissions from the nearby chlor-alkali plant, or historical contamination. Improved experimental setup, the influence of high local Hg concentrations and the seasonal activity of the plants must be considered when assessing vegetation–air Hg(0) fluxes in Hg-contaminated areas.

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