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Title: REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER

Abstract

A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), extremely inexpensive, and easy to replace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels was discharged from this plant for many years. Recently, the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated in 1999 to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levelsmore » up to 6.5-9.7 mM nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.« less

Authors:
;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
772985
Report Number(s):
LA-UR-01-55
TRN: AH200121%%73
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 Jan 2001
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; COLLOIDS; LIQUID WASTES; MICROORGANISMS; NITRATES; NUTRIENTS; PERCHLORATES; PLUMES; POROUS MATERIALS; RADIOISOTOPES; GROUND WATER

Citation Formats

B. STRIETELMEIER, and M. ESPINOSA. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER. United States: N. p., 2001. Web.
B. STRIETELMEIER, & M. ESPINOSA. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER. United States.
B. STRIETELMEIER, and M. ESPINOSA. Mon . "REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER". United States. doi:. https://www.osti.gov/servlets/purl/772985.
@article{osti_772985,
title = {REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER},
author = {B. STRIETELMEIER and M. ESPINOSA},
abstractNote = {A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), extremely inexpensive, and easy to replace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels was discharged from this plant for many years. Recently, the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated in 1999 to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mM nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2001},
month = {Mon Jan 01 00:00:00 EST 2001}
}

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  • A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), and extremely inexpensive and easy to emplace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatmentmore » Facility (RLWTF). Water with elevated nitrate levels has been discharged from this plant for many years, until recently when the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated this past year to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier. will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mhl nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.« less
  • The Los Alamos National Laboratory Colt facility has been used to create target plasma for Magnetized Target Fusion (MTF). The primary results regarding magnetic field, plasma density, plasma temperature, and hot plasma lifetime are summarized and the suitability of these plasma targets for MTF is assessed.
  • Research was conducted to evaluate a multiple-layer system of volcanic rock, limestone, Apatite mineral and a 'biobarrier' to impede migration of radionuclides, metals and colloids through shallow alluvial groundwater, while simultaneously destroying contaminants such as nitrate and perchlorate. The 'bio' portion of this Multi-Barrier system uses highly porous, slowly degradable, carbon-based material (pecan shells) that serves as an energy source and supports the growth of indigenous microbial populations capable of destroying biodegradable compounds. The studies, using elevated nitrate concentrations in groundwater, have demonstrated reduction from levels of 6.5-9.7 mM nitrate (400-600 mg/L) to below discharge limits (0.16 mM nitrate). Perchloratemore » levels of 4.3 {micro}M (350 {micro}g/L) were also greatly reduced. Elevated levels of nitrate in drinking water are a public health concern, particularly for infants and adults susceptible to gastric cancer. Primary sources of contamination include feedlots, agriculture (fertilization), septic systems, mining and nuclear operations. A major source of perchlorate contamination in water is ammonium perchlorate from manufacture/use of rocket propellants. Perchlorate, recently identified as an EPA contaminant of concern, may affect thyroid function and cause tumor formation. A biobarrier used to support the growth of microbial populations (i.e. a biofilm) is a viable and inexpensive tool for cleaning contaminated groundwater. Aquatic ecosystems and human populations worldwide are affected by contaminated water supplies. One of the most frequent contaminants is nitrate. Remediation of nitrate in groundwater and drinking water by biodegradation is a natural solution to this problem. Microbial processes play an extremely important role in in situ groundwater treatment technologies. The assumption of carbon limitation is the basis for addition of carbon-based substrates to a system in the development of bioremediation schemes for nitrate-contaminated groundwater. The biobarrier concept typically involves construction of a wall of porous carbon-based material that is placed in a trench perpendicular to the direction of groundwater flow that extends at least the width and depth of the contaminant plume. A biobarrier can be used as a stand-alone system when biodegradable materials are the only contaminants, or it can be used along with other barriers, as has been done in the LANL Multi-Barrier system, designed to remediate multiple contaminants. The groundwater system must be reasonably well characterized in terms of direction of flow, width and depth of plume, concentrations along the plume, flow velocity and hydraulic conductivity. Barrier technology is largely applicable to shallow, alluvial plumes (less than 20 feet deep), although permeable reactive barriers (PRBs) have been placed at much greater depths, up to 70 ft. deep. Under these conditions, a barrier could be placed across the plume downstream from the source to prevent migration from a controlled site. The most effective barrier materials are natural waste materials of high porosity, resistant to degradation, that will not require removal or replacement with time. Pecan shells are a significant waste problem in pecan-growing areas. The most commonly used solution is land disposal. Use in biobarriers provides a desirable alternative. Pecan shells are composed of cellulose and lignin, and they degrade very slowly, providing a 'time-release' carbon source. If left uncrushed, they provide a high porosity material. Fishbone is a waste product made of calcium phosphate, or hydroxyapatite, which is very resistant to deterioration. Apatite-II effectively removes dissolved metals and radionuclides from groundwater. The precipitates formed with metals and radionuclides are highly insoluble and very unlikely to leach subsequently from the barrier. The residual tissue associated with the fishbones provides nutrient materials that contribute to formation of a microbial population as an additional benefit. We have investigated denitrification and perchlorate reduction processes within a biobarrier. The batch studies involved comparison of two potential carbon-based biobarrier support materials: pecan shells alone and pecan shells mixed with dog food in a 10:1 ratio. The results of the column studies have been reported elsewhere. The column studies were used to confirm that the microbial reactions occurring under denitrifying conditions in the batch studies are not altered dramatically under flowing conditions with the introduction of oxygenated groundwater. The objectives of these studies were to: (1) determine the effectiveness of the materials in development of a biofilm, and in destruction of nitrate, (2) quantify microbial populations present in batch systems, (3) determine amounts of nitrite and ammonia produced, and (4) determine pH conditions produced by the microbial activity in the biobarrier.« less
  • The Highland Drive South Ravine (HDSR) is the discharge area for groundwater originating from the Highland Drive Landfill, the Pine Street North Extension (PSNE) roadbed parts of the Highland Drive roadbed and the PSNE Consolidation Site that contain historical low-level radioactive waste (LLRW). The contaminant plume from these LLRW sites contains elevated concentrations of uranium and arsenic and discharges with groundwater to shallow soils in a wet discharge area within the ravine, and directly to Hunt's Pond and Highland Drive South Creek, which are immediately to the south of the wet discharge area. Remediation and environmental management plans for HDSRmore » have been developed within the framework of the Port Hope Project and the Port Hope Area Initiative. The LLRW sites will be fully remediated by excavation and relocation to a new Long-Term Waste Management Facility (LTWMF) as part of the Port Hope Project. It is projected, however, that the groundwater contaminant plume between the remediated LLRW sites and HDSR will persist for several hundreds of years. At the HDSR, sediment remediation within Hunt's Ponds and Highland Drive South Creek, excavation of the existing and placement of clean fill will be undertaken to remove current accumulations of solid-phase uranium and arsenic associated with the upper 0.75 m of soil in the wet discharge area, and permeable reactive barriers (PRBs) will be used for in situ treatment of contaminated groundwater to prevent the ongoing discharge of uranium and arsenic to the area in HDSR where shallow soil excavation and replacement has been undertaken. Bench-scale testing using groundwater from HDSR has confirmed excellent treatment characteristics for both uranium and arsenic using permeable reactive mixtures containing granular zero-valent iron (ZVI). A sequence of three PRBs containing ZVI and sand in backfilled trenches has been designed to intercept the groundwater flow system prior to its discharge to the ground surface and the creek and ponds in the HDSR. The first of the PRBs will be installed immediately up-gradient of the wet discharge area approximately 50 m from the creek, the other two will be installed across the area of shallow soil replacement, and all will extend from ground surface to the base of the water table aquifer through which the impacted groundwater flows. The PRBs have been designed to provide the removal of uranium and arsenic for decades, although the capacity of the treatment mixture for contaminant removal suggests that a longer period of treatment may be feasible. The environmental management plan includes an allowance for on-going monitoring, and replacement of a PRB(s) as might be required. (authors)« less
  • The feasibility of using the sulfur/limestone autotrophic denitrification (SLAD) process as an in situ method for remediation of nitrate-contaminated surface water was investigated. Four bench-scale pond systems with working volumes of 21.4 liters each and hydraulic retention time (HRT) of 30 days were operated under mixed conditions. Under mixed (aerobic) conditions, with the addition of alkalinity to raise pH, NO{sub 3}{sup {minus}}-N removal in the SLAD ponds was 85--100%, while the control reactor showed negative removal. Sulfate production under mixed conditions was between 1,000--2,500 mg/l SO{sub 4}{sup 2{minus}}, which shows that 40--60 mg/l of SO{sub 4}{sup 2{minus}} is produced formore » every 1 mg/l of NO{sub 3}{sup {minus}}-N reduced. Although the system is very efficient in removing nitrates under simulated surface water conditions, the sulfate production makes the process questionable for use under aerobic conditions. However, batch experiments under anaerobic conditions demonstrate that system maybe very efficient in removing nitrate while not producing insufferable amounts of sulfates.« less