Victor F. Medina

Phytotreatment of TNT-Contaminated Groundwater

Phytoremediation is a viable technique for treating nitroaromatic compounds, particularly munitions. Continuous flow phyto-reactor studies were conducted at the following three influent concentrations of 2,4,6-trinitrotoluene (TNT): 1, 5, and 10 ppm. A control was also prepared with an influent TNT concentration of 5 ppm. Flow rates were systematically reduced to increase hydraulic retention times (HRT) which ranged from 12 to 76 days. Initially, the control reactor removed TNT as efficiently as the plant reactors. With time, however, the efficiency of the control became less than that of the plant reactors, suggesting that adsorption was initially the mechanism for removal. Up to 100% of the TNT was removed. Aminodinitrotoluene (ADNT) effluent concentration was higher for higher TNT influent concentrations. Increasing the retention time reduced ADNT concentration in the effluent. Supplementary batch studies confirmed that ADNT and diaminonitrotoluene (DANT) were phytodegraded. Preliminary batch studies w...

Treatment of Munitions in Soils Using Phytoslurries

ABSTRACT Phytoremediation is an established technology for the treatment of explosives in water and soil. This study investigated the possibility of using slurried plants (or phytoslurries) to treat explosives (TNT and RDX). The degradation of TNT in solution using intact and slurried parrotfeather (Myriophyllum aquaticum), spinach (Spinicia oleracea), and mustard greens (Brassica juncea) was evaluated. Phytoslurries of parrotfeather and spinach removed the TNT faster than the intact plant. Conversely, the removal rate constants for slurried and intact mustard greens were about the same. A study using pressurized heating to destroy enzymatic activity in the phytoslurries was also conducted to compare removal from released plant chemicals to adsorptive removal. Aqueous phase removal of TNT by autoclaved spinach phytoslurry was compared with nonautoclaved spinach phytoslurry. The autoclaved phytoslurry did remove TNT, but not as completely as nonautoclaved slurry. This suggests that some removal is due to adsorption, but not all. Phytoslurries of mustard greens and parrotfeather had higher RDX removal rates compared with intact plant removal, but the rates for parrotfeather in either case were relatively low. Phytoslurries of spinach had relatively modest increases in RDX removal rates compared with intact plant. Studies were then conducted with phytoslurry/soil mixtures at two scales: 60 ml and 1.5 l. In both cases, phytoslurries of mustard greens and spinach removed TNT and RDX at higher levels than control slurries.

Sterilization of Plants for Phytoremediation Studies by Bleach Treatment

ABSTRACT Bleach treatment of plants was studied as a simple alternative to axenic tissue cultures for demonstrating phytodegradation of aqueous and gas-phase environmental contaminants. Parrotfeather (Myriophyllum aquaticum), spinach (Spinacia oleracea), and wheat (Triticum aestivum) were exposed to 0.525% NaC10 solutions for 15 s, then rinsed in deionized water. Plate counts indicated that 97 to 100% of viable bacteria were removed from parrotfeather and spinach. Transformation rates for 2,4,6-trinitrotoluene (TNT) by bleached and untreated parrotfeather were virtually identical. Similarly, treated and untreated spinach, wheat heads, and wheat leaves removed methyl bromide (MeBr) from air at the same rates. However, wheat root with attendant adhering soil was rendered inactive by bleach treatment. Parrotfeather roots examined by dissecting microscope and by electron microscope showed no significant damage caused by bleach treatment.

Use of Macroinvertebrate and Chemical Indices to Assess Water Quality of an Irrigation Wasteway

Abstract The Amon Wasteway is an engineered drainage waterway for the Kennewick Irrigation District, which receives its water from the lowerYakima River near Prosser, Washington. Reference conditions that were established in a basin-wide macroinvertebrate and physicochemical study of the Yakima River were used to generate a macroinvertebrate community condition index and a non-pesticide agricultural intensity index. These indices were utilized to ascertain the ecological integrity of the wasteway. Despite the negative connotation often associated with such bodies of water, the wasteway compared well against both reference condition indices for the lower basin. The overall water quality of Amon Wasteway, as measured by macroinvertebrate and physicochemical analysis, was found to be better than its source, the Yakima River. The species composition of the wasteway most closely resembled the makeup of the Yakima River. This river is many times the size of the wasteway, but the nearest source in an arid climate to provide immigrants.

Corrosion and migration of zero-valent depleted uranium products in soil

Zero-valent metallic depleted uranium (DU) penetrators exposed in the environment after firing frequently undergo corrosion. Unlike previous field studies, this report evaluates metallic DU corrosion in a controlled laboratory setting using a 28 day wet–dry cycling method to simulate environmental corrosion. Carried out in construction-grade sand, the study evaluated the effect of three solutions: deionized (DI) water, 3.5% salt (NaCl) solution, and an acid solution. Two oxidation products in the reactors were noted at 14 days, both in the sand and on the penetrator. Oxidation product migrated to the sand media; the higher percentage of migration came from the corrosion fluid that produced the least amount of corrosion. Changes in mass percentages of uranium and oxygen correlated with density changes, as evidenced by relative brightness, to show differences in corrosion. Other elements (sodium, magnesium, iron, and calcium) increased in mass percentage with increasing corrosion. Five soil types were also used to corrode DU. Multiple soil physical and chemical characteristics appear to contribute to differences in the rates of corrosion, including soil pH, percentage of soil fines, and total organic carbon content. These studies suggest that limiting moisture and salt exposure could reduce corrosion of exposed DU and subsequent migration. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.

Evaluation of sulfide emissions from a hydraulic system at the Blue River Dam

Hydrogen sulfide releases occurred during a routine maintenance process in a hydraulic oil system at Blue River Dam, Oregon. The project worked under the hypothesis that the sulfide emissions most likely resulted from reductive biological processes. Hydraulic oil samples were collected from the Blue River Dam, and from two other nearby dams with similar hydraulic systems, Hills Creek Dam, and Cougar Dam. Water samples from the reservoir were also collected. Sulfur was found in all the oil and water samples, however, no patterns with sulfur to other parameters (such as percent water or acid neutralization number) were found in the oil samples. A microscopic review of hydraulic filters did not show any evidence of biofilm accumulation. The use of sulfate reductive bacterial genetic probes did not find any microbial activity expected to form sulfide. These results rejected the hypothesis that the sulfide production was from microbial activity. The Authors now hypothesize that the sulfide reaction was from abiotic reactions of an additive, Zinc Dialkyldithiophosphate (ZDDP). DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.

Evaluation of sludge pump clogging issue for an industrial waste pretreatment plant in the Ceres Industrial Park, Vicksburg, MS

Dr. Victor F. Medina conducted a site visit on 12 June 2017 for the evaluation of a sludge pump clogging issue at an industrial waste pretreatment plant in the Ceres Industrial Park, Vicksburg, MS. Escorted by Mr. Pablo Diaz of the Port of Vicksburg, the operating issue was that the sludge pump routinely clogs. The sludge material had accumulated around the ball that serves as the check valve, preventing its operation. The ERDC team offered recommendations based on the site visit to resolve the pump clogging issue. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.

Sustainable carbon dioxide sequestration as soil carbon to achieve carbon neutral status for DoD lands

Abstract : Sequestration of atmospheric carbon dioxide in soils is a promising alternative for mitigation of atmospheric carbon dioxide (CO2). The Department of Defense (DoD) owns significant land and water resources which can be managed to offset emissions. Accounting for this, sequestration could help DoD reach carbon neutrality. Many activities the DoD engages in for sustainable land management and training sustainment are conducive to soil carbon storage without even considering this as an important component; however, carbon storage could be greatly enhanced by increased understanding of optimal storage conditions and by making slight adjustments to existing practices. Land management techniques may require adjustments to maximize carbon storage while maintaining training and environmental quality. In order to achieve this, data gaps for estimating carbon fluxes need to be addressed so that accurate measurements can be taken. Unknown aspects of carbon storage as it relates to plant-soil-soil microbe interations need to be investigated to maximize carbon storage while maintaining land use requirements. Geo-engineering concepts require further refinement to increase carbon storage in soils. These knowledge gaps are not insurmountable and could be addressed through focused research to maximize and accurately quantify carbon storage on DoD lands.