William A. Jackson

Uptake of perchlorate in terrestrial plants.

Cucumber (Cucumis sativus L.), lettuce (Lactuca sativa L.), and soybean (Glycine max) were used to determine uptake of the perchlorate anion (100 ppb) from sand. Plants were watered with different ratios of Hydrosol (a diluted solution of Peters All-Purpose Plant Food) to Milli-Q water (18 MOmega) to determine if the presence of other nutrients (such as nitrate) influenced perchlorate uptake. Perchlorate concentrations in sand and plant tissues were determined weekly. Perchlorate uptake was observed in all three plant species. In most experiments, perchlorate was completely depleted from sand in which plants were growing. Perchlorate concentrations in lettuce were also significantly higher than those in cucumber and soybean (P < 0.0001). Perchlorate concentrations in sand decreased at a higher rate at lower ratios of Hydrosol to Milli-Q, indicating that plant (cucumber) uptake of perchlorate is influenced by the presence of external nutrients. The results of an 8-week uptake study in cucumber and a 6-week uptake study in lettuce suggest that a threshold perchlorate concentration is reached: for cucumber, 150 ppm and for lettuce, 750 ppm. Although the presence of external nutrients decreases the rate of perchlorate uptake by plants, significant concentrations of perchlorate occur in aboveground plant tissues even after relatively short periods of growth. The potential for trophic transfer of perchlorate from soil to higher organisms through plants exists.

Uptake of 17α-ethynylestradiol and triclosan in pinto bean, Phaseolus vulgaris.

Pharmaceuticals and personal care products (PPCPs) have emerged as a group of potential environmental contaminants of concern. PPCPs in soil may enter terrestrial food webs via plant uptake. We evaluated uptake of 17α-ethynylestradiol (EE2) and triclosan in bean plants (Phaseolus vulgaris) grown in sand and soil. The extent of uptake and accumulation of EE2 and triclosan in plants grown in sand was higher than in plants grown in soil. In sand (conditions of maximum contaminant bioavailability), bioconcentration factors (BCFs) of EE2 and triclosan in roots (based on dry weights) were 1424 and 16,364, respectively, whereas BCFs in leaves were 55 for EE2 and 85 for triclosan. In soil, the BCF of EE2 decreased from 154 in the first week to 32 in the fourth week while it fluctuated in leaves from 18 to 20. The BCF for triclosan in plants grown in soil increased over time to 12 in roots and 8 in leaves. These results indicate that the potential for uptake and accumulation of PPCPs in plants exists. This trophic transfer pathway should be considered when assessing exposure to certain PPCPs, particularly with the use of recycled wastewater for irrigation.

C60 Fullerene Soil Sorption, Biodegradation, and Plant Uptake

Assessments of potential exposure to fullerenes and their derivatives in the environment are important, given their increasing production and use. Our study focused on fate processes that determine the movement and bioavailability of fullerenes in soil. We evaluated the sorption, biodegradation, and plant uptake of C60 fullerene using (14)C-labeled C60 solutions in water produced by either solvent exchange with tetrahydrofuran or sonication/extended mixing in water. Organic carbon appeared to have an important influence on C60 soil sorption. The log Koc values for (14)C60 were equivalent for sandy loam and silt loam (3.55 log[mL/g]) but higher for loam (4.00 log[mL/g]), suggesting that other factors, such as pH, clay content and mineralogy, and cation exchange capacity, also influence C60 soil sorption. There was little (14)CO2 production in the silt loam or the sandy loam soil after 754 and 328 days, respectively, suggesting high resistance of C60 to mineralization in soil. Plant uptake was generally low (∼7%), with most of the uptaken (14)C accumulating in the roots (40-47%) and smaller amounts of accumulation in the tuber (22-23%), stem (12-16%), and leaves (18-22%). Our results indicate that C60 released to the environment will not be highly bioavailable but will likely persist in soil for extended periods.

Development and Testing of a TRL 5 Bioreactor for Pretreatment of a Lunar Surface Wastestream

Water is the most critical life support element, representing 65% of the daily mass input for crew members even under the most stringent water use approaches. A reliable water source is therefore a critical concern for long term space habitation, whether in orbit (e.g. ISS), on the moon, Mars, or beyond. Water recovery systems currently under development for space missions are intensive users of resources including power for processes such as distillation and consumables for post-treatment based on adsorption and chemical oxidation of contaminants. As such, current designs exchange one cost (stored water) for others (power generation, stored consumables). Logistic savings characteristic of water recycling would be better reduced by implementing alternative, low-input systems. A pre-distillation bioreactor would require few resources while substantially improving system performance: >90% removal of wastewater organics including surfactants, pH stabilization, oxidation of NH 4 + to NO 3 - , (up to 80%), and improved distillation brine properties. We report on the design, construction, and testing of a TRL 5 biological membrane aerated reactor for pre-treatment (carbon and ammonia oxidation) of an early planetary base (e.g. Lunar) wastewater capable of integration with physio-chemical systems.

Evaluation of Passive Sampling Devices as Potential Surrogates of Metal Uptake into Soybean

ABSTRACT Chelating anion exchange membrane (CAEM), Nafion® tubing, and Strong cation exchange cartridges (SCX) were evaluated as passive sampling devices for cadmium (Cd), copper (Cu), and lead (Pb) uptake in soybean (Glycine max). The CAEMs were sampled every hour for 12 h. Metal concentrations in plant tissues, SCX, and water solution in Nafion® tubing were determined weekly for 4 weeks. The amount of Cd and Pb on CAEM increased linearly with time in the sand experiment. Cadmium, Cu, and Pb uptake by soybean leaves was poorly correlated with metal concentration on CAEM. Regression analysis between log transformed Cd and Pb concentrations in water within Nafion® tubing and in sand solution extracted by water indicated that there was a significant linear relationship between them. Metals were not consistently detected in elution solution of SCX. Nafion® tubing may be a promising passive sampler for heavy metals in soil solution.

Optimization of a Membrane-Aerated Biological Reactor in Preparation for a Full Scale Integrated Water Recovery Test

Water recycling is a fundamental component of life support systems due to the substantial contribution of water to the total equivalent system mass. Optimizing the integrated water recycling systems is essential in any efforts to enable long term space habitation. Membrane aerated biological reactors (MABRs) have proven to be an efficient and sustainable pretreatment process for extra terrestrial wastewater recycling applications in closed loop life support systems. The CoMANDR (Counter-diffusion Membrane Aerated Nitrifying Denitrifying Reactor) system can be used to treat unstabilized wastewater composed of urine, hygiene water, humidity condensate, and laundry water. The operation and assessment of the CoMANDR is in support of the integrated systems test to be implemented by Johnson Space Center pairing a biological reactor with a forward/reverse osmosis unit to treat the aforementioned waste stream. After a two month start up period we have systematically evaluated the CoMANDR performance for a variety of loading rates and verified the operation of the system under pressurized conditions. Results support the ability of the system to effectively reduce organic carbon by over 90% and convert up to 70% of the total influent N to non-organic forms (e.g. NOx or N2). Operation has been demonstrated using both air and pure O2, although in each case further control refinements are required to help maximize the denitrification potential of the reactor. We have also demonstrated that for at least up to 3 weeks, CoMANDR can be put into recycle and brought back on line with no start up required supporting the ability to intermittently operate the system.

Performance of a TRL 5 Bioreactor for Pretreatment of an Extended Habitation Wastestream

Water is one of the most critical and costly life support elements, even under the most stringent water use approaches. Technologies that can increase the sustainability of water processing by reducing expendables and helping to close the water loop can have large impacts on mission costs. Current technologies for water processing are intensive users of resources, including power for processes such as distillation, and consumables for preand post-treatment. In particular, urine pre-processing requires the continuous consumption of hazardous and corrosive chemicals. Further, current recovery rates are limited partly by the chemical pre-processing, and the brine produced from this pre-treated chemical is challenging to process. Biological pre-treatment may offer substantial efficiencies over traditional technologies, and offer secondary benefits with only minor costs. For the past 9 months, we have operated a TRL 5 membrane aerated bioreactor processing an extended habitation waste stream (urine/hygiene/humidity condensate). The reactor has successfully processed the wastewater at loading rates of 20 L/d and 30 L/d and is currently being challenged at 40 L/d. The reactor has exceeded 70% NH4 + conversion, 86% DOC conversion, 55% TN reduction, and maintained a pH < 7. Conversion rates for NH4 + and DOC are approaching 1 g/m 2 -d. Finally, preliminary gas phase measurements reveal that the total O2 consumption is ~100 g/d, while CO2 production was ~ 4g/d and N2 production was estimated at 20 g/d (~13 L/d).

Perchlorate Remediation by Electrokinetic Extraction and Electrokinetic Injection of Substrates

Perchlorate (ClO4−) contamination of groundwater has recently become a major concern across the nation. Electrokinetic (EK) extraction with the simultaneous EK injection of organic material to promote degradation could allow for the efficient removal of perchlorate while simultaneously promoting degradation of perchlorate. Column experiments were conducted to evaluate the technology. Lactate and glycine served as organic substrates to promote degradation after injection into the columns as well as maintaining the pH near neutral. Removal of perchlorate from contaminated materials kaolin, sand, and a natural soil historically contaminated by perchlorate was controlled by the ionic flux of perchlorate and not by transport from the osmotic flux which was only significant for kaolin experiments. Perchlorate was removed from contaminated sand and clay below our detection limits (5 ppb). Both lactic acid and glycine were successfully injected into clay and a sand matrix. Results from a contaminated site soil indicate that the Chemical Oxygen Demand was increased after electrokinetic injection of glycine and lactate. Experiments using soil from a contaminated site confirmed that EK can be used to both remove perchlorate and stimulate bioremediation by the injection of lactate or glycine. The use of EK technology to both remove and provide for continued source removal by bioremediation offers a potential new tool to treat low permeability systems.

Biological and Physical Polishing of a Space Based Waste Stream

6 A hollow fiber membrane bio-reactor (HFMBR) and hollow fiber microfiltration (MF) 7 membrane cartridge treated a space habitation humidity condensate waste stream. The waste 8 stream has an ideal ratio of organic carbon to nitrogen (C:N = 7:1) to promote biological 9 treatment. Carbon and Nitrogen removal in the HFMBR was highest (76% and 43%, 10 respectively) for the shortest retention time. Addition of an outside macronutrient source and 11 pure oxygen, as opposed to lab air, showed a significant increase in carbon removal, but had no 12 significant affect on nitrification/dentrification reaction rates (areal or volumetric). The MF 13 module was used to polish the waste stream for potential reuse within the space habitation 14 environment. The MF module provided 5-log removal of bacteria from the post-processor 15 HFMBR effluent, as well as reducing turbidity and suspended solids to values less than 1 16 NTU/ppm. The MF module also showed small reductions in DOC and TN values (10-20%). The 17 MF permeate then could theoretically be reintroduced into the space habitation system for reuse 18 upon disinfection. 19