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A biofiltration system was tested to remove low levels of acetone from an indoor space. The biofilters were subjected to a range of air fluxes and concentrations of acetone between 100 and 500 ppbv. Passing low levels of acetone through a canopy of green plants did not improve the quality of the air. However, acetone removal by the biofilters with living moss as a principle substrate, reached a maximum of between 1 and 1.6 μmol s-1 m-2 with a loading rate of approximately 2 μmol s-1 m-2. Generally the removal efficiency decreased with increased loading rates over a range of air fluxes (0.05 to 0.2 m s-1) but appear to increase with loading within the slower fluxes. Neither ZERO nor FIRST order kinetics could adequately describe removal. Instead an empirical model that described the natural logarithm of the unloading rate as a function of the natural logarithm of the loading rate and the natural logarithm of the inverse of the air flux fit the data well.

The following abstract is that provided to first year undergraduate students as part of the recruitment effort for 1st Year Seminar Courses at the University of Guelph. When humankind begins the colonization of the moon or Mars, we will be bringing along more of Earth than one might think. A number of space and government agencies around the world, including researchers at the Controlled Environment Systems Research Facility, University of Guelph, are involved in the design and engineering of self-contained ecosystems based on Earthly biological processes. These processes can be harnessed, with complementary physical and chemical technologies to support human life (food production, air revitalization, psychology) in the hostile conditions of space.

A deterministic model of canopy CO, exchange for a soybean crop has been developed to describe vegetative and reproductive phases of growth. Using this profile as an example, a conceptual model for the design and management of integrated production systems is developed with the objective of dampening both the long term and photo-oscillatory gas exchange dynamics of plant canopies in sealed environments. The resulting conceptual model includes photoperiod offset coupled with staggered planting and attenuated lighting as operational means of achieving stable atmospheric CO, concentrations. The issue of cultural compatibility of crops for integrated production is discussed and an operational scenario is proposed for two production chambers having different crop compositions and photoperiod requirements. The resulting operational scenarios have application to large scale, planetary based bioregenerative life support systems.

This paper presents results generated from an EXCEL based static mass balance model for the incorporation of a higher plant chamber to the MELiSSA Pilot Plant. The model was parameterized using empirical data collected from beet and lettuce production trials and from trials conducted with Pilot Plant or bench scaled MELiSSA compartments. Of particular interest were the daily mass balances of CO2, O2 and nitrogen in the loop for a given set of input variables. The results allow the loop’s designers to foresee the range of conditions for which closure of the mass balances can be expected. This information will be used in the next phases of the MELISSA Pilot Plant integration project.

A biofiltration system is currently being tested as an alternative to maintain indoor air quality within an office building setting. The system is based on a complex plant community with both terrestrial and aquatic components. CO2 dynamics within the space offer a means of evaluating its potential efficacy. A model is presented based upon both exponential and linear processes, which accurately describes diurnal changes in CO2 levels and the removal of introduced CO2. The exponential dynamics indicate increasing rates of sequestering with increasing exposure levels. The CO2 is eventually fixed through the process of photosynthesis, but is most likely initially sequestered in the aquatic component of the system. The removal of the contaminant from the atmosphere and into the aquatic phase where it is subsequently metabolized by the biomass suggest the system may be an effective filter for removing contaminants from indoor settings.